387
FXUS64 KBMX 270110
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
810 PM CDT Thu Sep 26 2024

...New SHORT TERM...

.SHORT TERM...
(Tonight through Saturday)
Issued at 810 PM CDT THU SEP 26 2024

Category 4 Hurricane Helene is currently approaching the Florida
Big Bend region, with an axis of heavy rainfall falling along an
inverted trough and area of frontogenesis to its north across
southeast Alabama and Georgia. Meanwhile a deep upper low is
spinning over the Mid-South. Helene is tracking a bit east of the
previous forecast track, so the axis of heavy rainfall and higher
winds is trending eastward. Main impact will continue to be flash
flooding mainly in our counties along the Georgia state line.
Flash flood threat for the I-65 corridor is really dwindling and
may be able to cancel the watch early there. Wind gusts should
range from 35-40 mph along the Georgia state line to 25 to 35 mph
along the I-65 corridor. A dry slot causes the precipitation to
quickly shift north of the area tomorrow morning, before
additional wraparound showers come in from the northwest by
afternoon. As Helene merges with the upper low it will remain a
deep sub-980mb low over Kentucky by tomorrow evening. An axis of
40-50kt westerly flow at 850mb will move across the northern
counties during the afternoon and evening. With some afternoon
mixing, gradient wind gusts may be near wind advisory criteria
cross the northern counties. Have extended the wind advisory into
Friday evening across the north, and expanded across the northwest
counties for the afternoon and evening hours.

32/JDavis

Previous short-term discussion:
(This evening through Friday)
Issued at 1222 PM CDT THU SEP 26 2024

As Helene moves through the Gulf, widespread rain will move from
south to north over the southeast and eastern parts of the area
through the rest of the day. There could be a few breaks, but the
overall trend will be light to moderate rain fairly consistently.
As Helene approaches this evening, rain should increase in
coverage and intensity, with moderate to heavy rain in the east
and south, and light to moderate rain around the I65 corridor and
in areas west. Overnight tonight, Helene is expected to move east
of the area, and this will keep widespread consistent rain over
mostly the eastern half of the state. Models are diverging on
how much rain will actually make it to the western half of the
state, but with the amount of moisture associated with Helene,
have kept in slight chance to chance rainfall through the night.
Once Helene moves north of the area, the system will then take a
westward turn, with wrap around moisture staying over the northern
parts of Alabama. Models again disagree on how much moisture will
make it around Helene, but kept in slight chance in the northern
counties through the morning Friday. Friday afternoon could bring
slightly higher coverage and intensity as the bands continue to
wrap around Helene, and there is a little bit more instability to
work with, with the greatest chances across the northern third of
the area.

Areas in eastern Alabama received between 3-6" yesterday from the
training storms. These same areas are expected to receive
additional persistent, moderate to heavy activity through the
night. Widespread flooding is expected, with flash and river
flooding a threat. A Flash Flood Watch remains in effect for the
eastern half of the state to account for yesterdays rainfall
totals, added to the rain expected to accumulate through tomorrow
morning.

Winds will increase through the afternoon and evening, with the
highest sustained winds of 20-25 mph possible overnight tonight in
the southeastern and eastern part of Central Alabama. A Tropical
Storm Warning will be in effect for the southeast and eastern most
row of counties to account for these high wind speeds, and a Wind
Advisory will be effect tonight for areas along and between I65
and the TS Warning. With the amount of rain measured in the south
and east, combined with high wind speeds tonight could easily
knock trees down with roads blocked and power outages possible.

24

&&

.LONG TERM...
(Saturday through next Wednesday)
Issued at 338 AM CDT THU SEP 26 2024

The areas of rainfall will decrease around the cut-off low on
Saturday through Sunday. Meanwhile, the cut-off low persists over
the region through at least Monday before shifting to our east
Monday night into Tuesday. Still may see a few light shower
activity under the closed upper level low over the weekend, but
most guidance keeps the area rain-free, so confidence to mention
any rain chances remains too low right now, but it`s something
we`ll need to watch for in the next few days. If there is a better
day for for a brief shower or two it looks like Monday as the
upper low pushes east. Beyond Monday, high pressure will remain
in control with temperatures generally in the low to mid 80s.

16

&&

.AVIATION...
(00Z TAFS)
Issued at 625 PM CDT THU SEP 26 2024

Moderate to occasionally heavy tropical rain will continue to
impact all terminals except TCL as Hurricane Helene moves
northward from Florida to Georgia. Visibilities will occasionally
drop to IFR. Cigs will become at least MVFR. MGM/ANB/ASN have the
highest probabilities of IFR cigs with medium chances at BHM/EET.
Rain exits Friday morning, though some wraparound showers may move
in across the north by afternoon. MVFR cigs will linger across
much of the northern terminals through the afternoon. Wind gusts
will increase out of the northwest to 20 to 30 kts tonight,
remaining breezy out of the west on Friday.

32/JDavis

&&

.FIRE WEATHER...

With tropical moisture increasing ahead of Hurricane Helene and a
stalled frontal boundary, widespread rain is expected through
tonight, with rain chances diminishing through the day on Friday.
Highest chances on Friday will be across the north. Minimal RH
values will be above 60% through the weekend. Winds increase
substantially on this evening and overnight 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
50 mph in the eastern half of Central AL.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     63  73  61  75 / 100  50  30  20
Anniston    64  75  63  78 / 100  40  20  10
Birmingham  63  74  63  76 /  70  40  30  20
Tuscaloosa  63  76  63  79 /  20  40  30  10
Calera      64  77  65  79 /  60  30  20  10
Auburn      64  77  63  81 / 100  20  10  10
Montgomery  64  82  64  84 /  90  10  10   0
Troy        64  81  62  83 / 100   0   0   0

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 1 PM to 10 PM CDT Friday for the following
counties: Fayette-Lamar-Marion-Pickens-Tuscaloosa-Walker-Winston.

Flood Watch until 7 AM CDT Friday for the following counties:
Autauga-Barbour-Blount-Bullock-Calhoun-Chambers-Cherokee-Chilton-
Clay-Cleburne-Coosa-Elmore-Etowah-Jefferson-Lee-Lowndes-Macon-
Montgomery-Pike-Randolph-Russell-Shelby-St. Clair-Talladega-
Tallapoosa.

Wind Advisory until 10 PM CDT Friday for the following counties:
Blount-Calhoun-Clay-Etowah-Jefferson-Shelby-St. Clair-Talladega.

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

Wind Advisory until 10 AM CDT Friday for the following counties:
Autauga-Chilton-Coosa-Elmore-Lowndes-Montgomery-Tallapoosa.

&&

$$

SHORT TERM...32/JDavis
LONG TERM....16
AVIATION...32