MESOSCALE PRECIPITATION DISCUSSION 0299
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
322 AM EDT SAT JUL 04 2015
 
AREAS AFFECTED...SOUTHERN AR...NORTHERN MS...NORTHERN AL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 040705Z - 041230Z
 
SUMMARY...TRAINING SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS
MORNING. GIVEN THE INTENSE RAINFALL RATES ASSOCIATED WITH THE
ACTIVITY AND RECENT HEAVY RAINFALL...FLASH FLOODING IS LIKELY.

DISCUSSION...SHOWER AND THUNDERSTORM ACTIVITY HAS BEEN GRADUALLY
EXPANDING IN COVERAGE AND ORGANIZATION THE LAST COUPLE OF HOURS
ACROSS PORTIONS OF SOUTHERN AR...NORTHERN MS AND NORTHERN AL AHEAD
OF A SHORTWAVE TROUGH DIGGING SOUTHEAST THROUGH THE SOUTHERN
PLAINS AND LOWER MS VALLEY REGION. THE CONVECTION IS GRADUALLY
BECOMING FOCUSED IN A W/E FASHION WITHIN A VERY MOIST AND BROADLY
CONFLUENT LOW TO MID LEVEL FLOW REGIME IN VICINITY OF A LEFT OVER
OUTFLOW BOUNDARY. HOWEVER...THE CONVECTION IS FOCUSING WITHIN AN
ENVIRONMENT THAT IS HIGHLY CONDUCIVE FOR CELL TRAINING. VAD-WIND
PROFILER DATA IS NEARLY UNIDIRECTIONAL THROUGH THE 925 MB TO 500
MB LAYER FROM THE W/SW...AND THIS WILL RESULT IN GENERAL W/E
TRAINING OF CONVECTION THROUGHOUT THE REMAINDER OF THE NIGHT.

THE 00Z ARW/00Z NMMB AND 05Z RUN OF THE HRRR ALL FAVOR HEAVY
CONVECTIVE RAINS LEADING UP TO SUNRISE ACROSS PORTIONS OF
AR/MS/AL...BUT THEIR AXIS OF HEAVY RAINS ARE LIKELY A TAD TO FAR
SOUTH IN MS/AL. THE LATEST SATELLITE AND RADAR TRENDS FAVOR THIS
AXIS OCCURRING A BIT FARTHER NORTH...AND UNFORTUNATELY SETTING UP
OVER AREAS OF NORTHERN MS/NORTHERN AL THAT HAVE ALREADY SEEN VERY
HEAVY RAINFALL TOTALS OVER THE LAST 24 HOURS. 

GIVEN THE VERY MOIST ENVIRONMENT...WITH GOES-SOUNDER DATA
SUGGESTING 2 INCH PWATS...RAINFALL RATES WILL BE VERY INTENSE. THE
HIGH LIKELIHOOD FOR TRAINING CELLS WILL FAVOR LOCALLY VERY HEAVY
RAINFALL TOTALS. THE HI-RES GUIDANCE SUGGESTS ADDITIONAL TOTALS OF
3 TO 6 INCHES THROUGH 12Z WITH ISOLATED HEAVIER AMOUNTS. THIS WILL
LIKELY CAUSE SOME ADDITIONAL FLASH FLOODING.

ORRISON

ATTN...WFO...BMX...HUN...JAN...LZK...MEG...SHV...

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

LAT...LON   34588939 34548811 34458650 34178568 33688559 
            33368605 33218751 33158939 33169095 33219204 
            33369354 33829433 34259425 34369335 34429213 
            34539093 
!