268
FXUS64 KBMX 270445
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
1045 PM CST Tue Nov 26 2024

...New AVIATION...

.SHORT TERM...
(Tonight)
Issued at 925 PM CST TUE NOV 26 2024

Clouds associated with the front has exited stage right and
temperatures are dropping very quickly out there. Went ahead and
lowered temperatures a few degrees across the north and now having
near freezing temperatures across the northwest and just below in
the northeast. With the moisture still in place we are
already getting instances of fog across the north. I expect this
will be short lived north of I-20. Further south, the clouds hung
tough all day, so the moisture from the rain last night never
evaporated at all. Here we should see fairly widespread fog
develop, with the lowest visibilities in the south and southeast,
or US 80/I-85 corridor and parts south. Not quite ready to pull
the trigger on a dense fog advisory, but confidence is increasing
as we move into the late night period. Any fog should burn off by
9 AM.

16

Previous short-term discussion:
(Wednesday)
Issued at 1147 AM CST TUE NOV 26 2024

The next system will be quickly taking shape over the ArkLaTex
tomorrow afternoon, so our winds will shift back to the south,
sending 50s and low 60s dewpoints northward back into the area.
Warmer conditions are expected with highs ranging from the mid 60s
to lower 70s, and cloud cover will gradually increase throughout
the day. A surface low will be developing over the Midsouth region
towards the end of the short term period. This system will bring
rain and an isolated severe weather threat to the area beginning
late Wednesday night as detailed in the long term discussion.

86/Martin

&&

.LONG TERM...
(Wednesday night through next Monday)
Issued at 126 PM CST TUE NOV 26 2024

Key messages:

- Showers and thunderstorms are in the forecast Wednesday night
  into Thanksgiving ahead of a cold front. Some uncertainty
  remains with the timing of the front and how quickly the rain
  will come to an end Thursday afternoon.

- A Marginal Risk (Level 1 of 5) for severe storms is in place for
  late Wednesday night into Thanksgiving. Damaging winds, hail,
  and tornadoes appear possible.

- Much colder temperatures are expected Friday through Tuesday,
  with multiple nights in the 20s for much of the area during the
  extended holiday weekend.

A strengthening storm system will be moving quickly out of the mid
Mississippi Valley and across the region Wednesday night into
Thursday. Showers will overspread much of central and northern
Alabama overnight Wednesday/early Thursday. Initially the lower
levels of the atmosphere will be rather stable with a notable
capping inversion around 800 millibars. Despite that, favorable
mid level lapse rates will result in elevated instability and
potential for isolated elevated storms/convection late Wednesday
night.

With increased warm air advection and boundary layer moistening,
storms may become more surface based around 12z on Thanksgiving
along and just ahead of the surface front. The area is currently
in a Marginal (Category One of Five) Risk of severe weather for
late Wednesday night into Thursday. This look reasonable,
initially for isolated damaging wind or hail and then a very small
but non-zero threat of tornadoes along the front. The boundary
layer winds will be fairly veered along the front so that will
likely limit the overall tornado potential.

Rainfall should end from west (late afternoon) to east (late
evening) on Thanksgiving with much colder air working in behind the
front. Rainfall totals look to be generally 1/4 to 1/2 inch
areawide with some isolated higher amounts. The Friday through
Tuesday time frame looks dry with below to well below normal temps
through the period. In fact, we will see our first low
temperatures in the 20s since early in the calendar year. Some sub
20 temperatures are possible Monday morning across the north.

15/CBD

&&

.AVIATION...
(06Z TAFS)
Issued at 1045 PM CST TUE NOV 26 2024

Skies really cleared out and fog has developed in our south and
and isolated instances across the north. Will really drop VIS at
MGM through the night. eroding by 15. TCL, EET, and ANB may see
instances of fog through 10z, then some improvement as drier air
and some high clouds work into the area. Otherwise winds shift
back to the south by the afternoon and clouds will be on the
increase in the west. At this time the rain chances remain too low
to include at BHM at this time at the tail end of this cycle. I
will go ahead and put in a PROB30 for showers at TCL after 4z.

16

&&

.FIRE WEATHER...

A cold front has cleared all but the far southeast corner of
our area as of early afternoon with clearing skies in its wake.
Drier and cooler air will filter briefly into the state behind
this front with RH values between 50-70% Wednesday afternoon.
20ft winds will shift from the northwest this evening around to
the south on Wednesday at around 5-10 mph. Another weather system
will be close on the heels of this last front with rainfall
overspreading the area from the northwest Wednesday night into
Thanksgiving day.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     32  67  55  64 /   0   0  80  40
Anniston    36  67  57  66 /   0   0  70  40
Birmingham  39  68  58  64 /   0  10  80  40
Tuscaloosa  36  68  60  64 /   0  10  80  40
Calera      39  69  60  67 /   0   0  70  50
Auburn      41  68  60  69 /   0   0  40  50
Montgomery  41  73  61  72 /   0   0  40  60
Troy        42  73  60  73 /   0   0  30  50

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 9 AM CST Wednesday for the following
counties: Autauga-Barbour-Bullock-Dallas-Elmore-Greene-Hale-Lee-
Lowndes-Macon-Marengo-Montgomery-Perry-Pike-Russell-Sumter.

&&

$$

SHORT TERM...16
LONG TERM....15
AVIATION...16