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FOUS30 KWBC 160011
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
811 PM EDT WED APR 15 2026
DAY 1
VALID 01Z THU APR 16 2026 - 12Z THU APR 16 2026
...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR THE GREAT
LAKES/NORTHERN OHIO VALLEY AND IN/NEAR THE OZARKS..
..GREAT LAKES AND OHIO VALLEY
ANOTHER ROUND OF CONVECTION DEVELOPED DEVELOPED THIS AFTERNOON OVER
PORTIONS OF WISCONSIN AND IOWA WHERE MOISTURE AND INSTABILITY
POOLED AHEAD OF FRONTAL BOUNDARY. AS THE LINE OF STORMS CONTINUES
TO MOVE EASTWARD...THERE WILL CERTAINLY BE OVERLAP WITH AREAS THAT
WERE IMPACTED BY MULTIPLE DAYS OF MODERATE TO HEAVY RAINFALL. ANTECEDENT
CONDITIONS FAVOR A MORE SENSITIVE SOIL MOISTURE COMPOSITION ALONG
WITH REMNANT ELEVATED STREAMFLOWS SITUATED ACROSS THE AREA FROM
EASTERN IOWA THROUGH NORTHERN ILLINOIS AND SOUTHERN WISCONSIN.
THE AREA OF LOWER MICHIGAN REMAINED THE MOST SENSITIVE REGION.
PRECIPITABLE WATER ANOMALIES IN THE 95TH TO 99TH PERCENTILE RANGE
FOR THIS SEASONAL CLIMATOLOGY.
..OZARKS AND ADJACENT AREAS
ONE CHANGE IN THE AREA WAS TO INTRODUCE A SLIGHT RISK AREA
IN/NEAR THE OZARKS FOR THIS EVENING INTO THE OVERNIGHT HOURS.
DEWPOINTS IN THE LOWER 70S WERE LOCATED IMMEDIATELY UPSTREAM WHILE
A DRYLINE WAS APPROACHING FROM THE WEST AT THE SAME TIME. LOCALIZED
TRAINING/REPEATING CONVECTION IS LIKELY TO RESULT IN SPOTS OF 1 TO
2 INCH RAINFALL RATES AT TIMES, GIVEN THE TERRAIN...THINK THE
COMBINATION IS ENOUGH TO WARRANT A SLIGHT RISK. FATHER
NORTH...MAINTAINED A MARGINAL RISK AREA WHERE ANTECEDENT
CONDITIONS REMAINED PRETTY DRY WITH THE 1/3/6 HR FFG PARAMETERS ALL
SUFFICIENTLY ABOVE 2.5" FOR EACH THRESHOLD. THAT SAID, URBANIZED
AREAS WILL STILL SEE HIGHER RUN OFF CAPABILITIES WITH A POTENTIAL
FOR LOCALIZED FLASH FLOODING IN THE EVENING AND OVERNIGHT TIME
FRAME.
..NORTHEAST
LITTLE CHANGE MADE TO THE PREVIOUS OUTLOOK WITH A WIDESPREAD MRGL
RISK EXTENDING FROM WESTERN NEW YORK INTO PORTIONS OF
PENNSYLVANIA AND INTO PARTS OF SOUTHERN NEW ENGLAND. HREF
NEIGHBORHOOD PROBABILITIES ARE FAIRLY ROBUST FOR >1" (50-80%)
ACROSS MUCH OF THE ABOVE CORRIDOR WITH THE HIGHEST PROBS FOR BOTH
>1" AND >2" LOCATED DOWNWIND OF LAKE ERIE. URBANIZED ZONES WILL BE
THE PRIMARY AREAS OF CONCERN HERE.
BANN
DAY 2
VALID 12Z THU APR 16 2026 - 12Z FRI APR 17 2026
THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOODING GUIDANCE IS
LESS THAN 5 PERCENT.
CAMPBELL/KLEEBAUER
DAY 3
VALID 12Z FRI APR 17 2026 - 12Z SAT APR 18 2026
...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE MID-MISSISSIPPI VALLEY INTO THE CENTRAL PLAINS...
20Z UPDATE: A DEEP, POSITIVELY-TILTED LONGWAVE TROUGH WILL WANDER
EASTWARD OUT OF THE ROCKIES ON FRIDAY LEADING TO BROAD LARGE SCALE
ASCENT FROM THE SOUTHERN PLAINS TO THE MIDWEST. A WELL-DEFINED AXIS
OF DIFFLUENCE AHEAD OF THE MEAN TROUGH WITH SEVERAL SHORTWAVES
RIPPING THROUGH THE FLOW WILL ENHANCE AN AREA OF CONVECTIVE
DEVELOPMENT WITHIN A STRENGTHENING WARM-SECTOR ENVIRONMENT
POSITIONED BETWEEN A STRONG COLD FRONT OVER THE HIGH PLAINS AND A
QUICKLY ADVANCING WARM FRONT MIGRATING POLEWARD THROUGH THE
ADJACENT MISSISSIPPI AND OHIO VALLEY'S. THE CURRENT SETUP IS
CONDUCIVE FOR A LARGE HEAVY RAIN FOOTPRINT WITH ENSEMBLE MEAN QPF
ALREADY DENOTING AN EXPANSIVE 1-2" OUTPUT WITH EMBEDDED HIGHER
TOTALS. THIS IS EVEN PRIOR TO THE CAMS ADDITIONS THAT HANDLE THE
MAGNITUDE OF CONVECTION BETTER, SO ANTICIPATING SOME 3+ INCH MEANS
LIKELY TO MATERIALIZE IN FUTURE UPDATES.
THE MAIN TREND THIS PERIOD IS THE CONTINUATION OF THE ML OUTPUTS
BEING FURTHER SOUTH AND SOUTHWEST WITH THE QPF CORE AS THE PRIMARY
THETA_E RIDGE CORRELATES WELL WITH THE HEAVIEST PRECIP AS
CONVECTIVE MAGNITUDES WILL LIKELY BE MAXIMIZED WITHIN THAT DEEPER
MOIST, UNSTABLE ENVIRONMENT. GLOBAL DETERMINISTIC IS ALREADY
BEGINNING TO SHOW SIGNS OF LEANING IN THAT DIRECTION WITH THE 12Z
ECMWF THE MOST NOTABLE IN THE SOUTHERN ALIGNMENT OF THE HEAVIER QPF
FOOTPRINT. THIS ACTUALLY MATCHES THE ECAIFS, TO A DEGREE IN ITS
PRESENTATION, ANOTHER FAVORED OVERLAP THAT TENDS TO VERIFY WELL
ONCE WE REACH INSIDE 72 HRS FROM AN EVENT. IN THIS CASE, THE MAIN
AREA OF INTEREST WILL LIKELY BE A LITTLE FURTHER SOUTH AND
SOUTHWEST COMPARED TO WHAT WAS FORECAST PREVIOUSLY IN REGARDS TO
THE SLGT RISK. THAT SAID, THERE'S STILL HINTS THE OVERALL
MERIDIONAL PATTERN INVOLVED COULD STILL ENHANCE HEAVIER
PRECIPITATION FURTHER NORTH INTO THE MIDWEST WHERE THE PREVIOUS
SLGT RISK WAS ALIGNED. AS A RESULT OF THE TRENDS AND SOME
CONTINUITY, DECIDED TO EXPAND UPON THE SLGT RISK FURTHER SOUTH WITH
THE HIGHEST CONFIDENCE IN HEAVY PRECIP LIKELY LYING WITHIN THE
MISSOURI VALLEY DOWN INTO PERHAPS EASTERN KS AS THE UPPER JET
PRESENTATION WOULD LIKELY PROMOTE THE BEST THE LER DYNAMICS OVER
THAT PARTICULAR CORRIDOR. THIS IS A PERIOD TO MONITOR CLOSELY AS
THE EXPANSE OF HEAVIER PRECIP WILL LIKELY PRODUCE SCATTERED FLASH
FLOOD PROSPECTS GIVEN THE ENVIRONMENTAL FAVORABILITY, AS WELL AS
THE LOWER FFG'S IN PLACE ACROSS NORTHERN MO DOWN INTO EASTERN KS.
ANY FURTHER SOUTH PUSH WOULD PUT OK IN PLAY AS WELL, SO THIS
FORECAST COULD BE A BIT FLUID PENDING THE CONTINUED TRENDS.
KLEEBAUER
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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