MESOSCALE PRECIPITATION DISCUSSION 0291
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1120 AM EST SAT DEC 21 2013
 
AREAS AFFECTED...WRN KY AND TN...SE MO...SRN IL AND IN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 211620Z - 212120Z
 
SUMMARY...WIDESPREAD LIGHT TO MODERATE RAIN WILL CONTINUE TO
SUPPORT LOCAL INUNDATION PROBLEMS THROUGH EARLY AFTERNOON. MORE
INTENSE CONVECTIVE RAINFALL IS ANTICIPATED IN THE
AFTERNOON/EVENING HOURS...WITH A GREATER RISK OF FLASH FLOODING
DEVELOPING AFTER 20Z.

DISCUSSION...A BROAD SWATH OF 1 TO 1.5 AND LOCALLY 2.5 INCHES OF
RAIN HAD FALLEN OVERNIGHT IN THE LOWER OHIO AND MID MISSISSIPPI
VALLEYS. THUS FAR LOCAL STORM REPORTS INDICATED WATER OVER ROADS
AND GENERALLY STANDING WATER. ONGOING LIGHT TO MODERATE
RAIN...WITH RATES OF A HALF INCH OR LESS PER HOUR...WILL SUSTAIN
LOCAL PROBLEMS WITH INUNDATION...BUT THE RISK OF FLASH FLOODING IS
EXPECTED TO INCREASE LATER TODAY.

AT MID MORNING THIS REGION WAS BETWEEN SYNOPTIC SCALE FORCING
MECHANISMS...WITH A CORRIDOR OF MORE CONCETRATED LOW LEVEL
ADVECTIONS PASSING OFF TO THE NORTHEAST AND SEPARATING ITSELF FROM
THE INSTABILITY AXIS...AND THE PRIMARY UPPER WAVE STILL
APPROACHING THROUGH OK/TX. THUNDERSTORMS WITH LIGHT TO MODERATE
RAIN WILL LIKELY BE SUSTAINED WITHIN THE OUTLINED AREA...OWING TO
CONTINUED STRONG MOISTURE TRANSPORT AND A LOW LEVEL
FRONTOGENETICAL CIRCULATION. RAIN RATES ARE ANTICIPATED TO
INCREASE...HOWEVER...AFTER ABOUT 19-20Z PER HRRR AND RUC
FORECASTS. DEEP LAYER ASCENT ARRIVING FROM THE WEST...AN
INCREASINGLY MOIST BOUNDARY LAYER WITH PRECIPITABLE WATER VALUES
APPROACHING 1.70 INCHES...AND A BOOST TO CAPE FROM PARTIAL HEATING
IN THE INFLOW REGI0N...ALL FAVOR MORE VIGOROUS THUNDERSTORMS LATER
THIS AFTERNOON.

BURKE

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

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

LAT...LON   38598548 38628629 38388734 37648943 37149031 36629068
            36119016 35978948 35948876 36408732 37358585 38298504
            38598548