-- Discussion containing changed information from previous version are highlighted. --
171
FXUS62 KTBW 172354
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
754 PM EDT Tue Sep 17 2024

...New UPDATE, AVIATION...

.UPDATE...
-- Changed Discussion --
Issued at 752 PM EDT Tue Sep 17 2024

A few storms continue across Highlands County as the latest surface
analysis suggests the southern interior and SWFL remain on the "warm
and moist" side of the stationary boundary. Portions of the interior
and ECFL continue to see additional moisture pooling and slightly
enhanced forcing for ascent as well, aided by the light westerly
background flow. This combo has allowed storms to grow more robust
and last longer than elsewhere. While some isolated storms have
tried to pop up farther north in places like Polk, Pasco, and Sumter
counties, the deeper dry air pocket, noted on the 0Z sounding has
been a significant limiting factor.

Now that the sun is setting, activity should quickly quiet down over
the next couple hours, with a quiet night in store. Tomorrow looks
like there could be a couple more storms with a brief improvement in
the depth of the moisture. However, a westerly flow and some
continued dry air presence will continue to limit overall coverage,
especially at the coast. Keeping a 20% to 30% chance for the Nature
Coast and Tampa Bay Area, and generally 40% to 50% for the southern
interior and SWFL.

A few adjustments have been made to the POPs to reflect current
conditions and to adjust convective timing for tomorrow, but
otherwise, the forecast remains on track.
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&&

.DISCUSSION...
Issued at 250 PM EDT Tue Sep 17 2024

Upper level cutoff low will remain over the southeast U.S. through
Wednesday then open up and lift northeast. However, the overall
upper level troughing will remain along the U.S. east coast south
into Florida into the weekend before ridging builds over the Gulf
of Mexico early next week. Meanwhile in the lower levels the weak
pressure pattern will persist through midweek with an overall
southwest to west flow across the area. Late in the week a weak
cool front, or really a moisture boundary, will move south across
the area as high pressure begins to build south. This high will
shift the flow to a more northeast to east direction Friday
through early next week with some slightly drier air, dew points
potentially falling into the middle and upper 60s over the
weekend, moving into the region.

For tonight through Thursday, the pattern will remain pretty much
unchanged as the southwest to west flow combined with limited
moisture keeps the highest rain chances over the interior and
southwest Florida. On Friday, the wind shift to northeast will bring
some drier air into the area, but still should be enough for
isolated to scattered afternoon and evening convection, with best
chances remaining over the interior and southwest Florida. Over the
weekend and into early next week precipitable water values remain
between about 1.5 and 1.7 inches, but do vary from day to day as
pockets of slightly more moisture move west southwest. Overall this
should be enough to allow isolated to scattered showers and
thunderstorms to develop each afternoon and evening.

&&

.AVIATION...
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(00Z TAFS)
Issued at 752 PM EDT Tue Sep 17 2024

Another late night/early morning where MVFR CIGs could briefly come
in cannot be completely ruled out, but there is not enough
confidence to add mention for any TAFs at this time. The main
concern for this TAF cycle is the potential for thunderstorms
tomorrow afternoon. Confidence is greatest across SWFL where deeper
moisture and instability remains. Confidence is lower (and the
window for impacts is shorter) at Tampa Bay area terminals. A
westerly flow is the reason for this, and will continue for the next
couple days. Drier will continue to be a limiting factor for
convective impacts.
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&&

.MARINE...
Issued at 250 PM EDT Tue Sep 17 2024

The rather light and variable flow will continue through Thursday
with a sea breeze developing near the coast each afternoon. Friday
through the weekend high pressure will build in from the north
shifting the flow to northeast to east at around 10 knots with
evening surges bumping winds up to around 15 knots, possibly
exercise caution levels early next week. Isolated to scattered
showers and thunderstorms will remain possible through the period,
but no headlines are anticipated at this time.

&&

.FIRE WEATHER...
Issued at 250 PM EDT Tue Sep 17 2024

Enough moisture will remain across the region for the next few days
to allow for isolated to scattered showers and thunderstorms each
afternoon and evening, especially over the interior and southwest
Florida. Relative humidity values will remain above critical levels
with no fire weather hazards expected.

&&

.PRELIMINARY POINT TEMPS/POPS...
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TPA  76  90  76  89 /  10  30  20  40
FMY  76  93  76  92 /  20  50  30  60
GIF  75  93  75  92 /  20  40  20  50
SRQ  76  91  76  91 /  10  30  20  40
BKV  71  91  71  90 /  10  30  10  40
SPG  80  90  79  90 /  10  30  20  40
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&&

Sea Breeze Thunderstorm Regime For Wednesday: 4
Sea Breeze Thunderstorm Regime For Thursday: 4

For additional information on sea breeze regimes, go to:
     https://www.weather.gov/tbw/ThunderstormClimatology

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.

&&

$$

UPDATE/AVIATION...Flannery
PREVIOUS DISCUSSION...Close