270
AWUS01 KWNH 032200
FFGMPD
INZ000-ILZ000-040400-
MESOSCALE PRECIPITATION DISCUSSION 0075
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
558 PM EDT FRI APR 03 2026
AREAS AFFECTED...NORTH CENTRAL IL...WESTERN IN
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY
VALID 032200Z - 040400Z
SUMMARY...THUNDERSTORMS FORMING ALONG AND NORTH OF A WARM FRONT
WILL BE CAPABLE OF PRODUCING UP TO 2"/HR RAINFALL RATES. WITH
PROLONGED, MOIST SOUTHWESTERLY FLOW EXPECTED TO INTERSECT THE
FRONT FOR SEVERAL HOURS, FLASH FLOODING IS LIKELY THROUGH EARLY
EVENING.
DISCUSSION...DOPPLER RADAR SHOWS SCATTERED THUNDERSTORMS HAVING
FORMED ALONG A WARM FRONT THAT EXTENDS FROM THE STRENGTHENING AREA
OF LOW PRESSURE IN NORTHWEST MO EASTWARD INTO NORTHERN OH.
LOW-LEVEL SOUTHWESTERLY FLOW IS PROVIDING HEALTHY THETA-E AND
MOISTURE ADVECTION WHILE MLCAPE ALONG AND JUST SOUTH OF THE WARM
FRONT IS >2,000 J/KG. PWS ARE FORECAST TO SURPASS 1.5" THIS
EVENING, WHICH IS ABOVE THE 99TH CLIMATOLOGICAL PERCENTILE FOR
EARLY-MID APRIL. MEANWHILE, SHEARED SHORTWAVE ENERGY RACING NORTH
FROM THE SOUTH CENTRAL U.S. WILL PROVIDE ADDITIONAL SYNOPTIC SCALE
LIFT ALOFT LATER THIS EVENING. VERTICAL WIND PROFILES WILL FAVOR
SUPERCELLS WITH >40 KTS OF EFFECTIVE BULK SHEAR AND UP TO 200
M2/S2 OF SRH. AS STORM FORM ALONG THE FRONT, PERSISTENT INFLOW
INTO THE WARM FRONT AS IT SLOWLY MOVES NORTH GIVES RISE TO
BACK-BUILDING AND TRAINING STORMS, INCREASING CONCERNS FOR LONGER
RESIDENCY TIMES FOR THESE STORMS.
LATEST 18Z HREF SHOWS MODERATE CHANCES (40-60%) FOR RAINFALL
TOTALS >2" IN NORTH-CENTRAL IL. THIS IS SUPPORTED BY THE 21Z WOFS
USING CUMULATIVE >2" PAINT BALLS THROUGH 03Z. THERE ARE SEVERAL
CAMS MEMBERS (RRFS, NSSL-MPAS, 20Z HRRR) THAT SHOWS THIS CLUSTER
OF STORMS HAVING THE POTENTIAL TO PRODUCE LOCALIZED RAINFALL
AMOUNTS >4" THROUGH THIS EVENING. 1-HR FFGS ARE GENERALLY BELOW
1.5" FOR THE MAJORITY OF THE AT-RISK REGION, AND EVEN 3-HR FFGS
ARE <2" (LESS THAN 1.5" ON THE SOUTHERN PERIPHERY OF THE
CHICAGOLAND AREA). THE SOUTHERN TIER OF CHICAGOLAND COULD CONTEND
WITH EXCESSIVE RAINFALL THIS EVENING AS ELEVATED INSTABILITY MOVES
NORTHWARD AND THE STORMS LIFT NORTHWARD WITH THE WARM FRONT.
WITH CONCERNS FOR TRAINING AND BACK-BUILDING STORMS IN AN
ATMOSPHERIC ENVIRONMENT SUITABLE TO GENERATE UP TO 2"/HR RAINFALL
RATES, CASES OF FLASH FLOODING ARE LIKELY IN PARTS OF CENTRAL AND
NORTHERN IL, AND POTENTIALLY IN WESTERN IN THIS EVENING. SHOULD
THOSE >4" AMOUNTS ON VARIOUS CAMS COME TO FRUITION, LOCALLY
SIGNIFICANT FLASH FLOODING COULD UNFOLD. POOR DRAINAGE AREAS AND
URBANIZED COMMUNITIES ARE MOST VULNERABLE TO FLASH FLOODING THIS
EVENING.
MULLINAX
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...DVN...ILX...IND...IWX...LOT...LSX...
ATTN...RFC...MSR...TIR...NWC...
LAT...LON 41768809 41418739 40948612 40618601 40098627
40018747 39918909 39659073 39979130 40539086
40919006 41388917
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