MESOSCALE PRECIPITATION DISCUSSION 0289
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
427 AM EST SAT DEC 21 2013
 
AREAS AFFECTED...CENTRAL AND NORTHERN AR...SOUTHEAST MO...SOUTHERN
IL...SOUTHWEST IN...WESTERN KY 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 210925Z - 211400Z
 
SUMMARY...A BROKEN AND LOOSELY ORGANIZED BAND OF HEAVY SHOWERS AND
THUNDERSTORMS WILL HAVE THE POTENTIAL TO TRAIN OVE THE SAME AREAS
THROUGH THE EARLY AND MID-MORNING HOURS. THEREFORE...SOME FLASH
FLOODING WILL BE POSSIBLE.

DISCUSSION...AN IMPRESSIVELY STRONG UPPER LOW EJECTING EAST OUT OF
FAR NORTHERN MEXICO IS APPROACHING THE SOUTHERN PLAINS CURRENTLY
AND WILL BE INTERACTING WITH A STRONG FRONT ORIENTED SW/NE ACROSS
THE LOWER MS AND OH VALLEYS THROUGH THE EARLY AND MID-MORNING
HOURS. 

ALREADY THE LATEST WV/IR SAT IMAGERY SHOWS VERY DIVERGENT FLOW
ALOFT INTERACTING WITH THE FRONT...WITH NUMEROUS CLUSTERS OF
COLD-TOPPED CONVECTION EXTENDING FROM NORTHWEST AR EAST-NORTHEAST
INTO WESTERN KY. OVER THE NEXT FEW HOURS...CONVECTION SHOULD TEND
TO CONSOLIDATE AND BECOME MORE LINEARLY ORGANIZED ALONG THE FRONT
AS THE UPPER LOW APPROACHES AND FURTHER ENHANCES STRONG DEEP LAYER
ASCENT OVER THE REGION. MEANWHILE...FAVORABLE THERMODYNAMICS ARE
EXPECTED TO BE IN PLACE WITH THE AID OF A 60 KT LOW LEVEL JET
AIMED OUT OF THE GULF OF MEXICO AND INTO THE FRONTAL ZONE. THE
CONVECTION WILL LIKELY TRAIN OVER THE SAME AREA GIVEN DEEP LAYER
SWLY FLOW THAT IS ALIGNED NEARLY PARALLEL TO THE AFOREMENTIONED
FRONT.

RAINFALL RATES OF 1 TO 1.5 INCHES/HR ARE POSSIBLE WITH THE LATEST
RAP ANALYSIS AND GOES-SOUNDER DATA ALREADY SHOWING THE NOSE OF 1.5
INCHES PWATS LIFTING UP THROUGH CENTRAL AR. CONSIDERING THE
TRAINING CONVECTIVE ENVIRONMENT...THERE WILL BE A RISK OF AT LEAST
SOME FLASH FLOODING THROUGH MID-MORNING. WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...LMK...IND...PAH...MEG...LSX...LZK...SGF...TSA...

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

LAT...LON   36869207 37519086 38128935 38518789 38458636 38098582
            37668588 37358651 37088760 36628878 35779055 34559197
            34129276 34169375 34659420 35619366 36149306 36869207