MESOSCALE PRECIPITATION DISCUSSION 0043
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
156 AM EST TUE FEB 07 2017
 
AREAS AFFECTED...NORTHERN AND CENTRAL ARKANSAS...EXTREME SOUTH
CENTRAL MISSOURI... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 070655Z - 071100Z
 
SUMMARY...AN ENVIRONMENT SUPPORTIVE OF TRAINING CONVECTIVE CELLS
WITH 1-2 IN/HR RAINFALL RATES COULD LEAD TO FLASH FLOODING FOR
SOME LOCATIONS. 

DISCUSSION...TWO BANDS OF CONVECTION HAVE DEVELOPED EARLY THIS
MORNING OVER CENTRAL/NORTHERN ARKANSAS IN AN INCREASINGLY
SUPPORTIVE SYNOPTIC ENVIRONMENT AHEAD OF AN APPROACHING
MID/UPPER-LVL SHORTWAVE. THE LOW/MID-LEVEL ENVIRONMENT APPEARS
SUPPORTIVE OF BACKWARD PROPAGATION AS EVIDENCED BY RAP CORFIDI
VECTORS. THIS HAS BEEN OBSERVED, WITH TRAINING OF CONVECTION
EVIDENT ON RADAR IN A COUPLE LOCATIONS. THE CONVECTION IS BEING
FUELED BY A VIGOROUS 50KT LOW-LEVEL JET WHICH IS TRANSPORTING VERY
MOIST (850 HPA DEWPOINTS NEAR 12 DEG C) AND AND UNSTABLE (MLCAPES
OF 1000-2000 J/KG) NORTHWARD INTO THE OUTLINED AREA. AT THE MID
AND UPPER-LEVELS, SYNOPTIC SCALE DIFFLUENCE IS INCREASING ACROSS
THE AREA AS A RATHER VIGOROUS SHORTWAVE APPROAHCES. CURRENT RADAR
ESTIMATED RAINFALL RATES ARE OVER 2 IN/HR AT A FEW LOCATIONS,
ALTHOUGH THESE ARE LIKELY OVERDONE DUE TO HAIL CONTAMINATION, AND
ARE MORE LIKELY IN THE 1-2 IN/HR RANGE.

HI-RES CAMS DO NOT HAVE A GOOD HANDLE ON THE ONGOING CONVECTION,
AND APPEAR TO BE OF LIMITED VALUE FOR THE NEXT SEVERAL HOURS. THE
LATEST RAP RUN SHOWS THE ENVIRONMENT REMAINING CONDUCIVE TO
TRAINING/BACKBUILDING FOR A FEW MORE HOURS BEFORE THE BEST
LOW-LEVEL MOIST INFLOW BEGINS TO GRADUALLY SHIFT EASTWARD. FLASH
FLOOD GUIDANCE IS RELATIVELY HIGH ACROSS THESE AREAS, HOWEVER
GIVEN THE CURRENT RAINFALL RATES AND THE PROSPECT OF CONTINUED
CELL TRAINING FOR A FEW MORE HOURS, THE POTENTIAL IS THERE FOR
EXCEEDING FFG IN SOME AREAS, WITH TOTAL RAINFALL AMOUNTS OF 2-4
INCHES POSSIBLE.


RYAN

ATTN...WFO...LZK...MEG...SGF...TSA...

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

LAT...LON   36869159 36519120 35679102 34729125 34039197 
            33989251 34089353 34529415 35079434 35769394 
            36219320 36719238