Area Forecast Discussion
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FXUS62 KTAE 261416
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
1016 AM EDT Tue Mar 26 2024

...New UPDATE, MARINE...

...STRONG TO SEVERE STORMS WITH POCKETS OF HEAVY RAIN POSSIBLE
TODAY...

.UPDATE...
Issued at 949 AM EDT Tue Mar 26 2024

No major changes to today`s forecast were required. Rain chances
were adjusted to the hourly level until 18Z to best capture
current radar and the latest hi-res trends. A line of showers
with embedded thunder is moving across the Lower MS Valley into
the Wiregrass Region late this morning ahead of a cold front
attendant to its parent Low over the Great Lakes. This activity
will be monitored closely for severe weather potential. Thus far,
convection has underperformed, however, there are indications of
convective upticks east of Mobile Bay. It appears the greatest
possibility for severe storms to materialize is over the FL
Panhandle, especially closer to the coast over the next few hrs
where a tongue of instability is noted per SPC mesoanalysis.

The 12Z KTAE sounding revealed a fairly dry (1.07" PW) and stable
airmass with caps noted at 850 mb & 700 mb. Shear is plentiful
though as values are >40 kts in the lowest 1 km and is just above
50 kts up to 6 km. There is also a notable turning of the winds
within the mixed layer from SSE to SSW before the remainder of the
column goes unidirectional. Additionally, a strong low-level jet
is apparent just above the surface at 40-45 kts. Therefore, any
surface-based storms will be capable of mixing those stronger
winds down and may produce a tornado or two. We are still looking
at a diminishing trend with east extend as the afternoon
progresses.

&&

.NEAR TERM...
(Today and tonight)
Issued at 425 AM EDT Tue Mar 26 2024

As of 3AM ET, line of showers and thunderstorms stretches from
central Tennessee southwestward to southern Mississippi and is
advance eastward. At the surface, cold front stretches from the Mid
South down to southwest Louisiana with low pressure located in
southeast Missouri. Aloft, an upper low is situated in the central
Plains, troughing extends south into Mexico, and mid level ridge is
draped over the east coast from a high in the western Caribbean.

The line of convection will continue moving east overnight and
reaching our western counties after sunrise into mid morning. The
atmosphere on arrival of the line will be characterized by good
shear with bulk shear values of 50-60 knots but cape values are at
or below 500 J/kg. The better forcing moves away from the area but
given the aforementioned variables and the linear mode of
convection, a few strong to damaging wind gusts in the strongest
storms and perhaps a brief tornado are possible. SPC continues the
marginal risk for severe weather today. The line will continue east
this afternoon but will face a gradual weakening trend towards late
afternoon and evening.

It will be another breezy day for the area as the pressure gradient
remains tight between high pressure to the northeast and low
pressure to our west. Gusts of 25 to 30 mph will be common.

The cold front reaches the central portions of our service area
tonight then essentially stalls in that general area. Showers and
storms by this evening will decrease in coverage with perhaps a
brief lull before additional showers and storms redevelop in the
overnight hours. This is when an upper jet gets closer increasing
diffluence aloft and low level convergence in the vicinity of the
cold front. This period begins the heavy rain threat persisting into
Wednesday night as the front doesn`t move much. A flood watch has
been issued and begins at 03Z tonight essentially from Gulf county
northeast to Worth county and points eastward.

&&

.SHORT TERM...
(Wednesday through Thursday night)
Issued at 425 AM EDT Tue Mar 26 2024

A large upper trough will continually slide east over
the southern plains with an embedded shortwave trough ejecting
northeast over the Great Lakes. An attendant surface low will
continue to occlude over the great lakes with a cold front extending
toward our area. The cold front is expected to stall over the area,
likely along the Flint/Apalachicola Rivers, resulting in a
substantial amount of rain across areas along and east of the
aforementioned rivers.

The main concern with this event is heavy rainfall due to the front
stalling with mid-level flow parallel to the front, resulting in
training convection along the front. PWAT`s across the area are
expected to reach around 1.7"-1.9", perhaps exceeding 2" which would
put this event over the 90th percentile for PWAT`s in the forecast
area. There is still some uncertainty regarding where the front will
stall, though models have begun to hone in on a line extending from
Gulf County FL to Turner County GA. As such, a flood watch has been
issued for counties along and east of the aforementioned line. West
of the line, rainfall totals are expected to remain around 1-2". For
areas east of the line, rainfall amounts will range from 2-3" with
locally higher amounts possible, perhaps 4"+.  Currently, the WPC
has a slight risk (level 2/4) for the aforementioned areas.

Daytime highs will generally stay within the 70s on Wednesday and
Thursday. Overnight lows Thursday morning before the cold front
moves into the area will generally remain in the 50s.

&&

.LONG TERM...
(Friday through Monday)
Issued at 425 AM EDT Tue Mar 26 2024

Ridging will gradually build in through the long
term as the longwave upper trough slides off the East Coast. Breezy
conditions are expected as a tight pressure gradient sets up over
the region. Surface winds will subside come Friday when high
pressure in the mid-upper levels builds in. Friday will kick off a
warming trend with daytime highs in the mid to upper 70s across SE
AL and our FL counties with some low 70s areas across SW GA. Through
the weekend, daytime highs will gradually warm from the low 80s to
the upper 80s by Monday. Friday morning will be cold in the post
frontal environment with temperatures in the 40s across the board.
Overnight lows will also see a warming trend with temperatures in
the upper 50s and perhaps the low 60s come Monday morning.

&&

.AVIATION...
(12Z TAFS)
Issued at 622 AM EDT Tue Mar 26 2024

Line of convection is moving into southern AL attm, expected to
reach DHN and ECP this morning. Cigs will decrease in advance,
falling into MVFR to IFR with SHRA/TSRA by mid morning. Vsbys will
decrease as well with heavier rain. Rain moves eastward today,
weakening as it reaches ABY and TLH. Cigs and Vsbys will also
decrease ahead of the line. More uncertain if any aspect of the
line reaches VLD this evening before falling apart. Low cigs will
remain even if convection diminishes. Later overnight,
redevelopment is likely but uncertainty exists where rainfall will
occur.

&&

.MARINE...
Issued at 949 AM EDT Tue Mar 26 2024

Late-morning trends support allowing the Gale Warning to expire
at 12Z across the western legs. Buoy 42012 was reporting a SSE
winds near 12 kts with 9-ft seas and dominant period of 9 sec,
while Buoy 42036 showed sustained SSE winds at 18 kts, near 7-ft
seas, and a dominant period of 5 sec. These observations prompt
the continuation of a Small Craft Advisory mainly for elevated
seas at all zones outside of the easternmost nearshore legs.

From the CWF Synopsis...Gales have diminished this morning, but
advisory level seas remain across zones away from the Nature
Coast. Seas should be slowest to subside west of Apalachicola
until tonight. A line of showers with embedded thunderstorms ahead
of a cold front pushes through the waters today. Gusty winds,
lightning, and the potential for waterspouts are in play with this
activity. Late tonight, into tomorrow the front stalls likely
somewhere over Apalachee Bay with maritime convection redeveloping
along it. Boating conditions improve after the system exits to
the east Thursday through the weekend.

&&

.FIRE WEATHER...
Issued at 425 AM EDT Tue Mar 26 2024

Other than marginally high dispersions in the eastern Florida Big
Bend today, there are no fire weather concerns over the next few
days. A cold front will bring wetting rains throughout the area
beginning today through early Thursday morning. Beyond this low
pressure system, dry conditions are anticipated through the
weekend.

&&

.HYDROLOGY...
Issued at 425 AM EDT Tue Mar 26 2024

Today, a coastal flood advisory is in effect for Franklin,
Wakulla, and Jefferson through Tuesday as moderate to strong east-
southeast winds persist through Tuesday afternoon. This will serve
to push water onto the coast across the aforementioned areas which
may interact with high tide between 12AM-8PM Tuesday.

Regarding rainfall, around 1-3" is expected areawide with the higher
amounts likely falling east of the Apalachicola and Flint Rivers
where a cold front is forecast to stall. Two rounds of rainfall are
expected to occur with the first occurring across SE AL and the FL
Panhandle as the cold front begins its push into the area Tuesday
morning through afternoon. The WPC currently has our SE AL, FL
Panhandle, and portions of our SW GA counties in a slight risk (2/4)
for excessive rainfall.

The cold front will then stall along the aforementioned area
resulting in our second round of rainfall on Wednesday. There is
higher confidence regarding the area of heaviest rainfall, resulting
in a flood watch for the areas of interest east of a line extending
from Gulf County FL to Turner County GA. Storm totals are forecast
to reach around 2-3" with locally higher amounts 5"+ where heavier
rain may be possible. The WPC has a slight risk (2/4) outlined
across our FL Big Bend and SW GA counties. Flash flooding appears
possible with this event with flash flood guidance showing 4-5" in
6hrs across FL with lower values across SE AL and SW GA around 3.5-
4.5".

Regarding rivers, all have fallen out of flood stage. However, there
is a chance they could return to action stage and perhaps minor
flooding as a result of the expected rainfall.

&&

.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...
Tallahassee   76  64  74  55 /  30  90  90  70
Panama City   74  61  75  55 /  80  70  60  40
Dothan        74  57  76  51 /  90  50  40  30
Albany        77  61  74  52 /  70  80  60  60
Valdosta      82  65  74  56 /  20  80  90  80
Cross City    83  65  75  59 /   0  60  70  80
Apalachicola  71  65  71  56 /  40  90  90  60

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch from this evening through late Wednesday night for
     FLZ014>019-026>029-034-114-115-118-127-128-134.

     High Rip Current Risk through Wednesday morning for FLZ108-112-
     114-115.

     High Surf Advisory until 1 AM CDT Wednesday for FLZ108-112.

     Coastal Flood Advisory until 8 PM EDT this evening for FLZ115-
     118-127.

GA...Flood Watch from this evening through late Wednesday night for
     GAZ127>131-145>148-156>161.

AL...None.
GM...Small Craft Advisory until 1 AM CDT Wednesday for GMZ750-752-770-
     772.

     Small Craft Advisory until 8 PM EDT this evening for GMZ755-775.

&&

$$

UPDATE...IG3
NEAR TERM...Scholl
SHORT TERM...Worster
LONG TERM....Worster
AVIATION...Scholl
MARINE...IG3/Worster
FIRE WEATHER...Scholl
HYDROLOGY...Worster


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