379
FXUS62 KTBW 261149
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
749 AM EDT Thu Sep 26 2024

...New AVIATION...

.AVIATION...
(12Z TAFS)
Issued at 744 AM EDT Thu Sep 26 2024

We`re seeing worsening conditions across the region this morning as
rainbands from Hurricane Helene spread north. This system will bring
MVFR and occasional IFR conditions into tonight. Gusty southeast
winds at 10 to 20 knots will increase to 25 to 35 knots by this
afternoon then shift to southerly late this afternoon and evening.
Wind gusts will also increase up to 45 to 55 kts in some of the
stronger rainbands this afternoon. Winds will begin diminishing and
conditions will begin to improve by 02/03Z.

&&

.SHORT TERM...
(Today and tonight)
Issued at 221 AM EDT Thu Sep 26 2024

Hurricane Helene remains the dominant feature for our weather
through tomorrow. Helene is centered in the Southern Gulf of Mexico
north of the Yucatan Peninsula. It is forecast to rapidly strengthen
through today as the storm moves north to northeast with an
increasing forward speed, eventually making landfall in the Florida
Big Bend Region. Widespread impacts are expected across West-Central
and Southwest Florida beginning early today and lasting through
Friday morning.

* Storm Surge - Life threatening storm surge is expected today into
  Friday. Potential peak surge amounts are 10 to 15 feet from
  Chassahowitzka to Suwannee River, 8 to 12 feet from Anclote River
  to Chassahowitzka, 5 to 8 feet from Middle of Longboat Key to
  Anclote River, 4 to 7 feet from Englewood to Middle of Longboat
  Key, and 3 to 5 feet from Bonita Beach to Englewood. Elevated
  water levels are possible through Friday.

* Flooding Rain - Flooding rain threat will run from today through
  this weekend with rainfall amounts of 3 to 6 inches with locally
  higher amounts up to 10 inches possible. Even after Helene pulls
  away, additional rounds of heavy rainfall are expected this
  weekend.

* Wind - Hurricane and tropical storm force winds will be possible
  today and tonight with the highest probabilities along the coast.

* Tornadoes - Several tornadoes are possible today and tonight
  across the area.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 221 AM EDT Thu Sep 26 2024

As Helene pulls away on Friday, the trough axis pushing it off to
the northeast will drag a frontal boundary into the vicinity of
central Florida. This boundary is expected to stall out across the
center of the state and will linger for several days to come. In the
warm sector, a breezy southwest flow will prevail with scattered to
numerous storms, aided by the moisture pooling along the boundary as
well as the enhanced ascent. North of the boundary, conditions will
be drier, but a WSW flow will still prevail.

This setup means some impacts may linger. The SW flow could make it
more difficult for all the water to drain as quickly; thus higher
water levels could linger well after the storm is lifting north.
Additional rainfall also has the potential to  existing flooding
concerns.

By early next week, however, the gradient looks to collapse. While a
SW flow will still prevail with the surface ridge to the east, the
flow will be pretty weak. However, additional moisture will still
keep scattered storms in the forecast through the week. This should
be more typical diurnal convection. In a WSW flow, this means
convection earlier in the day for the coastal areas, and early to
mid-afternoon for inland areas.

By mid-week, the frontal boundary will finally get the push it needs
from another trough, bringing what should be a drier and more stable
airmass in for the end of the week. This should at first yield a
more northerly and eventually more easterly flow late in the week.
While drier, warm conditions are expected to continue.

&&

.MARINE...
Issued at 221 AM EDT Thu Sep 26 2024

Tropical Storm and Hurricane Warnings are in effect for all waters
as Hurricane Helene moves northward. The hurricane will continue to
move northward today, with very dangerous marine conditions
continuing as it strengthens into a major hurricane. Helene will
make landfall around the Big Bend region later today or tonight with
elevated winds continuing into Friday before decreasing for the
weekend. Waves will continue to build for the rest of the day and
remain elevated through Friday before beginning to decrease.
However, a persistent southwesterly flow suggests that the sea
state will take longer than normal to settle.

&&

.HYDROLOGY...
Issued at 221 AM EDT Thu Sep 26 2024

As Helene lifts northward, rain bands are overspreading the area.
Overnight stability continues to be a limiting factor, however, and
these bands are generally falling apart. Storm total accumulations
remain low in response at only an inch-and-a-half for the last 26
hours or so. Most of this rain fell earlier in the day too, not
posing much of an issue in the short-term if additional rainfall
occurs.

Once sunrise occurs, this instability will quickly increase and more
convection will overspread. Forecast rainfall totals are for 3 to 6
inches, with isolated totals up to 10 inches. Most of the heaviest
rainfall is likely to occur at the coast. When combined with storm
surge, this could cause significant issues in urban areas. This
combination also has the potential to impact rivers running near the
coast, such as the Myakka River, Alafia River, Cypress Creek, and
the Withlacoochee River. However, inland rivers like the Peace River
are less likely to experience significant river flooding, or even
significant water level rises at all.

With additional rainfall through the weekend, the threat will not
quickly subside even as the storm pulls away. Eventually, some
drier weather should return for the middle of next week. This will
be welcome, and should help dry things out.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  87  80  89  78 / 100  80  30  40
FMY  88  81  90  79 /  90  80  80  70
GIF  88  80  91  78 /  80  60  40  40
SRQ  88  81  90  79 /  90  80  40  50
BKV  88  77  90  74 / 100  80  30  20
SPG  88  82  90  81 /  90  80  30  40

&&

Sea Breeze Thunderstorm Regime For Thursday: 7
Sea Breeze Thunderstorm Regime For Friday: 5

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

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch 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.

     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.

     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/HYDROLOGY...Flannery/Shiveley
AVIATION...ADavis
DECISION SUPPORT/UPPER AIR...Carlisle/Pearce