388
FXUS62 KTAE 100149
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
949 PM EDT Thu May 9 2024

...New UPDATE...

.UPDATE...
Issued at 935 PM EDT Thu May 9 2024

The forecast message for tonight, and into early Friday, remains
largely intact. The main concerns in Friday morning continue to
revolve around a potentially strong MCS. However, the path of
this MCS still remains somewhat uncertain this evening. This is
mostly due to the fact that storms well to our west (across
Louisiana and Texas), and our northwest in northern Alabama are in
their initial stages of the formation of the MCS. Currently
across the forecast area, much of the area is under fairly stable
conditions thanks to the outflow boundary from earlier convection.
Current IR satellite imagery and observations are showing this
boundary to have stalled and as the next upper level system
approaches expect it to slowly move back north and east overnight
as low-level southerly flow helps the return an unstable airmass.
This unstable airmass will fuel the maintenance of the MCS that
will likely move through our AL/GA counties, and possibly into the
Panhandle counties tonight and around daybreak Friday. Main
concerns continue to revolve around damaging, possibly destructive
in localized areas, winds and the threat for some tornadoes and
large hail.

The main changes with the severe probabilities this evening was
mostly a 30 to 40 mile expansion to the south in the damaging wind
probabilities, and the enhanced (level 3 of 5) category.

&&

.NEAR TERM...
(Through Friday night)
Issued at 225 PM EDT Thu May 9 2024

Currently as of 18z (2pm EDT), a broken deck of widespread cumulus
clouds have puffed up across the entire region. We have temperatures
in the upper 80s to nearly 90 degrees with dew points in the 70s. A
broken line of strong to severe thunderstorms (along an Irwin Co GA
to Quitman Co GA line) will be moving south/southeast as the outflow
boundary pushes south this afternoon into the evening hours. Current
Mesoanalysis data (18z) indicates deep layer shear of around 40-50
kts, surface based CAPE around 3500 J/kg (18z balloon launch shows
2700 J/kg at Tallahassee), and low to mid-level lapse rates are
around 7C/km. All the ingredients are here for a potential severe
weather outbreak that includes all hazards.

We are expecting multiple rounds of severe weather today through
tomorrow. The first round is ongoing as of the issuance of this AFD.
As mentioned before, all hazards will be possible with the main
concerns being destructive winds up to 75 mph and large hail. Our
Alabama and Georgia counties are currently in an Enhanced (3 of 5)
risk for Severe weather this afternoon through early tomorrow
morning. From the Florida state line south to the Gulf coast is
included in a Slight (2 of 5) risk for severe weather. Along with
the storms comes the probability of heavy rainfall, which the WPC
has included areas along and north of I-10 in a Slight (2 of 4) risk
for excessive rainfall. Flash flooding will be a concern with any
training storms.

Round 1: Storms will be moving along an outflow boundary
south/southeast into our Georgia and Alabama counties this afternoon
and continue south/southeast into the evening hours. All hazards
will be possible with these lines of storms. The storms will likely
move into the Florida Big Bend region later this evening. Rain
chances are highest for our AL and GA counties with PoPs ranging
from 60-80 percent. For areas along and south of I-10, PoPs decrease
from 50% to about 30% for the extreme SE Big Bend this evening.

Between rounds, we expect a lull in convective activity.

Round 2: A line of storms will be coming in from the west that
develops along a shortwave perturbation, leading to a QLCS around
the Mississippi River and quickly moving across the Gulf States
during the early morning hours on Friday. This round of storms are
the more concerning ones for this event. This line of storms will
move quickly across the CWA during the morning hours. We are still
prior to 12z Friday at this time, so the Enhanced SPC risk is still
in place. The main concern for this round will be the destructive
winds. Hi-res guidance is indicating a possible widespread swath of
damaging winds, with possible gusts greater than 74 mph, and a few
tornadoes with this QLCS. A reminder, this round will be beginning
during the overnight hours and continuing through daybreak. PoPs for
Friday morning range from 50-80%, mainly along the state line and
areas north. This line of storms should complete its passage through
the CWA by mid-late morning, exiting to the SE Big Bend.

However, there may be some showers and thunderstorms following this
QLCS that may develop, but confidence is medium at the moment. That
will depend on how all previous storms behaved and whether the
atmosphere is stable or not.

After all that, the cold front will finally make its passage during
the evening hours Friday through the overnight hours.

Coming back to the present, temperatures today will be warm in the
upper 80s to low 90s, with overnight temps cooling to the low 70s.
Friday`s highs will be a little cooler in the mid-80s due to the
rain and cloud cover.

&&

.SHORT TERM...
(Saturday through Sunday Night)
Issued at 225 PM EDT Thu May 9 2024

No weather concerns during this time frame for any severe weather
recovery efforts. No precipitation is expected on Saturday and
Sunday with a cooler and drier air mass compared to earlier in the
week. It will be mostly sunny on Saturday with an increase in
mid and high level cloudiness on Sunday. Highs both days in the low
to mid-80s and lows in the upper 50s to lower 60s. Much lower dew
points will make for a comfortable air mass this weekend. Winds
will generally be around 10 mph.

&&

.LONG TERM...
(Monday through Wednesday)
Issued at 225 PM EDT Thu May 9 2024

On Monday another shortwave looks to move across the northern Gulf
states with our region possibly being impacted on Tuesday as winds
turn to being southeasterly. With this shortwave possibly moving
overhead, a stationary boundary to our south, left behind from the
previous system, and a low-level wind field again around 30-45 kts,
the potential for severe is once again present. We`ll have to see
how this progresses over the next few days to have better
confidence, be sure to come back for updates.

Expect relatively cooler temps to what we`ve been experiencing as of
late. Daytime highs will generally be in the low to mid 80s with
overnight lows generally in the upper 50s to mid 60s until Tuesday
morning. Beyond Tuesday morning, overnight lows look to rebound into
the mid and upper 60s.

&&

.AVIATION...
(00Z TAFS)
Issued at 800 PM EDT Thu May 9 2024

The main challenge will be with timing of a thunderstorm squall
line or large convective cluster that will move across the
terminals late tonight and in the morning. The main squall line
could be preceded by some isolated and discreet thunder cells,
then the main squall line could be followed by 3-5 hours of
trailing stratiform thunder. More scattered thunderstorm
redevelopment is possible on Friday afternoon.

Otherwise, IFR ceilings will try to move in late this evening, but
then the arrival of thunderstorms late tonight will disrupt the
low clouds and improve ceilings, even as the heaviest
thunderstorms are moving through.

&&

.MARINE...
Issued at 225 PM EDT Thu May 9 2024

An Atlantic ridge axis across the southern Florida Peninsula will
retreat southward tonight. A cold front will slowly approach from
the north on Friday, preceded by strong to severe thunderstorms over
the waters. Cautionary conditions could be possible Friday. The
front will limp across the waters on Friday night. It will be
followed by moderate to occasionally fresh northerly breezes on
Saturday morning. Surface high pressure over the southern Plains on
Saturday will move across the Southeast States on Sunday, causing
winds to clock around. High pressure will move east into the
Atlantic on Monday, brining a return to south-southeasterly flow.

&&

.FIRE WEATHER...
Issued at 225 PM EDT Thu May 9 2024

Multiple rounds of wetting rains and severe thunderstorms are
expected this afternoon through Friday morning. The first round is
this afternoon through the evening hours where all modes of severe
weather are possible. Outside of storms, high dispersions are still
likely for the rest of this afternoon for areas along the I-10/I-75
Corridor in the FL Big Bend.

The second round of storms is expected during the morning hours on
Friday. By the afternoon, showers and thunderstorms are expected to
have cleared the CWA with fair dispersions behind the storms.
Elevated dispersions will be just behind the front, possibly
clipping our northwestern-most counties in SE Alabama Friday
afternoon. Fair to moderate dispersions are expected for the rest of
the period. Following Friday`s cold front, winds will shift to be
northerly, with transwinds at about 10-15 mph. Temperatures will be
briefly cooler with MinRH in the mid-30s% to around 40%.

&&

.HYDROLOGY...
Issued at 225 PM EDT Thu May 9 2024

A slight risk of excessive rainfall exists along and north of I-10
today and tonight (SE AL, SW GA, and portions of the FL counties),
with a marginal risk for most of the area on Friday as a frontal
system looks to push through the region. The primary risk here being
torrential downpours or training within any thunderstorm(s) leading
to a localized flash flooding risk. Otherwise, area rivers are
expected to remain below flood stage. In the extended period the WPC
is forecasting 3-5 inches by midweek next week. This could introduce
some riverine concerns, however, it`s too far out to say with any
degree of confidence.

&&

.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   73  86  62  83 /  50  90  10   0
Panama City   74  84  64  83 /  40  80   0   0
Dothan        70  83  59  81 /  80  80   0   0
Albany        70  83  58  80 /  80  70   0   0
Valdosta      71  83  62  81 /  50  90  10   0
Cross City    73  86  64  85 /  10  60  30  10
Apalachicola  76  83  66  81 /  20  70  10   0

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Saturday morning for FLZ108-112-
     114-115.

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

$$

NEAR TERM...Montgomery
SHORT TERM...LF
LONG TERM....Oliver
AVIATION...Haner
MARINE...Oliver
FIRE WEATHER...Montgomery
HYDROLOGY...Oliver