Flash Flood Guidance
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
AWUS01 KWNH 212136

Mesoscale Precipitation Discussion 0372
NWS Weather Prediction Center College Park MD
535 PM EDT Mon Jun 21 2021

Areas affected...Southern/Southeast Louisiana...Southern

Concerning...Heavy rainfall...Flash flooding likely

Valid 212135Z - 220235Z

Summary...The flash flood threat will continue into the early
evening hours across southern to southeastern Louisiana and far
southern Mississippi. Slow moving thunderstorms producing intense
rain rates of 2-3"/hr will be possible.

Discussion...A mid level disturbance offshore the central Gulf
Coast and longwave troughing advancing through the central U.S. is
providing the necessary lift to interact with the very warm and
moist environment in place to spark widespread thunderstorms along
portions of the Gulf Coast. The PW environment is anomalously high
with the latest blended TPW product showing 2.2 to 2.3 inch

Diurnal heating and convective temperatures have allowed for a
line of loosely organized thunderstorms to develop across southern
to southeast Louisiana. Radar estimates are for 2"+/hr rates at
times as these storms slowly drift east/northeast, including in
and around the New Orleans metro.

This activity should continue through the early evening then begin
to subside with the loss of daytime heating. Until then, localized
2-4" totals in a very short time will be possible and driven by
cell mergers and boundary interactions. Localized flash flooding
will be possible, some of which could be significant over flood
prone urban locations around New Orleans.


...Please see www.wpc.ncep.noaa.gov for graphic product...



LAT...LON   31199271 30899201 30669161 30659061 30719009
            30928873 30448841 30228935 29508960 29429111
            29949251 30739318

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.