251
AWUS01 KWNH 141802
FFGMPD
INZ000-WIZ000-ILZ000-MNZ000-IAZ000-150000-
MESOSCALE PRECIPITATION DISCUSSION 0103
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EDT TUE APR 14 2026
AREAS AFFECTED...EASTERN IA...SOUTHERN WI...NORTHERN AND EASTERN
IL...WESTERN AND CENTRAL IN
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 141800Z - 150000Z
SUMMARY...DEVELOPING AND EXPANDING CLUSTERS OF HEAVY SHOWERS AND
THUNDERSTORMS COUPLED WITH LOCALLY WET/SENSITIVE ANTECEDENT
CONDITIONS WILL FOSTER AN ISOLATED TO SCATTERED THREAT FOR FLASH
FLOODING GOING THROUGH EARLY THIS EVENING.
DISCUSSION...EARLY AFTERNOON GOES-E VISIBLE SATELLITE IMAGERY
SHOWS STRONGER DIURNAL HEATING PROMOTING A STEADY DESTABILIZATION
OF THE BOUNDARY LAYER ACROSS EASTERN IA, WESTERN IL AND NOSING
INTO SOUTHWEST WI. THIS AIRMASS IS POOLING SOUTH AND EAST OF A
QUASI-STATIONARY FRONT AS MULTIPLE WAVES OF LOW PRESSURE ADVANCE
ALONG IT.
SOME MODEST CINH REMAINS IN PLACE ACROSS THESE AREAS, BUT MLCAPE
VALUES OF 2000 TO 3000 J/KG ARE ALREADY IN PLACE, AND THIS IS
BEING SUPPORTED BY STEEP MID-LEVEL LAPSE RATES TRANSITING THE
MIDWEST. MEANWHILE, SATELLITE IMAGERY SHOWS A MODEST MID-LEVEL
SHORTWAVE IMPULSE EJECTING NORTHEASTWARD ACROSS CENTRAL AND
EASTERN IA DOWN THROUGH NORTHERN MO AND INTO WESTERN IL. THIS
ENERGY COUPLED WITH ADDITIONAL SOLAR INSOLATION SHOULD ERODE THE
REMAINING CAP ACROSS THE REGION AND SET THE STAGE FOR CONVECTIVE
INITIATION. MUCH OF THIS SHOULD BE FOCUSED IN CLOSE PROXIMITY TO A
LEFTOVER/DIFFUSE OUTFLOW BOUNDARY FROM THE EARLY-DAY CONVECTION.
AS CONVECTION GROWS UPSCALE, THERE WILL GRADUALLY BE CONCERNS FOR
A FEW CELL-MERGERS AND SOME CELL-TRAINING. A COMBINATION OF
MULTICELLS AND SUPERCELLS WILL BE LIKELY GIVEN THE STRONG
INSTABILITY IN CONJUNCTION WITH STRONG SHEAR (EFFECTIVE BULK SHEAR
APPROACHING 50 KTS). THE LARGER SCALE ENVIRONMENT IS ALSO
INCREASINGLY MOIST WITH AID FROM A SOUTHWEST LOW-LEVEL JET OF 30
TO 40+ KTS. DEEPER LAYER SOUTHWESTERLY MOISTURE TRANSPORT IS NOTED
ALOFT TOO WITH ELEVATED CIRA-LVT MAGNITUDES.
LOCALLY SIGNIFICANT MODEL DISAGREEMENT IS NOTED THROUGH THIS
EVENING WITH THE PLACEMENT OF THE CONVECTION AND ITS GENERAL
EVOLUTION, BUT A MULTI-MODEL CONSENSUS SUGGESTS EASTERN IA,
NORTHERN IL AND SOUTHERN WI SEEING ONE FOCUS FOR CONVECTION, WITH
AREAS OF CENTRAL/EASTERN IL AND INTO WESTERN IN SEEING A SECOND
FOCUS.
RAINFALL RATES WILL BE CAPABLE OF REACHING 1 TO 2 INCHES/HOUR,
WITH SOME LOCALIZED TOTALS BY EARLY THIS EVENING OF 2 TO 4 INCHES.
THE ANTECEDENT CONDITIONS ARE LOCALLY QUITE SENSITIVE, AND
ESPECIALLY FROM EASTERN IA THROUGH NORTHERN IL AND SOUTHERN WI.
ISOLATED TO SCATTERED AREAS OF FLASH FLOODING WILL BE POSSIBLE AS
A RESULT.
ORRISON
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ARX...DMX...DVN...ILX...IND...IWX...LOT...MKX...
ATTN...RFC...MSR...TIR...NWC...
LAT...LON 43969015 43808891 43378810 42458766 41648679
41038574 40368523 39538567 39238682 39538845
40048943 41199043 41619249 41909331 42369330
42689297 43329238 43909121
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