Flash Flood Guidance
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000
AWUS01 KWNH 191458
FFGMPD
MSZ000-LAZ000-191811-

MESOSCALE PRECIPITATION DISCUSSION 0027
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
956 AM EST THU JAN 19 2017

AREAS AFFECTED...EASTERN LOUISIANA...CENTRAL AND SOUTHERN
MISSISSIPPI...

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

VALID 191456Z - 191811Z

SUMMARY...ONGOING CONVECTION/CELL MERGERS WITHIN INCREASINGLY
MOIST ENVIRONMENT WILL LEAD TO ADDITIONAL RAINFALL TOTALS OF TWO
TO THREE INCHES IN SOME LOCATIONS THROUGH 18Z...WITH SOME
LOCALIZED FLASH FLOODING POSSIBLE.

DISCUSSION...MID-MORNING RADAR MOSAIC SHOWED CONTINUED CONVECTION
PRODUCING MODERATE TO HEAVY RAINFALL...CENTERED JUST EAST OF A
BATON ROUGE TO JACKSON LINE. LATEST WATER VAPOR IMAGERY DEPICTING
A WELL DEFINED SHORTWAVE TROUGH PUSHING ACROSS N MEXICO INTO
SOUTHERN TEXAS...WHICH IS SERVING TO TRANSPORT  SUB-TROPICAL
MOISTURE FEED...AND PW VALUES AOA 1.75" NORTH ACROSS THE DEEP
SOUTH.

THE HRRR CONTINUES TO HANDLE THESE SHOWERS WELL...AND THE LATEST
TIME-LAGGED HRRR INDICATES A LIKELY AREA OF 1-2" RAINFALL AMOUNTS
WITHIN THE SAME AREA COINCIDENT WITH BEST SWATH OF LIFT/MOISTURE
SUPPORT...WITH SOME AREAS OF 2-3" RAINFALL OVER SE LA AND SOUTHERN
MS...WHICH IS CO-LOCATED WITH LOWEST FLASH FLOOD VALUES (MAINLY
ALONG AND NORTH OF I-12 AND SOUTH OF I-20). LOCALIZED HIGHER RAIN
RATES IN THESE AREAS COULD LEAD TO AREAS OF FLASH FLOODING WHICH
NUDGES TOTALS ABOVE THE 1-HR AND 3-HR FFG. THE ONLY REAL LIMITING
FACTOR IS A LACK OF LOW LEVEL FOCUS...AND THE PROGRESSIVE NATURE
OF THE CONVECTIVE LINE.

MONTEFUSCO

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

ATTN...WFO...JAN...LCH...LIX...MEG...

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

LAT...LON   33768908 33598837 33528841 32398889 32148903
            31548935 31048987 30379040 29749098 29469134
            29279189 29259195 29439200 29899201 31059155
            32039112 32579073 32809074 33009067 33269056
            33309051 33459015 33698951



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