698
FOUS30 KWBC 040056
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
856 PM EDT FRI OCT 3 2025
DAY 1
VALID 01Z SAT OCT 04 2025 - 12Z SAT OCT 04 2025
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN FLORIDA AND THE INTERMOUNTAIN WEST...
..FLORIDA'S EAST COAST
FOR THE 03/01Z UPDATE, MADE FEW CHANGES TO EITHER MARGINAL RISK
AREA. THE NORTHERN PORTION OF THE MARGINAL RISK AREA IN FLORIDA WAS
REMOVED FOR THE DURATION OF THE OVERNIGHT HOURS AS DRIER AIR
FILTERED IN FROM THE NORTH DURING THE DAY. THE RESPITE SHOULD BE
SHORT-LIVED. FARTHER SOUTH...MAINTAINED THE MARGINAL RISK AREA
WHERE THE MOISTURE WAS DEEPER AND RADAR STILL SHOWED SOME SHOWERS
AND THUNDERSTORMS POISED TO MOVE INLAND WITH SOME POTENTIAL TO
BRING BRIEF HEAVY RAINFALL TO HIGHLY URBANIZED AREAS IN THE SHORT
TERM.
ACROSS THE WEST...LATE AFTERNOON/EARLY EVENING WATER VAPOR
SATELLITE IMAGERY SHOWED A SHORTWAVE TROUGH MAKING ITS WAS ACROSS
THE SOUTHERN PORTION OF THE MARGINAL RISK AREA. THAT WAS HELPING
FOCUS SOME GENERALLY LIGHT SHOWERS. MAINTAINED THE MARGINAL RISK
AREA GIVEN RECENT HEAVY RAINFALL OVER PORTIONS OF THE GREAT BASIN
WILL LIKELY HAVE PRIMED SURFACES FOR RUNOFF FROM ADDITIONAL
PRECIPITATION. BURN SCARS CONTINUE TO BE OF CONCERN THIS EVENING.
ALSO NOTED THAT THE 18Z HREF EAS EXCEEDANCE PROBABILITIES CONTINUED
TO SHOW A LOW-END RISK OF 1- AND 3-HOURLY FLASH FLOOD GUIDANCE
BEING EXCEEDED INTO THE OVERNIGHT HOURS OVER NORTHERN/CENTRAL
NEVADA WHERE PWATS WILL BE BETWEEN 2-3 STANDARD DEVIATIONS ABOVE
NORMAL.
BANN
DAY 2
VALID 12Z SAT OCT 04 2025 - 12Z SUN OCT 05 2025
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
FLORIDA'S EAST COAST...
20Z UPDATE...
THE MARGINAL RISK WAS REMOVED FROM SOUTHEASTERN LOUISIANA.
CONSENSUS OF THE 12Z HREF AND 06Z RRFS SHOWED THEIR HIGHER
PROBABILITIES FOR ONSHORE HEAVY AMOUNTS THAT ARE ASSOCIATED WITH A
SLOW-MOVING WAVE REMAINING CONFINED TO THE IMMEDIATE COAST AND
AWAY FROM THE MORE VULNERABLE I-10 CORRIDOR. SHOULD THE MODELS
TREND BACK TO THE NORTH, A MARGINAL RISK MAY BE REINTRODUCED, BUT
FOR NOW THE AREA HAS BEEN REMOVED FROM THE OUTLOOK.
FOR THE FLORIDA EAST COAST, THE SIGNAL FOR WIDESPREAD SHOWERS AND
STORMS, WITH LOCALLY HEAVY AMOUNTS REMAIN. MODELS HAVE BEEN
GENERALLY TRENDING LIGHTER WITH THEIR QPF. HOWEVER, WITH THE HREF
STILL SHOWING SOME HIGHER PROBABILITIES FOR AMOUNTS OVER 3 INCHES,
LEFT THE SLIGHT RISK CENTERED ALONG THE SPACE/TREASURE COASTS IN
PLACE FOR NOW. ALSO EXTENDED THE MARGINAL RISK FURTHER SOUTH INTO
THE MIAMI METRO, WHERE THE HI-RES ENSEMBLES ALSO SHOW SOME HIGHER
FOR AMOUNTS OVER 3 INCHES.
PREVIOUS DISCUSSION...
..FLORIDA'S EAST COAST
THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP ALONG THE
INVERTED TROUGH AXIS ORIENTED NORTH-SOUTH ALONG FLORIDA'S EAST
COAST ON SATURDAY. MOISTURE WILL LIFT NORTH ALONG WITH THE MID-
LEVEL DISTURBANCE. THE INHERITED SLIGHT AND MARGINAL RISK AREAS
WERE MAINTAINED DUE TO A MOSTLY CONSISTENT SIGNAL FOR EXCESSIVE
RAINFALL OVER THE EAST CENTRAL COAST. ENSEMBLE EXCEEDANCE
PROBABILITIES OF 2 INCHES ARE BETWEEN 5-10% ACROSS THE MARGINAL
RISK AREA. 48 HOUR TOTALS BETWEEN 3-5 INCHES (LOCAL 6") WILL LIKELY
MAKE OVERCOMING FLASH FLOOD GUIDANCE A BIT EASIER.
PEREIRA/KEBEDE
DAY 3
VALID 12Z SUN OCT 05 2025 - 12Z MON OCT 06 2025
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE CENTRAL GULF COAST AND THE SOUTHEAST COAST...
20Z UPDATE...
NO SIGNIFICANT CHANGES WERE MADE TO THE PREVIOUS OUTLOOK.
PREVIOUS DISCUSSION...
..CENTRAL GULF COAST
THE MID-LEVEL DISTURBANCE CONTINUES PROPAGATING WESTWARD TOWARD THE
POSITIVELY TILTED UPPER TROUGH CENTERED OVER THE WEST ON SUNDAY.
THUS, THE HEAVY RAINFALL THREAT WILL LIKELY BLEED OVER FROM
SATURDAY EVENING INTO SUNDAY MORNING FOR PORTIONS OF THE CENTRAL
GULF COAST, BEFORE DISSIPATING BENEATH DIMINISHED SUPPORT ALOFT.
PWATS OF 2-2.5" AND INSTABILITY BETWEEN 500-1000 J/KG MUCAPE COULD
CHURN OUT RAIN RATES BETWEEN 1-1.5"/HR SATURDAY MORNING INTO
AFTERNOON. ENSEMBLE EXCEEDANCE PROBABILITIES OF 2 INCHES ARE
BETWEEN 5-15% ALONG THE FAR SOUTHEASTERN LOUISIANA TO FLORIDA
PANHANDLE CORRIDOR, WHICH SUPPORTS THE MARGINAL RISK AREA IN
PLACE.
..SOUTHEAST COAST
INVERTED TROUGHING CONTINUES ALONG THE FLORIDA/SOUTHEAST COAST
THROUGH THE LATTER PART OF THIS WEEKEND. ANOMALOUS MOISTURE (2-3
STNDV) WILL CONTINUE INTERACTING WITH THE SURFACE BOUNDARY TO
GENERATE SCATTERED TO ISOLATED THUNDERSTORMS ACROSS THE
FLORIDA/GEORGIA COAST. RAINFALL TOTALS OF 1-3" ARE LIKELY ALONG
THE FLORIDA/GEORGIA/SOUTH CAROLINA COAST ON SATURDAY. THE LATEST
GUIDANCE HAS TRENDED AWAY FROM TROPICAL MOISTURE MAKING ITS WAY
INLAND, THEREFORE A MARGINAL RISK WAS MAINTAINED FOR MUCH OF THE
SOUTHEAST COAST.
PEREIRA/KEBEDE
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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