780
FOUS30 KWBC 272021
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
421 PM EDT MON OCT 27 2025
DAY 1
VALID 16Z MON OCT 27 2025 - 12Z TUE OCT 28 2025
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE EASTERN FLORIDA COAST...
A FEW LOCATIONS OBSERVED SEVERAL INCHES OF RAINFALL THAT LEAD TO
AREAS OF FLASH FLOODING YESTERDAY. ADDITIONAL RAINFALL THIS
MORNING WILL CONTINUE TO BE IMPACTFUL TO THE VULNERABLE COASTAL
LOCATIONS. AN APPROACHING UPPER LEVEL TROUGH IS HELPING TO AID
DIVERGENCE/DIFLUENCE ALOFT. ONSHORE FLOW IS ALLOWING FOR SUFFICIENT
MOISTURE AND INSTABILITY TO MOVE ASHORE, AND THE LOW-LEVEL FLOW
AND UPPER LEVEL FLOW ARE NEARLY BALANCED, IMPLYING STORMS WITH
HEAVY RAINFALL SHOULDN'T GO ADVANCE TOO FAR INLAND. BACK BUILDING
AND TRAINING OF CONVECTION WILL BE POSSIBLE. A MARGINAL RISK AREA
WAS MAINTAINED FOR THE EASTERN COASTLINE GIVEN THE POTENTIAL
IMPACTS FROM ADDITIONAL RAINFALL OVER SATURATED SOILS.
OTHERWISE WITH THIS UPDATE, THE MRGL RISK ACROSS THE SOUTHERN
APPALACHIANS AND SURROUNDINGS WAS REMOVED AS RAINFALL RATES ARE
EXPECTED TO REMAIN BELOW 0.5"/HR WITH VERY LIMITED INSTABILITY.
WHILE LOCALIZED ~2" TOTALS ARE EXPECTED, THE RELATIVELY LONG
DURATION RAINFALL WITH DROUGHT CONDITIONS AND MUCH BELOW AVERAGE
STREAMFLOWS SHOULD ALLOW FOR BENEFICIAL RAINFALL FOR THE REGION.
CHURCHILL/CAMPBELL
DAY 2
VALID 12Z TUE OCT 28 2025 - 12Z WED OCT 29 2025
THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOOD GUIDANCE IS LESS
THAN 5 PERCENT.
2030Z UPDATE: AN INHERITED MRGL RISK CENTERED ON THE MID-SOUTH WAS
REMOVED FOR THIS UPDATE, AS A LACK OF INSTABILITY AND PREVAILING
DROUGHT CONDITIONS ARE EXPECTED TO RESULT IN LARGELY BENEFICIAL
RAINFALL FOR THE REGION (AS SUGGESTED BY LESS THAN 5% CHANCES FOR
1-HR, 3-HR, AND 6-HR FFG EXCEEDANCE PER LATEST 12Z HREF SUITE).
CHURCHILL
DAY 3
VALID 12Z WED OCT 29 2025 - 12Z THU OCT 30 2025
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS THE
SOUTHERN AND CENTRAL APPALACHIANS AND SURROUNDING PORTIONS OF THE
OHIO/TENNESSEE VALLEYS...
2030Z UPDATE: A CLOSED UPPER-LOW WILL PIVOT FROM THE MID-SOUTH TO
THE OH VALLEY, CAUSING RAINFALL TO OVERSPREAD THE TN/OH VALLEY WITH
ANOMALOUS LOW- LEVEL MOISTURE TRANSPORT DRIVING EAST-SOUTHEAST
MOISTURE TRANSPORT INTO THE SOUTHERN/CENTRAL APPALACHIANS. WHILE
THE BULK OF THIS RAINFALL IS EXPECTED TO BE BENEFICIAL, SHORT-TERM
FFGS (1-HR AND 3-HR) MAY BE LOW ENOUGH (AS LOW AS 1.0" AND 1.5",
RESPECTIVELY) TO ALLOW FOR LOCALIZED EXCEEDANCE ACROSS THE REGION.
THIS IS DESPITE LIMITED INSTABILITY (SIMILAR TO DAY 2 ACROSS THE
MID-SOUTH), AS THE DYNAMICS OF THE CLOSED LOW (NOTABLE PV ANOMALY
WITH ENHANCED DIVERGENCE ALOFT VIA LEFT EXIT REGION OF ~130 KT JET
STREAK @ 250 MB) MAY RESULT IN LOCALIZED 2" EXCEEDANCE IN THE OH/TN
VALLEY (WITH TERRAIN FORCING PRIMARILY DRIVING ANY LOCALIZED 2"
EXCEEDANCE ALONG/EAST OF THE SOUTHERN/CENTRAL APPALACHIANS).
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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