MESOSCALE PRECIPITATION DISCUSSION 0074
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
543 AM EDT TUE MAR 27 2018

AREAS AFFECTED...ERN OK INTO NRN AR/SRN MO

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

VALID 270941Z - 271540Z

SUMMARY...A RENEWED AXIS OF TRAINING HEAVY RAIN IS EXPECTED TO SET
UP OVER EASTERN OKLAHOMA INTO NORTHERN ARKANSAS AND PERHAPS
SOUTHERN MISSOURI BEYOND 12Z. RAINFALL RATES OF 1-2 IN/HR WITH 6
HOUR TOTALS OF 2-4 INCHES WILL BE POSSIBLE.

DISCUSSION...RADAR IMAGERY FROM 09Z SHOWED A SOUTHWEST TO
NORTHEAST ORIENTED AXIS OF RAINFALL...0.5-1.5 IN/HR PER KINX RADAR
ALONG I-40 IN NORTHEASTERN OKLAHOMA...CO-LOCATED WITH STRONG 850
MB CONVERGENCE. FARTHER SOUTHWEST...TWO INFERRED WEAK LOW LEVEL
CIRCULATIONS WERE EVIDENT IN REGIONAL RADAR IMAGERY OVER
SOUTH-CENTRAL OKLAHOMA AND WEST-CENTRAL TEXAS...EACH CONNECTED
WITH ARCING OUTFLOW BOUNDARIES.  THE TWO MESO-LOWS WERE MOVING
TOWARD THE NORTHEAST AT 40-50 KT...AND WERE LOCATED NEAR AN 850 MB
FRONTAL BOUNDARY WHICH STRETCHED FROM NEAR THE SOUTHERN EXTENT OF
I-44 ALONG THE OKLAHOMA/TEXAS BORDER TO THE BIG BEND REGION OF
TEXAS.

AS THE 850 MB FRONTAL BOUNDARY SLOWLY EDGES EAST OVER THE NEXT FEW
HOURS...LOW LEVEL CONVERGENCE IS EXPECTED TO INCREASE ALONG THE
EASTERN TEXAS/OKLAHOMA BORDER WITH 40-50 KT OF 850 MB FLOW
FOCUSING JUST AHEAD OF THE 850 MB FRONT FROM NORTHEASTERN TEXAS
INTO EASTERN OKLAHOMA AND WESTERN ARKANSAS. THE RAP/HRRR INDICATED
A POOL OF 500 J/KG MUCAPE WAS IN PLACE OVER MUCH OF EASTERN TEXAS
INTO SOUTHEASTERN OKLAHOMA...WHICH IS EXPECTED TO ADVECT
NORTHEASTWARD OVER THE NEXT FEW HOURS. AS THE ENTIRE MESOSCALE
SYSTEM OF CIRCULATIONS AND BOUNDARIES SHIFTS TOWARD THE
NORTHEAST...A RENEWED AXIS OF LOW LEVEL CONVERGENCE IS EXPECTED TO
FOCUS RAINFALL RATES OF 1-2 IN/HR WITH 6 HOUR RAINFALL OF 2-4
INCHES FROM EASTERN OKLAHOMA INTO NORTHWESTERN ARKANSAS AND
PERHAPS SOUTHERN MISSOURI. HEAVIER RAINFALL INTENSITY FOR
LOCATIONS FARTHER NORTH SHOULD BE LIMITED BY REDUCED INSTABILITY.
FLASH FLOODING WILL BE POSSIBLE WHERE TRAINING SETS UP.

OTTO

ATTN...WFO...FWD...LZK...OUN...SGF...SHV...TSA...

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

LAT...LON   36859242 36849199 36759168 36589152 36249157
            35859195 35259295 34519444 34049558 33829657
            34069684 34159685 34699678 35619630 36179577
            36529502 36789404 36779350 36819291