MESOSCALE PRECIPITATION DISCUSSION 0243
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
351 AM EDT SAT MAY 20 2017

AREAS AFFECTED...AR

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

VALID 200750Z - 201230Z

SUMMARY...FLASH FLOOD THREAT SHIFTS EAST ACROSS CENTRAL AND
NORTHERN ARKANSAS INTO THE EARLY MORNING HOURS.

DISCUSSION...CONVECTIVE PROPAGATION OVER NORTHWEST AR HAS RESULTED
IN THE SHIELD OF CONVECTION TO TAKE ON MORE OF A WEST TO EAST
ORIENTATION. STRONG SOUTHERLY FLOW INTO THIS CONVECTIVE SWATH IS
ALLOWING FOR CONTINUED BACKBUILDING OF CONVECTION. OVER THE NEXT
SEVERAL HOURS THE COLD FRONT IS EXPECTED TO GET PUSHED A BIT
QUICKER OFF TO THE EAST OVER OK...WHICH SHOULD ALLOW FOR WINDS
AHEAD OF THE FRONT TO VEER MORE TO THE SOUTHWEST. THIS IS EXPECTED
TO DECREASE MOISTURE TRANSPORT INTO THE CONVECTIVE
ACTIVITY...RESULTING IN A GRADUAL WEAKENING TREND OF CONVECTIVE
INTENSITY OVER AR. SOME BROAD SCALE WARMING CLOUD TOPS ON RECENT
IR IMAGERY SUGGESTS THIS PROCESS MAY BE BEGINNING.

WITH THAT SAID...STILL SEEING WIDESPREAD BACKBUILDING
CONVECTION...WITH EMBEDDED HEAVIER RAINFALL CORES. ALSO ACTIVITY
CONTINUES TO FORM ACROSS SOUTHEAST OK IN AN AREA OF STRONG LOW
LEVEL CONVERGENCE ALONG THE COLD FRONT. THIS CONVECTION WILL
STREAM NORTHEASTWARD HELPING INCREASE THE TRAINING POTENTIAL. THUS
EVEN THOUGH CONVECTIVE INTENSITY MAY TEND TO BE ON A
DECREASE....THE COMBINATION OF BACKBUILDING AND ONLY SLOW EASTWARD
PROGRESSION OF THE CONVECTION...WILL CONTINUE TO RESULT IN
LOCALIZED ADDITIONAL RAINFALL AMOUNTS OF 2-5". THUS WHILE THE
MAGNITUDE OF THE FLASH FLOOD THREAT IS PROBABLY LOWER THAN IT WAS
EARLIER OVER EASTERN OK...SOME THREAT WILL REMAIN OVER THE NEXT
SEVERAL HOURS ACROSS THE MPD AREA FROM FAR SOUTHEAST OK INTO
CENTRAL AND NORTHERN AR.

CHENARD

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

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

LAT...LON   36499122 36479073 36409012 35749029 35219147
            35109166 34569255 33889370 33639443 33759515
            34209548 34719494 35029447 35189417 35809315
            36489191