298
FXUS64 KBMX 231110
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
610 AM CDT Mon Sep 23 2024

...New AVIATION...

.SHORT TERM...
(Today through Tuesday)
Issued at 354 AM CDT MON SEP 23 2024

High pressure is in place across the eastern third of the U.S.
Meanwhile, a cold front in across the Southern Plains through the
Great Lakes. Also a weak inverted trough in place across the
Southeast. As we work through the next two days, we will see the
front edge closer to the area as the high pressure begins to slide
to the northeast. With the inverted trough in place will continue
to mention isolated showers/storms for much of the area. If you
are lucky enough to see a shower/storm, especially in the northern
half of the area, rainfall could be heavy for a brief time. Most
of the activity this afternoon will end by sunset.

On Tuesday, the front will begin to enter the northwest by the
afternoon. There are some discrepancies on how far south an east
the front can make it before sunset, but right now the northwest
looks to have the best coverage through 7 PM. With the additional
focus of front, we could see a strong to marginally severe storm,
especially in the peak heating of the day. Right now coverage is
too low to mention in the HWO, but if the models can tighten up
the solutions then a small area of severe may need to be added
with the midday update.

16

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 354 AM CDT MON SEP 23 2024

All eyes should be fixated on the Gulf of Mexico by midweek as we
watch a developing tropical cyclone. Operational models and
ensemble members are strongly indicating the potential for a
large tropical cyclone to move quickly from the Yucatan Channel
toward the Florida Panhandle. *For official tropical cyclone
forecasts, please refer to information from the National Hurricane
Center*

An upper-level trough is expected to move southward and become cut
off over Arkansas on Wednesday. An associated weak front will
move into northwestern Alabama bringing a potential for showers
and storms Tuesday night. The tropical cyclone is expected to
begin interacting with the mid-latitude trough and front on
Wednesday, with a developing inverted surface trough over Alabama.
Therefore, we will begin feeling the effects of the Gulf system
on Wednesday, with the potential for a nearly stationary corridor
of rain.

A highly unusual scenario is expected to play out as the tropical
cyclone moves toward the northern Gulf of Mexico. I do not recall
ever seeing the Fujiwara effect take place in this part of the
country, but that is indeed what nearly all models are indicating.
As the tropical cyclone becomes captured by the cut-off mid-
latitude trough, it appears the tropical cyclone will rapidly
accelerate northward while the cutoff moves southwestward. With
the two cyclones so close in proximity, these cyclones will rotate
around each other before merging into a larger gyre after the
tropical cyclone makes landfall Thursday or early Friday. The
exact track of the tropical cyclone is not pinned down, but there
is a potential for the center of this system to move into Alabama
or close enough to produce impacts from heavy rain and high winds
Thursday and early Friday. If the modeled forward speed of 20-25
knots is correct, the tropical cyclone will have little time to
weaken before reaching areas well inland.

As the systems merge to form a larger cut-off trough to our
northwest, a dry slot is expected to reduce our rain chances for
Friday afternoon through the weekend.

87/Grantham

&&

.AVIATION...
(12Z TAFS)
Issued at 601 AM CDT MON SEP 23 2024

VFR conditions are expected for the cycle with just isolated areas
of MVFR visibilities until 13z. Otherwise, look for light/variable
to near calm winds through the morning then 5 to 7 kts after 15z
though 23 to 1z. There will be a chance for some isolated SHRA/TSRA
in the afternoon with heating, but chances are too low to mention
in TAFs at this time.

NOTE: AMD NOT SKED for KANB UFN due to a comms issue.

16

&&

.FIRE WEATHER...

Isolated showers or storms are possible Monday and Tuesday
afternoons across the north, but expect most of the area to remain
dry. With temperatures in the 90s and a modestly dry airmass in
place, minimum RH values should range from 35 to 55 percent
through Tuesday. 20 foot winds will be westerly to southwesterly
at less than 7 mph today. A significant increase in moisture and
rain chances is expected on Wednesday and Thursday as a potential
tropical system moves toward the northern Gulf of Mexico.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     93  69  91  68 /  20  10  20  60
Anniston    93  70  91  69 /  20  10  10  50
Birmingham  93  72  91  70 /  20  10  20  50
Tuscaloosa  94  70  92  69 /  20  10  20  50
Calera      93  71  91  69 /  20  10  10  50
Auburn      93  71  91  70 /  10  10   0  30
Montgomery  95  72  94  71 /  10  10   0  40
Troy        94  69  91  71 /  10   0   0  30

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...16
LONG TERM....87
AVIATION...16