Graphic for MPD #0001
 
MESOSCALE PRECIPITATION DISCUSSION 0001
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
157 PM EST MON JAN 02 2017
 
AREAS AFFECTED...CNTRL GULF COAST INTO SERN AL/WRN GA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 021856Z - 030056Z
 
SUMMARY...AN INCREASE IN SW TO NE TRAINING CONVECTION IS EXPECTED
TO CAUSE FLASH FLOODING FROM THE CNTRL GULF COAST INTO PORTIONS OF
SRN MS/AL THROUGH 21Z AND BEYOND. 

DISCUSSION...1830Z REGIONAL RADAR IMAGERY SHOWED AN APPROACHING
SQUALL LINE IN CNTRL TO ERN LA RACING EAST WITH ADDITIONAL
THUNDERSTORMS ACROSS PORTIONS OF SRN MS AND CNTRL AL OUT AHEAD.
THE SQUALL LINE WAS OCCURRING AHEAD OF A COLD FRONT...TIED TO
ASCENT AHEAD OF A POTENT SHORTWAVE NOTED OVER THE ARKLATEX...WHICH
WAS ACQUIRING A NEGATIVE TILT. THE KLCH VAD WIND PLOT AT 850 MB
INDICATED A 5-10 KT SURGE IN MAGNITUDE JUST AHEAD OF THE SQUALL
LINE. FLOW IS UNIDIRECTIONAL IN THE CLOUD BEARING LAYER AND THERE
HAS ALREADY BEEN OBSERVED TRAINING AHEAD OF THE SQUALL LINE NEAR
THE LEADING EDGE OF DEEPER MOISTURE WITH DUAL POL ESTIMATED
RAINFALL RATES OF 1-2+ IN/HR. 18Z SURFACE OBSERVATIONS PLACED THE
LEADING EDGE OF DEEPER SURFACE MOISTURE EXTENDED WWD THROUGH SRN
AL INTO SRN MS AND CNTRL LA...WHICH IS SERVING AS A WARM FRONTAL
BOUNDARY. 

AS THE SHORTWAVE CONTINUES TO ADVANCE EWD OVER THE NEXT 3-6
HOURS...RAP FORECASTS SHOW INCREASING 850 MB WIND SPEEDS WILL
CONTINUE TO OVERSPREAD PORTIONS OF THE CNTRL GULF COAST INTO AL
AND EVENTUALLY FAR WRN GA BY 00Z. THE INCREASED ISENTROPIC
ASCENT...SUFFICIENT INSTABILITY AND A MARKED INCREASE IN UPPER
LEVEL DIFFLUENCE OUT AHEAD OF THE APPROACHING SHORTWAVE SHOULD
HELP TO INCREASE RAINFALL COVERAGE WITH TRAINING LIKELY FROM SW TO
NE. THE FLASH FLOOD CONCERN IS EXACERBATED DUE TO WIDESPREAD HEAVY
RAIN...AS HIGH AS 5-8 INCHES IN A FEW LOCATIONS...WHICH FELL OVER
THE PAST 24 HOURS FROM SRN MS INTO SRN AL AND CNTRL GA. THE 12Z
HI-RES MODELS HAVE COME INTO BETTER AGREEMENT ON THE SCENARIO LED
BY RECENT CONSISTENT RUNS OF THE HRRR.
 
OTTO

ATTN...WFO...BMX...FFC...JAN...LIX...MOB...TAE...

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

LAT...LON   33278618 32958509 31008644 30128821 29838962 
            29979104 30599149 31139085 31468959 32098862 
            


Last Updated: 157 PM EST MON JAN 02 2017