MESOSCALE PRECIPITATION DISCUSSION 0679
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
405 AM EDT SUN AUG 13 2017

AREAS AFFECTED...EAST-CENTRAL/NORTHEAST
OK...WEST-CENTRAL/NORTHWEST AR

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

VALID 130800Z - 131300Z

SUMMARY...PERSISTENT SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE
EARLY MORNING HOURS WITH HEAVY RAINFALL MAY RESULT IN SOME FLASH
FLOODING CONCERNS...AND ESPECIALLY WITH RELATIVELY WET ANTECEDENT
CONDITIONS.

DISCUSSION...AN APPROACHING SHORTWAVE TROUGH NOW EJECTING OUT
ACROSS WEST-CENTRAL TX AND EXTENDING NORTHEAST INTO SOUTHWEST OK
IS FACILITATING A STRENGTHENING OF THE LOW TO MID LEVEL WARM
ADVECTION PATTERN ACROSS THE SOUTHERN PLAINS. WELL NORTH OF A
QUASI-STATIONARY FRONT OVER NORTHEAST TX IS PROXIMITY OF AN
INVERTED SURFACE TROUGH THAT CROSSES THE RED RIVER THROUGH
SOUTHEAST OK AND UP INTO NORTHWEST AR. THIS INVERTED TROUGH HAS
BECOME BETTER DEFINED OVER THE LAST COUPLE OF HOURS AND IS
REFLECTIVE OF A STRENGTHENING OF THE ISENTROPIC LIFT OVER THE
REGION.

THE LATEST RADAR TRENDS SHOW HIGHLY ELEVATED CONVECTION BECOMING
MORE FOCUSED/CONCENTRATED OVER AREAS OF EAST-CENTRAL OK AND TO
SOME EXTENT INTO PARTS OF NORTHWEST AR. THE LATEST HRRR GUIDANCE
SUGGESTS SOME EXPANSION OF THE CONVECTION OVER THESE AREAS OVER
THE NEXT FEW HOURS...WITH THE POTENTIAL FOR SOME HIGHLY
CONCENTRATED 3 TO 5 INCH RAINFALL TOTALS THROUGH THE EARLY MORNING
HOURS. GIVEN THE RELATIVELY WET ANTECEDENT CONDITIONS...THIS MAY
BE ENOUGH TO CAUSE SOME SHORT-TERM FLASH FLOOD CONCERNS. WILL
CONTINUE TO MONITOR.

ORRISON

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

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

LAT...LON   36449458 36339375 36019328 35679306 35129301
            34399330 33999344 34199383 34549462 34659542
            34539601 34369667 34209725 35239641 36209553