Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 231229
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
729 AM CDT Sat Mar 23 2024

...New AVIATION...

.SHORT TERM...
(Today through Sunday)
Issued at 420 AM CDT SAT MAR 23 2024

A surface low is currently over South Central Alabama at this hour
with mainly showers cycling counter clockwise around it. The small
amount of TS we have is exiting the state into GA with not much more
than an isolated strike expected at best after that. The low will
continue to the ENE and into GA later this morning. A few hours
lagging the low, a cold front will move SEWD across C AL and push
any lingering showers out of the SE part of the CWA before midday.
Winds will become NRLY behind the front with some gusts during the
day. Although breezy, winds should stay below wind advisory
criteria. Gusts should taper down after sunset, but winds will stay
up during the evening with tighter surface pressure gradients behind
the front. This front will usher into the area a quick/short period
of colder air with lows tonight. We could see some patchy frost
during the pre-dawn/early morning hours in the NRN 1/3 of the area
with overnight lows expected from the middle 30s N to the lower 40s
S.

Sunday will be a nice one. After a chilly start, our atmosphere will
begin to moderate as the main surface ridge shifts EWD and our ridge
weakens. This will allow for mild highs from the middle 60s to the
lower 70s with only some fair weather clouds. Winds will turn around
SEWD in response for a slow moisture return. Even so, we will have
lower humidity for Sunday with some min RH`s in the afternoon in the
middle 20s in the NE counties for a couple of hours. Will hold off
on a red flag warning just yet as it should be brief and winds
should not be high.

08

&&

.LONG TERM...
(Sunday night through next Friday)
Issued at 325 AM CDT SAT MAR 23 2024

Monday morning will feature a trough across the Intermountain West
and much of the Plains with a couple of embedded disturbances; one
will sit near Omaha with an associated surface low, the other near
northern Mexico. A ridge will be positioned along the East Coast,
and this places much of the Lower MRV and Southeast in a
southwesterly flow regime. As the day draws on, a southerly low-
level jet is progged to move east toward AL with isentropic ascent
and increasing cloud cover. We`ll also experience moisture advection
with morning dewpoints in the 30s/40s rising to the 40s/50s by the
evening. Winds will be gusty at times, and we will probably need a
wind advisory when the time comes. High temperatures in the 60s/70s
are forecast.

Tropospheric moisture will continue to increase Monday night as the
front and elongated area of showers/thunderstorms move east across
the Mississippi River. The LLJ is forecast to strengthen to 50+ kts
as a SSW to NNE oriented jet streak positions to our north. As such,
rain chances take a stark increase across our forecast area Monday
night into Tuesday morning as the line of convection is expected to
move east into the Tennessee Valley - generally when the
aforementioned shortwave near northern Mexico rotates through.
Locally heavy rainfall is possible owing to convection and progged
PWs in the 1.4" to 1.6" range. This could lead to flooding in poor
drainage or low-lying areas. There`s also a small window where
instability nudges into our southwest counties early Tuesday morning
where dewpoints reach or exceed 60F. In fact, there`s pretty
remarkable agreement in the latest GFS/ECMWF/NAM for the progression
of a narrow warm sector getting pinched off across our southwest
counties. Due to the ample kinematics with this system, we`re
monitoring for a limited severe threat - thankfully over a small
area and time frame for southwest Central AL. Latest QPF is 1-3"
for areas west of I-65, though locally higher amounts will be
possible.

Frontal passage will occur on Tuesday with rain/storms ending west
to east throughout the day. Drier, cooler conditions return to the
area Tuesday night as a broad upper-level trough encompasses the
eastern CONUS. Stable weather will remain across the area for the
rest of the period with ridging/warm weather returning by next
weekend.

40/Sizemore

&&

.AVIATION...
(12Z TAFS)
Issued at 657 AM CDT SAT MAR 23 2024

Winds have shifted at TOI, so now surface low has passed all of
our TAF sites. -SHRA will continue to be possible for the next few
hours at MGM/TOI hours and possibly isolated sprinkles further to
the N, but I will forgo the isolated mentions. Not expecting any
TS with any of the lingering activity. The low will continue to
the ENE and into GA later this morning. At present we have varying
cigs from LIFR to VFR depending on showers and the proximity to
the front. Cig may vary with down a category over the next couple
of hours, but then they should start to improve. All sites should
become VFR by 18z or sooner. Winds will be NRLY behind the front
with some gusts during the day. Gusts should taper down after
sunset, but winds will stay up during the evening with tighter
surface pressure gradients behind the front.

08

&&

.FIRE WEATHER...

A low pressure system is moving across Central Alabama this
morning and this is favoring continued rain showers and elevated
moisture levels. Wetting rains will depart to the east later this
morning with cooler, drier air moving in behind. 20 ft winds will
become northerly at 10-15 mph this afternoon. Winds will become
easterly to southeasterly tomorrow afternoon at 5-10 mph with minimum
RH values in the 25-40% range forecast. Wetting rains and storms
return to the area Monday night through Tuesday afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     65  34  70  45 /  20   0   0   0
Anniston    66  36  70  45 /  20   0   0   0
Birmingham  65  39  70  49 /  20   0   0   0
Tuscaloosa  67  38  72  49 /  20   0   0   0
Calera      66  39  70  48 /  20   0   0   0
Auburn      68  42  68  46 /  40   0   0   0
Montgomery  71  40  71  49 /  40   0   0   0
Troy        71  42  72  49 /  40   0   0   0

&&

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

$$

SHORT TERM...08
LONG TERM....40/Sizemore
AVIATION...08


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