MESOSCALE PRECIPITATION DISCUSSION 0220
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
532 AM EDT THU MAY 19 2016
 
AREAS AFFECTED...NW SOUTH CAROLINA...N GEORGIA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 190930Z - 191430Z
 
SUMMARY...LINE OF INCREASING CONVECTION WITH CAPABILITY OF
TRAINING MAY LEAD TO LOCALIZED FLASH FLOODING. 

DISCUSSION...WV LOOP SHOWS A SUBTLE S/W IS TRACKING ENE THROUGH
CENT AL ATTM PROVIDING SOME DPVA AS WELL AS ADDITIONAL UVVS FROM
DIVERGENCE FROM RGT ENTRANCE JET DYNAMICS...THAT SHOULD BE
INCREASING AS THE 90-100 KT JET STREAK CONTINUES TO SHIFT NE
ACROSS THE CENTRAL APPALACHIANS.  THIS IS PROVIDING SOME SFC
PRESSURE FALLS WITH A STATIONARY LOW AROUND KAHN AS WELL AS BETTER
DEFINING THE FRONTAL ZONES FROM A STATIONARY FRONT THAT DRAPES SE
FROM THE LOW JUST W OF THE SC/GA LINE AND A COLD FRONT THAT
EXTENDS SW S OF MGM TOWARD MOB. ALONG THE COLD FRONT...MOISTURE
HAS POOLED WITH AN AXIS OF INCREASED TPW VALUES UP TO 1.5 IN
UPSTATE SC TO 1.8 NEAR MAXWELL AFB. WITH DPVA/HEIGHT
FALLS...INCREASED 850 MST TRANSPORT CHANNELS INCREASES MST
CONVERGENCE ALONG THIS AXIS...INSTABILITY IS A BIT MARGINAL ALONG
THIS FRONT WITH VALUES OF 500-750 J/KG OF MUCAPES THOUGH ALSO
DECREASING MUCIN OVER THE LAST FEW HOURS.  AS SUCH IR/RADAR MOSAIC
SHOWS INCREASED CONVECTIVE DEVELOPMENT ALONG THE 850 DEFORMATION
ZONE FROM HARALSON COUNTY ENE TO NEAR THE SURFACE LOW...AT THAT
POINT PERSISTENT UPGLIDE OVER THE STATIONARY FRONT HAS BEEN
PROVIDING DISORGANIZED BUT PERSISTENT REDEVELOPMENT OF CONVECTION
INTO UPSTATE SC FOR THE LAST 3+ HOURS...RESULTING IN NEAR 2" AT
KAND. 

DEEP NEARLY UNIDIRECTIONAL FLOW WITHIN/ALONG THE FRONTAL BOUNDARY
AS WELL AS A FAVORABLE TRACK TO THE S/W TO THE ENE SHOULD PROVIDE
A NARROW CORRIDOR (NEAR I-85) FOR PROLONGED TRAINING...RATES WILL
BE LIMITED TO 1.0"/HR BUT WITH INCREASED FORCING...SHORTER
DURATION RATES UP TO 1.5"/HR MAY BE PSBL.   THIS COULD PROVIDE
ADDITIONAL TOTALS IN THE 1-3" RANGE AS SUGGESTED BY RECENT RUNS OF
THE ESRL EXP. HRRR AND OPERATIONAL HRRR.  VERY HIGH FFG VALUES ARE
THE LIMITING FACTOR FOR ANY SIGNIFICANT FLASH FLOODING BUT
ISOLATED FF IS PSBL PARTICULARLY IN URBAN CENTERS. 

LATER THIS MORNING...CAMS SUGGESTING CONVECTIVE COMPLEX DEVELOPING
ALONG AL/GA BORDER IS WITHIN DEEPER INSTABILITY POOL AND THEREFORE
PRODUCING MORE EFFICIENT CONVECTION (RATES UP TO 2"/HR)...THIS
AREA WILL TRACK EASTWARD WITH THE POTENTIAL OF DEVELOPING
CONVECTION FROM THE SSELY RETURN FLOW OFF THE GULF STREAM WEST OF
THE STATIONARY FRONT...FOR CELL MERGERS WHICH MAY REQUIRE A NEW
MPD SOUTHWARD INTO EAST CENTRAL GA IF CONDITIONS WARRANT.  

GALLINA

ATTN...WFO...CAE...FFC...GSP...

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

LAT...LON   34648203 34598119 34178120 33988143 33898236 
            33728310 33448437 33988467 34278401 34598282