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 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
AWUS01 KWNH 240239
FFGMPD
FLZ000-ALZ000-MSZ000-LAZ000-ARZ000-TXZ000-OKZ000-240805-

MESOSCALE PRECIPITATION DISCUSSION 0388
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1039 PM EDT FRI JUN 23 2017

AREAS AFFECTED...PORTIONS OF LA & MS

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 240235Z - 240805Z

SUMMARY...THUNDERSTORMS WITH HEAVY RAINFALL ARE MOVING INTO AN
AREA WITH PARTIALLY SATURATED SOILS.  HOURLY RAIN RATES TO 2.5",
WITH LOCAL AMOUNTS TO 4", ARE EXPECTED THROUGH 08Z.

DISCUSSION...AN OUTFLOW BOUNDARY IS MOVING INTO A REGION WITH
CONVERGENT 850 HPA FLOW, WHICH HAS SET THE STAGE FOR THUNDERSTORM
FORMATION OUT AHEAD OF AN INCOMING OUTFLOW BOUNDARY.  MUCAPE
VALUES OF 1000-3000 J/KG LIE ACROSS THIS AREA.  PRECIPITABLE WATER
VALUES OF 2-2.4" EXIST HERE.  EFFECTIVE BULK SHEAR IS NEAR 25 KTS.

THE EXPECTATION IS FOR THE OUTFLOW BOUNDARY TO MARCH FORWARD,
THOUGH THERE IS A CHANCE THE WESTERN END OF THE LINE TRIES TO HANG
UP DUE TO THE 3000+ J/KG MUCAPE VALUES FARTHER WEST ACROSS LA AND
TX.  THE 12Z SPCWRF HAS THE BEST CONCEPT OF WHAT IS UPCOMING
THROUGH 08Z.  OVER THE EASTERN PORTION OF THIS AREA, GROUNDS ARE
PARTIALLY SATURATED DUE TO EARLIER RAINS CAUSED BY CINDY.  IN THE
WESTERN PORTION OF THE AREA, THIS COULD THREATEN THE HIGHER FLASH
FLOOD GUIDANCE VALUES  THE HOPE IS THAT CONVECTION ACROSS THIS
AREA WILL BE ON THE WANE BY 08Z, WHICH IS SUPPORTED BY THE 18Z
SSEO NEIGHBORHOOD PROBABILITY TRENDS.

ROTH

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BMX...FWD...HGX...JAN...LCH...LIX...MOB...SHV...

ATTN...RFC...ABRFC...LMRFC...SERFC...WGRFC...

LAT...LON   33879409 32959261 32919109 33109038 33658960
            33408847 31708732 30298754 29449031 29769193
            30199328 30839465 31589576 32459633 33499645
            33599624 33789542



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