Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 251847
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
147 PM CDT Sun Oct 25 2020

.UPDATE...
Midday Update and 18Z Aviation.

&&

.SHORT TERM...
/Updated at 0137 PM CDT Sun Oct 25 2020/

Through Tomorrow.

A weak surface low is centered over eastern Georgia producing light,
northwesterly winds across Central AL while the lingering boundary
over southern Alabama is quickly eroding and hardly identifiable.
Flow aloft is zonal and dry due to a flattened ridge moving into the
northern Gulf, but there is still enough low-level moisture
producing an overcast stratus layer across most of the Deep South
that will likely linger into tomorrow with little change. It will be
a few degrees warmer today and again tomorrow as heights begin to
rise, so highs will range from upper 60s northwest to lower 80s
southeast with lows tomorrow morning in the mid 50s to lower 60s.
Patchy fog and low ceilings will develop again during the pre-dawn
hours, but the slightly drier air and lack of preceding rainfall
should help to prevent conditions from deteriorating quite as
much as it did yesterday evening/this morning.

86

.LONG TERM...
/Updated at 0137 PM CDT Sun Oct 25 2020/

Tuesday through Saturday.

Features.

A southwest flow aloft will prevail through Tuesday as upper level
ridging is positioned to our southeast while a sharp positive-tilted
longwave trough extends from the High Plains southwest into The Four
Corners states.

The latest NHC forecast has Tropical Storm Zeta potentially becoming
a hurricane over the Central Gulf as it rides north to northeast
around the ridging to the east.

A closed low will develop over New Mexico and Western Texas late
Tuesday into early Wednesday as Zeta is forecast to be approaching
the Northern Gulf Coast.

Mid layer riding is expected to persist over the Southwest
Atlantic Basin, continuing to steer Zeta into the Central Gulf
Coast while the closed low moves eastward across Texas.

By Wednesday evening, Zeta is forecast by NHC to have made landfall
and to be persisting in its northeast motion, moving into South-
Central Alabama while the closed low advances further east into the
ArkLaTex region.

The remnants of Zeta are expected to quickly lift northeast into the
Southern Appalachians into the day Thursday as the upper low moves
into the Mid-South region.

Expect the upper low to move east across the Tennessee Valley
Region into the day Friday as shortwave ridging builds to our west
over the Southern Plains.

Forecast.

Expect increasing clouds with isolated showers with a few
thunderstorms moving north from the south on Tuesday followed by
higher chance for rain with a few thunderstorms possible on
Wednesday. There remains uncertainty with timing and placement of
features and due to this I capped PoP`s at 60 percent.

Rain with a few thunderstorms will remain in the forecast into early
on Thursday with decreasing PoPs south and west as drier air will
overspread the area from the southwest. The pronounced dry slot is
forecast to move over much of the forecast area into early in the
day on Friday.

Primary concerns for the forecast area will be potential effects of
Zeta as it moves northeast. There will be a risk for heavy rainfall
on the order of 1-2 inches generally. The relatively fast storm
motion of this system will help to limit the rainfall amounts from
becoming more excessive. With the current NHC track, much of our
Southeast and South-Central counties are on the right side of the
storm track, which will contain favorable wind shear profiles for
rotating storms and potential for tornadoes if instability is
sufficient.

The actual cold front associated with the mid-latitude storm system
is expected to move through the area during the day on Thursday. It
is expected with drier air moving in aloft that convective potential
will be lower, however, will continue to watch this time frame
closely.

On the Friday through Saturday time frame, drier conditions move
into the area with no concerns to end the forecast period.

05

&&

.AVIATION...
18Z TAF Discussion.

Dry conditions have returned to Central AL as the weak surface low
has moved well east of the area. Ceilings are beginning to return to
VFR after IFR prevailed for most of the morning, but the stratus low-
level deck will linger through this TAF period. Expect ceilings to
drop to IFR again early tomorrow morning with patchy fog possible
due to the lingering moisture at the surface. Northwesterly winds
will be around 5 kts shifting to northeasterly by late tomorrow
morning.

86

&&

.FIRE WEATHER...

Cloudy skies persist today followed by more low clouds tonight
with light northwest winds. Partly cloudy with light northeast
winds. Expect a period of drier conditions with less cloud cover
Monday into Tuesday followed by increasing clouds with greater
chances for rain and a few storms through midweek with increasing
southeast to southerly winds.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     60  74  59  79  60 /  10  10   0  20  30
Anniston    62  76  62  80  65 /  10  10   0  20  30
Birmingham  60  75  62  80  65 /  10   0   0  20  40
Tuscaloosa  59  76  61  81  65 /   0   0   0  20  40
Calera      60  76  62  79  66 /  10   0   0  20  40
Auburn      62  76  63  77  66 /  10  10   0  30  30
Montgomery  63  81  64  81  69 /   0   0   0  30  40
Troy        63  80  64  80  68 /   0   0   0  40  40

&&

.BMX WATCHES/WARNINGS/ADVISORIES/...
None.

&&

$$


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