MESOSCALE PRECIPITATION DISCUSSION 0558
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1030 AM EDT SAT AUG 13 2016
 
AREAS AFFECTED...FAR SOUTHEAST MO...SOUTHEAST
IL...CENTRAL/SOUTHWEST IN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 131430Z - 131930Z
 
SUMMARY...SLOW-MOVING AND TRAINING BANDS OF SHOWERS AND
THUNDERSTORMS WILL PRODUCE VERY HEAVY RAINFALL AND LIKELY SOME
FLASH FLOODING.

DISCUSSION...GOES-14 SRSOR IR/VIS IMAGERY OVER THE LAST HOUR HAS
SHOWN THE IMPRESSIVE DEVELOPMENT AND EXPANSION OF SW/NE ORIENTED
BANDS OF CONVECTION INVOLVING SOUTHEAST MO...SOUTHERN IL AND NOW
BECOMING INCREASINGLY FOCUSED ACROSS SOUTHWEST IN. CONVECTION IS
FOCUSING ALONG AND JUST AHEAD OF A SLOW-MOVING COLD FRONT WHICH IS
INTERACTING WITH VERY MOIST AND INCREASINGLY UNSTABLE AIRMASS.
PWATS ARE ALREADY ON THE ORDER OF 2.25 TO 2.5 INCHES AS PER THE
BLENDED-TPW PRODUCT AND AREA GPS DATA AND THIS POOLING OF MOISTURE
WILL REMAIN FOCUSED WITH DEEPER SOUTHERLY FLOW OUT AHEAD OF THE
FRONT. ADDITIONAL LARGE SCALE FORCING IS ALSO SETTING UP OVER THE
FRONT WITH IMPROVING 250 MB RIGHT-ENTRANCE REGION JET
DYNAMICS...AND THUS THE INGREDIENTS ARE QUICKLY COMING TOGETHER
FOR MORE ORGANIZED AND HEAVY RAINFALL POTENTIAL.

THE LATEST HRRR/HRRRP GUIDANCE SUGGESTS ADDITIONAL CONVECTIVE
ORGANIZATION OVER THE NEXT FEW HOURS AND THE GOES-14 1-MINUTE
IMAGERY IS CONFIRMING THIS TREND WITH COOLING CLOUD TEMPERATURES
AND A FEW OVERSHOOTING TOPS WHICH IS INDICATIVE OF STRONGER
FORCING/UPDRAFTS.

THE AFOREMENTIONED HIRES GUIDANCE FAVORS SW/NE ORIENTED BANDS OF
AS MUCH AS 3 TO 5 INCHES THROUGH MID-AFTERNOON...WITH SOME
ISOLATED HEAVIER AMOUNTS...ESPECIALLY OVER SOUTHEAST IL WHERE THE
HRRR/HRRRP IS TRENDING WETTER AND NOW SUGGESTS AS MUCH AS 8 INCHES
WILL BE POSSIBLE THROUGH MID-AFTERNOON. THIS SEEMS REASONABLE
WHERE STRONGER CONVECTIVE CORES/OVERSHOOTING TOPS AND TRAINING
CELLS ALIGN THEMSELVES. WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...ILN...ILX...IND...IWX...LMK...LSX...PAH...

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

LAT...LON   40478525 40238492 39468530 38318684 37138883 
            36729001 36849042 37249044 37978945 38858815 
            39598705 40358590