MESOSCALE PRECIPITATION DISCUSSION 0090
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EDT WED JUN 05 2013
 
AREAS AFFECTED...SOUTHEAST AR...NORTHERN AND CENTRAL MS...WESTERN
AL...NORTHEAST LA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 051800Z - 052200Z
 
SUMMARY...SLOW-MOVING CONVECTION FROM THE ARKANSAS/LOUISIANA
BORDER EASTWARD ACROSS NORTHERN MS INTO NORTHWEST ALABAMA COULD
LEAD TO FLASH FLOODING OVER THE NEXT SEVERAL HOURS.

DISCUSSION...AN OUTFLOW BOUNDARY COMBINED WITH A WEAK SURFACE
TROUGH ARE FOCUSING A BROAD BAND OF THUNDERSTORMS OVER NORTHERN
MS, WHICH ARE SLOWLY MOVING EASTWARD.  ANOTHER WEAK
TROUGH/POSSIBLE OUTFLOW BOUNDARY IS MOVING IN FROM SOUTHERN
ALABAMA, WHICH COULD ADD TO THE CONVERGENCE AND CONVECTIVE
COVERAGE ACROSS THE REGION LATER THIS AFTERNOON.  INSTABILITY
ACROSS THE REGION EXISTS DUE TO DAYTIME HEATING, AND THE REGION IS
IN DIFFLUENT FLOW ALOFT AHEAD OF A MESOSCALE CONVECTIVE VORTEX --
MCV -- ACROSS SOUTHWEST MO.  WHILE THE 12Z ARW HAS CAPTURED MOST
OF THE THUNDERSTORM ACTIVITY ACROSS THE SOUTHEAST AND MID-SOUTH
REASONABLY WELL, IT DOES NOT SEEM TO HAVE DONE AS WELL WITH THE
MCV.  THE 12Z HRRR CAPTURED THE MCV WELL BUT HAS NOT INITIATED THE
ONGOING PRECIPITATION ACROSS THIS AREA CORRECTLY.  PRECIPITABLE
WATER VALUES -- PWS -- ARE BETWEEN 1.5-2.0 INCHES IN THIS AREA. 
THE INFLOW AT 850 HPA IS FROM THE WEST AT AROUND 20 KTS PER VAD
WIND PROFILES...EXCEEDING 16Z RAP ESTIMATES, WHICH APPEAR TO BE
HELPING FOCUS CONVECTION ACROSS NORTHWEST MISSISSIPPI.  DUE TO THE
RAINBAND BECOMING ORIENTED WITH THE PROPAGATION VECTORS IN THIS
AREA -- WHICH ARE GENERALLY ALIGNED FROM WNW TO ESE - A COUPLE
HOURS OF RAINFALL COULD CAUSE FLASH FLOODING.  LOCAL AMOUNTS OF
3-5 INCHES ARE POSSIBLE WITHIN A COUPLE HOURS WHERE CELLS TRAIN.

ROTH


ATTN...WFO...BMX...MOB...MEG...JAN...LZK...

LAT...LON   32939179 34299051 34848945 34188804 33348762 32198822
            32139065 32939179