-- Discussion containing changed information from previous version are highlighted. --
712
FXUS64 KBMX 241127
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
627 AM CDT Tue Sep 24 2024

...New AVIATION...

.SHORT TERM...
(Today through Wednesday)
Issued at 342 AM CDT TUE SEP 24 2024

Currently, central Alabama is between two larger systems. The first
is a cold front to our northwest. The second is Potential Tropical
Cyclone 9 to our south. In between, southerly flow has strengthened
and weak isentropic lift has developed. This allowed some isolated
to scattered showers to develop and slide north through the central
sections of the area this morning. This will exit by midday, as the
front begins to enter the area. Rain chances will be on the increase
across the northwest through the afternoon and then will spread
south and east through the evening. Showers and storms will be
possible across the area. The best chance at seeing a strong to
conditionally severe storm will be in the northwest. Questions in
regard to the exact timing of the best coverage will keep the
mention out of the HWO this morning.

As we move into Wednesday, the front will stall out across the area
and eventually slide back to the west. At the same time additional
moisture from the southerly flow  will manifest scattered to
possibly widespread showers and storms across the area, especially
in the afternoon. We will also continue to monitor the tropics to
update any products throughout the next 2 to 3 days.

16&&

.LONG TERM...
-- Changed Discussion --
(Wednesday night through next Monday)
Issued at 342 AM CDT TUE SEP 24 2024

The main focus for the extended period is the potential tropical
cyclone in the Gulf of Mexico.

Guidance has been consistent in showing the larger-scale upper
trough developing into a cutoff low over the Mid-MS Valley Wednesday
night into early Thursday. As this takes place, the potential
tropical cyclone is forecast to be intensifying prior to landfall in
Florida. The tropical system is then expected to interact with the
cut-off upper low and we start to see the Fujiwara effect take
place with the tropical system and cut-off low rotating around
each other before the tropical low becomes absorbed in the broader
trough sometime Friday night into Saturday.

Impacts:

Flooding: Two separate features will lead to at least 2 distinct
areas of flooding potential. First, the stalled frontal
boundary/moisture convergence discussed in the short term. Then, the
banding on the northwest side of the tropical track that could set
up in the eastern and southeastern portions of Central AL Thursday.
The placement of this axis of heavy rain will greatly depend on the
eventual track, so updates on this area will be needed in coming
days.

Wind: Winds will steadily increase through the day on Thursday as
the system gets closer. The forward speed of this tropical system is
a big concern as the stronger winds will tend to translate further
inland with a faster-moving storm. Current forecasts have maximum
wind gusts generally in the 30-40mph range for the eastern half of
Central AL, and gusts of 20-30 in the western half. This could
change depending on the eventual track and intensity.

This is a quick-moving system and by Friday morning/early afternoon,
the potential tropical cyclone has largely merged in with the the
upper level low. We`ll still see some lingering rainfall on the
backside of the low through Friday evening, but that diminishes
by Friday night/Saturday morning, leaving lower rain chances
across the area for the weekend.

25/Owen
-- End Changed Discussion --

&&

.LONG TERM...
-- Changed Discussion --
(Wednesday night through next Monday)
Issued at 342 AM CDT TUE SEP 24 2024

The main focus for the extended period is the potential tropical
cyclone in the Gulf of Mexico.

Guidance has been consistent in showing the larger-scale upper
trough developing into a cutoff low over the Mid-MS Valley Wednesday
night into early Thursday. As this takes place, the potential
tropical cyclone is forecast to be intensifying prior to landfall in
Florida. The tropical system is then expected to interact with the
cut-off upper low and we start to see the Fujiwara effect take
place with the tropical system and cut-off low rotating around
each other before the tropical low becomes absorbed in the broader
trough sometime Friday night into Saturday.

Impacts:

Flooding: Two separate features will lead to at least 2 distinct
areas of flooding potential. First, the stalled frontal
boundary/moisture convergence discussed in the short term. Then, the
banding on the northwest side of the tropical track that could set
up in the eastern and southeastern portions of Central AL Thursday.
The placement of this axis of heavy rain will greatly depend on the
eventual track, so updates on this area will be needed in coming
days.

Wind: Winds will steadily increase through the day on Thursday as
the system gets closer. The forward speed of this tropical system is
a big concern as the stronger winds will tend to translate further
inland with a faster-moving storm. Current forecasts have maximum
wind gusts generally in the 30-40mph range for the eastern half of
Central AL, and gusts of 20-30 in the western half. This could
change depending on the eventual track and intensity.

This is a quick-moving system and by Friday morning/early afternoon,
the potential tropical cyclone has largely merged in with the the
upper level low. We`ll still see some lingering rainfall on the
backside of the low through Friday evening, but that diminishes
by Friday night/Saturday morning, leaving lower rain chances
across the area for the weekend.

25/Owen
-- End Changed Discussion --

&&

.AVIATION...
-- Changed Discussion --
(12Z TAFS)
Issued at 621 AM CDT TUE SEP 24 2024

VFR TAF forecast is expected for the next 12 hours. There is some
isentropic lift that has developed in the southeast and has helped
to generate some morning showers that may last through the late
morning. Went ahead and added in VCSH at numerous sites due to the
proximity of the light rain through 16z. Winds during the
afternoon will be generally SW between 5 and 8 kts except for MGM
which may be more southerly. Better shower activity will approach
from the NW ahead of a front moving toward the area. Went ahead
and continued with Prob30 starting at TCL after 22z and BHM after
00z. Added in at MGM after 06z.

16
-- End Changed Discussion --

&&

.FIRE WEATHER...

Increasing rain chances expected today through Thursday as a frontal
boundary moves into the region and stalls. Min RHs may drop into the
40% range today ahead of the frontal boundary, but tropical moisture
begins to build in ahead of the potential tropical cyclone
Wednesday through Friday keeping Min RHs 60-70%+. Winds increase
substantially on Thursday as the tropical system approaches. Gusts
could exceed 30mph in the eastern half of Central AL.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     90  68  79  64 /  20  60  90  70
Anniston    90  69  79  67 /  20  60  90  80
Birmingham  91  69  78  66 /  20  60  90  70
Tuscaloosa  91  69  79  66 /  30  60  80  60
Calera      91  69  81  68 /  20  60  90  70
Auburn      90  71  81  69 /  20  40  80  80
Montgomery  93  71  82  69 /  20  40  80  80
Troy        91  69  83  68 /  20  40  80  80

&&

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

$$

SHORT TERM...16
LONG TERM....25
AVIATION...16