MESOSCALE PRECIPITATION DISCUSSION 0717
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
417 AM EST MON DEC 28 2015
 
AREAS AFFECTED...EXTREME EASTERN MO...CENTRAL/SOUTHERN
IL...SOUTHWEST IN...WESTERN KY...WESTERN TN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 280900Z - 281500Z
 
SUMMARY...PERSISTENT MODERATE TO HEAVY RAINS WILL CONTINUE TO
FAVOR THE POTENTIAL FOR RUNOFF PROBLEMS AND SOME ISOLATED FLASH
FLOODING THROUGH MID MORNING.

DISCUSSION...WHILE THE HEAVIEST RAINS ARE CURRENTLY CONFINED TO
THE LOWER MS VALLEY REGION. STRONG WARM ADVECTION AND INCREASINGLY
DIVERGENT FLOW ALOFT AHEAD OF A MID LEVEL LOW CENTER CROSSING THE
ARKLATEX REGION THIS MORNING IS GENERATING A RATHER BROAD AREA OF
MODERATE TO HEAVY RAINS ALONG WITH SOME EMBEDDED ELEVATED
CONVECTION.

ANOMALOUS MOISTURE CONTINUES TO SURGE NORTH FROM THE GULF COAST
STATES VIA A 50 KT LOW LEVEL JET NOSING INTO THE OH VALLEY...AND
WITH PW ANOMALIES AS HIGH AS 3 TO 4 STD DEV ABOVE NORMAL...AND
APPROACHING 1.4 TO 1.5 INCHES...THE RAINFALL RATES CONTINUE TO BE
LOCALLY HEAVY AND CLOSE TO 1 INCH/HR WITHIN THE STRONGER
CONVECTIVE ELEMENTS.

THE LATEST HIRES GUIDANCE CONTINUES TO FAVOR AS MUCH AS AN
ADDITIONAL 1 TO 2 INCHES OF RAIN THROUGH 15Z...WITH THE HEAVIEST
AMOUNTS GENERALLY FOCUSED OVER CENTRAL/SOUTHERN IL AND PARTS OF
SOUTHWEST IN. HOWEVER...BY MID MORNING THE APPROACHING CYCLONE
OVER THE ARKLATEX AND IMPROVING JET FORCING WILL ALLOW SOME OF THE
UPSTREAM CONVECTION OVER THE LOWER MS VALLEY TO MOVE INTO WESTERN
TN AND WESTERN KY WITH ADDITIONAL AMOUNTS HERE OF POSSIBLY 1 TO 2
INCHES.

THE VERY WET ANTECEDENT CONDITIONS WILL CONTINUE TO FAVOR RUNOFF
PROBLEMS AND AT LEAST AN ISOLATED THREAT OF FLASH FLOODING THIS
MORNING.

ORRISON

ATTN...WFO...ILX...IND...LMK...LOT...LSX...MEG...OHX...PAH...

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

LAT...LON   40648810 40438707 39718605 38818566 38128564 
            37268603 36208688 35838749 35558813 35448877 
            35808899 36488909 37858944 38478987 38799041 
            38969116 38919151 38989182 39609134 40209038 
            40558921