MESOSCALE PRECIPITATION DISCUSSION 0427
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
842 PM EDT WED JUL 06 2016
 
AREAS AFFECTED...W KENTUCKY...N CENT TENNESSEE...EXT SE
MISSOURI...EXT S ILLINOIS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 070045Z - 070645Z
 
SUMMARY...INCREASING CONVECTIVE DEVELOPMENT WITH THE POTENTIAL FOR
TRAINING PROVIDING INCREASED LIKELIHOOD FOR FLASH FLOODING
CONDITIONS OVERNIGHT...WARRENTING AN UPGRADE OF EXCESSIVE RAINFALL
OUTLOOK TO MODERATE RISK AT 01Z.

DISCUSSION...GOES-E INDICATES STRONG MCV/SHORTWAVE ACROSS S IL AT
THIS TIME WITH NEW CONVECTION DEVELOPING IN THE VICINITY.  THIS
DEVELOPMENT IS IN RESPONSE TO ISENTROPIC ASCENT (ALONG THE 305K
SURFACE) ADVECTING SOME OF THE INSTABILITY GENERATED THIS
AFTERNOON OVER S MO/N AR FROM INSOLATION INDICATED BY MID-80S SFC
TEMPS OVER MID-70S TDS. THIS INSTABILITY GRADIENT/ISENTROPIC
SURFACE IS ORIENTED NW-SE ACROSS THE MS RIVER FROM CGI TO AROUND
BNA. VAD WIND PROFILES INDICATE FLOW IS MORE WESTERLY AT THIS TIME
WITH 7H FLOW TO 50KTS THOUGH LOWER LEVEL FLOW IS CURRENTLY WEAKER
LESS THAN 25KTS FROM THE WSW BUT PROVIDES SUFFICIENT CONVERGENCE
OR SOME ELEVATED CONVECTION. BY 04Z FLOW WILL STRENGTHEN TO
35-40KTS AND CROSS THE ISENTROPIC SURFACE PERPENDICULARLY
PROVIDING VERY STRONG MOISTURE FLUX AND ASCENT TO DEVELOP
WIDESPREAD CONVECTIVE LINE.  THIS WHILE CLOUD BEARING STEERING
FLOW WILL DIRECT CELLS GENERALLY SE PARALLEL TO THE INSTABILITY
GRADIENT... ALLOWING FOR TRAINING PROFILES ACROSS W KY/N CENT TN. 
SATURATED PROFILES WITH PWATS IN THE 2-2.25" RANGE WILL SUPPORT
CONVECTION TO BE HIGHLY EFFICIENT WITH RAIN RATES UP TO 2"/HR
LEADING AND TOTALS IN THE 3-5" RANGE THROUGH 06Z WITH THE
POTENTIAL FOR ADDITIONAL RAIN THEREAFTER.  

RECENT RAPID REFRESH HI-RES GUIDANCE PARTICULARLY THE HRRR VER2
AND VER3 ALONG WITH THE RAP ARE QUITE SUPPORTIVE OF THIS SCENARIO
UNFOLDING...WITH GREATEST QUESTION REMAINING ON EXACT POSITIONING
OF THE NW-SE CORRIDOR OF HIGHEST TOTALS.  THIS WOULD BE OF GREATER
CONCERN ACROSS W (I-24 CORRIDOR) AND/OR S CENTRAL KY WHERE EARLIER
RAINFALL (1-1.5") THIS AFTERNOON HAS LOWERED FF THRESHOLDS SOME. 

GALLINA

ATTN...WFO...LMK...MEG...OHX...PAH...

ATTN...RFC...LMRFC...NCRFC...OHRFC...

LAT...LON   38048901 37778794 37498694 37268512 35578569 
            35638676 35928785 36348892 36988975 37598993