textproduct: Tampa Bay Area

KEY MESSAGES

- Hot and humid conditions continue, with heat indices just below to near advisory criteria on Friday.

- Moisture gradually continues to increase, leading to greater chances for showers and thunderstorms, especially as the weekend approaches.

UPDATE

Issued at 815 PM EDT Thu Aug 20 2026

Minor PoP/Wx adjustments made to reflect latest radar trends, otherwise no changes planned for the evening update. Moist onshore flow pattern continues locally, with overnight showers and storms favoring coastal waters and adjacent coastal areas ashore. Guidance indicates likelihood of predawn activity across SWFL extending through the morning before gradually diminishing early afternoon as focus of activity shifts into interior S FL. Slightly later timing for areas further north across WCFL into the Nature Coast, with mid to late morning through early afternoon favored across coastal locations before shifting inland over the remainder of the afternoon.

DISCUSSION

Issued at 224 PM EDT Thu Aug 20 2026 Scattered showers and storms continue to make their way eastward across the region and should be mostly out of the forecast area by this evening. Flow becomes more west-southwest tonight into Friday, resulting in earlier rain chances over the Gulf and coastal areas in the morning.

Previous discussion modified...High pressure surface and aloft persists over the Florida peninsula. Another hot and humid day continues with high temperatures in the lower to mid 90s. A heat advisory is in effect for all of west central and southwest Florida for heat indices of up to 109. Onshore west to northwest boundary layer flow will help shift convection inland and increase in areal coverage through the remainder of the afternoon. A few strong storms will be possible with strong gusty winds, locally heavy rain and frequent lightning.

Heights aloft will lower a bit on Friday which will slightly decrease large scale subsidence over the forecast area. This should keep afternoon maximum heat indices just below advisory criteria, in the 104 to 107 range...although it will still be rather hot with temperatures in the lower 90s. Onshore west boundary layer flow will persist, with storms developing over the coastal counties during the morning/early afternoon hours and again spreading inland and increasing coverage during the mid/late afternoon. A few strong storms will again be possible with strong gusty winds, locally heavy rain and frequent lightning.

A frontal boundary will approach north Florida Friday night and Saturday with winds veering to the southwest. Slightly drier air aloft will advect over the area mainly south of I-4 and will hold over the region into Sunday. This will decrease areal coverage of showers/storms with highest pops each day across the nature coast in vcnty of the frontal boundary.

Early next week, deep layer moisture will recover over the central and southern forecast area. The surface ridge axis will lift north across the central peninsula with the gradient weakening. The west coast sea breeze boundary will push inland during the afternoon hours and will likely collide with the east coast sea breeze boundary late in the day over the interior, which will be the zone for the best chance of rain.

By mid week, deep layer moisture will be enhanced across the southern forecast area which will become the best region for afternoon showers and storms.

AVIATION

(00Z TAFS) Issued at 730 PM EDT Thu Aug 20 2026

VFR expected overnight into Friday. Early morning VCTS potential for SWFL terminals, followed by late morning VCTS for WCFL terminals. Generally brief MVFR/LCL IFR impacts with convection through early to mid afternoon before activity pushes inland, with overall timing a bit later for inland KLAL terminal. Onshore flow pattern persists, with lighter flow overnight then increasing morning through afternoon.

MARINE

Issued at 224 PM EDT Thu Aug 20 2026 High pressure will hold over the waters through the period with relatively light winds and seas. The main hazard will be scattered showers and thunderstorms which may produce locally gusty winds and rough seas, mainly during the overnight and early morning hours.

FIRE WEATHER

Issued at 224 PM EDT Thu Aug 20 2026 No fire weather hazards are expected as sufficient moisture will keep minimum afternoon relative humidity values well above critical levels for the next several days.

PRELIMINARY POINT TEMPS/POPS

TPA 79 91 80 90 / 10 40 30 40 FMY 78 94 78 93 / 10 30 10 20 GIF 76 94 76 93 / 30 30 10 20 SRQ 78 91 78 91 / 10 20 20 20 BKV 74 92 74 90 / 10 40 40 50 SPG 80 90 80 89 / 10 30 20 30

TBW WATCHES/WARNINGS/ADVISORIES

FL...None. Gulf waters...None.