Circular No. 27/2023/TT-BTNMT stipulates the Technical Forecasting and Warning Procedures for Meteorological and Hydrological Conditions under Normal Circumstances.

PART I

GENERAL PROVISIONS

Article 1. Scope of Regulation

This Circular stipulates the technical procedures for meteorological and hydrological forecasting and warning under normal conditions.

Article 2. Applicability

This Circular applies to the national meteorological and hydrological forecasting and warning system and organizations and individuals involved in meteorological and hydrological forecasting and warning activities within the territory of the Socialist Republic of Vietnam.

Article 3. Explanation of Terms

In this Circular, the following terms are understood as follows:

1. Normal meteorological and hydrological conditions refer to the stable state and development of weather, climate, and hydrological and marine elements at a specific location over a defined period.

2. Forecast discussion refers to the exchange of information, analysis, and evaluation of forecast results by forecasters, experts, and different forecast scenarios to select the final forecast result.

3. CLIM is the monthly climate bulletin issued domestically.

4. ENSO is an abbreviation for El Niño Southern Oscillation (El Niño - Southern Oscillation) referring to both El Niño and La Niña phenomena and their relation to pressure oscillations between the eastern and western Pacific Ocean and the Indian Ocean.

Article 4. Elements and phenomena for meteorological and hydrological forecasting and warning

1. Meteorological elements and phenomena

a) Clouds: Amount of clouds;

b) Rain: Type of rain and intensity, possibility of rain, amount of rain, spatial distribution of rain, temporal distribution of rain;

c) Temperature: Air temperature at specific times, average air temperature, average highest air temperature, average lowest air temperature, absolute highest air temperature, absolute lowest air temperature;

d) Wind: Wind direction, wind speed;

đ) Humidity: Highest relative humidity, lowest relative humidity, average relative humidity, soil moisture;

e) Visibility;

g) Other related meteorological elements and phenomena.

2. Hydrological elements and phenomena

a) Water level: Water level at specific times, highest water level, lowest water level, average water level, water level range;

b) Flow rate: Flow rate at specific times, highest flow rate, lowest flow rate, average flow rate;

c) Other related hydrological elements and phenomena.

3. Marine elements and phenomena

a) Sea waves: Wave height, wave direction;

b) Tides: High tide, low tide, time of occurrence;

c) Flood: Height, time of occurrence;

d) Surface sea current: Average velocity, prevailing direction;

đ) Sea condition;

e) Other related marine elements and phenomena.

Chapter II

TECHNICAL PROCEDURES FOR METEOROLOGICAL AND HYDROLOGICAL FORECASTING AND WARNINGUNDER NORMAL CONDITIONS

Article 5. Basic steps for implementing meteorological and hydrological forecasting and warning under normal conditions

1. The basic steps for implementing meteorological and hydrological forecasting and warning under normal conditions include:

a) Collecting and processing various types of information and data;

b) Analyzing and evaluating the current status;

c) Implementing forecasting and warning plans;

d) Discussing forecasts and warnings;

đ) Preparing forecast and warning bulletins;

e) Providing forecast and warning bulletins;

g) Supplementing forecast and warning bulletins;

h) Evaluating the quality of forecasts and warnings.

2. The national meteorological and hydrological forecasting and warning system and organizations and individuals not belonging to the national meteorological and hydrological forecasting and warning system shall comply with the basic steps for implementing meteorological and hydrological forecasting and warning under normal conditions as stipulated in Clause 1 of this Article and the contents prescribed from Article 6 to Article 24 of this Circular, and regularly update professional procedures and regulations on meteorological and hydrological forecasting and warning.

Article 6. Technical process for short-term and very short-term weather forecasting and warning

1. Collecting and processing various types of information and data

a) Surface meteorological observation data and nearby areas (surface meteorology, radio sounding, pilot balloon, automatic rain measurement, marine observation, enhanced observation);

b) Simulation and forecast data from global and regional models;

c) Remote sensing data within the region (weather satellites, weather radar, lightning location);

d) Collecting environmental, living condition, infrastructure, economic and social activity data (if available);

đ) Assessing the completeness and accuracy of collected data and supplementing, correcting, standardizing data, calculating errors of existing reference forecast products up to the time of making the forecast.

2. Analyzing and evaluating the current status

a) Analyzing surface meteorological observation data and synoptic maps at standard pressure levels to determine past and current weather patterns;

b) Analyzing upper air sounding data on weather charts at the nearest observation time of radio soundings and pilot balloons nationwide;

c) Analyzing remote sensing data (weather satellites, weather radar, lightning location...);

d) Analyzing surface observation data of all observed phenomena and factors at stations nationwide;

đ) Analyzing historical average and extreme values of meteorological factors to determine the likelihood of recurrence of meteorological factors, especially extreme values;

e) Analyzing the development of upcoming weather systems based on synoptic maps and exploiting products of existing numerical models at the forecasting unit;

g) Analyzing environmental, living condition, infrastructure, economic and social activity data (if available);

h) During the data analysis process, if there is a possibility of dangerous weather phenomena occurring, additional technical processes for forecasting and warning dangerous meteorological and hydrological phenomena should be implemented accordingly;

i) For very short-term forecasting, to ensure timely issuance of information, focus on analyzing primary and secondary satellite, radar, lightning location products, high-resolution regional model products, rainfall estimation products, and automated short-term forecast reference products, and assessments in the most recent short-term forecast bulletins for the forecast area.

3. Implementing forecasting and warning plans

At least one of the following short-term and very short-term weather forecasting and warning plans must be implemented: Plan based on synoptic analysis method and experience; plan based on statistical method; plan based on numerical modeling method (deterministic and ensemble forecasting); plan based on interpolation, extrapolation, and inertia methods.

4. Discussing forecasts and warnings

Discuss short-term weather forecasts at least 30 minutes before issuing the bulletin; discuss very short-term weather forecasts at least 15 minutes before issuing the bulletin. Discussion content includes: Analysis and evaluation of past weather developments up to the forecast time based on observational data sources; information on weather trends during the forecast period; weather phenomena, detailed meteorological factor values over specified time intervals in a specific location or area; possibility of dangerous weather phenomena occurring and their impact on the environment, living conditions, infrastructure, economic and social activities; synthesis of initial forecast results from different plans and forecasters' assessments; analysis and evaluation of the reliability of forecast results using different methods, particularly the method used in the most recent forecast bulletin; the person responsible for issuing the bulletin selects the highest reliability final forecast and warning result suitable for the forecast period.

5. Preparing forecast and warning bulletins

Prepare the content of very short-term weather forecast and warning bulletins according to Clause 1 of Article 10 and Article 18 of Circular No. 08/2022/TT-BTNMT dated July 5, 2022, issued by the Minister of Natural Resources and Environment regarding types of bulletins and forecast and warning periods for meteorological and hydrological phenomena (hereinafter referred to as Circular No. 08/2022/TT-BTNMT); prepare the content of short-term weather forecast and warning bulletins according to Clause 2 of Article 10 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Providing forecast and warning bulletins

Provide very short-term and short-term weather forecast and warning bulletins to disaster prevention and control agencies, radio and television stations, and other agencies when requested.

7. Supplementing forecast and warning bulletins

In cases where meteorological factors and phenomena show unusual developments, supplementary bulletins need to be inserted between regular bulletins. Supplementary bulletins are carried out according to the provisions from Clause 1 to Clause 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluate the completeness and timeliness in accordance with Article 17 of Circular No. 41/2017/TT-BTNMT dated October 23, 2017, issued by the Minister of Natural Resources and Environment on technical guidelines for assessing the quality of weather forecasting and warning services (hereinafter referred to as Circular No. 41/2017/TT-BTNMT); evaluate the reliability of short-term and very short-term weather forecast and warning information as stipulated in Articles 12, 13, and 14 of Circular No. 41/2017/TT-BTNMT.

Article 7. Technical procedures for medium-range weather forecasting and warning

1. Collecting and processing various types of information and data

a) Weather map data;

b) Surface meteorological observation data;

c) Satellite data;

d) Data from numerical forecast model products;

đ) Statistical data on historical average and extreme values of forecasted meteorological factors;

e) Collect environmental, living conditions, infrastructure, and socio-economic activity data (if available).

2. Analyzing and evaluating the current status

a) Analyze surface meteorological observation data and synoptic maps at standard pressure levels to determine past and current weather patterns, and assess the error of existing reference forecast products up to the time of making the forecast;

b) Analyze historical average and extreme values of meteorological factors to determine the likelihood of recurrence of these factors, particularly extreme values;

c) Analyze the development of upcoming weather systems based on synoptic maps and utilize products from existing numerical forecast models at the forecasting unit;

d) Analyze environmental, living conditions, infrastructure, and socio-economic activity data (if available);

e) During the data analysis process, if there is a possibility of dangerous weather phenomena occurring, implement additional technical procedures for forecasting and warning of dangerous hydro-meteorological phenomena accordingly.

3. Implementing forecasting and warning plans

Implement at least one of the following medium-range weather forecasting and warning options: Option based on synoptic analysis and experience; option based on statistical methods; option based on numerical modeling (deterministic and ensemble forecasting).

4. Discussing forecasts and warnings

Discuss the medium-range weather forecast and warning before issuing the bulletin for at least one hour. The discussion content includes: Trends in weather development and total rainfall amount within the forecast period; phenomena, probability of rain, and air temperature values detailed for each one-day interval at a specific location or area; potential occurrence of dangerous weather phenomena and their impact on the environment, living conditions, infrastructure, and socio-economic activities; analyze and evaluate the reliability of forecast and warning results using different methods used in recent bulletins; synthesize initial forecast results from different methods and forecasters' opinions; the person responsible for issuing the bulletin selects the most reliable final forecast and warning result.

5. Preparing forecast and warning bulletins

Develop the content of the medium-range weather forecast and warning bulletin in accordance with Clause 3 of Article 10 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Providing forecast and warning bulletins

Provide the medium-range weather forecast and warning bulletin to disaster prevention and control agencies, search and rescue agencies, radio stations, television stations, and other relevant agencies upon request.

7. Supplement the forecast and warning bulletin

In cases where meteorological factors and phenomena show unusual developments, supplementary bulletins need to be inserted between regular bulletins. Supplementary bulletins are carried out according to the provisions from Clause 1 to Clause 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluate the completeness and timeliness in accordance with Article 17 of Circular No. 41/2017/TT-BTNMT; evaluate the reliability of medium-range weather forecast and warning information as stipulated in Articles 12, 13, 14, and 15 of Circular No. 41/2017/TT-BTNMT.

Article 8. Procedure for long-term climate forecasting and warning techniques

1. Collecting and processing various types of information and data

a) Space observation data in the Euro-Asian region to create average altitude terrain maps at the 500mb level;

b) Reanalyzed data to create average maps at standard pressure levels;

c) Daily surface meteorological observation data in the forecast area and adjacent areas;

d) CLIM data;

đ) Statistical data on the average and extreme values of meteorological factors within the forecast period;

e) Data analyzing ENSO forecasts and intra-seasonal climate indices;

g) Simulation and forecast data from long-term numerical models;

h) Collecting environmental data, living conditions, infrastructure, economic and social activities data (if available);

2. Analyzing and evaluating the current status

a) Analyze observational data, CLIM data, and average maps created from space observation data and reanalyzed data at standard pressure levels to determine past and current weather patterns;

b) Analyze past average and extreme values of meteorological factors to determine the likelihood of recurrence of these factors, especially extreme values during the forecast period;

c) Analyze initial fields of long-term numerical forecast model products;

d) Analyze environmental, living conditions, infrastructure, and socio-economic activity data (if available);

đ) During the data analysis process, if there is a possibility of dangerous meteorological phenomena occurring, implement additional forecasting and warning techniques for such phenomena;

3. Implementing forecasting and warning plans

Implement at least one of the following long-term climate forecasting and warning options: Option based on statistical methods (correlation and linear regression methods, circulation analog method, ENSO correlation method, process variation method); option based on numerical modeling methods; option based on other methods (if available);

4. Discussing forecasts and warnings

Discuss long-term climate forecasting and warning before issuing the bulletin at least one day prior. The discussion includes: Trends in average temperature and total rainfall compared to multi-year averages during the detailed forecast period from 10 to 15 days at a specific location or area; the possibility of dangerous weather events occurring and their potential impact on the environment, living conditions, infrastructure, economic and social activities; analysis and evaluation of the reliability of forecasting and warning results using different methods used in recent bulletins; synthesis of initial forecasting results from different methods and forecasters' opinions; the person responsible for issuing the bulletin selects the most reliable final forecasting and warning result;

5. Preparing forecast and warning bulletins

Develop the content of the long-term climate forecasting and warning bulletin according to Clause 1, Article 11 and Article 18 of Circular No. 08/2022/TT-BTNMT;

6. Providing forecast and warning bulletins

Provide the long-term climate forecasting and warning bulletin to disaster prevention and control command agencies, radio stations, television stations, and other relevant agencies upon request;

7. Supplementing forecast and warning bulletins

In cases where meteorological factors and phenomena show unusual developments, supplementary bulletins need to be inserted between regular bulletins. Supplementary bulletins are carried out according to the provisions from Clause 1 to Clause 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluate completeness and timeliness as stipulated in Article 17 of Circular No. 41/2017/TT-BTNMT; evaluate the reliability of long-term climate forecasting and warning as stipulated in Article 16 of Circular No. 41/2017/TT-BTNMT.

Article 9. Procedure for technical forecasting and warning of seasonal climate

1. Collecting and processing various types of information and data

a) Data from space observations in the Euro-Asian region to create maps of average seasonal terrain height at the 500mb level;

b) Reanalyzed data to create seasonal average maps at standard pressure levels;

c) Daily surface meteorological observation data in the forecast area and adjacent areas;

d) CLIM data;

đ) Statistical data on the average and extreme values of meteorological factors within the forecast period;

e) Data on analysis and forecasting of ENSO and intra-seasonal climate indices;

g) Data and seasonal forecasts from numerical model runs;

h) Collecting environmental data, living conditions, infrastructure, economic and social activities data (if available);

2. Analyzing and evaluating the current status

a) Observation data, CLIM, and maps built from surface observation, space observation, and reanalyzed data at standard pressure levels to determine past and current weather patterns;

b) Past average and extreme values of meteorological factors to determine the likelihood of recurrence of meteorological factors, particularly extreme values within the forecast period;

c) Analysis of environmental data, living conditions, infrastructure, and socio-economic activities (if available);

d) During the data analysis process, if there is a possibility of dangerous meteorological phenomena occurring, additional procedures for forecasting and warning of dangerous hydro-meteorological phenomena shall be implemented accordingly.

3. Implementing forecasting and warning plans

At least one of the following forecasting and warning methods for seasonal climate must be carried out: Method based on statistical approaches (circulation similarity method, ENSO correlation method, regression method); method based on numerical modeling; other methods (if available).

4. Discussing forecasts and warnings

Discuss the seasonal climate forecast before issuing the bulletin at least one day prior. The discussion includes: Trends in average temperature and total rainfall compared to long-term averages during the detailed forecast period from one to three months at a specific location or area; the possibility of dangerous weather events and their potential impact on the environment, living conditions, infrastructure, and socio-economic activities; analysis and evaluation of the reliability of forecast results using different methods in recent bulletins; synthesis of initial forecast results from various methods and forecasters' assessments; the person responsible for issuing the bulletin selects the most reliable final forecast result.

5. Preparing forecast and warning bulletins

Develop the content of the seasonal climate forecast and warning bulletin according to Clause 2, Article 11 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Providing forecast and warning bulletins

Provide the seasonal climate forecast and warning bulletin to disaster prevention and control agencies, search and rescue agencies, radio stations, television stations, and other relevant agencies upon request.

7. Supplementing forecast and warning bulletins

In cases where meteorological factors and phenomena show unusual developments, supplementary bulletins need to be inserted between regular bulletins. Supplementary bulletins are carried out according to the provisions from Clause 1 to Clause 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluate completeness and timeliness as stipulated in Article 17 of Circular No. 41/2017/TT-BTNMT; evaluate the reliability of seasonal climate forecasting and warning as stipulated in Article 16 of Circular No. 41/2017/TT-BTNMT.

Article 10. Procedure for technical forecasting of annual climate

1. Collecting and processing various types of information and data

a) Data on climatic factors (temperature, precipitation, humidity) within the territory of Vietnam;

b) Global reanalysis data of large-scale atmospheric/oceanic variables;

c) Information, reports, and analyses of global climate status by the World Meteorological Organization (WMO) and global climate centers including monsoon activity, large-scale atmospheric variables such as subtropical high pressure, continental cold high pressure, western low pressure, eastern trough, tropical jet stream;

d) Forecast data on large-scale atmospheric/oceanic variables from global and regional climate models;

f) Collect data on environmental conditions, living conditions, infrastructure, and socio-economic activities (if available).

2. Analyzing and evaluating the current status

a) Assess the current state of climatic factors (temperature, precipitation, humidity, evaporation, air pressure, wind) and extreme climates (severe cold, extreme cold, heatwaves, heavy rain, drought, typhoons/tropical depressions) over the past six months globally and regionally;

b) Analyze observational data on climatic factors (temperature, precipitation, humidity) and extreme climates (severe cold, extreme cold, heatwaves, heavy rain, drought, typhoons/tropical depressions) within the territory of Vietnam over the past six months to determine past and current climate conditions;

c) Analyze the variability of ENSO and intra-seasonal climate indices related to the Vietnamese climate;

d) Analyze data on environmental conditions, living conditions, infrastructure, and socio-economic activities (if available).

3. Implement forecasting options

At least one of the following annual climate forecasting methods must be carried out: Method based on statistical approaches; method based on numerical modeling; other methods (if available).

4. Discussion of forecasts

Discuss the annual climate forecast before issuing the bulletin at least three days prior. The discussion includes: Trends in average air temperature, total precipitation, extreme climate, and extreme climate phenomena on a global, regional, and national scale; analysis and evaluation of the reliability of forecast results using different methods in recent bulletins; synthesis of initial forecast results from various methods and forecasters' assessments; the person responsible for issuing the bulletin selects the most reliable final forecast result.

5. Develop the forecast bulletin

Develop the content of the annual climate forecast bulletin according to Clause 3, Article 11 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Provide the forecast bulletin

Provide the annual climate forecast bulletin to disaster prevention and control agencies, search and rescue agencies, radio stations, television stations, and other relevant agencies upon request.

7. Supplement the forecast bulletin

In case of unusual developments in forecast factors, supplementary bulletins should be issued between regular bulletins. The supplementation of bulletins is carried out according to provisions from Clause 1 to Clause 6 of this article.

8. Evaluate forecast quality

Evaluate the completeness and timeliness in accordance with Article 17 of Circular No. 41/2017/TT-BTNMT; assess the reliability of short-term and medium-term climate forecasts through comparing forecast factors with actual observations in accordance with regulations on forecast evaluation.

Article 11. Technical process for short-term and very short-term hydrological forecasting and warning

1. Collecting and processing various types of information and data

a) Collect rainfall data, water levels, flow rates from hydrological stations within the river basin, operational data, and anticipated operation data of hydropower and irrigation reservoirs, and related international rainfall, hydrological, and reservoir data (if applicable) according to observation hours;

b) Process various types of information and data: Analyze and check the rationality of data series; calculate characteristics of hydrological elements for forecasting and warning purposes;

c) Update collected measured data into the forecasting database and model;

d) Collect environmental data, living conditions, infrastructure, economic and social activities data (if applicable).

2. Analyzing and evaluating the current status

a) Analyze past rainfall patterns in the basin;

b) Analyze water level and flow rate changes at hydrological stations and reservoirs (if any) within the river basin over the last 24 hours;

c) Assess errors in hydrological forecast results and analyze forecast outcomes of referenced forecasting methods;

d) Analyze environmental, living conditions, infrastructure, and socio-economic activity data (if available);

d) During data analysis, if there is a possibility of dangerous hydrological phenomena occurring, implement additional technical processes for forecasting and warning of corresponding dangerous meteorological and hydrological phenomena.

3. Implementing forecasting and warning plans

Implement at least one of the following short-term and very short-term hydrological forecasting and warning methods: Method based on rainfall-runoff relationship; method based on upstream-downstream water level and flow rate relationships along the same riverbank or within the same basin; method based on mathematical modeling.

4. Discussing forecasts and warnings

Discuss short-term hydrological forecasts and warnings before issuing the bulletin for at least 30 minutes; discuss very short-term hydrological forecasts and warnings before issuing the bulletin for at least 15 minutes. Discussion contents include: Hydrological trend during the forecast period, detailed water level and flow rate values (if any) according to specified time intervals within the forecast period at specific locations on the river basin (for locations affected by tides, highest and lowest values and times of occurrence within the forecast period); likelihood of dangerous hydrological phenomena, potential impact on the environment, living conditions, infrastructure, economic and social activities; analysis and assessment of the reliability of forecast and warning results using different methods in recent bulletins; synthesis of initial forecast results from different methods and forecasters' opinions; the person responsible for issuing the bulletin selects the most reliable final forecast and warning result suitable for the forecast period.

5. Preparing forecast and warning bulletins

Develop the content of very short-term hydrological forecast and warning bulletins in accordance with Clause 1 of Article 12 and Article 18 of Circular No. 08/2022/TT-BTNMT; develop the content of short-term hydrological forecast and warning bulletins in accordance with Clause 2 of Article 12 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Providing forecast and warning bulletins

Provide very short-term and short-term hydrological forecast and warning bulletins to disaster prevention and rescue command agencies, radio and television stations, and other relevant agencies upon request.

7. Supplementing forecast and warning bulletins

In cases where abnormal hydrological factors or phenomena are detected, additional bulletins should be inserted between regular bulletins. The insertion of additional bulletins shall be carried out in accordance with Clauses 1 to 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluate completeness and timeliness in accordance with Articles 19 and 20 of Circular No. 42/2017/TT-BTNMT dated October 23, 2017, issued by the Minister of Natural Resources and Environment regarding hydrological forecast and warning quality evaluation techniques (hereinafter referred to as Circular No. 42/2017/TT-BTNMT); assess the reliability of very short-term and short-term hydrological forecasts and warnings in accordance with Article 15 of Circular No. 42/2017/TT-BTNMT.

Article 12. Procedure for hydrological forecasting and warning processes with medium-term duration

1. Collecting and processing various types of information and data

a) Collecting the largest, smallest, and average characteristics of hydrological factors, data on the operation of hydropower reservoirs and irrigation reservoirs, meteorological and hydrological data, and international reservoirs related to the forecasted area (if applicable) on a daily basis over a period of 5 to 10 days at forecast locations or river basins;

b) Processing various types of information and data: Analyzing and checking the rationality of the series of data; calculating the characteristics of hydrological factors for forecasting and warning purposes over time periods from two to five days for each forecast location or river basin;

c) Update collected measured data into the forecasting database and model;

d) Collect environmental data, living conditions, infrastructure, economic and social activities data (if applicable).

2. Analyzing and evaluating the current status

a) Analyzing water level and flow rate changes at monitoring stations or hydropower and irrigation reservoirs over a period of five days and ten days; comparing with multi-year average values or extreme values;

b) Analyzing and assessing the impact of tides on tide-influenced hydrological stations;

c) Referring to and analyzing weather forecasting products with a duration of five days and ten days from Vietnam and abroad;

d) Referring to and analyzing hydrological forecasting products from Vietnam and abroad related to the forecasted area;

đ) Information on the operation of reservoirs over the next five days and ten days;

e) Tide forecasting products for forecasted areas (for tidal-influenced river basins);

g) Analyzing environmental data, living conditions, infrastructure, economic and social activities (if available);

3. Implementing forecasting and warning plans

Implementing at least one of the medium-term hydrological forecasting and warning schemes: A scheme based on the use of correlation charts between rainfall and runoff, rainfall-runoff-tide relationships (for tidal regions), water level and flow rate relationships with upstream reservoir outflow, water level and flow rate relationships between upper and lower stations along the same riverbank; a scheme based on statistical similarity methods; a scheme based on mathematical modeling methods;

4. Discussing forecasts and warnings

Discussing medium-term hydrological forecasts and warnings before issuing the bulletin at least two hours prior. The discussion includes: Trends and average, maximum, and minimum values of water levels and flow rates (if applicable) in detail over time periods from two to five days for specific forecast locations or river basins; the possibility of dangerous hydrological phenomena occurring, the potential impact on the environment, living conditions, infrastructure, economic and social activities; analyzing and evaluating the reliability of forecasting and warning results using different methods in recent bulletins; synthesizing initial forecasting results from different methods and forecasters' assessments; the person responsible for issuing the bulletin selects the final forecasting and warning result with the highest reliability;

5. Preparing forecast and warning bulletins

Building the content of the medium-term hydrological forecasting and warning bulletin according to Clause 3 of Article 12 and Article 18 of Circular No. 08/2022/TT-BTNMT;

6. Providing forecast and warning bulletins

Providing the medium-term hydrological forecasting and warning bulletin to disaster prevention and control agencies, rescue agencies, radio and television stations, and other relevant agencies upon request;

7. Supplementing forecast and warning bulletins

In cases where abnormal hydrological factors or phenomena are detected, additional bulletins should be inserted between regular bulletins. The insertion of additional bulletins shall be carried out in accordance with Clauses 1 to 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluating the completeness and timeliness as stipulated in Articles 19 and 20 of Circular No. 42/2017/TT-BTNMT; evaluating the reliability of medium-term hydrological forecasting and warning as stipulated in Article 16 of Circular No. 42/2017/TT-BTNMT.

Article 13. Procedure for long-term hydrological forecasting and warning

1. Collecting and processing various types of information and data

a) Collecting the largest, smallest, and average characteristics of hydrological factors, data on the operation of hydropower and irrigation reservoirs, meteorological and hydrological data, and international reservoirs related to the forecast area (if any) at each ten-day interval within the month at forecast locations or river basins;

b) Processing various types of information and data: Analyzing and checking the rationality of the series of data; calculating the characteristics of hydrological factors for forecasting and warning at each ten-day to fifteen-day interval within the month for each forecast location or river basin;

c) Update collected measured data into the forecasting database and model;

d) Collect environmental data, living conditions, infrastructure, economic and social activities data (if applicable).

2. Analyzing and evaluating the current status

a) Analyzing the water level and flow rate changes at monitoring stations or hydropower and irrigation reservoirs over the past month at each ten-day to fifteen-day interval; comparing with multi-year average characteristic factors or extreme factors;

b) Analyzing and assessing the impact of tides on tide-influenced hydrological stations;

c) Assess errors in hydrological forecast results and analyze forecast outcomes of referenced forecasting methods;

d) Referring to and analyzing monthly meteorological forecasting products from Vietnam and abroad;

đ) Referring to and analyzing hydrological forecasting products from Vietnam and abroad related to the forecast area;

e) Information on the operation of reservoirs in the following month at each ten-day to fifteen-day interval;

g) Tide forecasting products for forecast areas (for river basins affected by tides);

h) Analyzing environmental data, living conditions, infrastructure, economic and social activities (if any);

3. Implementing forecasting and warning plans

Implementing at least one of the long-term hydrological forecasting and warning schemes: Scheme based on correlation diagram method; scheme based on statistical method; scheme based on mathematical model method;

4. Discussing forecasts and warnings

Discussing long-term hydrological forecasts and warnings before issuing the bulletin at least one day prior. The discussion content includes: Trends in water level and flow rate changes (if any) compared to multi-year average values during the forecast period, detailed specific values of average, maximum, and minimum water levels and flow rates (if any) at each ten-day to fifteen-day interval for specific forecast locations or river basins; possibility of dangerous hydrological phenomena occurring, impact on the environment, living conditions, infrastructure, economic and social activities; analyzing and evaluating the reliability of forecasting and warning results using different methods used in recent forecasting and warning bulletins; synthesizing initial forecasting results from different methods and forecasters' opinions; the person responsible for issuing the bulletin selects the final forecasting and warning result with the highest reliability;

5. Preparing forecast and warning bulletins

Building the content of the long-term hydrological forecasting and warning bulletin according to Clause 4, Article 12 and Article 18 of Circular No. 08/2022/TT-BTNMT;

6. Providing forecast and warning bulletins

Providing the long-term hydrological forecasting and warning bulletin to disaster prevention and control command agencies, radio and television stations, and other agencies when requested;

7. Supplementing forecast and warning bulletins

In cases where abnormal hydrological factors or phenomena are detected, additional bulletins should be inserted between regular bulletins. The insertion of additional bulletins shall be carried out in accordance with Clauses 1 to 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluating completeness and timeliness as stipulated in Articles 19 and 20 of Circular No. 42/2017/TT-BTNMT; evaluating the reliability of long-term hydrological forecasting and warning as stipulated in Article 16 of Circular No. 42/2017/TT-BTNMT.

Article 14. Procedure for hydrological forecasting and warning processes for seasonal periods

1. Collecting and processing various types of information and data

a) Collecting the largest, smallest, and average characteristics of hydrological factors, data on the operation of hydropower reservoirs and irrigation reservoirs, meteorological and hydrological data, and international reservoirs related to the forecast area (if any) monthly over a period of 01 month, 03 months, and 06 months at forecast locations or river basins;

b) Collecting simulation and forecast data from global and regional models: information about ENSO, regional circulation affecting rainfall patterns, and flow rates in river basins within the forecast area and adjacent regions;

c) Processing various types of data: Analyzing and checking the rationality of data series; calculating the characteristics of hydrological factors for forecasting and warning purposes over time intervals from 01 month to 03 months for each forecast location or river basin;

d) Updating actual measurement data collected into the forecast database and forecast model;

f) Collect data on environmental conditions, living conditions, infrastructure, and socio-economic activities (if available).

2. Analyzing and evaluating the current status

a) Analyzing water level and flow rate changes at monitoring stations or hydropower and irrigation reservoirs over the past months in time intervals from 01 month to 03 months; comparing with multi-year average characteristic factors or extreme factors (during dry seasons);

b) Analyzing and assessing the impact of tides on tide-influenced hydrological stations;

c) Assess errors in hydrological forecast results and analyze forecast outcomes of referenced forecasting methods;

d) Referring to and analyzing seasonal weather forecast products from Vietnam and abroad;

đ) Referring to and analyzing hydrological forecasting products from Vietnam and abroad related to the forecast area;

e) Information on reservoir operations over time intervals from 01 month to 03 months ahead;

g) Tide forecasting products for forecast areas (for river basins affected by tides);

h) Analyzing environmental data, living conditions, infrastructure, economic and social activities (if any);

3. Implementing forecasting and warning schemes Implementing at least one of the following seasonal hydrological forecasting and warning schemes: Scheme based on correlation diagram method; scheme based on statistical method; scheme based on mathematical modeling method.

4. Discussing forecasts and warnings

Discussing hydrological forecasting and warning for seasonal periods before issuing the bulletin at least 01 day prior. The discussion content includes: Trends in water level and flow rate changes (if applicable) compared to detailed multi-year average values over time intervals from 01 month to 03 months at specific forecast locations or river basins; possibility of dangerous hydrological phenomena occurring, impact on the environment, living conditions, infrastructure, economic and social activities; analyzing and evaluating the reliability of forecasting and warning results using different methods used in recent bulletins; synthesizing initial forecasting results from different schemes and forecasters' assessments; the person responsible for issuing the bulletin selects the final forecasting and warning result with the highest reliability.

5. Preparing forecast and warning bulletins

Building the content of the seasonal hydrological forecasting and warning bulletin according to Clause 5, Article 12 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Providing forecast and warning bulletins

Providing the seasonal hydrological forecasting and warning bulletin to disaster prevention and control agencies, search and rescue agencies, radio and television stations, and other relevant agencies upon request.

7. Supplementing forecast and warning bulletins

In cases where abnormal hydrological factors or phenomena are detected, additional bulletins should be inserted between regular bulletins. The insertion of additional bulletins shall be carried out in accordance with Clauses 1 to 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluating completeness and timeliness as stipulated in Articles 19 and 20 of Circular No. 42/2017/TT-BTNMT; assessing the reliability of seasonal hydrological forecasting and warning as stipulated in Article 17 of Circular No. 42/2017/TT-BTNMT.

Article 15. Short-term water resource forecasting technical process

1. Collecting and processing various types of information and data

a) Collect the largest, smallest, and average characteristics of hydrological factors, hydropower reservoir operation data, meteorological and hydrological data, and international reservoirs related to the forecast area (if applicable) on a daily basis within seven days at forecast locations or river basins;

b) Process various types of information and data: Analyze and check the rationality of the series of data; calculate the flow rate characteristics and total water volume for forecasting and warning purposes over a period of seven days for each forecast location or river basin;

2. Analyzing and evaluating the current status

a) Analyze the total rainfall, flow rate, and total water volume trends at observation stations or hydropower and irrigation reservoirs over the past seven days on a daily basis; compare the total water volume values with the long-term average values;

b) Analyze and assess the impact of tides on water resource stations affected by tidal influences;

c) Refer to and analyze short-term weather forecasting products from Vietnam and abroad;

d) Referring to and analyzing hydrological forecasting products from Vietnam and abroad related to the forecasted area;

d) Daily operation information of reservoirs for the next seven days;

e) Tide forecasting products for forecast areas (for river basins affected by tides);

3. Implement forecasting options

Implement at least one of the following short-term water resource forecasting and warning schemes: Scheme based on the rainfall-runoff relationship method, the relationship between the total water volume at the forecast point and the upstream reservoir discharge, the station-to-station total water volume relationship along the same riverbank; scheme based on the statistical similarity method; scheme based on mathematical modeling;

4. Discussion of forecasts

Discuss short-term water resource forecasts before issuing the bulletin for at least one hour. The discussion content includes: Trends in total rainfall and surface water volume, water shortages during the forecast period, detailed total rainfall and surface water volume values for each time interval from one day to three days, natural disasters related to water shortages; analyze and evaluate the reliability of forecasting results using different methods used in recent bulletins; synthesize initial forecasting results from different methods and forecasters' assessments; the person responsible for issuing the bulletin selects the final forecasting result with the highest reliability;

5. Develop the forecast bulletin

Develop the content of the short-term water resource forecasting bulletin in accordance with Clause 1 of Article 13 and Article 18 of Circular No. 08/2022/TT-BTNMT;

6. Provide the forecast bulletin

Provide the short-term water resource forecasting bulletin to disaster prevention and rescue command agencies, radio and television stations, and other relevant agencies upon request;

7. Supplement the forecast bulletin

In case of unusual developments in forecast factors, supplementary bulletins should be issued between regular bulletins. The supplementation of bulletins is carried out according to provisions from Clause 1 to Clause 6 of this article.

8. Evaluate forecast quality

Evaluate completeness and timeliness in accordance with Article 19 and Article 20 of Circular No. 42/2017/TT-BTNMT; evaluate the reliability of short-term water resource forecasting through comparing forecast factors with actual observations in accordance with Article 18 of Circular No. 42/2017/TT-BTNMT;

Article 16. Technical process for medium-term, long-term, seasonal, and annual water resource forecasting

1. Collecting and processing various types of information and data

a) Collect the largest, smallest, and average characteristics of hydrological factors, hydropower and irrigation reservoir operation data, meteorological and hydrological data, and international reservoirs related to the forecast area (if applicable) over periods of seven to fifteen days for medium-term, fifteen to thirty days for long-term, one to three months for seasonal, and six to twelve months for annual forecasts at forecast locations or river basins;

b) Collect simulation and forecasting data from global and regional models: Information about ENSO, regional circulation affecting rainfall patterns, total flow volumes in river basins within the forecast area and adjacent regions;

c) Process various types of information and data: Analyze and check the rationality of the series of data; calculate flow rate characteristics and total water volume for forecasting and warning purposes over periods of seven to fifteen days for medium-term, fifteen to thirty days for long-term, one to three months for seasonal, and six to twelve months for annual forecasts for each forecast location or river basin;

2. Analyzing and evaluating the current status

a) Analyze the total rainfall, flow rate, and total water volume trends at observation stations or hydropower and irrigation reservoirs over periods of seven to fifteen days for medium-term, fifteen to thirty days for long-term, one to three months for seasonal, and six to twelve months for annual forecasts; compare the total water volume values with the corresponding long-term average values for each period;

b) Analyzing and assessing the impact of tides on tide-influenced hydrological stations;

c) Refer to and analyze seasonal weather forecasting products from Vietnam and abroad;

d) Referring to and analyzing hydrological forecasting products from Vietnam and abroad related to the forecasted area;

d) Reservoir operation information over periods of seven to fifteen days for medium-term, fifteen to thirty days for long-term, one to three months for seasonal, and six to twelve months for annual forecasts corresponding to the subsequent forecast period;

e) Tide forecasting products for forecast areas (for river basins affected by tides);

3. Implement forecasting options

Implement at least one of the following medium-term, long-term, seasonal, and annual water resource forecasting schemes: Scheme based on correlation diagram method; scheme based on statistical method; scheme based on mathematical modeling.

4. Discussion of forecasts

Discuss the forecast of water resources for short-term, medium-term, seasonal, and annual periods at least one day before issuing the bulletin. The discussion content includes: trends in total rainfall, surface water volume, water shortages during the forecast period, detailed values of total rainfall and surface water volume according to specified time intervals within the forecast period, related natural disasters affecting water shortages; analysis and evaluation of the reliability of forecast results using different methods used in recent bulletins; synthesis of initial forecast results from different methods and observations of forecasters; the person responsible for issuing the bulletin selects the final forecast result with the highest reliability suitable for the forecast period.

5. Develop the forecast bulletin

Develop the content of the short-term water resource forecast bulletin in accordance with Clause 2, Article 13 and Article 18 of Circular No. 08/2022/TT-BTNMT; develop the content of the long-term water resource forecast bulletin in accordance with Clause 3, Article 13 and Article 18 of Circular No. 08/2022/TT-BTNMT; develop the content of the seasonal water resource forecast bulletin in accordance with Clause 4, Article 13 and Article 18 of Circular No. 08/2022/TT-BTNMT; develop the content of the annual water resource forecast bulletin in accordance with Clause 5, Article 13 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Provide the forecast bulletin

Provide the short-term, long-term, seasonal, and annual water resource forecast bulletins to disaster prevention and rescue command agencies, radio stations, television stations, and other relevant agencies upon request.

7. Supplement the forecast bulletin

In case of unusual developments in forecast factors, supplementary bulletins should be issued between regular bulletins. The supplementation of bulletins is carried out according to provisions from Clause 1 to Clause 6 of this article.

8. Evaluate forecast quality

Evaluate completeness and timeliness in accordance with Article 19 and Article 20 of Circular No. 42/2017/TT-BTNMT; evaluate the reliability of short-term, long-term, seasonal, and annual water resource forecasts in accordance with Article 18 of Circular No. 42/2017/TT-BTNMT.

Article 17. Technical procedures for forecasting and warning of marine hydrological conditions for very short-term and short-term periods.

1. Collecting and processing various types of information and data

a) Monitor weather forecast information for the sea (monsoon, typhoon, tropical depression, low pressure area, weather patterns capable of causing abnormal water levels and large waves, thunderstorms, tornadoes, waterspouts).

b) Collect observational data from meteorological stations in the forecast region and nearby areas, remote sensing data (satellite, weather radar) in the forecast region, simulation and forecast data from numerical models (global and regional); marine hydrological observational data (wave height and direction, high tide and low tide levels and times, surface current velocity and direction if available) from meteorological marine stations in the forecast region; wave and ocean current observational data from buoys and marine radars in the forecast region (if available); wave observational data from ships operating in the forecast region (if available); wave, current, and water level forecast data from other domestic and international forecasting centers (if available).

c) Process various types of data: Analyze and check the rationality of collected data; calculate characteristics of meteorological factors (rainfall, wind, air pressure) and marine hydrological factors (waves, currents, water levels) for each specified time interval within the forecast period for each location or forecast area.

d) Updating actual measurement data collected into the forecast database and forecast model;

f) Collect data on environmental conditions, living conditions, infrastructure, and socio-economic activities (if available).

2. Analyzing and evaluating the current status

a) Analyze meteorological observational data (rainfall, wind, air pressure) and marine hydrological data (waves, currents, water levels) to determine past and current weather patterns and marine hydrological conditions.

b) Analyze the evolution of meteorological factors (rainfall, wind, air pressure) and marine hydrological factors (waves, currents, water levels) based on observational data and products from numerical model forecasts.

c) Analysis of environmental data, living conditions, infrastructure, and socio-economic activities (if available);

d) During data analysis, if there is a possibility of dangerous marine hydrological phenomena occurring, implement corresponding technical procedures for forecasting and warning of dangerous marine hydrological phenomena.

3. Implementing forecasting and warning plans

a) Implement at least one of the following sea weather forecasting methods (rainfall, visibility, wind, air pressure, sea surface state): Statistical method-based approach; numerical model-based approach (deterministic and ensemble); interpolation, extrapolation, inertia-based approach.

b) Implement at least one of the following wave and current forecasting methods: Analytical method-based approach; numerical model-based approach; statistical method-based approach.

c) Implement at least one of the following tidal forecasting methods: Harmonic analysis-based approach; numerical model-based approach.

4. Discussing forecasts and warnings

Discuss the short-term marine hydrological forecast and warning at least 30 minutes before issuing the bulletin; discuss the very short-term marine hydrological forecast and warning at least 15 minutes before issuing the bulletin. The discussion content includes: Trends in marine hydrological conditions during the forecast period, weather phenomena over the sea, specific values of characteristic factors (visibility, wind direction and speed, sea surface state, high tide and low tide levels and times, wave height and direction, surface current velocity and direction) according to specified time intervals within the forecast period in the specific sea area; potential occurrence of dangerous marine hydrological phenomena, potential impact on the environment, living conditions, infrastructure, economic and social activities; analysis and evaluation of the reliability of forecast and warning results using different methods used in recent bulletins; synthesis of initial forecast and warning results from different methods and observations of forecasters; the person responsible for issuing the bulletin selects the final forecast and warning result with the highest reliability suitable for the forecast period.

5. Preparing forecast and warning bulletins

Develop the content of the very short-term marine hydrological forecast and warning bulletin in accordance with Clause 1, Article 14 and Article 18 of Circular No. 08/2022/TT-BTNMT; develop the content of the short-term marine hydrological forecast and warning bulletin in accordance with Clause 2, Article 14 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Providing forecast and warning bulletins

Provide the very short-term and short-term marine hydrological forecast and warning bulletins to disaster prevention and rescue command agencies, radio stations, television stations, and other relevant agencies upon request.

7. Supplementing forecast and warning bulletins

In cases where marine meteorological factors or phenomena exhibit unusual developments, additional bulletins should be inserted between regular bulletins as necessary. The supplementation of bulletins shall be carried out in accordance with the provisions from Clause 1 to Clause 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluate completeness and timeliness in accordance with Article 14 of Circular No. 16/2019/TT-BTNMT dated September 20, 2019, issued by the Minister of Natural Resources and Environment on technical guidelines for assessing the quality of marine meteorological forecasting and warning (hereinafter referred to as Circular No. 16/2019/TT-BTNMT); evaluate the reliability of short-term and very short-term marine meteorological forecasting and warning in accordance with Clause 2 and Clause 6 of Article 12 and Articles 13 and 14 of Circular No. 41/2017/TT-BTNMT and Articles 10, 11, 12, and 13 of Circular No. 16/2019/TT-BTNMT.

Article 18. Technical Forecasting and Warning Procedures for Medium-Term and Long-Term Marine Meteorology

1. Collecting and processing various types of information and data

a) Collect data from weather maps, surface meteorological observation data, satellite data; rainfall, wind, and atmospheric pressure forecast data from numerical model prediction within the forecast period;

b) Gather wave, water level, and flow measurement data (if available) at marine meteorological stations in the forecast area; wave and sea current measurement data from buoys and radar stations in the forecast area (if available); wave measurement data from ships operating in the forecast area (if available); forecast wave, current, and water level data within the forecast period disseminated by other domestic and international forecasting centers;

c) Process various types of information and data: Analyze and check the rationality of data series; calculate characteristics of meteorological (wind, pressure) and oceanographic (waves, currents, water levels) factors serving forecasting and warning according to specified time intervals within the forecast period for each forecast location or area;

d) Updating actual measurement data collected into the forecast database and forecast model;

f) Collect data on environmental conditions, living conditions, infrastructure, and socio-economic activities (if available).

2. Analyzing and evaluating the current status

a) Analyze meteorological observational data (rainfall, wind, air pressure) and marine hydrological data (waves, currents, water levels) to determine past and current weather patterns and marine hydrological conditions.

b) Analyze the development trends of meteorological (rainfall, wind, atmospheric pressure) and oceanographic (waves, currents, water levels) factors based on observed data and products from existing numerical models at the forecasting unit within the forecast period;

c) Analysis of environmental data, living conditions, infrastructure, and socio-economic activities (if available);

d) During data analysis, if there is a possibility of dangerous marine hydrological phenomena occurring, implement corresponding technical procedures for forecasting and warning of dangerous marine hydrological phenomena.

3. Implementing forecasting and warning plans

a) Implement at least one of the following weather forecasting methods: Method based on synoptic analysis; method based on statistical approach; method based on numerical modeling (deterministic and ensemble); method based on interpolation, extrapolation, and inertia;

b) Implement at least one of the following wave and current forecasting methods: Method based on analytical approach; method based on numerical modeling;

c) Implement at least one of the following tidal forecasting methods: Harmonic analysis-based approach; numerical model-based approach.

4. Discussing forecasts and warnings

Discuss medium-term marine meteorological forecasts and warnings at least one hour before issuing the bulletin; discuss long-term marine meteorological forecasts and warnings at least one day before issuing the bulletin. Discussion contents include: Trends in tidal changes during the forecast period; values and times of occurrence of high water levels, low tide, detailed wave height values according to specified time intervals within the forecast period in specific sea areas; possibility of dangerous marine phenomena occurring, impact on the environment, living conditions, infrastructure, socio-economic activities; analyze and evaluate the reliability of forecasting and warning results using different methods used in recent forecasting and warning bulletins; consolidate initial forecasting results from different methods and forecasters' assessments; the person responsible for issuing the bulletin selects the most reliable final forecasting and warning result suitable for the forecast period;

5. Preparing forecast and warning bulletins

Develop the content of medium-term marine meteorological forecasting and warning bulletins in accordance with Clause 3 of Article 14 and Article 18 of Circular No. 08/2022/TT-BTNMT; develop the content of long-term marine meteorological forecasting and warning bulletins in accordance with Clause 4 of Article 14 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Providing forecast and warning bulletins

Provide medium-term and long-term marine meteorological forecasting and warning bulletins to disaster prevention and rescue command agencies, radio and television stations, and other relevant agencies upon request.

7. Supplementing forecast and warning bulletins

In cases where marine meteorological factors or phenomena exhibit unusual developments, additional bulletins should be inserted between regular bulletins as necessary. The supplementation of bulletins shall be carried out in accordance with the provisions from Clause 1 to Clause 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluate completeness and timeliness in accordance with Article 14 of Circular No. 16/2019/TT-BTNMT; evaluate the reliability of medium-term and long-term marine meteorological forecasting and warning in accordance with Clause 2 and Clause 6 of Article 12 and Articles 13 and 14 of Circular No. 41/2017/TT-BTNMT and Articles 10, 12, and 13 of Circular No. 16/2019/TT-BTNMT.

Article 19. Procedure for forecasting and warning marine weather conditions during the season

1. Collecting and processing various types of information and data

a) Collecting observational data on water levels at meteorological and marine stations in the forecast area; forecast data on water levels within the forecast period issued from other forecasting centers both domestically and internationally (if available);

b) Processing various types of information and data: Analyzing and checking the rationality of collected data; calculating characteristics of wave, flow, and water level factors over time periods ranging from 01 to 03 months for each forecast location or area;

c) Update collected measured data into the forecasting database and model;

d) Collect environmental data, living conditions, infrastructure, economic and social activities data (if applicable).

2. Analyzing and evaluating the current status

a) Analyzing observational data on meteorology, waves, flows, and water levels to determine past and current marine conditions;

b) Analyzing the evolution of water level factors based on observational data and products of existing numerical models at the forecasting unit within the forecast period;

c) Analysis of environmental data, living conditions, infrastructure, and socio-economic activities (if available);

d) During data analysis, if there is a possibility of dangerous marine hydrological phenomena occurring, implement corresponding technical procedures for forecasting and warning of dangerous marine hydrological phenomena.

3. Implementing forecasting and warning plans

a) Implementing at least one of the wave and flow forecasting options: Option based on analytical methods; option based on numerical modeling methods;

b) Implementing at least one of the tide forecasting options: Option based on harmonic analysis methods; option based on numerical modeling methods.

4. Discussing forecasts and warnings

Discussing marine weather forecasts and warnings before issuing the bulletin at least 01 day prior. The discussion includes: Trends in wave and tidal water level (high tide height, low tide height, and times of occurrence) over detailed time periods ranging from 01 to 03 months in specific sea areas; possibility of dangerous marine phenomena occurring, impact on the environment, living conditions, infrastructure, economic and social activities; analyzing and evaluating the reliability of forecast and warning results using different methods in recent bulletins; synthesizing initial forecast and warning results from different methods and forecasters' assessments; the person responsible for issuing the bulletin selects the most reliable final forecast and warning result.

5. Preparing forecast and warning bulletins

Building the content of the marine weather forecast and warning bulletin according to Clause 5, Article 14 and Article 18 of Circular No. 08/2022/TT-BTNMT.

6. Providing forecast and warning bulletins

Providing the marine weather forecast and warning bulletin to disaster prevention and rescue command agencies, radio and television stations, and other relevant agencies upon request.

7. Supplementing forecast and warning bulletins

In cases where marine meteorological factors or phenomena exhibit unusual developments, additional bulletins should be inserted between regular bulletins as necessary. The supplementation of bulletins shall be carried out in accordance with the provisions from Clause 1 to Clause 6 of this Article.

8. Evaluating the quality of forecasts and warnings

Evaluating the completeness and timeliness as stipulated in Article 14 of Circular No. 16/2019/TT-BTNMT; assessing the reliability of marine weather forecasts and warnings as stipulated in Article 12 of Circular No. 16/2019/TT-BTNMT.

Article 20. Procedure for forecasting meteorological and hydrological conditions serving agriculture during short-term periods

1. Collecting and processing various types of information and data

a) Observational data on surface meteorological and agricultural meteorological factors in the forecast area and nearby regions;

b) Production situation and progress of major agricultural crops in each region, growth stages, pests, diseases, yield, and quality of crops;

c) Forecast and warning information on meteorological and hydrological conditions from the national meteorological and hydrological forecasting and warning system;

d) Processing and calculating agricultural meteorological characteristics based on information about air temperature, air humidity, soil moisture, rainfall, and evaporation;

đ) Updating data into forecasting tools such as tables, statistical charts, graphs, predictive models, and simulation models;

e) Evaluating the completeness and accuracy of collected data and supplementing, correcting, and standardizing the data.

2. Analyzing and evaluating the current status

a) Analyzing weather trends: Assessing accumulated temperature, photosynthetic radiation, effective rainfall, actual evaporation, and water balance; leaf wetness degree;

b) Analyzing agricultural data: Growth stage and development level of major agricultural crops, production progress; pest and disease situation of crops; common technical measures implemented for crop care;

c) Analyzing and determining the suitability level of agricultural meteorological conditions for production activities.

3. Implement forecasting options

Implementing at least one of the short-term meteorological and hydrological forecasting options serving agriculture: Option based on data analysis and experience; option based on agricultural forecasting methods (water balance, agricultural drought, crop yield dynamic model).

4. Discussion of forecasts

Discussing short-term meteorological and hydrological forecasts serving agriculture before issuing the bulletin at least 30 minutes prior. The discussion includes: Values of factors (air temperature, air humidity, soil moisture, rainfall, hydrological regime) in detail over daily time periods at a location or area and their potential impact on the growth and development process or agricultural technical measures for major crops; analyzing and evaluating the reliability of forecast results using different methods in recent bulletins; synthesizing initial forecast results from different methods and forecasters' assessments; the person responsible for issuing the bulletin selects the most reliable final forecast result.

5. Develop the forecast bulletin

Building the content of the short-term meteorological and hydrological forecast bulletin serving agriculture according to Point a, Clause 1, Article 15 of Circular No. 08/2022/TT-BTNMT.

6. Provide the forecast bulletin

Providing the short-term meteorological and hydrological forecast bulletin serving agriculture to disaster prevention and rescue command agencies, radio and television stations, and other relevant agencies upon request.

7. Supplement the forecast bulletin

In case of unusual developments in forecast factors, supplementary bulletins should be issued between regular bulletins. The supplementation of bulletins is carried out according to provisions from Clause 1 to Clause 6 of this article.

8. Evaluate forecast quality

Evaluating the completeness and timeliness as stipulated in Article 17 of Circular No. 41/2017/TT-BTNMT; assessing the reliability of the short-term meteorological and hydrological forecast bulletin serving agriculture as stipulated in Articles 12, 13, and 14 of Circular No. 41/2017/TT-BTNMT and Article 15 of Circular No. 42/2017/TT-BTNMT.

Article 21. Meteorological and hydrological forecasting technical procedures serving medium-term agriculture

1. Collecting and processing various types of information and data

a) Observational data on surface meteorological and agricultural meteorological factors in the forecast area and nearby regions;

b) Production situation and progress of major agricultural crops in each region, growth stages, pests, diseases, yield, and quality of crops;

c) Providing point forecasts and weather warnings on a national scale from the national meteorological and hydrological forecasting and warning system;

d) Processing and calculating agricultural meteorological characteristics based on information about air temperature, air humidity, soil moisture, total rainfall, and total evaporation;

đ) Updating data into forecasting tools such as tables, statistical charts, graphs, predictive models, and simulation models;

e) Evaluating the completeness and accuracy of collected data and supplementing, correcting, and standardizing the data.

2. Analyzing and evaluating the current status

a) Weather trend analysis: Evaluating over a general period (seven days or ten days) regarding accumulated temperature, photosynthetic radiation, effective rainfall, actual evaporation, and water balance; leaf wetness level;

b) Analyzing agricultural data during a period (seven days or ten days): Stage and degree of growth and development of key agricultural objects, production progress; pest and disease situation; common technical measures implemented for crop care;

c) Analyzing and determining the suitability level of agricultural meteorological conditions for production activities.

3. Implement forecasting options

Implementing at least one of the following meteorological and hydrological forecasting options serving medium-term agriculture: An option based on numerical data analysis methods and experience; an option based on agricultural forecasting models (water balance, agricultural drought, crop yield dynamic models);

4. Discussion of forecasts

Discussing medium-term agricultural meteorological and hydrological forecasts before issuing the bulletin, at least one hour prior to issuance. The discussion includes: Values of factors (air temperature, air humidity, soil moisture, rainfall, hydrological regime) detailed for each two-day to five-day period at a location or area and their potential impact on growth and development processes or agricultural technical measures for key agricultural objects; analyzing and evaluating the reliability of forecast results using different methods in recent bulletins; synthesizing initial forecast results from different methods and forecasters' assessments; the person responsible for issuing the bulletin selects the most reliable final forecast result;

5. Develop the forecast bulletin

Building the content of the medium-term agricultural meteorological and hydrological forecast bulletin according to Clause b, Paragraph 1, Article 15 of Circular No. 08/2022/TT-BTNMT;

6. Provide the forecast bulletin

Providing the medium-term agricultural meteorological and hydrological forecast bulletin to disaster prevention and control agencies, rescue agencies, radio stations, television stations, and other relevant agencies upon request;

7. Supplement the forecast bulletin

In case of unusual developments in forecast factors, supplementary bulletins should be issued between regular bulletins. The supplementation of bulletins is carried out according to provisions from Clause 1 to Clause 6 of this article.

8. Evaluate forecast quality

Assessing completeness and timeliness according to Article 17 of Circular No. 41/2017/TT-BTNMT; assessing the reliability of medium-term agricultural meteorological and hydrological forecast bulletins according to Articles 12, 13, 14, and 15 of Circular No. 41/2017/TT-BTNMT and Article 16 of Circular No. 42/2017/TT-BTNMT;

Article 22. Meteorological and hydrological forecasting technical procedures serving long-term agriculture

1. Collecting and processing various types of information and data

a) Observational data on surface meteorological and agricultural meteorological factors in the forecast area and nearby regions;

b) Production situation and progress of major agricultural crops in each region, growth stages, pests, diseases, yield, and quality of crops;

c) Providing point forecasts and weather warnings for a ten-day period on a national scale, assessing meteorological and hydrological conditions for the month from the national meteorological and hydrological forecasting and warning system, and global model predictions;

d) Processing and calculating agricultural meteorological characteristics based on information about air temperature, air humidity, soil moisture, total rainfall, and total evaporation;

d) Updating data into forecasting tools such as statistical tables, charts, graphs, and simulation models;

e) Evaluating the completeness and accuracy of collected data and supplementing, correcting, and standardizing the data.

2. Analyzing and evaluating the current status

a) Weather trend analysis: Evaluating up to the time of forecasting regarding accumulated temperature, photosynthetic radiation, effective rainfall, water balance, and agricultural drought levels;

b) Agricultural data analysis: Determining specifically the stage and degree of growth and development of key agricultural objects, production progress, pest and disease situations at the time of forecasting;

3. Implement forecasting options

Implementing at least one of the following long-term agricultural meteorological and hydrological forecasting options: An option based on numerical data analysis methods and experience; an option based on agricultural forecasting models (water balance, agricultural drought, crop yield dynamic models);

4. Discussion of forecasts

Discussing long-term agricultural meteorological and hydrological forecasts before issuing the bulletin, at least one day prior to issuance. The discussion includes: Values of factors (air temperature, soil moisture, total rainfall, hydrological regime) detailed for each ten-day to fifteen-day period at a location or area and their potential impact on growth and development processes or agricultural technical measures for key agricultural objects; analyzing and evaluating the reliability of forecast results using different methods in recent bulletins; synthesizing initial forecast results from different methods and forecasters' assessments; the person responsible for issuing the bulletin selects the most reliable final forecast result;

5. Develop the forecast bulletin

Building the content of the long-term agricultural meteorological and hydrological forecast bulletin according to Clause c, Paragraph 1, Article 15 of Circular No. 08/2022/TT-BTNMT;

6. Provide the forecast bulletin

Providing the long-term agricultural meteorological and hydrological forecast bulletin to disaster prevention and control agencies, rescue agencies, radio stations, television stations, and other relevant agencies upon request;

7. Supplement the forecast bulletin

In case of unusual developments in forecast factors, supplementary bulletins should be issued between regular bulletins. The supplementation of bulletins is carried out according to provisions from Clause 1 to Clause 6 of this article.

8. Evaluate forecast quality

Assessing completeness and timeliness according to Article 17 of Circular No. 41/2017/TT-BTNMT; assessing the reliability of long-term agricultural meteorological and hydrological forecast bulletins according to Article 16 of Circular No. 41/2017/TT-BTNMT and Article 16 of Circular No. 42/2017/TT-BTNMT.

Article 23. Technical process for meteorological and hydrological forecasting serving agriculture during the season

1. Collecting and processing various types of information and data

a) Observational data on surface meteorological and agricultural meteorological factors in the forecast area and nearby regions;

b) Production situation and progress of major agricultural crops in each region, growth stages, pests, diseases, yield, and quality of crops;

c) Information on meteorological and hydrological conditions in the month and season from the national meteorological and hydrological forecast and warning system, predictive information from global models;

d) Processing and calculating agricultural meteorological characteristics based on air temperature, air humidity, total rainfall, and total evaporation data;

d) Updating data into forecasting tools such as statistical tables, charts, graphs, and simulation models;

e) Evaluating the completeness and accuracy of collected data and supplementing, correcting, and standardizing the data.

2. Analyzing and evaluating the current status

a) Weather trend analysis: Evaluating accumulated temperature, photosynthetic radiation, effective rainfall, water balance, agricultural drought levels, or information on preparing for planting the new crop season up to the time of making the forecast;

b) Agricultural data analysis: Determining specific growth and development stages, production progress, pest and disease situations of major agricultural objects at the time of making the forecast or preparation for planting the new crop season;

3. Implement forecasting options

Implementing at least one of the seasonal agricultural meteorological and hydrological forecasting options: An option based on numerical data analysis methods and experience; an option based on agricultural forecasting modeling methods (water balance, agricultural drought);

4. Discussion of forecasts

Discussing the agricultural meteorological and hydrological forecast for the season before issuing the bulletin at least one day prior. The discussion includes: Detailed values of factors (air temperature, total rainfall, hydrological regime) over periods from one to three months at a location or region and their potential impact on the growth and development processes or agricultural technical measures for major agricultural objects; analyzing and evaluating the reliability of forecast results using different methods used in recent bulletins; synthesizing initial forecast results from different methods and forecasters' assessments; the person responsible for issuing the bulletin selects the final forecast result with the highest reliability;

5. Develop the forecast bulletin

Establishing the content of the agricultural meteorological and hydrological forecast bulletin for the season according to Point d Clause 1 Article 15 Circular No. 08/2022/TT-BTNMT;

6. Provide the forecast bulletin

Providing the agricultural meteorological and hydrological forecast bulletin for the season to disaster prevention and control agencies, radio stations, television stations, and other agencies upon request;

7. Supplement the forecast bulletin

In case of unusual developments in forecast factors, supplementary bulletins should be issued between regular bulletins. The supplementation of bulletins is carried out according to provisions from Clause 1 to Clause 6 of this article.

8. Evaluate forecast quality

Evaluating completeness and timeliness as stipulated in Article 17 Circular No. 41/2017/TT-BTNMT; evaluating the reliability of the agricultural meteorological and hydrological forecast bulletin for the season as stipulated in Article 16 Circular No. 41/2017/TT-BTNMT and Article 17 Circular No. 42/2017/TT-BTNMT;

Article 24. Technical process for specialized meteorological and hydrological forecasting according to user requirements

1. Collecting and processing various types of information and data

a) Collecting types of meteorological, hydrological, and marine information and data suitable for the phenomenon, period, and area of the forecast as requested by the user;

b) Processing types of information and data: Analyzing and checking the rationality of collected data; calculating the characteristics of meteorological, hydrological, and marine phenomena consistent with the forecast requirements for phenomena, period, and area;

2. Analyzing and evaluating the current status

a) Analyzing types of meteorological, hydrological, and marine information and data of all observed phenomena and elements at meteorological, hydrological, and marine stations in the forecast area;

b) Analyzing historical average and extreme values of meteorological, hydrological, and marine elements to determine the likelihood of recurrence of special meteorological, hydrological, and marine elements, particularly extreme values;

c) Analyzing the development of upcoming weather systems in the forecast area based on synoptic maps and exploiting products from existing numerical models at the forecasting unit;

d) Analyzing hydrological and marine developments in the forecast area when there are changes in weather patterns based on exploiting products from existing numerical models at the forecasting unit;

3. Implementing forecasting and warning plans

Based on specific requirements for phenomena, period, and area of the forecast, forecasting units use appropriate forecasting options according to the conditions and capabilities of the forecasting unit;

4. Discussing forecasts and warnings

Discussing the forecast before issuing the bulletin at least 30 minutes prior. The discussion includes: Analyzing and assessing past meteorological and hydrological trends up to the forecast time based on observational data sources; synthesizing initial forecast results from different methods and forecasters' assessments; analyzing and evaluating the reliability of forecast results using different prediction methods, especially those used in the latest forecast and warning bulletins; the person responsible for issuing the bulletin selects the final forecast result ensuring the highest reliability;

5. Preparing forecast and warning bulletins

The forecast and warning bulletin is established with content agreed between the forecasting unit and the user, while complying with legal regulations on bulletin content and format;

6. Providing forecast and warning bulletins

Specialized meteorological and hydrological forecast bulletins or those requested by users are directly provided by the forecasting unit to the user according to the agreement between both parties;

7. Supplementing forecast and warning bulletins

In case of unusual developments in forecast factors, supplementary bulletins should be issued between regular bulletins. The supplementation of bulletins is carried out according to provisions from Clause 1 to Clause 6 of this article.

8. Evaluating the quality of forecasts and warnings

Forecasting units and users of specialized forecast bulletins agree on evaluation methods and content based on legal regulations on the quality assessment of meteorological and hydrological forecasts and warnings;

Chapter III

IMPLEMENTING PROVISIONS

Article 25. Effective Date

1. This Circular takes effect from February 15, 2024;

2. This Circular replaces Circular No. 40/2016/TT-BTNMT dated December 19, 2016, issued by the Minister of Natural Resources and Environment regarding the technical process for routine meteorological and hydrological forecasting and warning;

Article 26. Responsibility for Implementation

1. The Minister, Heads of Ministries equivalent to Ministries, Heads of Government Agencies, Chairpersons of People's Committees of provinces and centrally-administered cities, Heads of Units under the Ministry of Natural Resources and Environment, and related organizations and individuals are responsible for implementing this Circular;

2. The Director of the Hydro-Meteorological General Department is responsible for assisting the Minister of Natural Resources and Environment in supervising and inspecting the implementation of this Circular.