625
FXUS62 KTBW 251143
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
743 AM EDT Wed Sep 25 2024

...New AVIATION...

.DISCUSSION...
Issued at 329 AM EDT Wed Sep 25 2024

At the surface, weak high pressure across northern Florida will
get edged out today as Tropical Storm Helene strengthens and
lifts north into the southern Gulf of Mexico. Due to the approach
of Helene, a tightening pressure gradient across the Florida
Peninsula will result in winds becoming breezy today, while
increasing moisture will also result in more numerous showers and
storms through the afternoon and evening. With the onset of
tropical storm force winds not expected before tonight or tomorrow
morning, residents should finish up any final preparations today.

Conditions will continue to rapidly deteriorate overnight, with
tropical rain bands spreading across the area and winds increasing
as the center of Helene approaches the eastern Gulf of Mexico as a
hurricane. The biggest threat to life and property will be from
storm surge along the coast Thursday and Friday, with peak surge
values of 10-15 feet possible at points along the coast in Levy
and Citrus counties, and as much as 5-8 feet possible at points
along the coast in the Tampa Bay. Onshore winds behind the system
on Friday will also keep coastal flooding ongoing longer than
other tropical hazards. Storm surge is historically the biggest
killer from tropical systems, so it is important that residents
heed evacuation orders from local officials. Evacuate before surge
begins to rise, as surge waters move in quickly and will cut off
escape routes.

Helene also poses an extreme wind threat, with the system expected
to produce a very large wind field, with hurricane and tropical
storm force winds expected to be felt well away from the center.
The timing of the greatest wind impacts is expected to start in
southwest Florida early Thursday morning and expand northward
through the Nature Coast through the late morning. Tropical Storm
force winds are expected to begin to subside over southwest
Florida Thursday evening, around the Tampa Bay around midnight,
and exit the Nature Coast during the early morning hours on
Friday. The highest wind speeds are forecast to be along the coast
and especially over the northern half of the forecast area as
Helene moves northeast. Residents should be prepared to shelter
out of the wind Thursday in well built structures away from surge
zones and flood prone areas.

Flooding rains will also pose a significant threat to life and
property. After the round of showers today, rain bands sweep
through the area tonight through Thursday night. After a brief
dry slot pushes into the area Thursday night and early Friday, a
band of deep tropical moisture trailing behind Helene will setup
across the Florida Peninsula Friday through the weekend, resulting
in additional rounds of heavy rainfall well after Helene departs.
5 day rain totals are expected to generally range from 3-6
inches, with localized amounts of up to around 10 inches
possible. The highest totals are most likely to be along the
coast. A flood watch is in effect for the entire forecast area.
Stay out of flood waters and do not attempt to drive across
flooded roads.

Otherwise, there is also a limited threat of tornadoes embedded
in the rain bands, mainly on Thursday. As Helene pulls away Friday
and Saturday, onshore winds will also continue to produce high
surf and a high risk or rip currents at area beaches.

By Monday and Tuesday, weak high pressure will setup across the
Florida Peninsula with the weakened remains of Helene to the north.
Somewhat drier air will fill in under weak westerly and
northwesterly flow, resulting in scattered showers and storms in
the afternoon.

&&

.AVIATION...
(12Z TAFS)
Issued at 742 AM EDT Wed Sep 25 2024

VFR conditions will generally prevail this morning but MVFR/local
IFR conditions is expected by the afternoon as scattered to
numerous showers and isolated thunderstorms develop and spread
northward. Surface winds out of the ESE winds this morning will be
around 5 to 10 knots and will gradually increase throughout the
day as Tropical Storm Helene moves into the southern Gulf of
Mexico. As a result, sustained ESE winds increase to 10 to 15
knots later this morning through the afternoon and then increase
further to 15-20 kts tonight with some higher gusts of 30 kts or
greater by overnight.

&&

.MARINE...
Issued at 329 AM EDT Wed Sep 25 2024

Tropical Storm Helene in the northwest Caribbean Sea is forecast to
continue to strengthen as it lifts into the southern Gulf of
Mexico today. An increasing pressure gradient ahead of this
system is leading to building winds and seas tonight and
Wednesday, as well as increasing rain chances. Wednesday night and
Thursday the marine conditions will become extremely dangerous as
Helene is forecast to strengthen to a major hurricane and move
northeast through the eastern Gulf of Mexico. Conditions will
slowly improve Friday and Friday night as Helene pulls away,
although rain chances will stay elevated through the weekend.

&&

.FIRE WEATHER...
Issued at 329 AM EDT Wed Sep 25 2024

No humidity concerns. Conditions will become breezy today with
rain chances increasing from the south as Tropical Storm Helene
pushes north into the Gulf of Mexico. Conditions will then rapidly
deteriorate tonight and Thursday as Helene strengthens and moves
northeast through the eastern Gulf of Mexico, with hurricane and
tropical storm conditions possible.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  90  76  87  80 /  80  80 100  70
FMY  90  78  88  81 /  90  90  90  80
GIF  91  77  88  79 /  80  70  90  70
SRQ  92  76  88  80 /  80  90 100  80
BKV  92  74  87  77 /  80  80 100  70
SPG  91  79  87  82 /  80  90 100  80

&&

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

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

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...Tropical Storm Warning for Coastal Charlotte-Coastal
     Hillsborough-Coastal Lee-Coastal Manatee-Coastal Sarasota-
     DeSoto-Hardee-Highlands-Inland Charlotte-Inland Citrus-
     Inland Hernando-Inland Hillsborough-Inland Lee-Inland
     Manatee-Inland Pasco-Inland Sarasota-Pinellas-Polk-Sumter.

     Flood Watch from this 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 Hillsborough-Coastal Manatee-Coastal
     Sarasota-Inland Citrus-Inland Hernando-Inland Pasco-
     Pinellas.

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

     Hurricane Warning for Coastal Citrus-Coastal Hernando-Coastal
     Levy-Coastal Pasco-Inland Levy.

Gulf waters...Tropical Storm Warning for Charlotte Harbor and Pine Island
     Sound-Coastal waters from Bonita Beach to Englewood FL out
     20 NM-Coastal waters from Englewood to Tarpon Springs FL
     out 20 NM-Tampa Bay waters-Waters from Bonita Beach to
     Englewood FL out 20 to 60 NM.

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

     Hurricane Warning for Coastal waters from Tarpon Springs to
     Suwannee River FL out 20 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.


&&

$$

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