Graphic for MPD #0772

MESOSCALE PRECIPITATION DISCUSSION 0772...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
526 AM EDT THU AUG 31 2017

CORRECTED FOR FLASH FLOODING POSSIBLE

AREAS AFFECTED...FL PANHANDLE...SOUTHERN AL...WESTERN GA

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

VALID 310923Z - 311523Z

SUMMARY...DEEP MOISTURE ALONG WITH AMPLE INSTABILITY AND FAVORABLE
FORCING ALOFT IS SUPPORTING EXPANDING SHOWER AND THUNDERSTORM
COVERAGE WITH INCREASING RAINFALL RATES...RAISING THE POTENTIAL
FOR HEAVY ACCUMULATIONS AND RUNOFF CONCERNS.

DISCUSSION...CONFLUENT LOW LEVEL WINDS CONTINUE TO TRANSPORT DEEP
TROPICAL MOISTURE INTO THE EASTERN GULF COAST REGION AND
SOUTHEASTERN U.S....SUPPORTING A NARROW AXIS OF HIGH PWS FROM
COASTAL AL AND THE WESTERN FL PANHANDLE NORTHEASTWARD INTO
NORTHERN GA.  LATEST SPC MESOANALYSIS INDICATES PWS OF 2 TO 2.2
INCHES ACROSS THIS REGION...WITH THE 07 UTC RAP SHOWING 30 KT
SOUTHWESTERLY FLOW LEVEL INFLOW SUPPORTING PWS AROUND 2 INCHES
THROUGH THE REMAINDER OF THE OVERNIGHT INTO THE EARLY DAYLIGHT
HOURS.  MUCAPE VALUES ARE CURRENTLY BETWEEN 1000-3000 J/KG ACROSS
SOUTHERN AL...SOUTHWESTERN GA AND THE FL PANHANDLE...WITH THE RAP
MAINTAINING SIMILAR VALUES THROUGH 15 UTC. MEANWHILE...DIVERGENT
FLOW ALOFT...AFFORDED IN PART BY AN UPPER JET CENTERED OVER THE
MID ATLANTIC REGION WILL HELP TO SUPPORT LARGE SCALE LIFT ACROSS
THE REGION.  STORMS THROUGH MUCH OF THE OVERNIGHT HAVE BEEN
LARGELY DISORGANIZED IN NATURE...HOWEVER RECENT RADAR RETURNS FROM
KMOB AND KEVX HAVE SHOWN RAINFALL RATES INCREASING TO 1.5-2 IN/HR
WITHIN SOME OF THE STORMS OVER THE FL PANHANDLE AND SOUTHERN AL. 
MEANWHILE...GOES-16 IR IMAGERY ALSO SHOWS A CONSOLIDATING LINE OF
COOLING CLOUD TOPS EXTENDING FROM NEAR MOBILE BAY BACK INTO THE
CENTRAL GULF.

WHILE THERE IS A GENERAL SIGNAL FROM THE 00 UTC HI-RES GUIDANCE
AND RECENT RUNS OF THE HRRR FOR AT LEAST LOCALLY HEAVY
AMOUNTS...THEY ARE FAR FROM AGREEMENT WITH RESPECT TO THE DETAILS.
 HOWEVER...EVEN IF CONVECTION REMAINS SCATTERED...LOCALIZED
RAINFALL RATES OF 1.5-2 IN/HR CAN BE EXPECTED TO CONTINUE...WHICH
MAY POSE RUNOFF CONCERNS...ESPECIALLY ACROSS PORTIONS OF
SOUTH-CENTRAL TO WEST-CENTRAL AL WHERE THE LATEST FLASH FLOOD
GUIDANCE VALUES ARE RELATIVELY LOW.

PEREIRA

ATTN...WFO...BMX...FFC...GSP...MOB...TAE...

ATTN...RFC...SERFC...

LAT...LON   34558338 33838410 32988457 30388549 30298670
            29938794 31028756 32768639 33998538 34508443
           


Last Updated: 526 AM EDT THU AUG 31 2017