-- Discussion containing changed information from previous version are highlighted. --
973
FXUS62 KTAE 250548
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
148 AM EDT Wed Sep 25 2024

...New AVIATION...

.UPDATE...
Issued at 1110 PM EDT Tue Sep 24 2024

The 11 pm EDT advisory package from NHC effectively has little or
no change. The center of Helene is still forecast to make
landfall along the Big Bend coast as a Cat 3 late Thursday.

Mostly unrelated to Helene, Wednesday should be an active day of
thunderstorms and heavy rain, especially for the Panhandle and
southeast Alabama. A slow-moving or nearly stationary surface
boundary will set up over the Panhandle, serving as a focus for
thunderstorm development against the backdrop of moderate
instability, a moistening air mass, and about 25-30 knots of bulk
shear to help storms organize into clusters. Convection will start
to blossom along the Emerald Coast before sunrise on Wednesday.

&&

.SYNOPSIS...
Issued at 354 PM EDT Tue Sep 24 2024

Weather turns active on Wednesday as showers/thunderstorms
increase ahead of Tropical Storm Helene. Isolated severe weather
and heavy rain is possible with this activity.

Helene is forecast to approach Apalachee Bay as a likely major
hurricane on Thursday with conditions deteriorating from south to
north. Landfall is forecast somewhere along the NE Gulf Coast as a
major hurricane and bring a myriad of potentially significant
threats: life-threatening storm surge, tropical storm/hurricane-
force winds, flash flooding, and isolated tornadoes.

Conditions should improve heading into the weekend as Helene
exits the region.

&&

.NEAR TERM...
(Through Wednesday)
Issued at 354 PM EDT Tue Sep 24 2024

The benign weather we have been experiencing the past couple days
gives way to increasing rain chances tomorrow. A frontal boundary
attendant to a broad/energetic upper trough over the Central
Plains interacts with tropical moisture off the Gulf to be the
primary foci for showers/thunderstorms. The environment is
forecast to be somewhat conducive for loosely organized convection
capable of isolated gusty/damaging winds, locally heavy rain, and
perhaps a brief tornado or two. For these reasons, the SPC
introduced a Marginal Risk (level 1 of 5) of severe weather in the
Day 2 Outlook for SE AL, the FL Panhandle, and parts of the FL
Big Bend/SW GA.

The 18Z HRRR initiates convection off the Emerald Coast as a N-S-
oriented cluster in the morning before spreading inland with
time. Storm mode appears to take on linear-like banding shapes,
which could spell heavy rain/flooding trouble that`s not even
directly associated with TC Helene, yet. In response to this
evolution, the WPC maintains a Slight Risk (level 2 of 4) over
parts of the Emerald/Forgotten Coasts and Marginal Risk (level 1
of 4) elsewhere for the Day 2 Outlook. The former may drop
southward to the Wiregrass Region in subsequent outlooks.

With weather aiming to be active on Wednesday, users are highly
encouraged to finalize any outdoor preparedness plans ahead for
Helene sooner than later. Given the increased cloud cover/rain
chances, expect relatively cooler daytime temperatures with
widespread highs in the 80s. Overnight lows drop to the low 70s.

&&

.SHORT TERM...
(Wednesday night through Friday)
Issued at 354 PM EDT Tue Sep 24 2024

The focus will be the approaching Tropical Storm Helene, which is
expected to become a hurricane or major hurricane prior to
landfall somewhere along the Florida Panhandle or Big Bend.

There will be a developing upper level trough over the middle
Mississippi Valley that will pull in Tropical Storm Helene,
bringing it up north through the Gulf of Mexico. Tropical Storm
Helene is expected to strengthen to a hurricane bringing
significant impacts to the Florida Panhandle and Big Bend,
possibly extending further inland to SE Alabama and SW Georgia.
Winds will be gradually increasing through the day on Thursday
with scattered showers already occurring.

The 11AM EDT Advisory still indicates that Tropical Storm Helene
will make landfall along the Florida Big Bend as a Major Category
3 Hurricane sometime late Thursday evening.

The 12z ensemble runs do not show much shift east or west from
the 06z ensemble runs as to where the center may go. The object to
focus on is that this will be a very large storm in size. Impacts
will be felt well outside of the cone of uncertainty. Expect
conditions to begin deteriorating by midday Thursday. All
locations along the northern Gulf and along the eastern portions
of the Florida Big Bend and west coast of Florida are at risk
currently for a major hurricane bringing significant wind, storm
surge inundation, and rainfall. Additionally, Tropical Storm
Helene is likely to have a faster than usual storm motion as it
accelerates north around landfall and moves inland. When combined
with the storm`s large size and fast forward motion, significant
winds and gusts could extend further inland than folks are
typically accustomed to seeing during tropical systems.

Reminder, every storm is unique in its own way with what it
brings in regards to threats and hazards, and each system brings
uncertainty that can leave you unprepared if you`re not ready for
a *reasonable* worst case scenario. Don`t underestimate the danger
you could experience with Helene just because you avoided impacts
from previous storms.

With watches issued and upcoming warnings are likely, if you are
under a tropical/hurricane/surge watch or warning, be sure to
check the forecast at weather.gov (type your zip code to see
watches/warnings at your location) and read the tropical
watch/warning text. These watches/warnings will list out
conditions that you should be prepared for. These watches/warnings
also list out reasonable worst case scenarios you should be ready
for at your location.

&&

.LONG TERM...
(Friday Night through Monday)
Issued at 354 PM EDT Tue Sep 24 2024

Helene will be out of the region by the start of this long term
period. We can expect to return to typical conditions for late
September with highs in the mid-80s with overnight lows in the
upper 60s/low 70s. PoPs chances will be low during the weekend but
the upper level trough from before the hurricane will be moving
east/northeast across the eastern one-third of the U.S. pushing a
frontal boundary across the TAE CWA that may increase rain chances
to about 30% by the end of the long term.

&&

.AVIATION...
-- Changed Discussion --
(06Z TAFS)
Issued at 148 AM EDT Wed Sep 25 2024

Southerly flow aloft will increase somewhat through sunrise,
bringing a more richly moist and moderately unstable air mass
north off the Gulf. This will interact with a surface boundary
over the Panhandle and southeast Alabama, along with a landbreeze
near the Panhandle coast, to bring a blossoming of convection
over ECP before sunrise, expanding north to DHN after sunrise. TLH
and ABY will be near the eastern edge of convection through the
morning.

On Wednesday afternoon, rain-cooled air near ECP and DHN may
bring a decrease in convection, but areas that did not previously
see thunder will see convection and perhaps thunder bubbling up in
the afternoon.

A large area of stratiform rain and embedded thunder will spread
north on Wednesday evening, well in advance of Helene. This will
bring a more widespread reduction in cigs and visibilities.
-- End Changed Discussion --

&&

.MARINE...
Issued at 1110 PM EDT Tue Sep 24 2024

At 11 pm EDT Tuesday, the center of Tropical Storm Helene was
located over the far northwest Caribbean Sea. Helene will move
northward across the eastern Gulf on Wednesday and Thursday,
rapidly strengthening to a major hurricane before making landfall
along the Big Bend Coast late Thursday. Helene will quickly move
inland on Friday, so conditions will improve over the waters.
Gentle to moderate southwest breezes will prevail this weekend, as
a large area of low pressure spins over the Lower Mississippi
Valley.

&&

.FIRE WEATHER...
Issued at 354 PM EDT Tue Sep 24 2024

Fire weather concerns are minimal over the next 3 days as rain
chances markedly increase from a frontal system moving into the MS
Valley, followed by the arrival of TC Helene late this week.

For Wednesday, showers and thunderstorms mainly focus west of the
Apalachicola River basin. Some may be strong to severe capable of
gusty/damaging winds, and locally heavy rain.

On Thursday, tropical moisture surging off the Gulf from the
approaching Helene is expected to bring squally weather with
conditions deteriorating ahead of landfall somewhere along the NE
Gulf coast as a likely major hurricane. Hurricane conditions are
possible across the FL Big Bend while tropical storm conditions
are possible for eastern portions of the FL Panhandle. Widespread
wetting rains are expected with potential for flash flooding
(locally considerable).

Very high dispersions are forecast on Friday thanks to breezy
gradient winds from Helene`s large circulation despite pulling
away from the region.

&&

.HYDROLOGY...
Issued at 354 PM EDT Tue Sep 24 2024

Primary focus continues to on the approach of Tropical Storm
Helene to the region. The system has the potential to bring
significant rain to the region, even accounting for its fast
forward motion as it nears the Florida Big Bend. Model guidance
has been in good agreement that a precursor event of heavy
rainfall will overspread the Florida Big Bend and Panhandle
Wednesday evening with the bulk of the rainfall arriving later on
Thursday. This will lead to some heavy rainfall totals across
North Florida and South Georgia totaling 5 to 10 inches of rain
with isolated maximum totals approaching 10 to 15 inches.

The entire forecast area is included in a Moderate risk for flash
flooding (level 3 out of 4) for Thursday. It is possible that
this risk level is increased in future outlooks. Nonetheless,
these amounts will lead to considerable urban flash flooding along
with the potential for moderate flooding, especially on the
Ochlockonee River Basin. Depending on where the heaviest rains are
distributed inland, it is entirely possible that other river
basins could experience moderate riverine flooding in the days
ahead.

For storm surge information, please refer to the latest
information from the National Hurricane Center. This is an
extremely dangerous storm surge threat in the Apalachee Bay. Storm
Surge around Apalachee Bay will not just merely be a coastal
event in this system, but will spread many miles inland. If
ordered to evacuate, heed the advice of local emergency managers -
it could save your life!

&&

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
Tallahassee   86  72  79  72 /  50  90  90  90
Panama City   85  72  79  72 /  80  90  90  80
Dothan        85  70  76  68 /  70  90  90  80
Albany        87  72  78  70 /  50  80  90  90
Valdosta      88  72  81  73 /  30  80  90  90
Cross City    90  73  85  76 /  60  90  90  90
Apalachicola  84  73  81  74 /  70 100 100  80
-- End Changed Discussion --

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
FL...Flood Watch from this evening through Friday morning for
     FLZ007>019-026>029-034-108-112-114-115-118-127-128-134.

     Tropical Storm Warning for FLZ011>013-112.

     Hurricane Warning for FLZ014>019-026>029-034-114-115-118-127-128-
     134.

     Storm Surge Warning for FLZ027-115-118-127-128-134.

     High Rip Current Risk through late Friday night for FLZ114-115.

GA...Flood Watch from this evening through Friday morning for
     GAZ120>131-142>148-155>161.

     Tropical Storm Watch for GAZ120>131-142>144-155.

     Hurricane Watch for GAZ145>148-156>161.

AL...Flood Watch from this evening through Friday morning for
     ALZ065>069.

     Tropical Storm Watch for ALZ067-069.

GM...Tropical Storm Warning for GMZ750-770.

     Hurricane Warning for GMZ730-752-755-765-772-775.
-- End Changed Discussion --

&&

$$

NEAR TERM...IG3
SHORT TERM...Montgomery
LONG TERM....Montgomery
AVIATION...Haner
MARINE...Haner
FIRE WEATHER...IG3
HYDROLOGY...Godsey