MESOSCALE PRECIPITATION DISCUSSION 0454
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
543 AM EDT SAT JUL 08 2017

AREAS AFFECTED...ARKANSAS

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 080940Z - 081400Z

SUMMARY...A CLUSTER OF STRONG THUNDERSTORMS WITH INTENSE RAINFALL
RATES TO OVER 2 INCHES/HR MAY RESULT IN SOME FLASH FLOODING
CONCERNS OVER THE NEXT FEW HOURS..AND ESPECIALLY NEAR ANY
URBANIZED AREAS.

DISCUSSION...THE LATEST EXPERIMENTAL GOES-16 10.3 MICRON/IR
SATELLITE IMAGERY SHOWS A FAIRLY LARGE CLUSTER OF HEAVY SHOWERS
AND THUNDERSTORMS DROPPING SOUTH THROUGH WESTERN AND NORTH-CENTRAL
AR. THERE HAS BEEN SOME COOLING OF THE CONVECTIVE TOPS OVER THE
LAST HOUR...AND THE AREA DUAL-POL RADAR DATA IS INDICATING
RAINFALL RATES EXCEEDING 2.5 INCHES/HR.

THE CONVECTION IS FORMING IN AN AREA WHERE THERE IS A SPLIT IN THE
UPPER JET AND WITH A RATHER DIFFLUENT SIGNATURE ALOFT. ALSO THERE
IS AN AXIS OF RELATIVELY FOCUSED SURFACE MOISTURE FLUX CONVERGENCE
OVER THE REGION WHICH COUPLED WITH ABOUT 1500 TO 2000 J/KG OF
MUCAPE APPEARS TO BE SUSTAINING AND EVEN ENHANCING FURTHER THE
CONVECTION.

GIVEN THE HEAVY RAINFALL RATES AND RELATIVELY MOIST SOIL
CONDITIONS...THERE WILL BE SOME SHORT-TERM CONCERNS FOR ENHANCED
RUNOFF AND SOME FLASH FLOODING. THE PRIMARY THREAT THOUGH WILL BE
TO ANY URBANIZED ENVIRONMENT...INCLUDING THE LITTLE ROCK
METROPOLITAN AREA AND ADJACENT SUBURBS OVER THE NEXT COUPLE OF
HOURS. AREAS AROND FORT SMITH ARE ALREADY BEING IMPACTED AND THE
HOT SPRINGS AREA TO THE SOUTH SHOULD ALSO MONITOR THIS CONVECTION.

EXPECT AS MUCH AS 3 TO 4 INCHES OF RAIN WITH ISOLATED HEAVIER
TOTALS TO BE POSSIBLE UNTIL THIS CONVECTIVE COMPLEX MOVES FARTHER
SOUTH AND WEAKENS TOWARD LATE MORNING.

ORRISON

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

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

LAT...LON   36029409 35749294 35769201 35479098 34919045
            34519068 34169120 34009175 34039252 34409375
            35089453 35719462