MESOSCALE PRECIPITATION DISCUSSION 479
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
837 AM EDT WED JUL 20 2016
 
AREAS AFFECTED...EASTERN IA...EASTERN MO...WESTERN IL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 201236Z - 201636Z
 
SUMMARY...A FLASH FLOOD THREAT WILL CONTINUE ALONG AND JUST EAST
OF THE MISSISSIPPI RIVER THROUGH 11 AM LOCAL TIME. ADDITIONAL
RAINFALL TOTALS OF 2-4 INCHES WILL BE POSSIBLE IN A FEW LOCATIONS.

DISCUSSION...RADAR IMAGERY AS OF 12Z SHOWED RAPIDLY DEVELOPING
THUNDERSTORM ACTIVITY NEAR A STATIONARY FRONT WITH MULTIPLE
TRAINING OF CONVECTIVE CELLS.  THE LATEST SPC MESOSCALE ANALYSIS
INDICATES A ZONE OF DEEP LAYER MOISTURE FLUX CONVERGENCE OVER THIS
REGION ALONG WITH INSTABILITY ON THE ORDER OF 1000 TO 2000 J/KG
OVER SOUTHERN ILLINOIS ALONG WITH PRECIPITABLE WATER VALUES NEAR
2.1 INCHES.

GIVEN THE SLOW EASTWARD PROGRESSION OF THESE STORMS, A THREAT FOR
FLASH FLOODING WILL PERSIST OVER THE NEXT FEW HOURS.  CELL MERGERS
AND ANTECEDENT MOIST GROUND FROM EARLIER RAINFALL OVER THE PAST
FEW DAYS WILL ONLY ENHANCE THE RISK OF FLOODING.  THE HRRR AND
PARALLEL HRRR SEEM TO HAVE THE BEST DEPICTION OF THE ONGOING
CONVECTION OVER THE NEXT THREE HOURS, WHILE THE EXPERIMENTAL HRRR
HAS THE HEAVIEST RAIN TOO FAR EAST.  EXPECT LOCALIZED RAINFALL
RATES IN EXCESS OF 2 INCHES PER HOUR AT TIMES.

HAMRICK

ATTN...WFO...DVN...ILX...IND...LOT...LSX...PAH...

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

LAT...LON   42529085 42368989 41588960 40658921 39298839 
            38188727 37258717 36628855 37148998 37839069 
            38719121 39449153 40549198 41599222 42079218 
            42349187