Flash Flood Guidance
Issued by NWS

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000
AWUS01 KWNH 271246
FFGMPD
FLZ000-TNZ000-ALZ000-MSZ000-LAZ000-ARZ000-271844-

MESOSCALE PRECIPITATION DISCUSSION 0139
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
844 AM EDT WED MAY 27 2015

AREAS AFFECTED...LA...MS...TN...AL

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

VALID 271244Z - 271844Z

SUMMARY...FLASH FLOODING WILL BECOME INCREASINGLY POSSIBLE ACROSS
PORTIONS OF LA/MS/TN/AL THROUGH EARLY AFTERNOON.

DISCUSSION...REGIONAL ANALYSIS SHOWS A SQUALL LINE CROSSING LA AND
APPROACHING 2 RESIDUAL BOUNDARIES...1 ACROSS NORTH CENTRAL
MS...AND ANOTHER DRAPED ALONG THE LA COAST...BOTH WITH SUBTLE
THERMAL AND MOISTURE GRADIENTS. 12Z RAOBS AT LIX AND JAN SHOW VERY
MOIST CONDITIONS EXTENDING TO ABOUT 600 MB...MIXED LAYER CAPES OF
1500-2300 J/KG...AND MEAN CLOUD LAYER WINDS OF 15 TO 20 KNOTS.

GIVEN ANOTHER 3 TO 6 HOURS OF INSOLATION...
CAPE VALUES SHOULD CONTINUE TO RISE ALONG WITH DIMINISHING CIN
SUCH THAT WIDESPREAD CONVECTION SHOULD EXPAND AHEAD OF THE SQUALL
LINE AS IT EVENTUALLY MERGES WITH THE OTHER BOUNDARIES
16-19Z...WITH THE INTENSITY AND DEPTH OF CONVECTION ALONG WITH THE
WEAK CLOUD LAYER WINDS SUPPORTING HOURLY RATES OF 2 INCHES PER
HOUR. THESE RATES ARE CAPABLE OF EXCEEDING LOCAL FFG
VALUES...ESPECIALLY ACROSS CENTRAL MS INTO WESTERN TN...WHERE THE
VALUES ARE SLIGHTLY LOWER.

JAMES

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

ATTN...WFO...BMX...HUN...JAN...LCH...LIX...MEG...MOB...OHX...

ATTN...RFC...LMRFC...SERFC...

LAT...LON   36028790 34928755 32448882 31208892 30868768
            30128707 29318718 29108911 29429150 30029261
            31089237 32649161 34299062 35858926


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