251
FXUS64 KBMX 081843
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
1243 PM CST Wed Jan 8 2025

...New SHORT TERM...

.SHORT TERM...
(This evening through Thursday)
Issued at 1243 PM CST WED JAN 8 2025

Key Messages:
- Cold Weather Advisory in effect from 10 pm tonight through 8 am
  Thursday morning for much of eastern and southern Central
  Alabama. Very cold conditions are forecast with air temperatures
  in the upper teens to low 20s and wind chill values from near 10
  degrees northeast to the low 20s southwest overnight.

This afternoon.

A northwest flow prevails over the local area today with longwave
troughing persisting over much of the Eastern portion of the
country while shortwave ridging was over West Texas and is
positioned east of a deep upper low over the Northern Baja of
California. Expansive surface high pressure extends from North of
the Great Lakes southwest to across the Southern Plains.

Expect skies to continue to clear across the northern portion of
the area today. Winds will be from the northwest from 8-14 mph.
High temperatures will range from the upper 30s far north and in
the higher elevations east to readings in the mid 40s southeast.

Tonight.

The flow pattern aloft amplifies overnight with a northwest flow
persisting over our area as longwave troughing persists over much
of New England and the Mid Atlantic while shortwave ridging
amplifies over the Southern and Central Plains with the closed low
moving east over Northwest Mexico. Elongated surface high
pressure will extend from near the Great Lakes south to across the
Mid-South region.

Look for mostly clear skies overnight with winds from the north
at 3-6 mph. Low temperatures will range from the upper teens north
and east to the lower 20s south. The combination of temperatures
and winds may create wind chills as low as near 10 degrees across
the higher elevations of our northeast and east central counties
with readings in the upper teens to low 20s further southwest.

Thursday.

Ridging will further amplify over much of the Mississippi River
Valley while mid-level troughing moves off the Northeast Coast.
The upper low will open into a compact vigorous shortwave trough
as it continues moving east over Northern Mexico. Surface high
pressure will become extended from across the Eastern Great Lakes
southeast into the Tennessee Valley Region.

Mostly sunny skies will start the day Thursday, followed by some
high clouds increasing from the west during the mid to late
afternoon hours. Winds will become northeast with speeds from 4-8
mph. High temperatures will range from near 40 far north to the
upper 40s south.

05

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 410 AM CST WED JAN 8 2025

Key Messages:

1. A Winter Storm now appears likely, especially across the northern
half of Central Alabama late Thursday night through Saturday
morning. Significant impacts are expected due to accumulations of
snow, sleet, and possibly freezing rain. Travel is expected to be
very difficult or impossible for counties within the newly issued
Winter Storm Watch.

2. Slick and hazardous road conditions are expected to continue
through Saturday morning as temperatures fall below freezing once
again Friday night.

Forecast trends are coming together this morning that indicate a
high likelihood of a Winter Storm occurring across Central Alabama
starting late Thursday night and lasting through Friday evening.
Guidance trends as of the 00z runs are depicting a more suppressed
low pressure system that will navigate eastward along the Gulf Coast
during the day on Friday. Due to the system being more suppressed in
nature, colder air is also present across Central Alabama as
moisture quickly streams northeastward within the strong 500-700mb
flow. At least a mixed bag of precipitation is expected to begin
across far southern and southwest counties initially late Thursday
night with a completely saturated sounding profile all the way up to
250mb. Radar returns will likely be widespread by midnight Thursday
night in southwestern and western counties as the precipitation
aloft falls through the drier column of air closer to the surface.
With dynamic cooling, forecast soundings are showing a potential for
a burst of snow or wintry mix as far south as the U.S. 80/I-85
corridors before changing over to all rain during the mid-morning
hours.

Farther to the north is where our impacts are expected to occur,
with dynamic cooling dropping temperatures below the freezing mark
and mostly all snow expected along and north of the I-20 corridor
through the mid-morning hours on Friday. Cold infrastructure leading
up to the precipitation will be problematic, as accumulations may
occur very quickly once heavier precipitation reaches the surface.
The morning commute could be heavily impacted along the I-20
corridor, and interests need to plan ahead for the potential of
encountering difficult travel conditions. The far northern tier of
counties from Marion eastward to Cherokee appears to be a slam dunk
Winter Storm situation if current guidance trends hold up.
Accumulations of 2 to 6 inches of snow and sleet are certainly not
out of the question. The other factor to continue to watch out for
is the easterly wedge that will be in place with the surface ridge
centered off to our northeast. Eastern and northeastern counties
have a potential to see temperatures remain below freezing for a
longer duration than guidance is currently indicating. With all
these factors considered, A Winter Storm Watch has been issued for
roughly the northern half of the area, including the Birmingham
Metro. We may need to include a few additional counties before all
is said and done along the I-20/59 corridor southwest of Birmingham
if colder guidance trends are realized over the next 24 hours. As
we`ve reiterated several times, a temperature change of only a
couple of degrees will mean the difference between major and minor
impacts with this system. Bottom line is that if you`re located
along and north of the U.S 80/I-85 corridors, you need to go ahead
and plan for winter weather impacts Friday morning, especially
between midnight and 10am.

The freezing line is still expected to move northward through
midday, with snow changing over to a wintry mix and then all rain
for the southern half of the area during the afternoon. The I-20
corridor may end up being the dividing line for the winter weather
during the afternoon, as locations across the far northern counties
will struggle to reach the freezing mark due to accumulating
snowfall and continued dynamic cooling. Stay tuned, as more details
will continue to be ironed out over the next 24 hours!

The deeper moisture will exit the state by Friday evening, with the
potential for some wrap-around snow showers across the north through
Saturday morning as the main 500mb vort max and upper trough axis
moves across the region. Black ice and slick roadways will be a
concern areawide as temperatures drop below freezing Friday night
with plenty of ground moisture left over. Thankfully, sunshine will
make an appearance by Saturday afternoon with temperatures rising
into the mid 30s to lower 40s to help thaw some things out. If
significant accumulations of snow occur across the far north, snow
pack may help temperatures drop toward the mid teens for locations
such as Haleyville, Oneonta, and Centre by Sunday morning. Low to
mid 20s are expected elsewhere with mostly clear skies. Cold
temperature trends show no signs of letting up through the rest of
the forecast period, with another shot of cold arctic air moving
into the region by Monday night and into Tuesday.

56/GDG

&&

.AVIATION...
(18Z TAFS)
Issued at 1108 AM CST WED JAN 8 2025

VFR conditions will prevail through this cycle. Expect clouds to
continue to mix out across the far northern portion of the area
this afternoon with low-level winds from the northwest around 10
kts. Only a few high clouds are expected tonight and through
midday Thursday across the far north and west portions of the area
while low-level winds become more northeast with time with speeds
from 4-8 kts.

05

&&

.FIRE WEATHER...

High pressure will provide cold and dry weather through Thursday.
An approaching storm system will bring widespread rain and a
wintry mix beginning Thursday night, lasting through the day on
Friday. Relative humidity levels drop to the low 30s to low 40s this
afternoon. Relative humidity levels drop to the upper 20s to mid 30s
on Thursday afternoon, with less than 10 mph 20 foot winds
expected both days. Moisture levels will be on the rise through
the end of the week with min RH values rebounding back into the
50-60% range.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     17  44  23  34 /   0   0  30 100
Anniston    17  45  27  35 /   0   0  40 100
Birmingham  20  44  29  35 /   0   0  50 100
Tuscaloosa  22  45  30  37 /   0   0  80 100
Calera      19  45  30  35 /   0   0  60 100
Auburn      20  47  30  36 /   0   0  30 100
Montgomery  21  47  30  39 /   0   0  60 100
Troy        20  48  30  41 /   0   0  40  90

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from late Thursday night through late Friday
night for the following counties: Blount-Calhoun-Cherokee-Clay-
Cleburne-Etowah-Fayette-Jefferson-Lamar-Marion-Randolph-Shelby-
St. Clair-Talladega-Walker-Winston.

Cold Weather Advisory from 10 PM this evening to 8 AM CST
Thursday for the following counties: Autauga-Barbour-Bibb-
Bullock-Calhoun-Chambers-Cherokee-Chilton-Clay-Cleburne-Coosa-
Dallas-Elmore-Etowah-Greene-Hale-Jefferson-Lee-Lowndes-Macon-
Marengo-Montgomery-Perry-Pike-Randolph-Russell-Shelby-St. Clair-
Sumter-Talladega-Tallapoosa-Tuscaloosa.

&&

$$

SHORT TERM...05
LONG TERM....56
AVIATION...05