-- Discussion containing changed information from previous version are highlighted. --
731
FXUS62 KTBW 230721
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
321 AM EDT Mon Sep 23 2024

...THERE IS A HIGH CHANCE OF TROPICAL CYCLONE DEVELOPMENT THIS
WEEK, NOW IS THE TIME TO ENSURE HURRICANE PLANS ARE IN PLACE...

.SHORT TERM...
-- Changed Discussion --
(Now through Tuesday)
Issued at 321 AM EDT Mon Sep 23 2024

* Key Point: Mostly quiet weather today and tomorrow with just a few
  storms across the southern interior and SWFL.

A sprawling ridge axis is situated over the Western Gulf with weak
surface high pressure dominant across the SE and Gulf Coast regions.
In response to this upper-level ridge, a northerly upper-level flow
is advecting a continental airmass across the region. Thus, mid and
upper-level dry air remains persistent across the region, with very
few clouds even of note. There is also subsidence suppressing
overall instability. This means that conditions - for most - are
favored to be warm and sunny, with a light easterly surface flow.

However, there does look to be enough moisture and instability over
the southern interior and SWFL to perhaps support a few isolated to
scattered thunderstorms late this afternoon. While ridging remains
dominant, there is a weak trough feature over Florida, associated
with a remnant frontal boundary that pushed through. This
combination could be just enough late today for storms, especially
as the sea breeze tries (rather unsuccessfully given the prevailing
10 kts of easterly flow) to form late this afternoon and evening.
What storms do form, will probably be low-topped and short-lived in
an environment that is not particularly conducive.

Tuesday is not shaping up to be much different, but the gradient
does begin to tighten as the ridge axis is eroded from the north by
a digging trough and from the south by a developing tropical system.
An easterly flow looks to prevail in response, but becomes stronger
with the tightening gradient. A late day surge in PWATs will again
be in place to support a few storms late in they day across the
southern interior and SWFL.
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&&

.LONG TERM...
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(Wednesday through Monday)
Issued at 321 AM EDT Mon Sep 23 2024

What We Know:

* There is a 70% chance that a tropical system will develop in the
  next 48 hours and a 90% chance that a tropical system will develop
  this week.

* The system is forecast to strengthen while moving northward over
  the Gulf of Mexico. There is the potential for storm surge, heavy
  rainfall, and strong winds across portions of our area.

* Dangerous marine conditions are expected. High seas offshore,
  large breaking waves at beaches, and a high risk of rip currents
  will accompany this system.

What We Don`t Know:

* The exact magnitude of impacts. This will become more clear in
  the next 24 to 48 hours.

* Track and intensity specifics. Reconnaissance aircraft flights
  later today and over the next few days, along with extra weather
  balloon releases for offices along the Gulf coast will provide
  more insight. These items will ramp up today and into tonight.

There is a lot of uncertainty in the extended range as a tropical
system lifts northward into the Gulf of Mexico. These discrepancies
will have a significant impact on exactly what conditions are
realized across West Central and SWFL. However, confidence is
increasing in a tropical system moving into the Gulf and
facilitating an environment conducive storm surge, heavy
rainfall, and strong winds, along with poor marine and beach
conditions. The worst of the weather appears to take place between
late Wednesday and early Friday.

It is important to continue monitoring the forecasts from the
National Hurricane Center as well as from local NWS Offices. Now is
a great time to ensure hurricane plans are in place. More specifics
are likely to be flushed out in the next 24 to 48 hours as
additional data becomes available and the storm system begins to
become better organized.

As the system clears the Gulf region by late week and into the week,
the forecast gradually returns to a more typical late summerlike
pattern. However, the moisture pulled northward by the system may
linger. It also looks like a WSW flow will be dominant through the
weekend. Thus the combo supports decent rain chances and an overall
warm and muggy pattern to take us into next week.
-- End Changed Discussion --

&&

.AVIATION...
(06Z TAFS)
Issued at 122 AM EDT Mon Sep 23 2024

There is a about a 30% chance for a TSTM to impact terminals from
SRQ southward from 21 to 24Z, with only about a 10% to 15% chance
for TPA, PIE and LAL during the same time-frame. Otherwise, VFR
conditions prevail with an easterly flow. There is an increasing
likelihood of high aviation impacts for mid-to-late week as a
tropical system approaches.

&&

.MARINE...
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Issued at 321 AM EDT Mon Sep 23 2024

An easterly flow will prevail through mid-week, with the highest
winds in the evening as resistance to the flow along the coast
breaks down, allowing the winds to accelerate. A few thunderstorms
could also develop and move over coastal waters around the same
time. Away from thunderstorms, peak wave heights during this time do
not look to exceed 2 feet. However, winds and seas begin to build by
mid-week, becoming dangerous for boaters by Thursday as a tropical
system moves into the Gulf. These dangerous conditions will last
into the weekend, before gradually subsiding thereafter. However,
lingering moisture will keep higher chances for storms in the
forecast into next week.
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&&

.FIRE WEATHER...
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Issued at 321 AM EDT Mon Sep 23 2024

Conditions are forecast to be driest today and tomorrow, but
isolated to scattered storms remain possible mainly across the
southern interior and SWFL late in the day. Increasing moisture (and
winds) will come into play by mid-week as a tropical disturbance
lifts northward into the Gulf. No fire weather concerns exist at
this time given the ample moisture that will be present, even with a
couple drier days today and tomorrow.
-- End Changed Discussion --

&&

.HYDROLOGY...
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Issued at 321 AM EDT Mon Sep 23 2024

With some drier conditions, water levels continue to decline on area
rivers, and are forecast to continue to do so with minimal QPF
expected in river basins over the next 48 hours. This is good news
as a surge in moisture and higher rainfall totals are expected for
the middle to later part of the week. Days 1-5 QPF values are
running in the 4 to 6 inch range areawide currently, and there is a
Marginal to Slight risk of excessive rainfall Wednesday - Friday.
Local totals could be higher, up to around 10 inches based upon
longer range QPF guidance. The bulk of the rainfall is expected from
late Wednesday through early Friday as the tropical system moves
through the region.

Soils continue to remain on the saturated side, and urban areas may
struggle with drainage depending on how close the tropical system
passes to the coast. Elevated water levels would make it more
difficult for water to drain. There will be a concern for flash
flooding under the circumstances, and water levels are likely to
rise again on area rivers, particularly near the coast. More
specifics will become clear over the next couple days.
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&&

.PRELIMINARY POINT TEMPS/POPS...
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TPA  92  76  94  77 /  10  10  20  10
FMY  93  76  94  78 /  30  20  40  30
GIF  93  75  94  77 /  20   0  10  10
SRQ  93  75  94  77 /  30  20  20  20
BKV  94  71  94  74 /  10   0  10  10
SPG  93  79  94  80 /  20  10  20  20
-- End Changed Discussion --

&&

Sea Breeze Thunderstorm Regime For Monday: 2
Sea Breeze Thunderstorm Regime For Tuesday: 3

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

&&

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

&&

$$

Flannery