Circular No. 40/2016/TT-BTNMT on the technical forecasting and warning procedures for meteorological and hydrological conditions under normal circumstances

✦ 스마트 요약

This Chapter stipulates the technical forecasting and warning procedures for seasonal weather. It includes steps such as data collection, current status analysis, implementation of forecasting plans, and result discussion.

적용 범위

This applies to the national meteorological and hydrological forecasting and warning system and organizations and individuals operating in this field.

핵심 사항

Data Collection: Satellite observation data, reanalysis data, monthly climate statistics, extreme value averages of meteorological factors, and forecast simulation data.
Current Status Analysis: Determining past and present weather patterns, and the likelihood of recurring meteorological factors within the forecast period.
Implementation of Forecasting Plans: Utilizing statistical methods, numerical prediction methods, and other methods if applicable.
Result Discussion: Analyzing the reliability of the forecast results, synthesizing expert opinions to produce the final report.
Evaluating forecast quality through comparison with actual data.

🌐 이 문서의 사회적 영향

Aids in enhancing the effectiveness and accuracy of seasonal weather forecasting work.
Provides a scientific basis for decision-making in disaster risk management.

❓ 자주 묻는 질문

To which entities does this process apply?

This applies to the national meteorological and hydrological forecasting and warning system and organizations and individuals operating in this field.

What forecasting methods for seasonal weather are used?

Statistical methods such as correlation, linear regression, numerical prediction methods, and other methods if applicable.

How is the quality of seasonal weather forecast reports evaluated?

Evaluation is conducted through comparing forecast results with past and current actual data.

전문

MINISTRY OF NATURAL RESOURCES AND ENVIRONMENT ENVIRONMENT -------	SOCIALIST REPUBLIC OF VIET NAM Independence - Freedom - Happiness ---------------
Number: 40/2016/TT-BTNMT	Hanoi, the 19th the December 2016

CIRCULAR

REGULATIONS ON TECHNICAL PROCEDURES FOR WEATHER AND HYDROMETEOROLOGICAL FORECASTING AND WARNING UNDER NORMAL CONDITIONS

Pursuant to the Law on Meteorology and Hydrology dated November 23, 2015;

WHEREAS, Decree No. 38/2016/NĐ-CP dated May 15, 2016 of the Government detailing certain provisions of the Law on Meteorology and Hydrology;

Pursuant to Decree No. 21/2013/NĐ-CP dated March 4, 2013, promulgated by the Government, stipulating the functions, tasks, powers, and organizational structure of the Ministry of Natural Resources and Environment;

At the proposal of the General Director of the National Meteorological and Hydrological Center, the Director of the Meteorology, Hydrology and Climate Change Department, and the Head of the Legal Department;

The Minister of Natural Resources and Environment promulgates this Circular stipulating technical procedures for weather and hydrological forecasting and warning under normal conditions.

PART I

GENERAL PROVISIONS

Article 1. Scope of Regulation

This Circular stipulates technical procedures for weather and hydrological forecasting and warning under normal conditions for various types of forecasts and forecast periods.

Article 2. Applicability

This Circular applies to the national weather and hydrological forecasting and warning system; organizations and individuals engaged in forecasting and warning activities licensed by the Ministry of Natural Resources and Environment or the People's Committee of the province.

Article 3. Explanation of Terms

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

1. Forecasting scheme is a specific method for analyzing, calculating, forecasting, and warning about meteorological and hydrological factors or phenomena at a location or area.

2. Forecast quality assessment involves activities aimed at determining the completeness and timeliness of forecast bulletins and the reliability of forecasted factors and phenomena.

3. Supplementing forecast bulletins means increasing the number of forecast bulletins beyond the prescribed requirements to adjust and refine the bulletin contents based on the latest information, thereby ensuring timely response and forecast reliability. Supplementing forecast bulletins is an indispensable part of forecasting and warning activities.

4. Forecast discussion is an activity involving the exchange of information, analysis, and evaluation of forecast results among forecasters, experts, and different forecasting schemes to select the final forecast result with the highest reliability.

5. Forecast error is the difference between the forecast and the actual measurement of meteorological and hydrological phenomena or factors at the time of the forecast, including errors in value, time, space, and the likelihood of occurrence of phenomena.

Article 4. Factors and Phenomena Subject to Weather and Hydrological Forecasting and Warning

1. Meteorological Factors and Phenomena

a) Clouds: Amount of clouds, type of clouds, cloud base height;

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

c) Temperature: Average temperature, highest temperature, lowest temperature, absolute highest temperature, absolute lowest temperature;

d) Wind: Wind direction, wind speed;

đ) Relative Humidity: Highest relative humidity, lowest relative humidity, average relative humidity;

e) Visibility;

g) Sea Conditions;

h) Other related meteorological factors and phenomena.

2. Hydrological Factors and Phenomena

a) River Water Level: Highest water level, lowest water level, average water level, water level range, time of occurrence;

b) Reservoir Water Level: Inflow to reservoir, outflow from reservoir;

c) Flow Rate: Highest flow rate, lowest flow rate, average flow rate;

d) Salinity: Highest salinity, lowest salinity, average salinity, intrusion distance;

d) Other Related Hydrological Phenomena.

3. Marine Factors and Phenomena

a) Sea Waves: Wave height, wave direction;

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

c) Surge: Height, time of occurrence;

d) Surface Current Velocity: Average velocity, prevailing direction;

đ) Other Related Marine Factors and Phenomena.

Article 5. Frequency, time, and method of providing weather forecast and warning bulletins

1. Frequency and time of issuing bulletins

a) Short-term weather, hydrological, and marine weather forecast and warning bulletins

Depending on the nature and characteristics of weather, hydrological, and marine weather phenomena, the agency issuing the forecast and warning bulletins shall independently determine the time and frequency of issuance suitable for each specific case.

b) Other-term weather forecast and warning bulletins

b1) The Central Weather Forecasting Center within the national weather forecasting and warning system

- Short-term weather forecast and warning bulletins:

+ Weather trend analysis bulletin: Issued twice daily at 9:30 and 14:30. In cases of complex and unusual weather conditions, additional bulletins may be issued between the main bulletins.

+ Land weather forecast and warning bulletin: Issued twice daily at 4:30 and 15:30. In cases of complex and unusual weather conditions, additional bulletins may be issued between the main bulletins.

+ Marine weather forecast and warning bulletin: Issued three times daily at 4:30, 10:30, and 15:30. In cases of complex and unusual weather conditions, additional bulletins may be issued between the main bulletins.

- Short-term hydrological forecast and warning bulletin: Issued once daily at 10:30. In cases of complex and unusual hydrological conditions, additional bulletins may be issued between the main bulletins.

- Short-term marine weather forecast and warning bulletin: Issued twice daily at 9:30 and 15:30. In cases of complex and unusual marine weather conditions, additional bulletins may be issued between the main bulletins.

Information on large waves, currents, and tides can also be compiled and integrated into short-term marine weather and hydrological forecast bulletins.

- Medium-term weather forecast and warning bulletin:

+ Weather trend analysis bulletin: Issued once daily at 16:30. In cases of complex and unusual weather conditions, additional bulletins may be issued between the main bulletins.

+ Land weather forecast and warning bulletin: Issued once daily at 16:30. In cases of complex and unusual weather conditions, additional bulletins may be issued between the main bulletins.

- Medium-term hydrological forecast and warning bulletin:

+ For rivers (except the Mekong River): During flood season, issued six times monthly on the 5th, 10th, 15th, 20th, 25th, and last day of the month; during dry season, issued three times monthly on the 10th, 20th, and last day of the month. In cases of complex and unusual hydrological conditions, additional bulletins may be issued between the main bulletins.

+ For the Mekong River: Issued three times monthly on the 10th, 20th, and last day of the month. In cases of complex and unusual hydrological conditions, additional bulletins may be issued between the main bulletns.

- Medium-term marine weather forecast and warning bulletin: Issued three times monthly on the 10th, 20th, and last day of the month. In cases of complex and unusual marine weather conditions, additional bulletins may be issued between the main bulletins.

- Long-term weather, hydrological, and marine weather forecast and warning bulletin: Issued once monthly on the 1st of the month. Additional bulletins may be issued if necessary.

- Seasonal weather and hydrological forecast and warning bulletin: Issued six times annually on the 15th of February, April, June, August, October, and December. Additional bulletins may be issued if necessary.

- Climate forecast bulletin:

+ Short-term climate forecast bulletin: Issued twice annually on the 15th of January and July. Additional bulletins may be issued if necessary.

+ Medium-term climate forecast bulletin: Issued once annually on the 15th of January. Additional bulletins may be issued if necessary.

+ Long-term climate forecast bulletin: Issued once every five years on the 15th of January. Additional bulletins may be issued if necessary.

- Water resource forecast bulletin:

+ Short-term water resource forecast bulletin: Issued four times monthly on the 7th, 14th, 21st, and last day of the month. Additional bulletins may be issued if necessary.

+ Medium-term water resource forecast bulletin: Issued twice monthly on the 15th and last day of the month. Additional bulletins may be issued if necessary.

+ Seasonal water resource forecast bulletin: Issued once monthly on the 1st of the month. Additional bulletins may be issued if necessary.

+ Annual water resource forecast bulletin: Issued four times annually on the 15th of January, April, July, and October. Additional bulletins may be issued if necessary.

b2) Regional Meteorological and Hydrological Stations, Provincial Meteorological and Hydrological Stations within the national weather forecasting and warning system, and organizations and individuals not belonging to the national weather forecasting and warning system shall independently determine the frequency and time of issuing other-term weather forecast and warning bulletins as specified in point b, Clause 1 of this Article, in accordance with actual circumstances.

2. Bulletin delivery addresses

a) Units within the national weather forecasting and warning system shall be responsible for providing bulletins to agencies, units, and individuals according to the addresses specified in the Appendix of this Circular.

b) Organizations and individuals not belonging to the national weather forecasting and warning system shall independently determine the list of addresses to which bulletins will be provided, in accordance with actual needs.

3. Method of providing information

a) Specialized information systems serving disaster prevention and control work at central and local levels.

b) The communication information system, public information system including: Telephone, fax, radio and television broadcasting system, internet, email, web, postal and telecommunications services.

Chapter II

SHORT-TERM AND VERY SHORT-TERM WEATHER FORECASTING AND WARNING TECHNICAL PROCEDURE

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

1. Collection and processing of various types of information and data

a) Meteorological observation data of the forecast area and adjacent areas (surface meteorology, radio sounding, pilot balloon, automatic rain gauge, marine observation, enhanced observation);

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

c) Remote sensing data in the area (weather satellites, weather radar, lightning location);

d) Evaluation of the completeness and accuracy of collected data, supplementing, editing, and standardizing the data.

2. Analysis and assessment of current status

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

b) Analyzing upper-air sounding data on weather charts at the time of the most recent observations from nationwide radio sounding stations and pilot balloons;

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

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

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

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

g) During the data analysis process, if there is a possibility of dangerous weather phenomena occurring, switch to implementing the technical procedure for forecasting and warning of dangerous hydro-meteorological phenomena;

h) For very short-term forecasts, to ensure timely dissemination of information, focus on analyzing remote sensing data and assessments in the most recent short-term bulletins for the forecast area.

3. Implementation of forecasting and warning plans

a) Forecasting and warning plans commonly used for very short-term and short-term weather include:

a1) Plan based on synoptic analysis and experience methods;

a2) Plan based on statistical methods;

a3) Plan based on dynamic meteorological modeling methods;

a4) Plan based on combined methods;

a5) Plan based on interpolation, extrapolation, and inertia methods;

a6) Plan based on other methods (if applicable).

b) Forecasting and warning plans for very short-term and short-term weather are specified by the National Hydro-Meteorological Forecasting and Warning System as defined by the National Hydro-Meteorological Center.

c) Depending on specific conditions, organizations and individuals engaged in forecasting and warning outside the National Hydro-Meteorological Forecasting and Warning System shall independently define the use of forecasting and warning plans accordingly.

4. Discussion on forecasts and warnings

a) Content of discussion:

a1) Evaluating the reliability of forecast results using different methods in recent forecast and warning bulletins;

a2) Synthesizing initial forecast results from different methods and forecasters' assessments;

a3) Analyzing and evaluating past weather developments up to the forecast time based on observational, remote sensing, and model data;

a4) The person responsible for issuing the bulletin selects the final forecast result with the highest reliability.

b) Discussion time

b1) National Hydro-Meteorological Forecasting and Warning System

Short-term weather forecast discussions under normal conditions are conducted at least twice a day at 09:00 and 13:45; very short-term forecasts are conducted at least 30 minutes before issuing the bulletin.

b2) Organizations and individuals not part of the National Hydro-Meteorological Forecasting and Warning System independently define their discussion times for forecasts and warnings accordingly.

5. Construction of forecast and warning bulletins

a) Content of very short-term weather forecast and warning bulletins

a1) Bulletin title;

a2) Content of very short-term weather forecast and warning bulletins is implemented according to Clause 1, Article 9 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning periods for hydro-meteorological phenomena;

a3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

b) Content of weather trend analysis bulletins

b1) Bulletin title;

b2) Content of weather trend analysis bulletins is implemented according to Point a, Clause 2, Article 9 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning periods for hydro-meteorological phenomena;

b3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

c) Content of land-based weather forecast and warning bulletins

c1) Bulletin title;

c2) Content of land-based weather forecast and warning bulletins is implemented according to Point b, Clause 2, Article 9 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning periods for hydro-meteorological phenomena;

c3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

d) Content of marine weather forecast and warning bulletins

d1) Bulletin title;

d2) Content of marine weather forecast and warning bulletins is implemented according to Point c, Clause 2, Article 9 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning periods for hydro-meteorological phenomena;

d3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

6. Provision of forecast and warning bulletins

Short-term and very short-term weather forecast and warning bulletins shall be provided in accordance with the provisions of Clauses 2 and 3 of Article 5 of this Circular.

7. Supplement forecast and warning bulletins

In case abnormal meteorological factors or phenomena are detected, additional bulletins must be inserted between regular bulletins. The supplementation of bulletins shall be carried out in accordance with the provisions from Clause 1 to Clause 6 of this Article.

8. Quality assessment of forecasts and warnings

a) Content of assessment

a1) Assessment of the timely and complete implementation of the contents prescribed in the technical procedures for very short-term and short-term weather forecasting and warning;

a2) Assessment of the completeness and timeliness of the provision of very short-term and short-term weather forecast and warning bulletins as prescribed;

a3) Assessment of the quality of forecast and warning bulletins through comparison of forecasted elements and phenomena with actual observations in accordance with the regulations on forecast evaluation.

b) The National Hydro-meteorological Center shall specify in detail the methods and criteria for evaluating forecast and warning bulletins for very short-term and short-term weather within the national hydro-meteorological forecasting and warning system.

c) Organizations and individuals not belonging to the national hydro-meteorological forecasting and warning system must comply with current regulations on forecast quality evaluation.

Article 7. Technical procedures for very short-term and short-term hydrological forecasting and warning

1. Collection and processing of various types of information and data

a) Depending on each river basin, the following meteorological and hydrological observation data may be collected:

a1) Rainfall, water level, flow rate data from meteorological and hydrological stations, flood discharge and power generation data from hydropower reservoirs, irrigation dams in the forecast area according to observation hours;

a2) International meteorological and hydrological data related to the forecast area (if available) according to observation hours.

b) Processing various types of information and data:

b1) Analyzing data, checking, and verifying data when detecting unreasonable data series;

b2) Updating actual rainfall, water level, flow rate data at observation stations and reservoir data into the forecasting database;

b3) Plotting water level (flow rate) process lines and total rainfall charts of stations on graph paper, Excel, or other charting software;

b4) Calculating characteristics: Water level range, water level intensity, total rainfall, average watershed rainfall, etc.;

b5) Updating actual rainfall, water level (flow rate) data, and reservoir data into the forecasting model.

2. Analysis and assessment of current status

a) Rainfall trend analysis: Analyze information about the weather pattern causing rainfall, rainfall reaching flood thresholds, average watershed total rainfall, spatial distribution of rainfall (upstream, midstream, or downstream) and temporal distribution (beginning or end of the period) over the previous 6-hour, 12-hour, 18-hour, and 24-hour periods;

b) Water level (flow rate) trend analysis: Water level range, water rise and fall intensity, water level trend, flow rate (total water volume) to observation stations or reservoirs. Evaluate and analyze the impact of upstream reservoir discharge and power generation on downstream flow rates and water levels at observation stations or reservoirs over the previous 6-hour, 12-hour, 18-hour, and 24-hour periods;

c) Analyze rainfall forecast data from domestic and foreign forecasting models for the 6 to 48-hour period (for the Mekong River Basin up to 5 days), satellite images, radar images, products provided on websites and authorized agencies. Analyze and refer to quantitative rainfall forecast results;

d) Evaluate the accuracy of the most recent forecast results from referenced forecast products, assess the potential error of rainfall forecasts from models;

đ) During data analysis, if there is a possibility of dangerous hydrological phenomena occurring, switch to implementing the technical procedures for forecasting and warning of dangerous hydro-meteorological phenomena;

3. Implementation of forecasting and warning plans

a) Common approaches used in very short-term and short-term hydrological forecasting and warning include:

a1) Approaches based on the rainfall-runoff relationship method;

a2) Approaches based on the water level and flow rate relationship between upstream and downstream stations along the same river or watershed;

a3) Approaches based on mathematical models: Regression models; lumped parameter hydrological models; distributed parameter hydrological models; hydraulic models; reservoir regulation models.

b) Very short-term and short-term hydrological forecasting and warning approaches used in the national hydro-meteorological forecasting system are specified by the National Hydro-meteorological Center.

4. Discussion on forecasts and warnings

a) Discussion content

a1) Analyze and evaluate the reliability of forecast and warning results (characteristics of water levels, flows, time of occurrence of extreme values) using different approaches used in the latest forecast and warning bulletins;

a2) Synthesizing initial forecast results from different methods and forecasters' assessments;

a3) The person responsible for issuing the bulletin selects the final forecast and warning result with the highest reliability.

b) Discussion time

b1) National Hydro-Meteorological Forecasting and Warning System

Short-term hydrological forecasting discussions shall be conducted at least once daily at 9:00 AM; very short-term forecasting discussions shall be conducted at least 30 minutes before issuing the bulletin.

b2) Organizations and individuals not part of the National Hydro-Meteorological Forecasting and Warning System independently define their discussion times for forecasts and warnings accordingly.

5. Construction of forecast and warning bulletins

a) Content of very short-term hydrological forecast and warning bulletins

a1) Bulletin title;

a2) The content of very short-term hydrological forecast and warning bulletins shall be implemented in accordance with Clause 1 of Article 10 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning deadlines for hydro-meteorological conditions;

a3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

b) Content of short-term hydrological forecast and warning bulletins

b1) Bulletin title;

b2) The content of short-term hydrological forecast and warning bulletins shall be implemented in accordance with Clause 2 of Article 10 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning deadlines for hydro-meteorological conditions;

b3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

6. Provision of forecast and warning bulletins

Very short-term and short-term hydrological forecast and warning bulletins shall be provided in accordance with the provisions of Clauses 2 and 3 of Article 5 of this Circular.

7. Supplement forecast and warning bulletins

In case abnormal hydrological factors or phenomena are detected, additional bulletins must be inserted between regular bulletins. The supplementation of bulletins shall be carried out in accordance with the provisions from Clause 1 to Clause 6 of this Article.

8. Quality assessment of forecasts and warnings

a) Content of assessment

a1) Evaluate the full and timely implementation of the contents stipulated in the technical procedure for short-term and very short-term hydrological forecasting and warning.

a2) Assess the completeness and timeliness of the provision of short-term and very short-term hydrological forecast and warning bulletins as prescribed.

a3) Evaluate the quality of forecast and warning bulletins through comparisons of predictive factors with actual observations according to regulations on forecast evaluation.

b) The National Hydro-meteorological Center shall specify in detail the methods and criteria for evaluating short-term and very short-term hydrological forecast and warning bulletins within the national hydro-meteorological forecasting and warning system.

c) Organizations and individuals not belonging to the national hydro-meteorological forecasting and warning system must comply with current regulations on forecast quality evaluation.

Article 8. Technical Procedure for Short-Term and Very Short-Term Marine Forecasting and Warning

1. Collection and processing of 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 rise and large waves, thunderstorms, tornadoes, waterspouts).

b) Wind field and atmospheric pressure data from numerical model forecasts.

c) Collect observation data on wind, atmospheric pressure, waves, water levels, and currents at marine meteorological stations in the forecast area.

d) Observation data on waves and ocean currents at buoy and radar stations in the forecast area (if available).

đ) Observation data on waves from ships operating in the forecast area (if available).

e) Forecast data on waves and currents from other domestic and foreign forecasting centers.

g) Tide forecast data in the forecast area.

h) Prepare data at loose boundaries and river mouths for numerical models.

i) Evaluate the completeness and accuracy of collected data and supplement, adjust, and standardize the data.

2. Analysis and assessment of current status

a) Analyze meteorological (wind, pressure) and marine (waves, currents, water levels) observation data to determine past and current weather conditions and marine conditions.

b) Analyze the development trends of meteorological (wind, pressure) and marine (waves, currents, water levels) factors based on observation data and products from numerical models.

c) During data analysis, if there is a possibility of dangerous marine phenomena occurring, switch to implementing the technical procedure for forecasting and warning of dangerous hydro-meteorological phenomena.

3. Implementation of forecasting and warning plans

a) Common approaches used in short-term and very short-term marine forecasting and warning include:

a1) Approaches for wave and current forecasting:

- Approaches based on analytical formula methods.

- Approaches based on numerical model methods.

a2) Approaches for tide forecasting:

- Approaches based on harmonic analysis methods.

- Approaches based on numerical model methods.

b) Short-term and very short-term marine forecasting and warning approaches used in the national hydro-meteorological forecasting system are specified by the National Hydro-meteorological Center.

4. Discussion on forecasts and warnings

a) Discussion content

a1) Analyze and evaluate the reliability of forecast and warning results using different approaches in the most recent forecast bulletins.

a2) Synthesize initial forecast and warning results from different approaches and the forecasters' assessments.

a3) The person responsible for issuing the bulletin selects the final forecast and warning result with the highest reliability suitable for the forecast period.

b) Discussion time

b1) National Hydro-Meteorological Forecasting and Warning System

Discussions on short-term marine forecasting and warning under normal conditions are conducted at least twice a day at 9:00 and 13:45; discussions for very short-term forecasting and warning are conducted at least 30 minutes before issuing the bulletin.

b2) Organizations and individuals not part of the National Hydro-Meteorological Forecasting and Warning System independently define their discussion times for forecasts and warnings accordingly.

5. Construction of forecast and warning bulletins

a) Content of very short-term marine forecast and warning bulletins

a1) Bulletin title;

a2) The content of very short-term marine forecast and warning bulletins is carried out in accordance with Clause 1, Article 11 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning periods for hydro-meteorological phenomena.

a3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

b) Content of short-term marine forecast and warning bulletins

b1) Bulletin title;

b2) The content of short-term marine forecast and warning bulletins is carried out in accordance with Clause 2, Article 11 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning periods for hydro-meteorological phenomena.

b3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

6. Provision of forecast and warning bulletins

Very short-term and short-term marine forecast and warning bulletins are provided in accordance with Clause 2 and Clause 3, Article 5 of this Circular.

7. Supplement forecast and warning bulletins

In case of detecting unusual developments in marine factors or phenomena, additional bulletins should be inserted between regular bulletins. The insertion of additional bulletins is carried out in accordance with Clauses 1 to 6 of this Article.

8. Quality assessment of forecasts and warnings

a) Content of assessment

a1) Evaluate the full and timely implementation of the contents stipulated in the technical procedure for short-term and very short-term marine forecasting and warning.

a2) Assess the completeness and timeliness of the provision of short-term and very short-term marine forecast and warning bulletins as prescribed.

b) The National Hydro-meteorological Center shall specify in detail the methods and criteria for evaluating short-term and very short-term marine forecast and warning bulletins within the national hydro-meteorological forecasting and warning system.

c) Organizations and individuals not belonging to the national hydro-meteorological forecasting and warning system must comply with current regulations on forecast quality evaluation.

Chapter III

TECHNICAL PROCEDURE FOR MID-TERM AND LONG-TERM HYDROMETEOROLOGICAL FORECASTING AND WARNING

Article 9. Procedure for technical weather forecasting and warning for medium-term period

1. Collection and processing of various types of information and data

a) Data from weather maps;

b) Observational data of surface meteorological elements;

c) Satellite data;

d) Data of numerical forecast products;

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

2. Analysis and assessment of current status

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

b) Analyze historical average and extreme values of meteorological elements to determine the recurrence potential of meteorological elements, especially extreme values;

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

d) During the data analysis process, if there is a possibility of dangerous weather phenomena occurring, switch to implementing the technical procedure for forecasting and warning of dangerous hydro-meteorological phenomena accordingly.

3. Implementation of forecasting and warning plans

a) Common options used in medium-term weather forecasting and warning include:

a1) Option based on synoptic analysis method;

a2) Option based on numerical method;

a3) Option based on statistical method;

a4) Options based on other methods (if available).

b) Medium-term weather forecasting and warning options used in the national hydro-meteorological forecasting and warning system are specified by the National Hydro-Meteorological Center.

c) Depending on specific conditions, organizations and individuals engaged in forecasting and warning outside the national hydro-meteorological forecasting and warning system shall independently define the use of forecasting options appropriately.

4. Discussion on forecasts and warnings

a) Discussion content

a1) Analyze and evaluate the reliability of forecast and warning results using different approaches in the most recent forecast bulletins.

a2) Synthesize initial forecast and warning results from different approaches and the forecasters' assessments.

a3) The person responsible for issuing the bulletin selects the final forecast and warning result with the highest reliability.

b) Discussion time

b1) National Hydro-Meteorological Forecasting and Warning System

The discussion on medium-term weather forecasting and warning is conducted at least once a day at 10:30.

b2) Organizations and individuals not part of the National Hydro-Meteorological Forecasting and Warning System independently define their discussion times for forecasts and warnings accordingly.

5. Construction of forecast and warning bulletins

a) Title of the bulletin;

b) Content of the medium-term weather forecasting and warning bulletin is implemented according to Clause 3, Article 9 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016 issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning periods for hydro-meteorological events;

c) Time of issuing the bulletin, name of the bulletin builder and the bulletin reviewer; time of issuing the next bulletin.

6. Provision of forecast and warning bulletins

The medium-term weather forecasting and warning bulletin is provided according to Clause 2 and Clause 3, Article 5 of this Circular.

7. Supplement forecast and warning bulletins

In case of unusual weather developments, additional bulletins should be inserted between regular bulletins. The insertion of additional bulletins is carried out according to the provisions from Clause 1 to Clause 6 of this Article.

8. Quality assessment of forecasts and warnings

a) Content of assessment

a1) Evaluate the full and timely implementation of the contents stipulated in the technical procedure for medium-term weather forecasting and warning;

a2) Evaluate the completeness and timeliness of providing medium-term weather forecasting and warning bulletins as prescribed;

a3) Evaluate the quality of forecast and warning bulletins through comparisons of predictive factors with actual observations according to regulations on forecast evaluation.

b) The National Hydro-Meteorological Center specifies detailed methods and evaluation criteria for medium-term weather forecasting and warning bulletins within the national hydro-meteorological forecasting and warning system.

c) Organizations and individuals outside the national hydro-meteorological forecasting and warning system must comply with current regulations on quality assessment of forecasts.

Article 10. Procedure for technical long-term weather forecasting and warning

1. Collection and processing of various types of information and data

a) Data from space observations over the Euro-Asian region to build 500mb mean height contour maps;

b) Japanese JRA 55 reanalysis data to build mean maps at standard pressure levels;

c) Daily observational data of surface meteorological elements in the forecast area and adjacent areas;

d) CLIM data (monthly climate bulletin issued domestically);

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

e) Data on ENSO;

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

2. Analysis and assessment of current status

a) Analyze observational data, CLIM, mean maps built from space observation data and reanalysis data at standard pressure levels to determine past and present weather patterns;

b) Analyze historical average and extreme values of meteorological elements to determine the recurrence potential of meteorological elements, especially extreme values during the forecast period;

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

3. Implementation of forecasting and warning plans

a) Common options used in long-term weather forecasting and warning include:

a1) Option based on statistical methods: Correlation and linear regression methods; analog circulation method; ENSO correlation method; regime method;

a2) Option based on numerical forecasting method;

a3) Options based on other methods (if available).

b) Long-term weather forecasting and warning options used in the national hydro-meteorological forecasting and warning system are specified by the National Hydro-Meteorological Center.

4. Discussion on forecasts and warnings

a) Discussion content

a1) Analyze and evaluate the reliability of forecast and warning results using different options in recent bulletins;

a2) Synthesize initial forecast and warning results from different approaches and the forecasters' assessments.

a3) The person responsible for issuing the bulletin selects the final forecast and warning result with the highest reliability.

b) Discussion time

b1) National Hydro-Meteorological Forecasting and Warning System

Long-term weather forecasting and warning discussions are conducted at least one day before issuing the bulletin.

b2) Organizations and individuals outside the national hydro-meteorological forecasting and warning system are responsible for defining the discussion time for forecasting and warning.

5. Construction of forecast and warning bulletins

a) Title of the bulletin;

The content of the long-term weather forecasting and warning bulletin is implemented according to Clause 4, Article 9 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016 issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning periods for hydro-meteorological events;

c) Time of issuing the bulletin, name of the bulletin builder and the bulletin reviewer; time of issuing the next bulletin.

6. Provision of forecast and warning bulletins

The long-term weather forecasting and warning bulletin is provided according to Clause 2 and Clause 3, Article 5 of this Circular.

7. Supplement forecast and warning bulletins

In case of unusual developments of meteorological factors and phenomena, additional bulletins may be added. The addition of additional bulletins is carried out according to the provisions from Clause 1 to Clause 6 of this Article.

8. Quality assessment of forecasts and warnings

a) Content of assessment

a1) Evaluate the full and timely implementation of the contents stipulated in the technical procedure for long-term weather forecasting and warning;

a2) Evaluate the completeness and timeliness of providing long-term weather forecasting and warning bulletins as prescribed;

b) The National Hydro-Meteorological Center shall specify in detail the methods and criteria for evaluating long-term weather forecast and warning bulletins within the national hydro-meteorological forecasting and warning system.

c) Organizations and individuals not belonging to the national hydro-meteorological forecasting and warning system must comply with current regulations on forecast quality evaluation.

Article 11. Technical process for medium-range hydrological forecasting and warning

1. Collection and processing of various types of information and data

a) Rainfall, water level, and flow data from meteorological and hydrological stations in the forecast area according to observation hours;

b) Operation data (water levels, inflow and outflow flows) of hydropower and irrigation reservoirs in the forecast area according to observation hours;

c) International meteorological and hydrological data related to the forecast area (if available) according to observation hours;

d) Evaluation of the completeness and accuracy of collected data, supplementing, editing, and standardizing the data.

2. Analysis and assessment of current status

a) Analysis of rainfall trends: Weather patterns causing rain, average basin rainfall volume, changes in total rainfall and rainfall area over space and time in the past 5, 10 days.

b) Analysis of water level and flow trends at monitoring stations or hydropower and irrigation reservoirs in the past 5, 10 days:

b1) Water level and flow trends;

b2) Flow release and power generation trends of hydropower reservoirs affecting the monitoring station or downstream reservoir in the past 5, 10 days;

b3) Flood amplitude and intensity (when floods occur), flood peak;

b4) Comparison with multi-year average characteristics or extreme factors (during dry season);

c) Analysis of tidal impact on hydrological stations affected by tides;

d) Reference and analysis of medium-range weather forecasts of 5, 10 days from Vietnam and abroad:

d1) Weather pattern causing rain, forecast of total rainfall and distribution of rain in the next 5, 10 days;

d2) Determination of areas where rain will occur;

d3) Determination of the start and end times of rain;

đ) Reference and analysis of medium-range hydrological forecasts from Vietnam and abroad relevant to the forecast area;

e) Reservoir operation information for the next 5, 10 days;

g) Tidal forecast products for the forecast areas (for tidal-influenced river basins);

h) During data analysis, if there is a possibility of dangerous hydrological phenomena occurring, switch to implementing the technical process for forecasting and warning of dangerous hydro-meteorological phenomena;

3. Implementation of forecasting and warning plans

a) Commonly used methods in medium-range hydrological forecasting and warning include:

a1) Methods using correlation charts constructed based on the following approaches: Rainfall-runoff relationship; rainfall-runoff-tide relationship (for tidal regions); water level, flow relationship with upstream reservoir outflow; water level, flow relationship between upper and lower stations along the same riverbank;

a2) Method using statistical similarity approach;

a3) Method using mathematical models: Regression model; analytical and statistical model; lumped parameter hydrological model; distributed parameter hydrological model; hydraulic model; reservoir regulation model; tidal forecasting model;

b) Medium-range hydrological forecasting and warning methods used in the national hydro-meteorological forecasting and warning system are specified by the National Hydro-Meteorological Center;

4. Discussion on forecasts and warnings

a) Discussion content

a1) Analyze and evaluate the reliability of forecast and warning results using different options in recent bulletins;

a2) Synthesizing initial forecast results from different methods and forecasters' assessments;

a3) The final forecast value is selected from different methods based on the following grounds:

- Forecasting method evaluated for high reliability and stability over many years;

- Analysis and judgment based on experience, discussion, and expert opinions;

- In cases where methods at a location produce slightly different forecast results, analyze and select the most reasonable forecast value;

- In cases where forecast values from different methods differ, do not calculate the average of forecast values;

a4) The person responsible for issuing the bulletin selects the highest reliable final forecast and warning result;

b) Discussion time

b1) National Hydro-Meteorological Forecasting and Warning System

Discussion on medium-range hydrological forecasting and warning is conducted at least once before issuing the bulletin at 10:30 AM;

b2) Organizations and individuals outside the national hydro-meteorological forecasting and warning system are responsible for defining the discussion time for forecasting and warning.

5. Construction of forecast and warning bulletins

a) Content of the bulletin analyzing hydrological trends

a1) Bulletin title;

a2) The content of the bulletin analyzing hydrological trends is carried out in accordance with point a, Clause 3, Article 10 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning deadlines for hydro-meteorological phenomena;

a3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

b) Content of the medium-range hydrological forecast and warning bulletin

b1) Bulletin title;

b2) The content of the medium-range hydrological forecast and warning bulletin is carried out in accordance with point b, Clause 3, Article 10 of Circular No. 06/2016/TT-BTNMT dated May 16, 2016, issued by the Ministry of Natural Resources and Environment regarding types of bulletins and forecast and warning deadlines for hydro-meteorological phenomena;

b3) Bulletin issuance time, name of the bulletin constructor and reviewer; next bulletin issuance time.

6. Provision of forecast and warning bulletins

The medium-range hydrological forecast and warning bulletin is provided in accordance with Clause 2 and Clause 3, Article 5 of this Circular;

7. Supplement forecast and warning bulletins

8. Quality assessment of forecasts and warnings

a) Evaluation content:

a1) Evaluation of the full and timely implementation of the contents prescribed in the technical process for medium-range hydrological forecasting and warning;

a2) Evaluation of the completeness and timeliness of providing medium-range hydrological forecast and warning bulletins as prescribed;

a3) Evaluate the quality of forecast and warning bulletins through comparisons of predictive factors with actual observations according to regulations on forecast evaluation.

b) The National Hydro-Meteorological Center shall specify in detail the methods and criteria for evaluating medium-range hydrological forecast and warning bulletins within the national hydro-meteorological forecasting and warning system.

c) Organizations and individuals outside the national hydro-meteorological forecasting and warning system must comply with current regulations on quality assessment of forecasts.

Article 12. Procedure for long-term hydrological forecasting and warning

1. Collection and processing of various types of information and data

Depending on the forecasting scheme, the following types of data may be collected:

a) The largest, smallest, and average characteristics over monthly periods at the forecast locations;

b) Characteristics of inflow to reservoirs and outflow from hydropower and irrigation reservoirs related to the forecast area;

c) Meteorological characteristics at meteorological stations related to the forecast area;

d) The series of data collected for forecasting must be sufficiently long and meet the technical requirements of the forecasting scheme being used.

2. Analysis and assessment of current status

a) Determine the trend of the forecast factors within the forecast area up to the time of issuing the forecast bulletin;

b) Analyze the rainfall trend across the watershed and compare it with the multi-year average value for the past month;

c) Analyze the water level (discharge) trend to monitoring stations or reservoirs, discharge of upstream hydropower reservoirs affecting downstream monitoring stations or reservoirs, and compare it with the multi-year average value for the past month;

d) Refer to hydro-meteorological forecasting products from Vietnam and abroad, including: Rainfall products from numerical models and products provided on websites;

3. Implementation of forecasting and warning plans

a) Common schemes used in long-term hydrological forecasting and warning include:

a1) Schemes using correlation charts constructed based on methods: Rainfall-runoff relationship; rainfall-runoff-tide relationship (for tidal areas); water level, flow rate with upstream reservoir discharge relationship; water level, flow rate station above-station below relationship along the same riverbank;

a2) Schemes based on similar analysis and statistical methods;

a3) Schemes using mathematical models: Statistical models according to objective statistical methods; statistical models according to identification methods; multiple regression statistical models; harmonic analysis statistical models; statistical mathematical models; artificial intelligence network models;

b) Long-term hydrological forecasting and warning schemes used in the national hydro-meteorological forecasting and warning system are specified by the National Hydro-Meteorological Center.