MESOSCALE PRECIPITATION DISCUSSION 0053
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
431 PM EST TUE MAR 08 2016
 
AREAS AFFECTED...FAR EASTERN TX...NORTHWEST LA...SOUTHERN AR 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 082131Z - 090131Z
 
SUMMARY...CONVECTION CONTINUES TO MOVE EAST NORTHEAST WITH
ISOLATED FLOOD THREAT.

DISCUSSION...CONVECTION CONTINUES TO MOVE EAST NORTHEAST ACROSS
PORTIONS OF OKLAHOMA AND TEXAS THIS AFTERNOON AHEAD OF A SUBTLE
SHORTWAVE AND IN THE RIGHT ENTRANCE REGION OF A STRONG UPPER JET
ACROSS THE CENTRAL PLAINS. 

MOISTURE CONTINUES TO INCREASE IN AND JUST AHEAD OF THE CONVECTIVE
AREA. BEGINNING TO SEE A BIT MORE OF A PACIFIC CONNECTION TO THE
MOISTURE STEAM NOW PER LAYER TPW PRODUCTS. PRECIPITABLE WATER
VALUES ARE NOW AT THE 1.5" OR GREATER LEVEL FROM SOUTEHRN AR SOUTH
INTO EASTERN TX AND WESTERN LA...WITH WET BULB ZERO HEIGHTS ARE
ALSO NEAR CLIMATOLOGICAL MAX VALUES PER THE 18Z SHREVEPORT
SOUNDING. THUS IT CONTINUES TO BE AN EFFICIENT ENVIRONMENT FOR
HEAVY RAINFALL...DESPITE THE LIMITED INSTABILITY.

THE MAIN AREA OF FOCUS FOR POTENTIAL FLASH FLOODING NOW APPEARS TO
BE ACROSS NORTHEAST TX INTO NORTHWEST LA AND SOUTHWEST AR. IT IS
HERE WHERE THE EASTWARD MOVING CONVECTIVE LINE IS MERGING WITH
CONVECTION STREAMING NORTH IN THE STRONG DEEP SOUTHETLY FLOW
ALLOWING FOR SOME TRAINING AND THUS AN INCREASED DURATION OF
MODERATE TO AT TIMES HEAVY RAINFALL. 

HIGH RESOLUTION GUIDANCE APPEARS TO BE HANDLING THE SITUATION
BETTER THAN THIS MORNING. WHILE NOT PERFECT THE PAST SEVERAL RUNS
OF THE HRRR AND EXPERIMENTAL HRRR SEEM TO BE HANDLING THE OVERALL
EVOLUTION OKAY...WITH THE 12Z ARW ALSO SEEMING REASONABLE. THREE
HOUR FLASH FLOOD GUIDANCE IS AT LEAST 2.5" IN 3 HOURS ACROSS THE
OUTLOOKED AREA. HAVE SEEN REPORTS AND QPE ESTIMATES AS HIGH AS
1.5-2" OF RAIN IN THREE HOURS SO FAR. SEEING ENOUGH CONSOLIDATION
AND MERGING CELLS IN THE OUTLOOKED AREA TO SUGGEST ISOLATED
AMOUNTS POTENTIALLY AS HIGH AS 2-4"...WHICH IS SUPPORTED BY OUR
PREFERRED HIGH RES GUIDANCE MENTIONED ABOVE. STILL GENERALLY
THINKING FLASH FLOODING WILL STAY ISOLATED OVER THE NEXT SEVERAL
HOURS. THE BETTER THREAT STILL APPEARS TO COME FROM THE SECOND
ROUND OF CONVECTION TONIGHT INTO TOMORROW.


CHENARD

ATTN...WFO...JAN...LCH...LZK...SHV...

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

LAT...LON   34629228 34169175 33769160 33159160 32869158 
            32179179 31409210 30679270 30309296 29939314 
            29769339 29779373 30079393 30649406 31069412 
            31429418 31839437 32219440 32579454 32639462 
            32859464 33119457 33399440 34229364 34619307