232
FOUS30 KWBC 172242
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
542 PM EST MON FEB 17 2025
DAY 1
VALID 01Z TUE FEB 18 2025 - 12Z TUE FEB 18 2025
SOUTHERN FLORIDA...
SURFACE EASTERLIES ARE RETURNING WHICH SHOULD LEAD TO A SLIGHT
UPTICK IN MOISTURE, WITH PRECIPITABLE WATER VALUES OF 1-1.25"
ANTICIPATED BEFORE TUESDAY MORNING WITH SOME DEGREE OF INSTABILITY
MOVING IN FROM THE GULF STREAM. ENOUGH EFFECTIVE BULK SHEAR EXISTS
TO TRY TO ORGANIZE ANY CONVECTION THAT ATTEMPTS TO FORM. HOWEVER,
WITH PRECIPITABLE WATER VALUES THIS LOW, ANY SHORT TRAINING BANDS
WOULD BE BOTH RANDOM AND ISOLATED. HOURLY RAIN TOTALS OF 0.5"+ AND
2"+ EXIST IN THE 00Z-12Z TIME FRAME WITHIN THE 18Z HREF GUIDANCE,
BUT REMAIN NEAR TO BELOW 50%. WHILE AN ISOLATED HEAVY RAIN/FLASH
FLOOD ISSUE CAN'T BE COMPLETELY RULED OUT, THE INGREDIENTS SUGGEST
THAT THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOOD GUIDANCE
REMAINS LESS THAN FIVE PERCENT, SO NO MARGINAL RISK AREA HAS BEEN
DRAWN IN.
ROTH
DAY 2
VALID 12Z TUE FEB 18 2025 - 12Z WED FEB 19 2025
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG PORTIONS OF
THE CENTRAL GULF COAST...
..21Z OUTLOOK UPDATE
RECENT MODELS (AND PARTICULARLY CAMS) DEPICT SUBSTANTIALLY
INCREASED RAINFALL POTENTIAL (INTO THE 2-4 INCH RANGE) LATE
TUESDAY INTO EARLY WEDNESDAY ACROSS SOUTHERN LOUISIANA, WITH A
GREATER FOCUS FOR TRAINING CONVECTION NEAR LAKE CHARLES
AROUND/AFTER 00Z. A SLIGHT RISK WAS CONSIDERED FOR THIS UPDATE, BUT
CONCERNS ABOUT ANTECEDENT GROUND CONDITIONS (DRY SOILS, LACK OF
RAINFALL) AND CONFIDENCE IN THE SPECIFIC AXES OF HEAVIER RAINFALL
WERE MITIGATING FACTORS. THE MARGINAL RISK WAS EXPANDED
NORTHWESTWARD TOWARD EAST TEXAS AND WEST/NORTHWEST LOUISIANA WHERE
SOILS WERE WETTER AND CONVERGENCE ON THE NOSE OF 850MB FLOW COULD
RESULT IN A FEW HEAVIER DOWNPOURS AND ISOLATED RUNOFF ISSUES.
SEE THE PREVIOUS DISCUSSION BELOW FOR MORE INFORMATION.
COOK
..PREVIOUS DISCUSSION
STRENGTHENING SOUTHWESTERLY WINDS AHEAD AN AMPLIFYING UPPER LEVEL
SHORTWAVE AND AN ASSOCIATED COLD FRONT ARE EXPECTED TO DRAW DEEPER
MOISTURE INTO PARTS OF THE GULF COAST, WITH PWS CLIMBING TO AROUND
1.5 INCHES. THIS MOISTURE ALONG WITH INCREASING LIFT AND
INSTABILITY MAY BE SUFFICIENT FOR HEAVY RAINFALL RATES. MODELS
OFFER A MODEST SIGNAL FOR TRAINING STORMS AHEAD OF A SURFACE LOW
THAT IS FORECAST TO DEVELOP AND ADVANCE EAST ALONG THE COAST
WEDNESDAY MORNING. THIS MAY HELP SUPPORT LOCALIZED HEAVY RAINFALL,
WITH SOME POTENTIAL FOR ISOLATED FLASH FLOODING, ESPECIALLY IN
URBANIZED AREAS.
PEREIRA
DAY 3
VALID 12Z WED FEB 19 2025 - 12Z THU FEB 20 2025
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF NORTHERN FLORIDA AND SOUTHERN GEORGIA...
..21Z OUTLOOK UPDATE
A CONVECTIVE COMPLEX SHOULD BE ONGOING ACROSS SOUTHEASTERN
LOUISIANA AND ADJACENT NORTH-CENTRAL GULF WATERS AT THE BEGINNING
OF THE FORECAST PERIOD. THIS COMPLEX WILL MIGRATE EASTWARD TOWARD
THE FLORIDA PANHANDLE AND VICINITY THROUGHOUT THE MORNING HOURS,
ALTHOUGH HEAVIER RAINFALL SHOULD REMAIN OFFSHORE DUE TO A LACK OF
INLAND INSTABILITY. LIGHT/MODEST RAIN RATES ARE EXPECTED ACROSS
MOST OF THE SOUTHEASTERN U.S. DOWNSTREAM OF THE COMPLEX, AND MODELS
HAVE TRENDED LOWER WITH QPF ESPECIALLY THROUGH NORTHEASTERN
FLORIDA.
GIVEN THE LATEST TRENDS, THE MARGINAL RISK PREVIOUSLY IN EFFECT HAS
BEEN CONFINED TO AREAS FROM SOUTHEASTERN LOUISIANA THROUGH THE WESTERN
FLORIDA PANHANDLE CLOSER TO WHERE THE BEST INSTABILITY SHOULD
RESIDE.
SEE THE PREVIOUS DISCUSSION FOR MORE INFORMATION.
COOK
..PREVIOUS DISCUSSION
SURFACE LOW DEVELOPING ALONG THE CENTRAL GULF COAST ON DAY 2 WILL
CONTINUE TO TRACK EAST EARLY IN THE PERIOD, BEFORE TRACKING
NORTHEAST ALONG THE SOUTHEAST COAST LATER IN THE DAY. TRAINING
STORMS, WITH POTENTIALLY HEAVY RAINFALL RATES FUELED BY DEEP
MOISTURE (PWS 1.5-1.75 INCHES) AHEAD OF THE WAVE AND ALONG ITS
TRAILING COLD FRONT, MAY PRODUCE LOCALLY HEAVY AMOUNTS AND AN
ISOLATED FLASH FLOODING THREAT ON WEDNESDAY.
PEREIRA
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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