MESOSCALE PRECIPITATION DISCUSSION 0142...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
522 PM EDT THU JUN 19 2014
CORRECTED FOR MISSING WORDS IN SECOND PARAGRAPH
AREAS AFFECTED...PORTIONS OF SOUTHERN WI, EASTERN IA, AND NORTHERN
IL
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 192116Z - 200116Z
SUMMARY...A LINE OF THUNDERSTORMS WITH HEAVY RAINFALL IS MOVING
INTO A SATURATED AREA. SEVERAL OCCURRENCES OF FLASH FLOODING ARE
EXPECTED.
DISCUSSION...AN ADVANCING LINE OF THUNDERSTORMS WITH AN MCV AT ITS
APEX NEAR THE IA/WI BORDER HAS PRODUCED RAINFALL RATES UP TO 5" AN
HOUR AS MEASURED BY OBSERVERS IN EASTERN IA EARLIER THIS
AFTERNOON. THE BAND IS MOVING INTO A REGION SATURATED BY DAYS OF
HEAVY RAINFALL, INCREASING THE RISK OF FLASH FLOODING. THE MOTION
OF THE LINE IS 15-20 KTS, MATCHING THE FORWARD PROPAGATING CORFIDI
VECTORS FROM THE 12Z GFS, WHICH IS LIKELY TO MAGNIFY STORM
RELATIVE INFLOW INTO THE BAND ABOVE WHAT IS SEEN IN THE 850 HPA
AND 700 HPA WIND PATTERN.
AVAILABLE CAPES (PER THE 12Z ARW) SUGGEST THAT THE THUNDERSTORMS
SHOULD MAINTAIN INTEGRITY AS THEY MOVE INTO SOUTHERN WI AND
NORTHERN IL OVER THE NEXT FOUR HOURS. THE MESOSCALE GUIDANCE
APPEARS TO BE MOVING THIS ACTIVITY TOO SLOWLY TO THE EAST, SO HAVE
USED ITS CURRENT MOTION AS A PROXY FOR FUTURE MOTION. DESPITE ITS
RECENT INCREASE IN SPEED, RAINFALL RATES ARE 1-2" AN HOUR PER
RADAR ESTIMATES, WHICH WOULD OVERWHELM THE CURRENT FLASH FLOOD
GUIDANCE IN THE REGION. SEVERAL POCKETS OF FLASH FLOODING ARE
EXPECTED. USED THE POSSIBLE CATEGORY DUE TO THE LINE'S FORWARD
PROGRESSION.
ROTH
ATTN...WFO...LOT...MKX...DVN...ARX...
ATTN...RFC...NCRFC...
LAT...LON 41298896 41549017 41649088 42219088 43339106 42918954
42108882 41298896
Last Updated: 522 PM EDT THU JUN 19 2014