308
AWUS01 KWNH 041201
FFGMPD
WIZ000-041630-
MESOSCALE PRECIPITATION DISCUSSION 1195
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
800 AM EDT FRI SEP 04 2026
AREAS AFFECTED...CENTRAL AND EASTERN WI
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 041200Z - 041630Z
SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS WITH SOME ADDITIONAL
CELL-TRAINING CONCERNS WILL CONTINUE FOR AT LEAST A FEW MORE
HOURS. A THREAT FOR MAINLY URBAN FLASH FLOODING WILL PERSIST THIS
MORNING AS A RESULT.
DISCUSSION...THE EARLY MORNING GOES-E IR SATELLITE IMAGERY SHOWS A
BAND OF STRONG CONVECTION WITH VERY COLD CLOUD TOPS IMPACTING
AREAS OF CENTRAL AND EASTERN WI. THE HEAVY SHOWER AND THUNDERSTORM
ACTIVITY IS FOCUSED IN CLOSE PROXIMITY TO A QUASI-STATIONARY FRONT
WHERE A COMBINATION OF STRONGER SURFACE CONVERGENCE AND POOLING OF
ELEVATED INSTABILITY IS WORKING IN TANDEM WITH RELATIVELY
DIVERGENT FLOW ALOFT TO SUSTAIN THE CONVECTIVE MASS.
MUCAPE VALUES ARE GENERALLY NEAR 2000 J/KG WITH PWS OF 1.5 TO 1.75
INCHES. CIRA LVT DATA SHOWS A WELL-DEFINED LOW TO MID-LEVEL
ADVANCE OF MOISTURE INTO CENTRAL AND EASTERN WI WHICH IS ROUNDING
THE TOP SIDE OF THE SUBTROPICAL RIDGE SITUATED FARTHER SOUTH OVER
PARTS OF THE OH VALLEY AND MIDDLE MS VALLEY. A WESTERLY LOW-LEVEL
JET OF ABOUT 30+ KTS IS FACILITATING THIS MOISTURE TRANSPORT.
SATELLITE TRENDS SHOW ADDITIONAL AREAS OF COOLING CLOUDS TOPS
UPSTREAM OVER WESTERN WI AND EVEN BACK INTO FAR SOUTHEAST MN AND
NORTHEAST IA. THIS SUGGESTS A LIKELY PERSISTENCE OF THE CONVECTIVE
THREAT FOR AT LEAST A FEW MORE HOURS DOWNSTREAM ACROSS AREAS OF
CENTRAL AND EASTERN WI WHERE RECENT RADAR DATA SHOWS SOME
CELL-TRAINING OCCURRING.
HEAVY RAINFALL RATES OF 1.5 TO 2.5 INCHES/HOUR ARE POSSIBLE WITH
THE STRONGER STORMS, AND THE LATEST HIRES GUIDANCE LED BY THE RRFS
AND REFS SUGGESTS ADDITIONAL RAINFALL AMOUNTS OF AS MUCH AS 3 TO
4+ INCHES GOING THROUGH LATE THIS MORNING. THE ADDITIONAL RAINFALL
POTENTIAL IS EXPECTED TO DRIVE THE PERSISTENCE OF AT LEAST AN
URBAN FLASH FLOOD THREAT AS A RESULT.
ORRISON
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ARX...GRB...MKX...
ATTN...RFC...MSR...NWC...
LAT...LON 44468907 44218795 43638716 43128725 42828781
42918865 43198948 43659020 44089034 44428998
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