MESOSCALE PRECIPITATION DISCUSSION 0364
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
221 AM EDT THU SEP 11 2014
 
AREAS AFFECTED...NORTHEASTERN AR/SOUTHEASTERN MO/WESTERN
TN/WESTERN KY/SOUTHERN IL... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 110621Z - 110936Z
 
SUMMARY...HEAVY RAINFALL CONTINUES TO FALL ACROSS SECTIONS OF
SOUTHEASTERN MO/NORTHEASTERN AR EARLY THIS MORNING. WHILE FFG
VALUES ARE RELATIVELY HIGH...LOCALLY HEAVY DOWNPOURS MAY PRODUCE
FLASH FLOOD CONDITIONS. EXPECT THE THREAT TO CONTINUE THE NEXT FEW
HOURS AS THE FRONTAL ZONE BRIEFLY STALLS ALONG THE MO/AR BORDER.

DISCUSSION...WHILE A MAJORITY OF THE BAROCLINIC ZONE HAS BEEN MORE
PROGRESSIVE IN NATURE...THE SOUTHERN EXTENT HAS BEGUN TO STALL
ACROSS NORTHERN AR/SOUTHERN MO. THE CURRENT DOPPLER RADAR IMAGERY
SHOWED A BROAD AREA OF TRAINING CONVECTION WITH LOCALIZED HOURLY
RAINFALL RATES IN THE 1 TO 2 INCH RANGE. THE PRIMARY CONCERN IS
THE BACKBUILDING NATURE OF THE CONVECTION MAY PERSIST THROUGH AT
LEAST 09Z BASED ON THE LATEST RAP FORECAST STORM MOTION VECTORS.
AMPLE MOISTURE IS BEING ADVECTED INTO THE REGION WITH PWATS IN
EXCESS OF 2.25 INCHES NOTED ON THE SPC MESOANALYSIS PAGE. VAD WIND
PROFILERS ACROSS AR SHOWED A MODEST LLJ IN EXCESS OF 30 KNOTS
PROVIDING STEADY INFLOW INTO THE STORM ENVIRONMENT.
ADDITIONALLY...THE ATMOSPHERE REMAINS QUITE UNSTABLE ALONG THE
BAROCLINIC ZONE WITH MUCAPE VALUES RANGING FROM 1000 TO 2000 J/KG.

THERE IS A STRONG SIGNAL IN THE HIGH-RESOLUTION GUIDANCE OF HEAVY
RAINFALL PERSISTING THROUGH 12Z ACROSS NORTHERN AR
EAST-NORTHEASTWARD INTO WESTERN KY/TN. IN SPITE OF THE HIGH FFG
VALUES...EXPECT HEFTY RAINFALL RATES TO CONTINUE THE THREAT FOR
FLASH FLOODING. THIS IS PARTICULARLY THE CASE WHERE PRECIPITATION
HAS BEEN ONGOING AND THE SOILS ARE BECOMING SLOWLY MORE SATURATED.
WILL RE-ASSESS THE SITUATION AROUND 0930Z.


RUBIN-OSTER

ATTN...WFO...LMK...LZK...MEG...OHX...PAH...SGF...

ATTN...RFC...LMRFC...OHRFC...

LAT...LON   37828647 37358604 36828701 35718874 35358993 
            35289108 35599188 36339178 36889030 37378905 
            37778751