919
FXUS64 KBMX 221858
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
1258 PM CST Fri Nov 22 2024

...New LONG TERM...

.SHORT TERM...
(This evening through Saturday)
Issued at 1239 PM CST FRI NOV 22 2024

Key Messages:
- Freezing temperatures are forecast across all but the far
  southeast portion of Central Alabama from midnight tonight
  through 8 am Saturday morning.
- A widespread frost is expected across all of Central Alabama
  from midnight tonight through 8 am Saturday morning.

This afternoon.

A northwest flow pattern prevails aloft over the state today as
the forecast area remains positioned between a sprawling upper low
over the Northeast and broad amplified ridging over much of the
Plains states. A strong surface low was centered across Southeast
New York State while expansive surface high pressure extended from
South-Central Canada southeast to the Central Florida Peninsula.

Skies will be sunny over much of the area today with only a few
high clouds across the far north and northeast. Winds will be
breezy at times from the northwest at 12-24 mph. High temperatures
will range from the upper 40s in the higher elevations north and
east to the upper 50s southwest and south-central. The combination
of wind with these temperatures will create wind chills that will
be in the mid to upper 40s across the higher elevations north and
east this afternoon.

Tonight.

The sprawling upper low will migrate southward, becoming centered
over New Jersey overnight while mid-level ridging will continue
to build eastward over the Midwest and Lower Mississippi River
Valley Regions with amplified longwave ridging extending from over
Colorado northwest to over Interior Southwest Canada. Surface low
pressure will move offshore of New England while surface high
pressure migrates further east, extending from South-Central
Canada southeast through the Lower Mississippi River Valley
Region.

With surface high pressure just to the west, lighter winds from
the northwest at 3-5 mph will allow for less mixing overnight and
coupled with strong radiational cooling under clear skies will
result in a freeze across much of the forecast area with exception
across portions of our far southeast counties. The lighter winds
will also promote frost formation, which will be possible across
the entire forecast area. Low temperatures will range from around
30 north and northwest to the mid 30s across portions of the far
southeast.

Saturday.

The upper low moves east off the Northeast Coast while mid-level
ridging continues to amplify from over Texas northward to over
South-Central Canada. Strong surface low pressure becomes centered
offshore of the Coast of Maine while elongated surface high
pressure extends from South-Central Canada southeast into the
local forecast area.

Mostly sunny skies are forecast over the northern and central
counties Saturday with sunny skies south. Winds will remain from
the northwest with speeds from 6-12 mph. High temperatures will
range from the mid 50s in the higher elevations east to the low
60s generally near and south of the U.S. Highway 80 corridor.

05

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 1247 PM CST FRI NOV 22 2024

Only made minor changes to the forecast, speeding up the front
Monday into Tuesday slightly. It now appears the front may push
south and east of our area by early Tuesday afternoon, ending rain
chances earlier than previously forecast.

Not much more clarity for the Thanksgiving system. Model guidance
still varies considerably on the evolution of the trough and low
pressure system that will move through the region. For now, have
kept rain chances similar to as before. The big question will be
whether any instability is able to build in before the cold front
pushes through - essentially, does a warm sector materialize or
not, and to what degree. It`ll be something we continue to watch
for any potential severe threat on Thursday, but guidance still
generally hints at limited instability overall.

25/Owen


Previous long-term discussion:
(Saturday night through next Thursday)
Issued at 324 AM CST FRI NOV 22 2024

One more chilly night is expected Saturday night and into Sunday
morning with good radiational cooling and mainly calm winds.
Cooler valley locations will likely drop down close to the
freezing mark or just below, with most other locations falling
into the lower and middle 30s with widespread frost once again.
The surface ridge moves off to the east on Sunday, with warm air
advection and southerly flow returning. Temperatures will warm
into the 60s on Sunday and 70s by Monday, along with increasing
low level moisture and dewpoints rising into the upper 50s and
lower 60s.

The next cold front is expected to arrive by Tuesday
with better agreement amongst guidance during this period with the
front moving into Central Alabama. With the base of the longwave
trough axis well to our north over the Great Lakes and surface low
moving into eastern Canada, the southward movement of the front is
expected to slow considerably. Rain showers will move in from the
northwest ahead of the front Monday night and into Tuesday
morning, before all rain diminishes completely by late Tuesday
afternoon. We`ll have to see how far south the front will make it
Tuesday night and into Wednesday morning, as temperatures will be
greatly affected by the position of the front.

Guidance trends are hinting at the front returning back to the
north as a warm front by Thanksgiving Day as the next system takes
shape off to our west. Needless to say, we have lots of details
to still iron out in terms of how potent the approaching system
will be. However, it does appear that a strong upper level
southwesterly jet developing on Thanksgiving Day through Friday of
next week could lead to a fairly widespread rain event developing
over much of the Deep South. The depth of the warm sector would
then better indicate the chance for storms during that period.
More details to come over the coming days.

56/GDG

&&

.AVIATION...
(18Z TAFS)
Issued at 1107 AM CST FRI NOV 22 2024

VFR conditions will prevail through this cycle. Only a few high
clouds will be over the east-central northern terminals this
afternoon and tonight. A few high clouds will be over the northern
sites on Saturday. Low-level winds will be gusty from the
northwest today from 10-20 kts at times, with lighter winds
overnight from 3-6 kts. Low-level winds will be from the northwest
on Saturday from 4-8 kts.

05

&&

.FIRE WEATHER...

Continued rain-free weather expected the air mass gradually
moderates before the next cold front on Tuesday. Min RHs over the
weekend will be generally above 35%, increasing the 50-70% by
Monday as moisture returns ahead of the front. Northwesterly winds
will continue through tonight before decreasing and becoming more
calm by Saturday evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     31  57  31  65 /   0   0   0   0
Anniston    31  57  35  67 /   0   0   0   0
Birmingham  33  56  36  66 /   0   0   0   0
Tuscaloosa  33  60  36  68 /   0   0   0   0
Calera      32  58  37  68 /   0   0   0   0
Auburn      34  59  39  66 /   0   0   0   0
Montgomery  33  62  36  69 /   0   0   0   0
Troy        33  61  36  68 /   0   0   0   0

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from midnight tonight to 8 AM CST Saturday for
the following counties: Autauga-Bibb-Blount-Bullock-Calhoun-
Chambers-Cherokee-Chilton-Clay-Cleburne-Coosa-Dallas-Elmore-
Etowah-Fayette-Greene-Hale-Jefferson-Lamar-Lowndes-Macon-Marengo-
Marion-Montgomery-Perry-Pickens-Randolph-Shelby-St. Clair-Sumter-
Talladega-Tallapoosa-Tuscaloosa-Walker-Winston.

Frost Advisory from midnight tonight to 8 AM CST Saturday for
the following counties: Barbour-Lee-Pike-Russell.

&&

$$

SHORT TERM...05
LONG TERM....25/Owen
AVIATION...05