465
AWUS01 KWNH 031519
FFGMPD
OHZ000-MIZ000-WIZ000-032115-
MESOSCALE PRECIPITATION DISCUSSION 1183
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1117 AM EDT THU SEP 03 2026
AREAS AFFECTED...CENTRAL AND EASTERN WI...PORTIONS OF LOWER MI
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 031517Z - 032115Z
SUMMARY...INCREASING COVERAGE OF SHOWERS AND THUNDERSTORMS WITH
LOCALLY HIGH RAINFALL RATES MAY DRIVE SOME UPTICK IN THE THREAT
FOR MAINLY ISOLATED AND URBAN AREAS OF FLASH FLOODING OVER THE
NEXT SEVERAL HOURS.
DISCUSSION...GOES-E IR SATELLITE IMAGERY AND RADAR DATA SHOWS SOME
BROADENING OF THE CONVECTIVE FOOTPRINT ACROSS AREAS OF THE
MIDWEST, INCLUDING AREAS OF CENTRAL AND EASTERN WI THROUGH
PORTIONS OF LOWER MI. COOLING CLOUD TOP TEMPERATURES ARE NOTED AS
A SHORTWAVE IMPULSE BEGINS TO ROUND THE TOP SIDE OF SUBTROPICAL
RIDGE OVER THE OH VALLEY.
THIS SHORTWAVE ENERGY WILL BE INCREASING THE WARM ADVECTION
PATTERN ACROSS THE REGION WHILE INTERACTING WITH A WELL-DEFINED
AND QUASI-STATIONARY SYNOPTIC FRONT. ADDITIONALLY, A STRENGTHENING
INSTABILITY GRADIENT IS EXPECTED OVER THE NEXT SEVERAL HOURS WITH
THE DIURNAL HEATING CYCLE, AND THIS WILL FURTHER HELP FACILITATE
AN EXPANDING AXIS OF CONVECTION IN CLOSE PROXIMITY TO THE FRONT
AND IN AN ELEVATED FASHION TO THE NORTHEAST OF IT.
MUCAPE VALUES OF 1000 TO 2000 J/KG ARE NOTED IN CLOSE PROXIMITY TO
THE AXIS OF ONGOING ELEVATED CONVECTION, AND PROPAGATION VECTORS
SUGGEST MUCH OF THE CONVECTION SHOULD TRANSLATE DOWN TO THE
EAST-SOUTHEAST GOING THROUGH THE EARLY TO MID-AFTERNOON HOURS.
SOME CELL-TRAINING CONCERNS WILL BE POSSIBLE IN TIME, ESPECIALLY
ACROSS LOWER MI AS THE ACTIVITY OVER CENTRAL AND EASTERN WI
ADVANCES DOWNSTREAM AND EXPANDS IN COVERAGE.
RAINFALL RATES ARE EXPECTED TO BE AS HIGH AS 1 TO 2 INCHES/HOUR
WITH THE STRONGER STORMS, AND THE CELL-TRAINING CONCERNS WILL
SUPPORT POTENTIAL FOR HIGHLY LOCALIZED SWATHS OF 2 TO 4 INCHES.
SOME 12Z CAM SOLUTIONS SUGGEST THIS POTENTIAL, BUT OVERALL THE FFG
EXCEEDANCE PROBABILITIES ARE QUITE MODEST GIVEN THE ANTECEDENT
CONDITIONS WHICH ARE GENERALLY RATHER DRY FOR MOST OF THE AREA.
THEREFORE, THE EXPECTATION IS THAT THERE MAY BE ENOUGH RAINFALL TO
FOSTER A HIGHLY ISOLATED AND MAINLY URBAN FLASH FLOODING THREAT
OVER THE NEXT SEVERAL HOURS AS THESE SHOWERS AND THUNDERSTORMS
ADVANCE OFF TO THE EAST-SOUTHEAST.
ORRISON
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...APX...CLE...DTX...GRB...GRR...IWX...MKX...MQT...
ATTN...RFC...MSR...TIR...NWC...
LAT...LON 45428817 45218634 44398409 43558274 42518225
41698284 41768457 42288690 42968849 43738930
44838920
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page