722
FXUS62 KTAE 090545
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
145 AM EDT Thu May 9 2024

...New AVIATION...

.UPDATE...
Issued at 950 PM EDT Wed May 8 2024

On the forecast update, have added patchy fog to our Big Bend and
south-central GA counties late tonight and around sunrise. The
dewpoint of 78F at Buoy 42036 suggests a favorable environment
for fog as the moister air moves northeast overnight.

Otherwise, the latest HRRR runs are speeding up the timing with
the first round of storms coming in from the north tomorrow
afternoon.

&&

.NEAR TERM...
(Through Thursday)
Issued at 344 PM EDT Wed May 8 2024

The gusty winds will calm down this evening and the overnight hours.
Temperatures tonight will fall to the low 70s. More clouds will
filter in during the overnight hours. Patchy fog may be possible but
not expected to be widespread as it has been for the past couple of
mornings.

For Thursday: The upper level ridge over the Gulf will flatten
through the day as mid-level perturbations traverse east over
Alabama and Georgia ahead of a strong cold front. Our northernmost
counties will likely see thunderstorms during the afternoon hours on
Thursday. Thursday afternoon and evening is expected to be quite
active as the environment will be favorable for severe weather.
Instability will be elevated with CAPE ranging between 1000-2000
J/kg and deep-layer shear around 35-45 kts and steep lapse rates.
These parameters will be conducive to strong to destructive wind
gusts (up to 75 mph), large hail, and a few tornadoes. The storm
mode looks to approach the region as a squall line moving south
through the afternoon hours and evening hours.

Because of these threats, the SPC has upgraded the risk for our
northern AL and GA counties (Tifton, GA to Enterprise, AL) to an
Enhanced (3 of 5) risk for severe weather Thursday afternoon through
the night. From that line down to I-10, these areas are included in
a Slight (2 of 5) risk for severe weather. The threats are the same,
but the amount of coverage for this area is less from numerous
storms to scattered storms. South of I-10 to the coast is in a
Marginal (1 of 5) risk for severe storms. There is also a heavy rain
threat for our northwest counties, hence the WPC highlighted the
area in a Marginal (1 of 4) risk for excessive rainfall. The
Enterprise, AL to Dawson, GA line has a forecast PWAT greater than
1.75". The northern most part along that line is clipped into a
Slight (2 of 4) risk for excessive rainfall. PoPs for Thursday
afternoon range from 30-60 percent for areas north of I-10. South of
I-10 has about a 20% chance for showers and thunderstorms.

Timing of storms:

We expect an overall three rounds of storms for Thursday afternoon,
the second round happening Thursday night into Friday, and the third
happening around daybreak Friday.

Round 1 storm timing will begin around 12pm ET for our northern
counties in AL and GA, moving south during the afternoon through the
evening. Round 2 will have the greatest risk for severe storms,
which will be discussed in the short term.

Not everyone will see showers and thunderstorms on Thursday, so
temperatures are still expected to rise to the low 90s, as storms
are not expected until the late afternoon. Heat indices for areas
around the I-75/I-10 corridor will be in the upper 90s.

&&

.SHORT TERM...
(Thursday night through Friday night)
Issued at 344 PM EDT Wed May 8 2024

The main story will be the potential for severe weather. The D2
forecast from SPC added an Enhanced Risk for severe weather from
about Berrien Co GA to Coffee Co AL northwards, south of that
line, a Slight Risk of severe weather to about I-10, with a
marginal risk dipping down into the the coastal counties and most
the FL Big Bend. The situation is a one-two punch for severe
weather. The first round could be an MCS dropping into SW GA from
the north which is talked about in the near term. Then we have the
main event Thu night into Friday where we could have a squall line
come through. This is expected to be the larger event where we
could see numerous severe storms capable of producing damaging and
potentially destructive winds, large hail, and even embedded
tornadoes. There is the potential for a third event / squall line
Friday afternoon which will be dependent on boundaries and prior
convective systems.

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 344 PM EDT Wed May 8 2024

We will be post frontal by Saturday with high pressure building in
for the weekend. Northerly winds will usher in cooler air to the
region, placing highs in the upper 70s and low 80s for the GA and
AL counties, and in the low to mid 80s in FL. The reprieve in
temperatures will continue overnight with lows falling into the
mid to upper 50s for most of the region. Warming returns on Sunday
with highs in the low to mid 80s.

By early next week the pattern looks to change and become wet
again. 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 as well as the
threat for heavy rain. We`ll have to see how this progresses over
the next few days to have better confidence, be sure to come back
for updates.

&&

.AVIATION...
(06Z TAFS)
Issued at 137 AM EDT Thu May 9 2024

Low cigs are developing from south to north off the Gulf into our
western half of the CWA with an overall expansion north and east
will take place overnight. Cig heights will lower to low MVFR or
IFR across all TAF sites through mid morning. Surface winds will
be slightly elevated so vsbys may not be too much of an issue.
Will return to VFR by mid morning. Into the afternoon, will be
watching a line of TSRA moving south from central Alabama/Georgia
which is progged to move into our area. Have used high res
guidance to time the line into DHN/ABY 19-23Z. Less confidence
further south into VLD/TLH and have PROB30 22-02Z. Will need to
watch future model runs for possible increase in confidence if the
line can hold together towards the coast. Outside of convection,
winds will be from the southwest and breezy with gusts 18-23 knots
from mid morning through the afternoon hours. Winds could be
stronger as the line arrives.

&&

.MARINE...
Issued at 950 PM EDT Wed May 8 2024

An Atlantic ridge axis across the southern Florida Peninsula will
retreat southward on Thursday. A cold front will slowly approach
from the north on Friday, preceded by strong to severe
thunderstorms over the waters. 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,
and low pressure will deepen over the Southern Plains.

&&

.FIRE WEATHER...
Issued at 344 PM EDT Wed May 8 2024

Wetting rains and severe storms are expected for our northern GA
districts Thursday afternoon through Friday. All regions are
expected to receive a wetting rain from early Friday through the
afternoon. Along with the rain; gusty, damaging winds are expected
in thunderstorms, with large hail, and possible tornadoes.

Outside of rain and thunderstorms, high dispersions are expected for
Thursday afternoon for areas south and east of the storms. So, along
the I-75 corridor will have dispersion indices around 75 units.
Mixing heights will be around 4000 feet.

The cold front will pass through during the day on Friday, shifting
the winds northerly by Friday night. Dispersions will increase to
about 60-70 units with the front on Friday afternoon for our
northwestern most counties. Elevated dispersions are expected for
Saturday afternoon with northerly winds and dry conditions. The
MinRH for Saturday will be around 35-40%.

&&

.HYDROLOGY...
Issued at 344 PM EDT Wed May 8 2024

The forecast generally remains on track with a Slight Risk
clipping our extreme northern counties in AL and GA for Excessive
Rainfall with a Marginal Risk extending from Ben Hill Co in GA to
Geneva Co in AL. For Friday, the Marginal Risk is expanded south
clipping most of the CWA. Moisture looks to be bountiful with
PWATs around 2 inches or so. The main concern looks to be with
flash flooding if storms move slowly or train.

&&

.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   72  85  62  82 /  30  80  10   0
Panama City   73  83  63  81 /  30  70   0   0
Dothan        70  83  58  79 /  50  80   0   0
Albany        69  84  58  80 /  50  80   0   0
Valdosta      72  85  60  81 /  40  90  10   0
Cross City    71  85  63  84 /  20  80  30   0
Apalachicola  73  82  66  81 /  20  60   0   0

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 8 AM EDT /7 AM CDT/ this morning for
     FLZ108-112-114-115.

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

$$

NEAR TERM...Montgomery
SHORT TERM...KR
LONG TERM....KR
AVIATION...Scholl
MARINE...Haner
FIRE WEATHER...Montgomery
HYDROLOGY...Haner