-- Discussion containing changed information from previous version are highlighted. --
770
FXUS62 KTBW 241752
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
152 PM EDT Tue Sep 24 2024

...New AVIATION...

.DISCUSSION...
Issued at 301 AM EDT Tue Sep 24 2024

For today, high pressure holding north of the area will keep
easterly flow and drier air aloft in place. Precipitable water
will be slightly higher over the southern half of the area,
which should allow for isolated to scattered showers and storms to
develop this afternoon and push west across the area, although
mainly rain free conditions are expected over the Nature Coast.

The weather will begin to deteriorate tonight as what is currently
called Potential Tropical Cyclone Nine moves north and strengthens
into a Tropical Storm later today. The National Hurricane Center
is forecasting the system will then reach hurricane strength by
Wednesday evening and continue to lift north and northeast through
the eastern Gulf of Mexico through Thursday. The current track
forecast has the storm moving almost parallel to the Florida
Peninsula coast on Thursday, which will make predicting the
eventual area of landfall difficult. If the storm moves along the
center or western side of the current cone of uncertainty, a
landfall in the Panhandle or Big Bend of Florida is likely.
However, if the center tends towards the east side of the cone,
then a landfall along the west coast of the Florida Peninsula
becomes more likely, with small adjustments in direction
potentially shifting the worst impacts significantly south. It is
also important to remember that the cone of uncertainty is
forecasting where the center of the system will go, but
significant impacts will occur away from the center and fall
outside of the cone.

Regardless of the exact track, tropical impacts will begin to
unfold across the area Wednesday and Thursday. Moisture will
increase from the south tonight through Thursday leading to
numerous to widespread showers and thunderstorms on Wednesday as
well as increasing cloud cover, then the highest rain totals are
expected on Thursday. The pressure gradient on the edge of the
tropical system will also produce breezy conditions on Wednesday,
with tropical storm conditions possible Wednesday night through
Thursday night, as well as hurricane conditions along much of the
coastal areas on Thursday. Apart from the winds and rain, this
track forecast also has the potential to result in significant
storm surge for areas east and south of where the center makes
landfall as onshore winds pile water onto the coast. The rain also
cannot be ignored, with areas along the coast forecast to receive
4-6 inches through Saturday, with locally isolated totals of up
to around 10 inches. A Flood Watch has been issued for the entire
area beginning 8 PM Wednesday.

The rain and flooding threat will also not necessarily end after
landfall, since models are showing a band of deep moisture
trailing behind the tropical system holding across the Florida
Peninsula through at least the weekend before drier air can fill
back in early next week. For areas that get heavy rainfall from
the storm Wednesday night through Thursday night, additional
rounds of heavy rainfall lasting through the weekend could result
in worsening flooding before the previous flood waters get an
opportunity to recede. Otherwise, onshore winds will also result
in a high risk of rip currents at area beaches continuing Friday
and Saturday behind the storm.

&&

.AVIATION...
-- Changed Discussion --
(18Z TAFS)
Issued at 148 PM EDT Tue Sep 24 2024

VFR conditions will generally prevail through the remainder of the
day, though brief isolated/scattered TSRA will be possible at
times through this evening. Otherwise, wind speeds and rain
chances will increase area-wide by Wednesday morning into the
afternoon as Tropical Storm Helene moves into the Gulf of Mexico.
This will result in ESE winds on Wednesday around 10-12 kts and
gusts over 20 kts and flight restrictions at times due to
increasing TSRA through the end of the period.
-- End Changed Discussion --

&&

.MARINE...
Issued at 301 AM EDT Tue Sep 24 2024

High pressure holds north of the waters today, with generally
easterly flow less than 15 knots, and scattered showers and storms
possible, mainly off the southwest Florida coast. Winds will start
to degrade tonight as the system currently called Potential
Tropical Cyclone Nine begins to lift out of the northwest
Caribbean Sea, and moving into the Gulf of Mexico by Wednesday.
Winds and rain chances will increase Tuesday night and Wednesday,
with tropical storm or hurricane conditions possible Wednesday
night though Thursday night as the storm moves north and northeast
through the Gulf. Winds will turn to southwesterly and westerly
and subside behind the system Friday and Saturday, although rain
chances will remain high through the weekend as a band of moisture
holds over the area.

&&

.FIRE WEATHER...
Issued at 301 AM EDT Tue Sep 24 2024

No humidity concerns. Wind speeds and rain chances will start to
increase on Wednesday as Potential Tropical Cyclone Nine
approaches the southern Gulf of Mexico.

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
TPA  78  90  77  86 /   0  70  90  90
FMY  78  87  77  87 /  20  80  90  90
GIF  76  89  77  88 /   0  60  80  90
SRQ  78  90  76  88 /  10  80  90  90
BKV  74  90  74  87 /   0  60  80  90
SPG  81  88  79  88 /  10  80  90  90
-- End Changed Discussion --

&&

Sea Breeze Thunderstorm Regime For Tuesday: 7
Sea Breeze Thunderstorm Regime For Wednesday: 7

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

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
FL...Tropical Storm Watch for Coastal Charlotte-Coastal Lee-DeSoto-
     Hardee-Inland Charlotte-Inland Hillsborough-Inland Lee-
     Inland Manatee-Inland Sarasota-Polk-Sumter.

     Flood Watch from Wednesday evening through Friday morning for
     Coastal Charlotte-Coastal Citrus-Coastal Hernando-Coastal
     Hillsborough-Coastal Lee-Coastal Levy-Coastal Manatee-
     Coastal Pasco-Coastal Sarasota-DeSoto-Hardee-Highlands-
     Inland Charlotte-Inland Citrus-Inland Hernando-Inland
     Hillsborough-Inland Lee-Inland Levy-Inland Manatee-Inland
     Pasco-Inland Sarasota-Pinellas-Polk-Sumter.

     Hurricane Watch for Coastal Citrus-Coastal Hernando-Coastal
     Hillsborough-Coastal Levy-Coastal Manatee-Coastal Pasco-
     Coastal Sarasota-Inland Citrus-Inland Hernando-Inland Levy-
     Inland Pasco-Pinellas.

     Storm Surge Watch for Coastal Charlotte-Coastal Citrus-Coastal
     Hernando-Coastal Hillsborough-Coastal Lee-Coastal Levy-
     Coastal Manatee-Coastal Pasco-Coastal Sarasota-Pinellas.

Gulf waters...Tropical Storm Watch for Charlotte Harbor and Pine Island Sound-
     Coastal waters from Bonita Beach to Englewood FL out 20 NM.

     Hurricane Watch for Coastal waters from Englewood to Tarpon
     Springs FL out 20 NM-Coastal waters from Tarpon Springs to
     Suwannee River FL out 20 NM-Tampa Bay waters-Waters from
     Bonita Beach to Englewood FL out 20 to 60 NM-Waters from
     Englewood to Tarpon Springs FL out 20 to 60 NM-Waters from
     Tarpon Springs to Suwannee River FL out 20 to 60 NM.
-- End Changed Discussion --


&&

$$

DISCUSSION/AVIATION/MARINE/FIRE WEATHER...Shiveley
DECISION SUPPORT...Pearce
UPPER AIR/CLIMATE...Pearce