732
FOUS30 KWBC 150051
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
851 PM EDT TUE APR 14 2026
DAY 1
VALID 01Z WED APR 15 2026 - 12Z WED APR 15 2026
...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE UPPER MIDWEST TO THE OHIO VALLEY...
.. OHIO VALLEY
ONLY MINOR ADJUSTMENTS WERE MADE BASED ON SHORT-TERM RADAR IMAGERY
BUT DID NOT REFLECT WHOLE-SALE CHANGE IN PREVIOUS FORECAST
REASONING. THE LATEST HREF AND ARW RUNS STILL FAVORED THE AREA
WHILE RAINFALL AND RELATED PROBABILITY OF EXCEEDANCE FROM THE RRFS
WERE LOWER. HIGH SEASONABLE PWATS AND ABUNDANT INSTABILITY ALSO
SUPPORT THE POTENTIAL FOR HIGH HOURLY RAINFALL RATES.
..WISCONSIN AND MICHIGAN
MADE A NORTHWARD EXPANSION OF THE SLIGHT RISK IN PARTS OF
WISCONSIN AND MICHIGAN IN RESPONSE TO SHORT-TERM TRENDS IN RADAR
AND SATELLITE IMAGERY. GIVEN THE PLACEMENT OF CONVECITIVE
INITIATION...STARTING TO GIVE MORE CREDENCE TO THE HREF CAMP FOR
OVERNIGHT CONVECTION AND RISK OF EXCESSIVE RAINFALL. IN PARTICULAR,
CONCERN INVOLVES THE POTENTIAL FOR STORMS TO EXPAND NORTHEASTWARD
AND EASTWARD ACROSS WISCONSIN AND NORTHEAST IOWA GIVEN FAVORABLE
INTERACTION IF A WARM FRONT AT THE SURFACE AND STEEP MID-LEVEL
LAPSE RATES YIELDING 1.5 TO 2 INCH PER HOUR RATES IN THE SHORTER
TERM BEFORE RATES BEGIN TO DIMINISH...ALTHOUGH AREAS DOWNSTREAM
HAVE BEEN MADE MORE PRONE TO FLOODING BY 3 TO 5 INCH RAINFALL
AMOUNTS OVER THE PAST FEW DAYS. SEE MPD 0105 FOR FURTHER DETAILS.
..IOWA/ILLINOIS
EXPANDED THE SLIGHT RISK AREA WESTWARD INTO IOWA IN THE WAKE OF
ONE ROUND OF SHOWERS AND THUNDERSOTMS OVER THE NORTHEAST PART OF
THE STATE DUE TO CONCERN OVER CONVECTIVE REDEVELOPMENT. NORMALLY
THIS WOULD BE A CANDIDATE FOR REMOVAL FROM THE SLIGHT RISK
AREA...BUT MOIST SOUTH TO SOUTHWEST FLOW AT LOW LEVELS OVER-RUNNING
THE SURFACE OUTFLOW BOUNDARY HAS THE POTENTIAL TO IGNITE ADDITION
STORMS CAPABLE OF PRODUCING LOCALLY INTENSE RAINFALL RATES. IF
THAT SCENARIO IS REALIZED...RAINFALL RATES IN EXCESS OF 1 INCH PER
HOUR ARE POSSIBLE WHERE 1-HOUR FLASH FLOOD GUIDANCE IS
COMPARABLE...WITH THE POTENTIAL FOR STORMS TO TRACK ALONG THAT SAME
INTERFACE INTO ILLINOIS. SEE MPD 0106 FOR FURTHER DETAILS.
...CENTRAL PLAINS SOUTHWESTWARD TO THE LOWER TRANS-PECOS/BIG
BEND...
..OKLAHOMA AND KANSAS
A BROAD CORRIDOR OF MOISTURE AND INSTABILITY IS EXPECTED TO REMAIN
IN PLACE OVERNIGHT...WITH THE HREF AND RRFS INDICATING THE
POTENTIAL FOR MULTIPLE ROUNDS OF CONVECTIONN FIRING IN PROXIMITY TO
THE DRYLINE. HREF NEIGHBORHOOD PROBABILTIES OF 24 HOUR RAINFALL
EXCEEDING 2 INCHES ARE FAIRLY HIGH (50-70%) AND 20-40% FOR
EXCEEDING 3 INCHES. WITH A STEADY STREAM OF PW VALUES OF 1.25 TO
1.5 INCHES BEING ADVECTING NORTHWARD THROUGH THE SOUTHERN/CENTRAL
PLAINS NEARLY PARALLEL TO THE DRYLINE...SLOW STORM MOTION IS
EXPECTED, MUCH AS BEFORE...THIS MARGINAL RISK AREA WAS A
SOUTHWESTWARD EXTENSION OF THE EXCESSIVE RAINFALL OUTLOOK AREAS
OVER PARTS OF THE UPPER MIDWEST/GREAT LAKES REGION.
BANN
DAY 2
VALID 12Z WED APR 15 2026 - 12Z THU APR 16 2026
...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR THE GREAT
LAKES AND NORTHERN OHIO VALLEY..
THE SURFACE TO MID-LEVEL ENVIRONMENT REMAINS VERY SIMILAR TO THE
PAST COUPLE OF DAYS WITH A STARK DRY LINE EXTENDING FROM THE PECOS
RIVER VALLEY ACROSS THE SOUTHERN PLAINS INTO THE UPPER MISSISSIPPI
VALLEY. A STATIONARY FRONT WILL CONTINUE TO ALIGN WEST TO EAST
FROM ILLINOIS TO NEW YORK AND SERVE AS A MECHANISM FOR HEAVY
RAINFALL POTENTIAL. THE LONGWAVE TROUGH WILL FINALLY BE MAKING
PROGRESS TOWARD THE CENTRAL PLAINS AND THE DEEP LAYER MOISTURE AXIS
AND INSTABILITY SHIFTS SLIGHTLY EASTWARD.
AN UPGRADE TO A SLIGHT RISK FOR EXCESSIVE RAINFALL WAS ADDED ACROSS
SOUTHERN WISCONSIN AND MICHIGAN. ACROSS THE NORTHERN OHIO VALLEY,
NORTHERN ILLINOIS, INDIANA, AND OHIO WERE INCLUDED IN THE RISK
AREA. A PERSISTENCE FORECAST WORKED WELL HERE WHERE INSTABILITY,
PLENTIFUL MOISTURE NEAR THE SURFACE (PWATS NEAR OR EXCEEDING 1.5
INCHES), AND A NEARBY STATIONARY BOUNDARY AND WEAK AREA OF LOW
PRESSURE WILL HELP CREATE AN ENVIRONMENT CAPABLE OF PRODUCING HEAVY
RAINFALL. WPC QPF INDICATES 1-3 INCHES OF RAIN OVER THE SAME
REGIONS THAT HAVE HAVE SEEN ROUNDS OF HEAVY RAINFALL OVER THE PAST
COUPLE OF DAYS. THE FLASH FLOOD GUIDANCE, MEANWHILE, HAS LOWERED TO
A HALF AN INCH TO AN INCH. ANOTHER CONSIDERATION WAS THE FLASH
FLOOD SENSITIVITY FOR URBAN AREAS SUCH AS MILWAUKEE, CHICAGO, AND
DETROIT. THE SLIGHT RISK DOES EXTEND SOUTHWARD ACROSS NORTHERN ILLINOIS
AND INDIANA TO ACCOUNT FOR UNCERTAINTY ON STORM TRACK AND THE
SPREAD OF 2 INCH HREF 24 HR QPF NEIGHBORHOOD PROBABILITY.
..EASTERN OKLAHOMA AND THE OZARKS
SIMILAR TO THE PAST COUPLE OF DAYS, AFTERNOON STORMS ARE LIKELY TO
FORM AND TREK FROM THE SOUTHWEST TO NORTHEAST AHEAD OF THE
LONGWAVE TROUGH MOVING INTO THE CENTRAL PLAINS. EASTERN OKLAHOMA
INTO THE OZARKS WILL BE IN THE RIGHT ENTRANCE OF THE JET STREAK,
WHICH WILL HELP PROVIDE LIFT. AT THE SURFACE, HIGH PWATS AND
SURFACE INSTABILITY WILL ONCE AGAIN PRIME THE ATMOSPHERE FOR HOURLY
RAINFALL RATES OF AN INCH/HR. QPF GUIDANCE DOES SHOW A MAXIMUM OF
1-2 INCHES ACROSS THE REGION, BUT MODEL GUIDANCE SHOWS LITTLE TO
NO PROBABILITY FOR ACCUMULATIONS EXCEEDING 2 INCHES. THEREFORE, A
MARGINAL RISK IS MAINTAINED FOR THE RISK AREA. ADDITIONALLY, THE
MORE FLASH FLOOD PRONE OZARK MOUNTAIN RANGE IS RELATIVELY DRY.
..NORTHEAST
A MARGINAL RISK FOR EXCESSIVE RAINFALL WAS EXPANDED EASTWARD ACROSS
NEW YORK STATE TO CONNECTICUT. MOISTURE TRANSPORT WILL INCREASE
ACROSS THE EAST AS THE LONGWAVE TROUGH SHIFTS EASTWARD INTO THE
CENTER OF THE COUNTRY. ADDITIONALLY, WEAK AREAS OF LOW PRESSURE
WILL RIDE ALONG A STATIONARY BOUNDARY ACROSS THE NORTHEAST THAT
WILL HELP FUNNEL MOISTURE ACROSS THE AREA. REMNANTS OF THE STORMS
ACROSS THE GREAT LAKES MAY BRING A ROUND OF SHOWERS AND STORMS IN
THE MORNING, FOLLOWED BY ANOTHER ROUND OF HEAVIER SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON. MODEL GUIDANCE SHOWS A CORRIDOR OF
1-1.5 INCHES RAINFALL WITH EMBEDDED HIGHER AMOUNTS DEPENDING ON THE
MODEL. THE RELATIVELY LOWER FLASH GUIDANCE ACROSS WESTERN
PENNSYLVANIA AND THE MORE URBAN FOOTPRINT OF AREAS SUCH AS
CONNECTICUT AND NEW ENGLAND ALSO HELP CONFIDENCE OF EXPANDING THE
MARGINAL EASTWARD.
WILDER
DAY 3
VALID 12Z THU APR 16 2026 - 12Z FRI APR 17 2026
THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOODING GUIDANCE IS
LESS THAN 5 PERCENT.
WILDER
DAY 1 THREAT AREA: HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/94EPOINTS.TXT
DAY 2 THREAT AREA: HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/98EPOINTS.TXT
DAY 3 THREAT AREA: HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/99EPOINTS.TXT
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