909
FOUS30 KWBC 031854
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
254 PM EDT TUE JUN 3 2025
DAY 1
VALID 1846Z TUE JUN 03 2025 - 12Z WED JUN 04 2025
...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
SOUTHEAST KANSAS...
..19Z SPECIAL UPDATE
A MODERATE RISK UPGRADE WAS INTRODUCED WITH THIS UPDATE FOR
PORTIONS OF SOUTHEASTERN KANSAS. A TRAINING LINE OF HEAVY
THUNDERSTORMS HAS SET UP ALONG AND SOUTH OF I-35 IN AND EAST OF
WICHITA IS PRODUCING AREAS OF CONSIDERABLE FLASH FLOODING. RATES IN
THE CONVECTION CURRENTLY ARE OVER 2 INCHES PER HOUR, AND SHOWING NO
SIGNS OF WEAKENING. THE LINE OF STORMS IS NEARLY STATIONARY, WITH
ADDITIONAL CONVECTION FORMING SOUTHWEST OF THE AREA WHICH ARE
LIKELY TO TRAIN OVER THESE SAME AREAS OVER THE NEXT SEVERAL HOURS.
LOCALIZED TOTALS OF 7 INCHES HAVE ALREADY FALLEN IN THE HARDEST HIT
AREAS. IT'S LIKELY SOME AREAS WILL EXCEED 10 INCHES OF RAIN BEFORE
THE LINE EVENTUALLY MOVES OFF TO THE EAST. ADDITIONAL SIGNIFICANT
FLASH FLOODING, INCLUDING FLASH FLOOD EMERGENCIES, ARE LIKELY OVER
THE NEXT SEVERAL HOURS.
PLEASE SEE MPD 351 AT
WPC.NCEP.NOAA.GOV/METWATCH/METWATCH_MPD_MULTI.PHP?MD=0351&YR=2025 FOR
ADDITIONAL DETAILS.
WEGMAN
DAY 2
VALID 12Z WED JUN 04 2025 - 12Z THU JUN 05 2025
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE UPPER MIDWEST, MIDDLE MISSISSIPPI VALLEY, SOUTHERN PLAINS, THE
FOUR CORNERS, AND THE SOUTHEAST COAST...
..FOUR CORNERS INTO CENTRAL/SOUTHERN HIGH PLAINS
ANOTHER ACTIVE DAY OF SHOWERS AND THUNDERSTORMS EXPECTED AS THE
UPPER LOW OVER NORTHERN BAJA FILLS AND EJECTS NORTHEAST ATOP THE
FOUR CORNERS. THE ACCOMPANYING ASCENT WILL MOVE INTO CONTINUED
ANOMALOUS PWS WHICH WILL EXCEED THE 99TH PERCENTILE (PER NAEFS).
THIS WILL FUEL WIDESPREAD CONVECTION CAPABLE OF LOCALIZED RAINFALL
RATES OF 0.5"/HR (OR AT TIMES HIGHER). STORMS WILL LIKELY MOVE
SLOWLY BENEATH THE UPPER TROUGH, LEADING TO A LONGER DURATION OF
HEAVY RAIN. ALTHOUGH TOTAL RAINFALL WILL BE MODEST IN MOST AREAS
(AS REFLECTED BY RELATIVELY LOW 24-HR PROBABILITY FROM ECENS/GEFS
FOR 1" EXCEEDANCE), WHERE THE HEAVY RAIN IMPACTS SENSITIVE TERRAIN
FEATURES OR URBAN AREAS INSTANCES OF FLASH FLOODING COULD RESULT.
PROBABILITIES HAVE ALSO INCREASED A BIT (PARTICULARLY FROM THE NEW
00Z ECENS SUITE) FURTHER EAST INTO THE CENTRAL/SOUTHERN HIGH
PLAINS AND THE MRGL RISK HAS BEEN EXPANDED ACCORDINGLY. SHOULD
MODELS COME INTO BETTER AGREEMENT, ADDITIONAL EXPANSION MAY BE
NEEDED FURTHER SOUTH INTO WEST TX (AND WITH ADDITIONAL CAM GUIDANCE
AND AGREEMENT, AN UPGRADE TO SLGT MAY ALSO BE NEEDED).
..SOUTHERN PLAINS AND MID-MISSISSIPPI VALLEY TO GREAT LAKES
THE COLD FRONT FROM D1 WILL CONTINUE ITS TREK EASTWARD ON
WEDNESDAY, BUT WILL START TO SLOW AND BECOME ALIGNED MORE WEST TO
EAST AS ITS TAIL GETS PULLED NORTHWARD BY AN APPROACHING SHORTWAVE
OVER THE FOUR CORNERS REGION. SHORTWAVES EMBEDDED WITHIN THE FLOW
WILL CONTINUE TO RACE NORTHEAST, ESPECIALLY FROM MISSOURI TO
MICHIGAN, WHICH IS WHERE THE GREATEST CONCENTRATION OF
THUNDERSTORMS IS EXPECTED ON D2 (THOUGH SOME MODELS ARE ALSO
INDICATED POTENTIAL FOR ISOLATED CONVECTIVE DEVELOPMENT FARTHER
SOUTHWEST INTO PORTIONS OF THE SOUTHERN PLAINS). STORM MOTIONS
ALONG THE FRONT ARE LIKELY TO BE PROGRESSIVE, LIFTING OFF TO THE
NORTHEAST ON 0-6KM MEAN WINDS OF 20-30 KTS, BUT WEAKER CORFIDI
VECTORS ALIGNED BOTH TO THIS MEAN WIND AND THE FRONT SUGGESTS A
POTENTIAL FOR TRAINING. AS RAINFALL RATES PEAK ABOVE 1"/HR WITHIN
FAVORABLE THERMODYNAMICS, THIS COULD RESULT IN STRIPES OF HEAVY
RAINFALL WITH ENSEMBLES INDICATING 10-40% CHANCE OF EXCEEDING 1"
AND UP TO 10% PROBABILITIES FOR EXCEEDING 2" (WITH THE NEW ECENS
BEING THE MOST AGGRESSIVE). THE INHERITED MRGL RISK WAS MAINTAINED
(AND EXPANDED A BIT SOUTHWEST) WITH THIS UPDATE.
..SOUTHEAST COAST
GUIDANCE CONTINUES TO BE SOMEWHAT AGGRESSIVE WITH A WAVE OF LOW
PRESSURE POTENTIALLY DEVELOPING ALONG AN INVERTED TROUGH SHIFTING
NORTHEAST ALONG THE FL/GA/SC COASTS. WHILE NHC CONTINUES TO
INDICATE A 10% PROBABILITY OF TROPICAL OR SUB-TROPICAL DEVELOPMENT
WITH THIS FEATURE, REGARDLESS OF WHETHER A CIRCULATION FORMS OR
NOT, THERE CONTINUES TO BE INCREASING CONFIDENCE THAT HEAVY RAIN
WILL SPREAD ACROSS THE FL PENINSULA AND THEN ROTATE ONSHORE THE
GA/SC COASTS ON WEDNESDAY. THERE ALSO HAS BEEN A CLEAR MODEL TREND
OF POTENTIAL INCREASED CONVECTIVE DEVELOPMENT FARTHER INLAND TO
THE FL PANHANDLE AND INTO SOUTHEAST AL AND SOUTHWEST GA (LIKELY
DUE TO A STRONGER CLOSED LOW AND THE ASSOCIATED DYNAMICS), SO THE
MRGL WAS EXPANDED TO REFLECT THIS. WITH PWS PROGGED TO EXCEED 2",
ABOVE THE 90TH PERCENTILE, SUPPORTED BY WARM CLOUD DEPTHS THAT MAY
EXCEED 15,000 FT, EFFICIENT RAINFALL RATES OF 1-2"/HR WILL BE
LIKELY IN ANY SHOWERS/THUNDERSTORMS. IT CERTAINLY REMAINS POSSIBLE
THAT THE HEAVIEST RAINFALL IN ASSOCIATION WITH THE POTENTIAL
SURFACE LOW WILL REMAIN JUST OFFSHORE, BUT IMPRESSIVE MOISTURE
CONVERGENCE FROM JACKSONVILLE, FL TO CHARLESTON, SC SHOULD SUPPORT
WAVES OF HEAVY RAINFALL REGARDLESS OF DEVELOPMENT OF THIS SYSTEM.
ADDITIONALLY, PLENTIFUL TROPICAL MOISTURE ACROSS THE REST OF THE FL
PENINSULA AND A SHORTWAVE CONTINUING TO PIVOT ACROSS THE GULF
COULD ENHANCE RAINFALL OVER MUCH OF FLORIDA WEDNESDAY, AND THE MRGL
WAS MAINTAINED ACCORDINGLY (WITH THE EXCEPTION OF THE FL KEYS,
WHICH WERE REMOVED DUE TO MODEL CONSENSUS THAT CONVECTION WILL BE
PULLING AWAY NORTHWARD BY 12Z WEDS).
CHURCHILL/WEISS
DAY 3
VALID 12Z THU JUN 05 2025 - 12Z FRI JUN 06 2025
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
SOUTHERN KANSAS AND NORTHERN OKLAHOMA...
..CENTRAL/SOUTHERN PLAINS INTO THE MIDWEST
MODEST RETURN FLOW FROM THE GULF OVERNIGHT ON D2 LOOKS TO RESULT IN
ELEVATED PWS ONCE AGAIN INTO THE SOUTHERN PLAINS BY D3, AS DPVA IN
ASSOCIATION WITH THE AFOREMENTIONED UPPER-LOW (NOW SHORTWAVE) MAY
HELP TO SPUR MORE SIGNIFICANT CONVECTIVE ORGANIZATION AND GROWTH.
WHILE MODELS ARE STILL IN RATHER SUBSTANTIAL DISAGREEMENT ON THE
SCALE OF ORGANIZATION AND ULTIMATE PLACEMENT OF HIGHER QPF AMOUNTS,
THERE'S ENOUGH AGREEMENT TO REINTRODUCE A SLGT TO PORTIONS OF
KS/OK (WHERE ECENS BEST OVERLAPS THE STRONGER GEFS SIGNAL).
DOWNSCALED GFS AND ECMWF SOLUTIONS SUGGEST THE POTENTIAL FOR
LOCALIZED 2-3" TOTALS (AS DO THE RESPECTIVE ENSEMBLE EXCEEDANCE
PROBS).
..SOUTHEAST/SOUTHERN MID-ATLANTIC COAST
GUIDANCE CONTINUES TO INDICATE THE POTENTIAL FOR FURTHER
DEVELOPMENT OF THE AFOREMENTIONED WAVE OF LOW PRESSURE. REGARDLESS
OF ANY TROPICAL OR SUB-TROPICAL DEVELOPMENT OF THIS FEATURE, HEAVY
RAINFALL IS LIKELY TO REMAIN IN CLOSE PROXIMITY TO THE COAST INTO
D3. THE MRGL WAS EXPANDED A BIT TO COVER THE RANGE OF SOLUTIONS
FROM THE MODELS AT THIS JUNCTURE.
CHURCHILL
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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