MESOSCALE PRECIPITATION DISCUSSION 0587
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
543 PM EDT FRI JUL 28 2017

AREAS AFFECTED...EASTERN OK...WESTERN & CENTRAL AR

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

VALID 282145Z - 290145Z

SUMMARY...HIGHLY EFFICIENT RAIN PRODUCTION WITH POTENTIAL
BACKBUILDING AND SLIGHT TRAINING PROFILE POSE A LEAST A POSSIBLE
FF THREAT PARTICULARLY IN OUACHITA TERRAIN.

DISCUSSION...SOUTHWARD MOVING VERY SHARP LOW LEVEL TROF DEFINED BY
WESTERLY FLOW IN ADVANCE FOLLOWED BY NORTHERLY/NORTHEASTERLY FLOW
SUPPORTS STRONG MOISTURE CONVERGENCE WITHIN AN ENVIRONMENT OF
MODEST INSTABILITY OF 2000+ J/KG MLCAPES THAT IS MAINLY VERY
SKINNY AS IT IS COINCIDENT WITH VERY ANOMALOUS DEEP MOISTURE
SUPPORTING TPWS OF 2.4-2.5" THROUGH THE COLUMN.  AS SUCH
EXPERIMENTAL GOES-16 IMAGERY SHOWS A LINEAR MCS DEVELOPING RAPIDLY
WITH NUMEROUS COOLING/OVERSHOOTING TOPS PIPPING -80C. ALL
CONSIDERED THIS SUPPORTS RAIN RATES OF 2.5-3"/HR.

THESE CELLS ARE ALSO SLIDING INTO A HIGHLY DIFFLUENT ALOFT ON THE
EASTERN SIDE OF UL ANTICYCLONE OVER TX PANHANDLE/W OK.  THIS
ALLOWS FOR THE MCS TO MOVE WITHIN A HIGHLY DIFFLUENT 500-1000MB
THICKNESS DIVERGENT PATTERN WHICH WILL SUPPORT PROPAGATION VECTORS
TOWARD THE WEST-NORTHWEST HANGING UP A BIT...THOUGH MEAN CLOUD
BEARING LAYER WINDS SHOULD ALLOW FOR FORWARD (SOUTHWARD) MOTIONS
TO LIMIT SIGNIFICANT HANG UPS OR REPEAT TRACKS.   A WEAK SHORTWAVE
ANALYZED NEAR THE EASTERN PORTION OF THE WAVE IS EXPECTED TO
CONTINUE TO SLIDE SEWARD AND WITH IT POTENTIALLY SUPPORT SLACKENED
MID-LEVEL FLOW/CLOUD BEARING WINDS WHILE ALSO BACKING THEM FROM
NORTHERLY TO NORTHWESTERLY WITH TIME ALLOWING FOR SOME POTENTIAL
TRAINING AS WELL.   THIS MAY SUPPORT TOTAL OF 3-4" THROUGH THIS
EVENING ACROSS WESTERN AND CENTRAL AR POTENTIALLY IN THE OUACHITA
MOUNTAINS WHERE THIS STYLE OF QUICK BURST/HIGH RAIN RATES CAN POSE
FLASH FLOODING CONCERNS. 

HOWEVER...GREATEST LIMITING FACTOR IS THE REGION HAS BEEN RECENTLY
DRY AND FFG VALUES
ARE QUITE HIGH.  THAT STATED THE FF CONCERN IS CONSIDERED POSSIBLE
AND LIKELY TO BE LIMITED SPATIALLY.

GALLINA

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

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

LAT...LON   35679499 35439375 34709156 33739171 33829328
            34359447 34699483 35439512