MESOSCALE PRECIPITATION DISCUSSION 0060
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1246 AM EST SUN MAR 11 2018

AREAS AFFECTED...CENTRAL/SOUTHEAST AR...CENTRAL MS...WEST-CENTRAL
AL

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

VALID 110545Z - 111030Z

SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER THE
NEXT SEVERAL HOURS WITH ADDITIONAL CONCERNS FOR TRAINING CELLS
WHICH WILL FOSTER SOME FLASH FLOODING CONCERNS.

DISCUSSION...A SHORTWAVE CONTINUES TO DIG TOWARD THE MID MS VALLEY
WHICH IS FOSTERING A VERY DIFFLUENT FLOW REGIME ALOFT ACROSS THE
LOWER MS VALLEY REGION. LARGE SCALE FORCING AHEAD OF THIS ENERGY
IS INTERACTING WITH A POOLING OF MODEST INSTABILITY AND MOISTURE
FROM THE WESTERN GULF COAST REGION WHICH IS ALL OVERRUNNING A
STATIONARY FRONT ACROSS THE REGION. THIS IS RESULTING IN AN
EXPANSIVE WNW/ESE AXIS OF STRONG CONVECTION WITH LOCALLY HEAVY
RAINFALL RATES THAT HAVE BEEN EXCEEDING 1 INCH/HR.

OVER THE NEXT SEVERAL HOURS...ISENTROPIC ASCENT OVER THE BOUNDARY
WITH THE AID OF A 30 TO 35 KT SOUTHWEST LOW LEVEL JET SHOULD
CONTINUE TO SUSTAIN THE SOUTHERN FLANK OF THE CONVECTION JUST
NORTH OF THE BOUNDARY...AND WITH THE AID OF ELEVATED INSTABILITY
TRANSPORT. THE HIRES CAM GUIDANCE IS NOT HANDLING THE ONGOING
CONVECTION WELL AT ALL AND ARE GENERALLY TOO FAR NORTH WITH THE
AXIS CURRENTLY. THE CONVECTION SHOULD TEND TO LOSE LATITUDE
OVERNIGHT AS THE LOW LEVEL WINDS BEGIN TO VEER.

PWATS ARE RATHER MODEST AT 1.1 TO 1.2 INCHES...BUT WITH LOCALLY
VERY COLD CONVECTIVE TOPS OWING TO STRONG UPDRAFTS AND THE LARGER
SCALE FORCING ENVIRONMENT...EXPECT RAINFALL RATES TO REMAIN
LOCALLY OVER 1 INCH/HR. THIS COUPLED WITH SOME PERIODIC TRAINING
OF CONVECTIVE CELLS GIVEN THE MEAN LAYER FLOW WILL SUPPORT SOME
ADDITIONAL HEAVY TOTALS THROUGH DAWN WITH AS MUCH AS AN ADDITIONAL
2 TO 3 INCHES POSSIBLE LOCALLY. THIS WILL FAVOR SOME ADDITIONAL
FLASH FLOODING CONCERNS.

ORRISON

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

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

LAT...LON   34849235 34339120 33849033 33468895 33128727
            32758678 32078710 31968821 32258978 32729109
            33049174 33609266 34209319 34729303