MESOSCALE PRECIPITATION DISCUSSION 0365
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
556 AM EDT THU SEP 11 2014
 
AREAS AFFECTED...WESTERN TO CENTRAL AR/SOUTHEASTERN OK/NORTHERN
MS/WESTERN TN... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 110956Z - 111326Z
 
SUMMARY...A LOOSELY ORGANIZED AXIS OF CONVECTION CONTINUES TO
AFFECT THE NORTHERN HALF OF AR AND  WESTERN TN. HOURLY RAINFALL
RATES HAVE ALREADY APPROACHED 2 INCHES WITH AT LEAST ONE FLASH
FLOOD REPORT IN WESTERN TN. UPSTREAM DEVELOPMENT ACROSS FAR
EASTERN OK/WESTERN AR SHOULD EVENTUALLY CROSS REGIONS WHICH HAVE
ALREADY SEEN ABUNDANT RAINFALL OVERNIGHT. FLASH FLOODING IS
POSSIBLE THROUGH AT LEAST 1330Z.

DISCUSSION...A FRONTAL BOUNDARY HAS REMAINED IN A STATIONARY
POSITION ACROSS AR EASTWARD INTO WESTERN TN. AN INCREDIBLE AMOUNT
OF MOISTURE HAS ANCHORED ITSELF ALONG THIS BAROCLINIC ZONE WITH
THE 08Z RAP SUGGESTING PWATS RANGING FROM 2.25 TO 2.50 INCHES. THE
MODELS INDICATE THE HIGH END MOISTURE CONTENT SHOULD REMAIN OVER
THE REGION THE NEXT SEVERAL HOURS. THE ONGOING HEAVY RAINFALL HAS
ORIENTED ITSELF IN A WEST TO EAST FASHION WITH ADDITIONAL
DEVELOPMENT OCCURRING UPSTREAM. WATER VAPOR IMAGERY DEPICTED
SEVERAL WEAK SHORTWAVES MIGRATING EASTWARD ACROSS OK WHICH HAS
HELPED FOCUS THE UPSTREAM ACTIVITY. EXPECT THIS CONVECTION TO
DRIFT TOWARD THE EAST SPREADING HEAVY RAINFALL TO REGIONS WHICH
HAVE ALREADY SEEN 2 TO 3 INCHES OVERNIGHT. FFG VALUES STILL REMAIN
RATHER HIGH EXCEPT FOR A FEW LOCATIONS ALONG THE AR/MO BORDER.
HOWEVER...HOURLY RAINFALL RATES HAVE PROVEN TO BE HIGH ENOUGH TO
WARRANT A THREAT FOR FLASH FLOODING THROUGH THE OVERNIGHT HOURS.

WHILE SOMEWHAT VARIABLE IN PLACEMENT...A VAST MAJORITY OF THE
CONVECTION ALLOWING MODELS SUPPORT A HEAVY AXIS OF CONVECTION FROM
CENTRAL TO NORTHERN AR EASTWARD INTO WESTERN TN THROUGH 15Z. THE
LACK OF INSTABILITY AND STRONG MID-LEVEL FORCING ARE PROBABLY THE
MOST DETRIMENTAL TO ALLOWING THE ACTIVITY TO SURVIVE BEYOND THE
EARLY/MID MORNING. WILL ALLOW DAY SHIFT TO REEVALUATE THE
SITUATION. 


RUBIN-OSTER

ATTN...WFO...LZK...MEG...OHX...PAH...SHV...TSA...

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

LAT...LON   36528991 36258811 35208777 34798913 34669089 
            34479205 34269317 34159404 34229483 34639522 
            35179510 35489482 35939342 36219201 36369118 
            
A