702 FXUS62 KTBW 111728 AFDTBWArea Forecast Discussion National Weather Service Tampa Bay Ruskin FL 128 PM EDT Thu Sep 11 2025
...New DISCUSSION, AVIATION, MARINE, FIRE WEATHER...
.DISCUSSION... Issued at 128 PM EDT Thu Sep 11 2025
Current water vapor imagery indicates some cooler cloud tops over the Gulf with widespread mid to high cloud cover extending across much of the Florida Peninsula. At the surface, a stationary boundary extends E-W across south Florida. Further to the north, there is a trough axis that extends from the eastern Great Lakes to the southeast across the Tennessee Valley. Water vapor imagery indicates drier air to the north of the boundary across the Deep South and this drier air is forecast to drift into the forecast area throughout the next few days. This mornings 12z TBW sounding is still rather saturated with 2.06 inches of PW, however, the JAX 12z sounding is much drier with 1.25 inches of PW. The 2.06 inches of PW is around the 90th percentile for mid-September and due to this, expect precipitation chances will remain elevated today, especially along and south of the I-4 corridor. Due to the higher PW values, there could be some heavier downpours today and WPC has the southern half of the area in a marginal risk for excessive rainfall. Most places will see below an inch of rain today but an isolated spot has a low chance of seeing 2-4 inches of rainfall. Most activity should come to an end overnight. Lows will range around 10 degrees across the forecast area from mid 60s across Levy county to mid 70s across southwest Florida.
The trough to the north drifts southeastward on Friday and will stretch from the Mid-Atlantic to the southwest to the northern Gulf Coast. Closer to home, upper and low level flow will not change too much and expect similar conditions on Friday as today. The front should remain in a similar location with most of the showers/storms south of I-4. Once again, heavier precipitation will be a threat with PW values over 2 inches.
The stalled boundary finally begins to move late in the day Friday and into the day on Saturday as the trough digs further to the southeast into the Florida Peninsula. Models indicate PW values will drop below 1.5 inches. These values are around the 25th percentile for mid-September. Despite the drier air, PoPs around 20-40% will continue in the forecast. The upper level trough will move overhead over the weekend with cyclonic flow aloft. Forecast model soundings indicate decent lapse rates aloft with the upper low overhead supporting at least some low mention for afternoon showers/storms over the weekend and into early next week.
Models indicate that this upper level low eventually closes off near the GA/SC/NC coast early next week. There are some indications of another potential front late in the forecast period. Overall, the forecast will be on the drier side with the the threat for isolated to scattered afternoon showers/storms. Morning lows will remain a bit on the cooler side in the upper 60s to low 70s for much of the upcoming week.
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.AVIATION... (18Z TAFS) Issued at 128 PM EDT Thu Sep 11 2025
VFR conditions continue at most of the terminals with ceilings around 3 kft at both KFMY and KRSW. A stalled E-W boundary continues to linger near these terminals. Best moisture this afternoon and evening will be across the southern terminals with drier air filtering in from the north. For now, have continued with dry conditions at KTPA, KPIE, and KLAL throughout the TAF period, with VCTS in the 20-02z timeframe at the remaining terminals. There is enough confidence that TSRA will occur at KFMY and KRSW that a TEMPO group was included from 21-23z.
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.MARINE... Issued at 128 PM EDT Thu Sep 11 2025
Showers and storms will continue to develop over the waters as a front remains stalled across south Florida supporting winds in the offshore waters around 10 to 15 knots. This trend will continue through Friday. After that a strong upper level trough will push through causing the front to push south. This will help to keep us mostly dry for the weekend however winds will still stay around 10 to 15 knots.
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.FIRE WEATHER... Issued at 128 PM EDT Thu Sep 11 2025
A frontal boundary remains stalled across south FL bringing ample moisture to southern half of the area through the rest of the week. North of there, pockets of drier air will be present throughout the day. Northeasterly winds are anticipated most of the period. Then, a strong upper level trough will push the front south for the weekend allowing humidity and rain chances to decrease, but RH values will remain well above critical levels.
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.PRELIMINARY POINT TEMPS/POPS... TPA 75 89 74 89 / 20 30 10 30 FMY 75 88 74 89 / 50 60 30 50 GIF 74 89 72 89 / 20 40 10 40 SRQ 74 88 72 89 / 30 40 20 30 BKV 69 88 69 89 / 10 20 0 30 SPG 75 87 74 87 / 20 30 10 30
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Sea Breeze Thunderstorm Regime For Thursday: 2 Sea Breeze Thunderstorm Regime For Friday: 2
For additional information on sea breeze regimes, go to: https://www.weather.gov/tbw/ThunderstormClimatology
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.TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None.
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DISCUSSION/AVIATION/MARINE/FIRE WEATHER...Anderson DECISION SUPPORT...Shiveley UPPER AIR/CLIMATE...Shiveley
NWS TBW Office Area Forecast Discussion