-- Discussion containing changed information from previous version are highlighted. --
349
FXUS64 KBMX 251910
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
210 PM CDT Wed Sep 25 2024

...New FIRE WEATHER...

.SHORT TERM...
-- Changed Discussion --
(This evening through Thursday)
Issued at 1218 PM CDT WED SEP 25 2024

A weak boundary will move through the state today, from northwest
to southeast. Ahead of this boundary, winds will be from the
south, with instability around 2000 j/kg and decent shear.
Scattered to widespread showers and thunderstorms will be moving
through this area, with training possible as storms will move from
southwest to northeast. While storms may be strong, the severe
threat seems to be diminishing through the afternoon with
convection more widespread. PW values will be around the 90th
percentile today, and with training storms, a lot of areas will
receive high rainfall rates with isolated flash flooding
possible.

Tonight, there could be a break in rain as the boundary weakens
and the outer bands of Helene move approach the coast. Scattered
activity will be possible, mainly in the east through the early
morning hours. The outermost bands of helene will begin to impact
the area beginning early Thursday, with widespread rain moving
south to north, with coverage increasing through the day as Helene
moves north. PW values will be at absolute max for this time of
year, with more consistent coverage, and higher accumulation
values in the east, with amounts decreasing incrementally the
farther west of I65 the bands reach. A Flood Watch will remain in
effect through Friday morning to account for the rain
accumulations from the scattered activity today, and the
widespread heavy rain expected to increase from Helene.

Winds will begin increasing in response to Helene by early
Thursday afternoon. With sustained winds up to 20 mph possible in
the far southeastern counties, and winds around 15 mph throughout
the rest of the area. A Tropical Storm Warning will be in effect
through Friday morning to account for increasing winds and high
rainfall totals.

24
-- End Changed Discussion --

&&

.LONG TERM...
(Friday through next Tuesday)
Issued at 337 AM CDT WED SEP 25 2024

Helene is expected to weaken to a tropical depression by Friday
morning and then quickly becomes absorbed into the larger-scale cut-
off low by Friday evening. There will be some wrap-around rainfall
across the northern half of Central AL during the day on Friday
before dry air gets wrapped in, decreasing the footprint of rainfall
around the cut-off low Saturday through Sunday. This cut-off low
persists over the region through at least Monday before shifting to
our east Monday night into Tuesday. I won`t completely rule out some
lingering shower activity under the closed upper level low over the
weekend, but most guidance keeps the area rain-free, so my
confidence to mention any rain chances is too low right now, but
it`s something we`ll need to watch for in the next few days.

25/Owen

&&

.AVIATION...
(18Z TAFS)
Issued at 1218 PM CDT WED SEP 25 2024

A boundary will allow for scattered to widespread showers and
thunderstorms in the southeastern third of the area, with
widespread showers in the northern two thirds of the area. A few
sites may have a VC in the prevailing due to uncertainty in timing
and coverage. Activity should weaken in the evening, with rain
increasing from southeast to northwest through the day Thursday.
Rainfall rates will be high with this activity so IFR conditions
are possible in any activity over a TAF site. Winds will increase
late in the TAF period as Helene approaches.

24

&&

.FIRE WEATHER...

-- Changed Discussion --
With tropical moisture increasing ahead of Hurricane Helene and a
stalled frontal boundary, widespread rain is expected through
Thursday, with rain chances diminishing through the day on Friday.
Minimal RH values will be above 60% through the weekend. Winds
increase substantially on Thursday as the tropical system
approaches the northern Gulf coast. Wind gusts of 25-30 mph are
possible for much of Central Alabama, with gusts exceeding 40mph
in the eastern half of Central AL.
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
Gadsden     63  72  62  74 /  50  80  90  70
Anniston    65  73  65  76 /  70  90  90  60
Birmingham  64  73  64  73 /  30  80  80  60
Tuscaloosa  63  77  63  75 /  20  50  60  50
Calera      64  73  65  75 /  40  80  80  50
Auburn      67  74  65  77 /  90 100  90  30
Montgomery  68  75  65  79 /  80  80  80  20
Troy        69  75  63  78 /  80  90  80  20
-- End Changed Discussion --

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Friday morning for the following counties:
Barbour-Bullock-Calhoun-Chambers-Cherokee-Clay-Cleburne-Coosa-
Elmore-Etowah-Lee-Macon-Montgomery-Pike-Randolph-Russell-St.
Clair-Talladega-Tallapoosa.

Tropical Storm Warning for the following counties: Barbour-
Bullock-Chambers-Lee-Macon-Pike-Russell.

&&

$$

SHORT TERM...24
LONG TERM....25/Owen
AVIATION...24