MESOSCALE PRECIPITATION DISCUSSION 0029
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1229 AM EDT MON APR 28 2014
 
AREAS AFFECTED...EASTERN AR/WESTERN TN/WESTERN KY/EASTERN
MO/SOUTHWESTERN IL... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 280428Z - 280858Z
 
SUMMARY...A PERSISTENT AREA OF HEAVY RAINFALL AND ASSOCIATED FLASH
FLOODING HAVE BEEN ONGOING THE PAST SEVERAL HOURS ACROSS AREAS OF
NORTHEASTERN AR/SOUTHEASTERN MO. ATMOSPHERIC CONDITIONS REMAIN
FAVORABLE TO ALLOW THIS TO PERSIST WELL INTO THE OVERNIGHT HOURS.

DISCUSSION...A POWERFUL MID-LATITUDE CYCLONE CONTINUES TO SWIRL
ACROSS THE CENTRAL PLAINS TONIGHT WITH ANOMALOUS MOISTURE CONTENT
SURGING NORTHWARD AHEAD OF THE SYSTEM. PWAT ANOMALIES SUGGEST THE
00Z RAOB VALUES RANGE FROM THE 95TH TO 99TH
PERCENTILE...PARTICUARLY FROM THE CENTRAL GULF COAST UP INTO
CENTRAL IL. THIS ARTIFACT COUPLED WITH VERY SLOW CELL MOTIONS HAS
LEAD TO MULTIPLE EPISODES OF TRAINING/BACKBUILDING CONVECTION. THE
CURRENT RADAR IMAGERY SHOWED AN AXIS OF NEARLY STATIONARY
THUNDERSTORM ACTIVITY ACROSS NORTHEASTERN AR/SOUTHEASTERN MO WITH
CONTINUAL CELL DEVELOPMENT AT THE LEADING EDGE OF THE STORM
INFLOW. THE AVAILABLE VAD WIND PROFILES INDICATED THE LLJ WAS
APPROACHING 65 KT WITH THE LOW TO MID-LEVEL FLOW NEARLY
PARALLELING THE AXIS OF ONGOING PRECIPITATION. WITH LITTLE CHANGE
EXPECTED IN THE STORM-SCALE ENVIRONMENT...THE POSSIBILITY OF FLASH
FLOODING WILL CONTINUE WELL INTO THE OVERNIGHT HOURS. THIS IS
DEFINITELY OF CONCERN TO THE AFFECTED AREA AS THERE HAVE ALREADY
BEEN SEVERAL REPORTS OF FLOODED/UNPASSABLE ROADS.

THE HIGH-RESOLUTION/CONVECTION-ALLOWING MODELS ARE SOMEWHAT AT
ODDS WITH THE PLACEMENT OF HEAVY RAINFALL DURING THE NEXT SEVERAL
HOURS. THE 12Z SSEO MEAN/EXPERIMENTAL HRW-ARW/HRW-NMM/WRF-NSSL ALL
HAVE A REASONABLE HANDLE WITH THE ONGOING PRECIPITATION. THE
SCALLOPED REGION GENERALLY FOLLOWED THIS OUTPUT WHILE ACCOUNTING
FOR THE CURRENT RADAR TRENDS.



RUBIN-OSTER

ATTN...WFO...PAH...ILX...MEG...LSX...LZK...SGF...TSA...

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

LAT...LON   34509382 36299326 37119266 38259157 38979060 39108950
            38628835 37298801 36228870 35708921 35118989 34359095
            33909193 34509382