MESOSCALE PRECIPITATION DISCUSSION 0131
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1159 PM EDT FRI APR 21 2017

AREAS AFFECTED...NORTHERN AR

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

VALID 220358Z - 220658Z

SUMMARY...SHOWERS AND THUNDERSTORMS ARE BEGINNING TO ALIGN ACROSS
NORTHERN AR.  HOURLY RAIN RATES UP TO 1.5", WITH LOCAL AMOUNTS OF
UP TO 3", COULD LEAD TO FLASH FLOODING OVER SATURATING SOILS.

DISCUSSION...THUNDERSTORMS APPEAR TO BE SHOWING SOME INCREASE IN
INTENSITY WITH COOLING CLOUD TOPS AND SOME INCREASE IN HOURLY RAIN
RATES AHEAD OF A WEAK FRONTAL WAVE NEAR FORT SMITH.  PRECIPITABLE
WATER VALUES OF 1.3-1.4" EXIST HERE.  INFLOW AT 850 HPA IS 20-40
KTS PER VAD WIND PROFILES (CLOSE TO THE MAGNITUDE OF THE MEAN
850-400 HPA WIND) AND SHOWS SOME CONVERGENCE TOWARDS THE AREA. 
MUCAPES ARE IN THE 500-1000 J/KG AREA.

MOST OF THE MESOSCALE APPEARS TOO FAR NORTH WITH ITS HEAVY RAIN
SIGNAL FOR THIS REGION, DISPLACED UP INTO SOUTHERN MO.  SOILS
SHOULD BE SATURATING ACROSS THE AREA AS RADAR ESTIMATES SHOW 1-3"
TOTALS THUS FAR.  WITH SOME TRAINING EXPECTED, HOURLY RAIN RATES
UP TO 1.5" WITH ADDITIONAL LOCAL AMOUNTS OF 3" COULD LEAD TO FLASH
FLOODING.

ROTH

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

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

LAT...LON   36329155 36289081 35799066 35349104 35309264
            35419386 36279336