MESOSCALE PRECIPITATION DISCUSSION 0153
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1217 AM EDT SAT APR 29 2017

AREAS AFFECTED...CENTRAL/ EASTERN OK...NORTHWEST AR...FAR
SOUTHWEST MO

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 290405Z - 291005Z

SUMMARY...THUNDERSTORMS WILL CONTINUE TO EXPAND IN COVERAGE OVER
THE NEXT FEW HOURS...WITH SOME CELL-TRAINING AND BACKBUILDING OF
CELLS POSSIBLE. FLASH FLOODING IS LIKELY.

DISCUSSION...EXPERIMENTAL GOES-16 IR SATELLITE IMAGERY IS SHOWING
RAPID CONVECTIVE EXPANSION/ORGANIZATION OCCURRING OVER PARTS OF
WESTERN AR AND INTRO EASTERN OK AS THE NOSE OF A STRONG LOW LEVEL
JET OVERRUNS A STATIONARY FRONT...AND TRANSPORTS A HIGHLY
FAVORABLE THERMODYNAMIC ENVIRONMENT WITH DEEPENING MOISTURE AND
STRONG INSTABILITY NORTHWARD. MEANWHILE...STRENGTHENING UPPER
LEVEL JET DYNAMICS WITH ENHANCING RIGHT-ENTRANCE REGION UPPER JET
FORCING IS PROVIDING LARGER SCALE ASCENT FOR SUSTAINABLE
CONVECTIVE GROWTH.

EXPECT VERY HEAVY RAIN TO OCCUR OVER PARTS OF CENTRAL/EASTERN OK
AND WESTERN AR AS CONVECTION CONTINUES TO ORGANIZE...EXPAND IN
COVERAGE AND LOCALLY BACKBUILD ACROSS THE REGION NORTH OF THE
AFOREMENTIONED FRONT. THE ENVIRONMENT IS CONDUCIVE FOR CELL
TRAINING AND THIS WILL WILL ENHANCE RAINFALL AMOUNTS.

RAINFALL RATES OF 2 TO 3 INCHES/HR WILL BE POSSIBLE GIVEN THE NOSE
OF 1.5 INCH+ PWATS INTO THE REGION AND FOCUSED ASCENT. SOME
OVERSHOOTING TOPS HAVE ALREADY BEEN NOTED OVER ESPECIALLY WESTERN
AR NEAR THE FORT SMITH AR AREA. HRRR GUIDANCE SUGGESTS AS MUCH AS
2 TO 4 INCHES...BUT THE CELL-TRAINING AND OVERSHOOTING TOP
ACTIVITY WILL FOSTER AS MUCH AS 5 INCHES LOCALLY. FLASH FLOODING
IS LIKELY AS A RESULT.

ORRISON

ATTN...WFO...OUN...SGF...TSA...

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

LAT...LON   36909468 36479381 35309393 34839539 34699686
            35039793 35609816 36069799 36489748 36809628