MESOSCALE PRECIPITATION DISCUSSION 0539
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
639 PM EDT THU OCT 01 2015
 
AREAS AFFECTED...TENNESSEEE...NE ALABAMA...NW GEORGIA...EXT E
NORTH CAROLINA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 012238Z - 020338Z
 
SUMMARY...SLOW MOVING HIGHLY EFFICIENT RAIN CORES HAVE POTENTIAL
FOR ISOLATED FLOODING CONCERNS. 

DISCUSSION...DEEPENING TROF OVER THE EASTERN THIRD S/W DIGGING
ACROSS AL AND ELONGATION OF THE TROF TOWARD A WEAKER VORT LOBE
OVER OHIO ALLOWS FOR S/W RIDGING ACROSS CENTRAL TN AND N GA WITH
GOOD DIVERGENCE SIGNALS DEPICTED IN THE MOST RECENT RAP ANALYSIS
FIELDS.  VISIBLE IMAGERY APTLY SHOWS LOW LEVEL STRATUS DECK THAT
REDUCED SOLAR INSOLATION BUT WITH SUFFICIENT MID-LEVEL LAPSE
RATES/COOLING ALOFT ALLOW FOR 250-500 J/KG MUCAPES TO SUPPORT
VERTICAL GROWTH FROM SOME MID-LEVEL CONVERGENCE BETWEEN 850-700MB
FOR BROAD SCATTERED DEEP CONVECTIVE INITIATION.   THOUGH THE CELLS
ARE ELEVATED...THE LOWER ATMOSPHERE IS QUITE MOIST WITH NEARLY
SATURATED PROFILES ELIMINATING DRY AIR INFLUENCES AND ALLOWING FOR
HIGHER RAINFALL PRODUCTION EVEN WITHOUT SIGNIFICANT MOISTURE
VALUES.  THESE CELLS HAVE BEEN GENERALLY IN THE 1.0-1.5"/HR RANGE
AND BEING SO CLOSE IN PROXIMITY TO THE UPPER LOW...STEERING FLOW
IS VERY LIGHT AS WELL GENERALLY NORTHEAST AT LESS THAN 5 KTS.  

SHORT TERM FORECASTS ARE FOR INCREASING EASTERLY COMPONENT
850-700MB FLOW WITH THE UPPER TROF SLIDING SOUTH...THE ENHANCEMENT
OF THE DEFORMATION ZONE ACROSS CENT TN/NE AL/N GA SHOULD ACT AS A
REMAINING FOCUS FOR A CORRIDOR OF INCREASED TOTALS AS SUGGESTED BY
THE 12Z NSSL-WRF...WHICH HANDLED EARLIER CONVECTION WELL. EVEN
THOUGH THE INSTABILITY IS FORECAST TO REDUCE BY NIGHT FALL...DEEP
ASCENT FROM STRENGTHENING UPPER LEVEL JET AND MOISTURE FLUX FROM
THE EAST SHOULD COMPENSATE TO MAINTAIN CORES OF HIGHLY EFFICIENT
RAINFALL AND ISOLATED FLASH FLOODING CONCERNS PARTICULARLY OVER
LOWER FFG IN NW GA/SE TN. 

GALLINA

ATTN...WFO...BMX...FFC...GSP...HUN...MRX...OHX...

ATTN...RFC...LMRFC...OHRFC...SERFC...

LAT...LON   36128590 36078535 36048448 35968389 35868326 
            35628330 35358362 35028394 34718430 34378455 
            33518459 33108532 33658607 34098657 34358682 
            34648704 35058768 35318790 35798777 36028702