MESOSCALE PRECIPITATION DISCUSSION 0130
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
934 PM EDT FRI APR 21 2017

AREAS AFFECTED...EAST CENTRAL AND NORTHEAST AR...EXTREME SE
MO...NORTHERN MS...WESTERN TN

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

VALID 220130Z - 220730Z

SUMMARY...THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS EAST
CENTRAL AND NORTHEAST AR DURING THE NEXT COUPLE HOURS AND MOVE
EAST-NORTHEAST INTO EXTREME SE MO AND NORTHERN MS AND WESTERN TN
THROUGH THIS EVENING AND EARLY SAT MORNING. THESE STORMS WILL
LIKELY PRODUCE LOCAL RAINFALL OF 1.5 TO 3 INCHES WITH FLASH
FLOODING POSSIBLE.

DISCUSSION...THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE
EASTERN PORTION OF AR DURING THE NEXT SEVERAL HOURS...AS LOW LEVEL
SOUTHERLY WINDS OF 25 KTS ADVECT VERY MOIST AIR NORTHWARD ACROSS A
STATIONARY FRONTAL BOUNDARY. PRECIPITABLE WATER SHOULD INCREASE TO
1.50-1.75 INCHES AS A RESULT. THE ENVIRONMENT IS ONLY MODESTLY
UNSTABLE WITH MUCAPE 500 TO 1000 J/KG WITH HIGHER CAPE TO THE
SOUTHWEST. HOWEVER THE APPROACHING UPPER TROUGH AND 110 KT JET
STREAK WILL HELP PROMOTE UPPER LEVEL DIFFLUENCE AND INCREASE
RAINFALL EFFICIENCY.

HOURLY RAIN RATES OF 1.0 TO 1.5 INCHES LOOK LIKELY AS THE
THUNDERSTORMS DEVELOP...WITH LOCAL RAINFALL ACCUMULATIONS OF 1.5
TO 3 INCHES POSSIBLE TOWARD 08-09Z. WITH 3 HOUR FLASH FLOOD
GUIDANCE GENERALLY 2 TO 3 INCHES IN THE AREA...LOCAL FLASH
FLOODING IS POSSIBLE.

MCDONNAL/OTTO 

ATTN...WFO...LZK...MEG...OHX...

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

LAT...LON   36368920 36108787 35148797 34658949 34169102
            34309229 35269202 35719155 36109082