MESOSCALE PRECIPITATION DISCUSSION 0122
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1007 AM EDT THU MAY 03 2018

AREAS AFFECTED...EAST-CENTRAL OK...NORTHWEST AR...SOUTH-CENTRAL TO
SOUTHEAST MO...FAR SOUTHERN IL...FAR WESTERN KY

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

VALID 031405Z - 031905Z

SUMMARY...MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS OVER THE
NEXT SEVERAL HOURS WILL TEND TO ELEVATE THE THREAT OF SOME FLASH
FLOODING GIVEN INCREASINGLY SATURATED SOIL CONDITIONS.

DISCUSSION...AN UPPER TROUGH CONTINUES TO EJECT GRADUALLY EAST OUT
ACROSS THE CENTRAL/SOUTHERN PLAINS WHICH IS FOSTERING A HIGHLY
DIFFLUENT FLOW REGIME ALOFT ACROSS AREAS FROM THE RED RIVER VALLEY
EAST ACROSS ADJACENT AREAS OF THE LOWER AND MID MS VALLEY. SOME
VORT ENERGY ROUNDING THE BASE OF THE TROUGH IS PROVIDING A BIT
STRONGER FORCING ACROSS AREAS OF THE RED RIVER VALLEY AND THE
LATEST RADAR IMAGERY SHOWS A WELL-DEFINED QLCS IS MOVING EAST
ACROSS CENTRAL OK AND EXTENDING SOUTH DOWN ACROSS NORTH TX.

THE CONVECTION IS BEING SUSTAINED BY A MODERATELY UNSTABLE AIRMASS
CHARACTERIZED BY A NOSE OF 2000 TO 3000 J/KG OF MUCAPE.
MEANWHILE...THE COLUMN IS QUITE MOIST WITH PWATS OF 1.6 TO 1.8
INCHES AS PER GPS-DERIVED DATA WHICH IS FAVORING ENHANCED RAINFALL
RATES OF AS MUCH AS 1.5 INCHES/HR.

ELSEWHERE...CONVECTION IN A BROKEN FASHION CONTINUES TO DEVELOP
AND OCCASIONALLY REPEAT OVER THE SAME AREA ACROSS NORTHWEST
AR...SOUTHERN MO AND APPROACHING AREAS OF FAR SOUTHERN IL AND FAR
WESTERN KY. THIS ACTIVITY HAS BEEN FOCUSING NORTH OF A
CONVECTIVELY REINFORCED OUTFLOW BOUNDARY.

THE LATEST HRRR/HRRR-EXP GUIDANCE HAS THE BEST OVERALL HANDLE ON
THE CURRENT ACTIVITY...AND THESE MODELS SUPPORT LOCALLY AS MUCH AS
AN ADDITIONAL 2 TO 4 INCHES OF RAIN THROUGH MID-AFTERNOON. GIVEN
THE INCREASINGLY WET ANTECEDENT CONDITIONS AND REPEATING NATURE OF
THE CONVECTION...SOME RUNOFF AND/OR FLASH FLOODING CONCERNS MAY
RESULT.

ORRISON

ATTN...WFO...LSX...LZK...MEG...OUN...PAH...SGF...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...OHRFC...

LAT...LON   38208943 38208860 37868796 37068831 36468919
            36069030 35489220 34939427 34709557 34719614
            34939640 35359660 35989631 36739441 37119334
            37669175 38029044