MESOSCALE PRECIPITATION DISCUSSION 0129
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
622 PM EDT FRI APR 21 2017

AREAS AFFECTED...NE OK...NW AR...EXTREME SW MO

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

VALID 212219Z - 220215Z

SUMMARY...THUNDERSTORMS WITH LOCALLY HEAVY RAIN WILL FALL ON
SATURATED GROUND ACROSS NE OK...NW AR...AND EXTREME SW MO DURING
THE NEXT FEW HOURS WHICH COULD PRODUCE ADDITIONAL FLASH FLOODING.

DISCUSSION...2 TO 4 INCHES OF RAIN HAS FALLEN ACROSS PARTS OF NE
OK...NW AR...AND EXTREME SW MO DURING THE PAST 24 HOURS...AND 3 HR
FFG VALUES ARE LOCALLY AS LOW AS 0.25 TO 1 INCH.

THUNDERSTORMS OVER CENTRAL AND NE OK ARE LIKELY TO PRODUCE LOCAL
RAINFALL OF 1 TO 2 INCHES THROUGH 9 PM CDT...WHICH WOULD EXCEED
THE FFG THRESHOLDS.

THE THUNDERSTORMS ARE DEVELOPING IN A REGION OF FAIRLY
UNIDIRECTIONAL SOUTHWEST WINDS ALONG WITH 25 TO 35 KT IN THE
850-700 MB LAYER. THE ENVIRONMENT IS CHARACTERIZED BY WEAK
MID-LAYER INSTABILITY WITH ESTIMATED CAPE AROUND 500-1000 J/KG AND
PRECIPITABLE WATER OF 1.2 TO 1.4 INCHES. DESPITE RELATIVELY WEAK
INSTABILITY...STRONGLY DIFFLUENT UPPER LEVEL FLOW SHOULD HELP TO
ENHANCE UPDRAFT STRENGTH IN ADVANCE OF AN APPROACHING 700-500 MB
SHORTWAVE TROUGH. THESE STORMS SHOULD PROGRESS EASTWARD DURING THE
NEXT FEW HOURS...MOVING ACROSS THE REGION OF SATURATED SOILS AND
LOW FFG THRESHOLDS.

THERE HAVE ALREADY BEEN SOME REPORTS OF FLASH FLOODING TODAY...AND
ADDITIONAL FLASH FLOODING IS POSSIBLE.

MCDONNAL/OTTO 

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

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

LAT...LON   36969344 36939281 36459217 35859252 35529332
            35399378 35299468 35269548 35429629 35619647
            35819648 36099592 36749486 36939437