MESOSCALE PRECIPITATION DISCUSSION 0715
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1211 AM EST MON DEC 28 2015
 
AREAS AFFECTED...FAR NORTHEAST AR...SOUTHEAST MO...WESTERN
TN...SOUTHERN IL...SOUTHWEST IN...WESTERN KY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 280500Z - 280900Z
 
SUMMARY...LOCALLY HEAVY SHOWERS AND THUNDERSTORMS MOVING OVER
LOCALLY SATURATED SOILS MAY RESULT IN SOME ISOLATED FLASH FLOOD
CONCERNS OVER THE NEXT FEW HOURS.

DISCUSSION...IR SATELLITE IMAGERY SHOWS SOME RATHER COLD-TOPPED
CONVECTION ADVANCING NORTH THROUGH WESTERN TN...WESTERN KY AND
SOUTHEAST MO. FFG VALUES THROUGHOUT THE LOWER OH VALLEY ARE QUITE
LOW DUE TO HEAVIER RAINS EARLIER IN THE DAY AND SO ADDITIONAL
RAINS WILL ELEVATED THE CONCERN FOR RUNOFF PROBLEMS.

THE CONVECTION IS BEING AIDED BY THE NOSE OF A 50 KT SOUTHERLY LOW
LEVEL JET ADVANCING NORTH AND INTERACTING WITH A FRONTAL ZONE
GRADUALLY LIFTING BACK NORTH THROUGH THE LOWER MS AND TN VALLEYS.
THE UPPER LEVEL FLOW IS ALSO RATHER DIFFLUENT ALOFT AND OVER THE
NEXT FEW HOURS ADDITIONAL CLUSTERS OF CONVECTION ARE LIKELY TO
DEVELOP ALONG THE WARM FRONT AND LIFT NORTH THROUGH WESTERN TN AND
TOWARD THE LOWER OH VALLEY REGION.

A NOSE OF 1.5 INCH PWATS IS EXPANDING NORTH WITH TIME TOWARD THE
LOWER OH VALLEY AND THIS WILL PROMOTE AN INCREASE IN RAINFALL
RATES WHICH MAY REACH 1 TO 2 INCHES/HR WITHIN SOME OF THE STRONGER
CONVECTIVE CORES.

THE HIRES GUIDANCE OVERALL IS HANDLING THIS ACTIVITY QUITE
POORLY...WITH ONLY THE HRRR HAVING ANY REAL DEPICTION OF THE
ONGOING ACTIVITY. EXPECT ADDITIONAL RAINFALL AMOUNTS OF 1 TO 3
INCHES WITH ISOLATED HEAVIER AMOUNTS THOROUGH ABOUT 09Z. THIS MAY
BE ENOUGH TO AT LEAST FOSTER SOME ADDITIONAL RUNOFF PROBLEMS AND
ISOLATED FLASH FLOODING.

ORRISON

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

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

LAT...LON   38728852 38458680 37488611 36188643 35578761 
            35058949 35169033 35839030 36519069 36909137 
            37139214 37749188 38409050