058
FXUS62 KTAE 271813
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
213 PM EDT Mon May 27 2024

...New AVIATION...

.UPDATE...
Issued at 1056 AM EDT Mon May 27 2024

Our 12z sounding this morning showed a rather impressive elevated
mixed layer (EML) with mid-level lapse rates in excess of 8 C/km,
which is very impressive for this part of the country. However,
there is a good bit of dry air in the mid and low levels as well
as a capping inversion around 800 mb. This makes sense as farther
south, the influence of the ridge is still present. However, an
approaching shortwave and diurnal heating could erode any
inversion farther north. We still expect that we`ll be plenty
unstable with about 30-35 kt deep layer shear and 850-1100 J/kg of
DCAPE. The question remains how much forcing will we have. If we
have less forcing, there may be fewer storms overall, and more
forcing means greater coverage of storms. Regardless, any storms
that do develop in this environment will be capable of becoming
strong to severe with damaging winds and large hail being the
primary severe concerns. Frequent lightning will accompany all
storms today.

Rain chances were tweaked, mainly in the Florida Panhandle later
this afternoon and evening where the hi-res guidance suggests that
storms may eventually move into. Storm motion today will generally
be east to southeast. High temperatures were also nudged upward a
bit, mainly in the southern and eastern parts of the area where a
bit more sunshine is starting to break through.

&&

.NEAR TERM...
(Today and tonight)
Issued at 426 AM EDT Mon May 27 2024

Overall, another warm to hot afternoon is expected with temperatures
pushing into the upper 80s to lower 90s for much of the area. The
concern with today`s forecast is the potential for strong to severe
thunderstorms later this morning and into the afternoon and evening.
The Storm Prediction Center has maintained a Slight Risk (level 2 of
5) for severe weather from a line that extends from northern Walton
County northeastward through Tifton and a Marginal Risk (level 1 of
5) from just north of Panama City through Tallahassee and just south
of Valdosta. Any storms that move through later this morning and
into the afternoon and/or are able to develop later today will have
the potential of producing damaging wind gusts and large hail.

Today`s thunderstorm potential is highly conditional on what happens
upstream of the region early this morning. Most Convection Allowing
Models (CAMs) are in decent agreement on the Mesoscale Convective
System (MCS) continuing to dive southeast through Mississippi and
Alabama this morning. However, they begin to differ on just how far
south the MCS can make it and whether any storms can develop in its
wake. If the MCS holds together through the morning, it is forecast
to arrive in our southeastern Alabama counties as early as 10-11AM
CDT before pushing southeast into the rest of the area in the
afternoon. This is during peak heating hours, so there will be
plenty of energy available for these storms to continue. One
limiting factor is the fact the bulk of the upper-level support is
expected to remain north of our area. Still, forecast soundings show
2,000 to 3,000 J/kg surface based CAPE along with Downdraft CAPE
(DCAPE) between 1,000 to 1,500 J/kg. Values that high coupled with
some mid-level dry air support the possibility of damaging wind
gusts. Mid-level lapse rates will generally be between 7 to 7.5
C/km, which will support the potential for large hail within any of
the stronger storms.

Later tonight, a weak cold front is forecast to push through most of
the region outside of the southeast Florida Big Bend. Temperatures
won`t fall a whole lot tonight, generally in the upper 60s to lower
70s, as the drier air will take a while longer to push into the
region.

&&

.SHORT TERM...
(Tuesday through Wednesday night)
Issued at 426 AM EDT Mon May 27 2024

In the wake of the weak late season cold frontal passage late
Monday night, a drier air mass will trickle in across the region
on Tuesday. Precipitable Water (PW) values will dry out well below
1.5 inches, which will suppress attempts at afternoon convection.

Am suspicious of the NBM`s dry forecast for Wednesday and
Wednesday night. Most guidance increases PW values on Wednesday,
albeit holding them a little below 1.5 inches. However, we will
be under cyclonic 500 mb flow, and some guidance members are
painting a shortwave rippling across the region on Wednesday.
Perhaps this will manifest itself as a leftover MCV from an
earlier thunderstorm complex well off to the west. Seabreeze
boundaries will also spread inland in the afternoon. This should
present a few ways to focus convection, if we can get enough
moisture. While most GEFS ensemble members are dry on Wednesday,
there are a few that produce moderate instability and respectable
QPF. Have therefore at least included slight chance PoPs, which is
supported by GFS- and NAM-based MOS guidance values along and
west of the Flint River.

&&

.LONG TERM...
(Thursday through Sunday)
Issued at 426 AM EDT Mon May 27 2024

Beyond Wed night through next weekend, the forecast area will lie
near a substantial north-south moisture gradient, with drier air
to the north and moister air to the south. This comes as surface
high pressure will move from the Ohio Valley on Friday night off
the U.S. Mid- Atlantic coast by Sunday. This will cause our low-
level flow to clock around more easterly and perhaps southeasterly
over the course of next weekend. Given our proximity to the
moisture gradient, small differences in its north-south position
have caused GEFS ensemble members to show a large range of
possible PW values, ranging from very moist to very dry. Looking
at trends in guidance for different runs over the last couple
days, there may be a trend toward less and less drying the air
mass late this week and next weekend. While the GEFS ensemble
means keep PW values in the drier 1.3 to 1.4 inch range late this
week and next weekend, there is a large number of ensemble members
up in the 1.5 to 1.8 inch range. Given the seabreeze to focus
convection in the presence of enough moisture and instability, the
latest forecast has slightly nudged up PoP more squarely into the
20-30 percent range heading into next weekend.

&&

.AVIATION...
(18Z TAFS)
Issued at 147 PM EDT Mon May 27 2024

Showers and thunderstorms are popping up in southern GA and
southeast AL, and are generally isolated to scattered in nature.
Expect storms to become a little more scattered to widespread over
these areas with the possibility for storms to become severe.
Damaging winds and hail will be the primary hazards. A Severe
Thunderstorm Watch is in effect for all AL counties and most of
southwest GA, except the southern tier of counties (Seminole to
Lowndes, and Lanier) at this time through 10PM EDT / 9PM CDT.
Once the storms clear, skies should clear. Where rainfalls, we may
have some reduced visibility down to MVFR status. Started to hint
at that in some of the TAF sites, with vis improving shortly
after sunrise.

&&

.MARINE...
Issued at 426 AM EDT Mon May 27 2024

Moderate southwest breezes will prevail through this evening, in
advance of a weak cold front that will enter the waters early
Tuesday morning. Westerly breezes will prevail behind the front on
Tuesday, before gradually clocking around northerly by late
Tuesday night. Though general northerly winds will continue
through Wednesday night, nearshore seabreeze effects will be at
play in the afternoon hours. The southern periphery of high
pressure will bridge down the Southeast Atlantic coast on Friday
night, bringing a marked turn and increase in easterly flow.

&&

.FIRE WEATHER...
Issued at 426 AM EDT Mon May 27 2024

Good dispersions are forecast this afternoon along and east of the
Flint and Apalachicola Rivers. Scattered showers and
thunderstorms are possible, mainly in Alabama and Georgia, this
afternoon and could produce strong, erratic wind gusts and
frequent lightning. A weak cold front arrives tonight and will
lead to drier conditions Tuesday and Wednesday afternoons with
MinRH values generally between 30 to 40 percent each afternoon.
Dispersions will be high for much of the region Tuesday and
Wednesday.

&&

.HYDROLOGY...
Issued at 426 AM EDT Mon May 27 2024

New flooding along the Suwannee River is possible this week, as
last weeks floodwaters on the Withlacoochee slowly route
downstream through the Suwannee. However, 7-day river forecasts
for the Suwannee have been gradually been trending down with the
respective crests from Branford down to Manatee Springs. Though
minor flooding is still the forecast a few days from now, this
seems to become less certain with each forecast update.

Otherwise, rainfall in the week ahead is unlikely to cause
flooding issues. Thunderstorms later today have potential to dump
a quick 1-3 inches in heavier pockets, which would merely cause
short- duration runoff issues. Additional rainfall through next
weekend is forecast to be hydrologically insignificant.

&&

.SPOTTER INFORMATION STATEMENT...

Spotter activation is requested. Spotters should safely report
significant weather conditions and/or damage by calling the
office or tweeting us @NWSTallahassee.

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   74  94  70  94 /  30  10  10  20
Panama City   76  92  72  90 /  30   0   0  10
Dothan        70  92  68  91 /  40   0   0  20
Albany        71  92  67  90 /  50   0   0  20
Valdosta      72  93  68  92 /  50  10   0  20
Cross City    73  93  69  94 /  30  30  10  10
Apalachicola  76  89  74  88 /  20  10   0  10

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through late tonight for FLZ108-112-114.

GA...None.
AL...None.
GM...None.
&&

$$

NEAR TERM...Reese
SHORT TERM...Haner
LONG TERM....Haner
AVIATION...Reese
MARINE...Haner
FIRE WEATHER...Reese
HYDROLOGY...Haner