Flash Flood Guidance

Main conclusion and guidance for flash flood in the Lower Mekong Basin (LMB):

(In critical weather conditions, the text below will be changed to red colour)
  • In the next 1, 3, and 6 hours no flash flood risk areas have been detected in the LMB.
  • Details on the location of the possible flash flood risk areas in the LMB are in the attached excel file and in KMZ file in case of critical weather conditions. Click on the links to download the flash flood risk areas and the Bulletin in pdf:
    file_bulletin      file_excel_result     
  • In the next 12 and 24 hours no flash flood risk has been detected in in the LMB (see Flash Flood Risk (FFR) map below).
  • The updated flash flood information will be provided at 2021-06-22 08:00

Note: The presented maps show not only the LMB but also areas outside of the LMB. This setup is based on the system configuration defined by the provider. However, in the provided excel file only FFG values are published from within the LMB. Please be aware of the different colour bar codes of each product. The present website provides the results of the MRC-FFGS for information and guidance. Member Countries and their National Line Agencies may refer and issue warning or alert notifications.

MEAN AREAL PRECIPATION (MAP) AND AVERAGE SOIL MOISTURE (ASM) Average Soil Moisture: Soil water saturation fraction (dimensionless ratio of contents over capacity) for the upper zone (approximately 20-30 cm depth).

1-hour MAP Mean Areal Precipitation: Amount of rainfall over the last 1 hour, estimated from bias-adjusted Micro-Wave Global Hydro Estimator (MWGHE) and GHE.

24-hour MAP Mean Areal Precipitation: Amount of rainfall over the last 24 hours, estimated from bias-adjusted Micro-Wave Global Hydro Estimator (MWGHE) and GHE.

6-hour ASM Average Soil Moisture: Soil water saturation fraction (dimensionless ratio of contents over capacity) for the upper zone (app. 20-30 cm depth) over the last 6 hours.

Small rainfall occurred in some areas in the LMB during the last 01- and 24-hour. Soil moisture was dry status in some areas in the LMB in the last 06-hour.

FLASH FLOOD GUIDANCE (FFG) FFG - Flash Flood Guidance: The amount of rainfall over a given duration (1, 3, 6 hours) which is just enough to cause bank-full flow in the draining stream outlet.

1-hour FFG Flash Flood Guidance: The amount of rainfall over 1 hour which is just enough to cause bank-full flow in the draining stream outlet.

3-hour FFG Flash Flood Guidance: The amount of rainfall over 3 hours which is just enough to cause bank-full flow in the draining stream outlet.

6-hour FFG Flash Flood Guidance: The amount of rainfall over 6 hours which is just enough to cause bank-full flow in the draining stream outlet.

No flash flood will possibly occur within the next 01-, 03-, and 06-hour in the LMB.

FORECAST MEAN AREAL PRECIPITATION (FMAP) FMAP - Forecast Mean Areal Precipitation: Accumulations of forecasted mean areal precipitation produced by numerical forecasts from the Weather Research and Forecasting (WRF) model. Each data product reflects basin-average precipitation accumulations from the navigation hour over the corresponding interval.

1-hour FMAP Forecast Mean Areal Precipitation: Forecasted basin-average precipitation accumulations for the next 1 hour produced by numerical forecasts from the Weather Research and Forecasting (WRF) model.

3-hour FMAP Forecast Mean Areal Precipitation: Forecasted basin-average precipitation accumulations for the next 3 hours produced by numerical forecasts from the Weather Research and Forecasting (WRF) model.

6-hour FMAP Forecast Mean Areal Precipitation: Forecasted basin-average precipitation accumulations for the next 6 hours produced by numerical forecasts from the Weather Research and Forecasting (WRF) model.

Small rainfall is forecasted for the next 01-, 03-, and 06-hour in the LMB.

FORECAST MEAN AREAL PRECIPITATION (FMAP) AND FLASH FLOOD RISK FFR - Flash Flood Risk: These products are computed every six hours and measure the occurrence of positive forecast flash flood threat (FMAP > FFG) over a given forecast period using forecast precipitation to drive the Soil and FFG models.

24-hour FMAP Forecast Mean Areal Precipitation: Forecasted basin-average precipitation accumulations for the next 24 hours produced by numerical forecasts from the Weather Research and Forecasting (WRF) model.

12-hour FFR Flash Flood Risk: Occurrence of positive forecast flash flood threat (FMAP > FFG) over a 12-hour forecast period using forecast precipitation to drive the Soil and FFG models.

24-hour FFR Flash Flood Risk: Occurrence of positive forecast flash flood threat (FMAP > FFG) over a 24-hour forecast period using forecast precipitation to drive the Soil and FFG models.

Small rainfall will likely occur in the LMB in the next 24-hour. No flash food risk for the next 12-, 24-hour has been detected that may occur in the LMB.

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