Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 221039
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
539 AM CDT Fri Mar 22 2024

...New LONG TERM...

.SHORT TERM...
(Today through Saturday)
Issued at 1255 AM CDT FRI MAR 22 2024

Look for deteriorating conditions over the next 8 to 12 hours as
the shortwave begins to slide through. Plenty of high level clouds
have moved in, so we will not see much more of a temperature drop
through the morning. The gulf low that we have been mentioning is
beginning to wrap up and will start to move into the forecast
area shortly after 1 PM. The low itself looks to move along the
southern third of Alabama and possibly be near the I-85 corridor
around Midnight. We will have a brief window in the south, from
sunset to early morning/pre-dawn in which thunderstorms will be
possible in the south. Otherwise we are looking a rain bands
wrapping around the low. So there is an extremely high chance for
periods of rain across the area. through Saturday morning.
Activity slides to the east during the morning hours of Saturday
before exiting by the afternoon.

16

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 400 AM CDT FRI MAR 22 2024

Saturday night through Sunday night.

Broad longwave ridging will move east from over the Southern Plains
to over the Lower Mississippi River Valley Region Saturday night
into Sunday while deep mid-level troughing will be positioned over
the Carolinas. The longwave ridge axis will move east of the area
during the day Sunday as it increases further in amplitude due to
the broadening of the mid-level trough over the Desert Southwest
east to over the Plains. Strong and expansive surface high pressure
will be positioned across Southern Canada to over the Great Lakes
that will expand southward across the Lower Mississippi River Valley
Region. The surface cold front will stall along the Northern Gulf
Coast later in the day on Sunday.

Expect fair skies with dry conditions Saturday night through Sunday
morning areawide, followed by gradual increasing clouds from the
west during the afternoon into the evening hours. Lows Sunday
morning will range from the mid 30s far north to the mid 40s far
southeast followed by highs from the mid 60s in the higher
elevations east to he low 70s south and central.

Monday through Tuesday.

The forecast area will become positioned between amplified longwave
ridging to our east and broad, deep troughing over the Desert
Southwest on Monday while a potent shortwave will swing northeast
over the Central Plains toward the Great Lakes Region. Locally, a
southwest flow will develop aloft while a potent surface low
develops along the Front Range of the Rockies and deepens with time
as it quickly moves northeast toward the Great Lakes late in the day
on Monday. Surface high pressure will become centered across
Southeast Canada with residual wedging effects down the Appalachians
into East/Northeast Alabama through Monday morning while the diffuse
remnant surface front along the Central Gulf coast begins moving
inland in response to the advancing trough over the South-Central
Plains.

On Tuesday, the longwave trough will continue to move further east
over the Central Plains while most modeling depicts an embedded
shortwave that will pivot northeast around the base of the trough
early Tuesday over South Texas and will take on a more negative tilt
as it swings northeast over the Mid-South Region Tuesday afternoon
and Evening. The corresponding cold front will extent from near
Chicago southwest to near Memphis during the morning while surface
low pressure is progged to develop near New Orleans at the triple
point where the remnant coastal/marine front will push inland across
South Alabama and the Western Florida Panhandle through the day.

The forecast will call for continued increasing clouds late Sunday
through Monday with chances for scattered showers and a few
thunderstorms during the afternoon hours Monday across the northwest
and west-central Counties. Expect this activity to continue to
expand east with time, affecting more of the area into the day on
Tuesday with widespread showers and at least isolated thunderstorm
activity reaching a climax during the afternoon through the mid
evening hours before activity begins to taper off from the northwest
late Tuesday night. Temperatures will moderate during this time
frame with lows from the mid 40s east to the low 50s west Monday
morning and highs from the mid 60s north and northeast to the low
70s south to lows areawide in the 50s Tuesday morning and highs from
the mid to upper 60s north while highs will reach into the mid 70s
far southeast Tuesday afternoon.

Sufficient wind shear with decent low-level instability appear to be
present on Tuesday, especially from midday through early evening, to
support some strong to severe storms with better potential across
the southern, southeast and east-central counties that look to be
near and south of a developing surface low track that may
materialize from near New Orleans to near Atlanta through this time
frame that would permit the warm sector to advect northward with
time towards the Interstate 20 corridor, potentially allowing the
warm sector to move north into this area from midday Tuesday through
the early evening. There are, however, some limiting factors
including weak mid to upper level lapse rates and uncertainty
regarding how unstable the low levels can become given such high
rain chances through much of the day. This time frame will continue
to be closely monitored as additional modeling becomes available and
as we get a more detailed look at the environment once higher-
resolution modeling becomes available for this time frame.

Wednesday through Thursday.

Broad and expansive mid-level troughing will be over much of the
Country with a deep upper low over the far Northern Plains on
Wednesday. A southwest flow will persist over our area while
expansive surface high pressure will be centered across much of the
Plains while surface low pressure will be centered across South
carolina. A diffuse cold front will be positioned roughly parallel
to the Interstate 59 corridor on Wednesday morning as it continues
to decelerate with time.

Longwave ridging looks to build over the Four Corners States late
Wednesday into Thursday, resulting in the downstream trough over the
Plains to respond accordingly by deepening in amplitude. The more
progressive nature in the flow pattern aloft will help force the
trough further east over the Mid and Lower Mississippi River Valley
Regions by early Thursday morning and moving east over the forecast
area later in the day. Feature timing and placement issues are quite
notable between some global model solutions during this time frame,
resulting in a lower than usual confidence in this portion of the
forecast.

Clouds will gradually decrease from west to east while some shower
activity may linger across the east and southeast Counties through
midday Wednesday. Shower chances will continue to decrease through
the afternoon with dry conditions forecast areawide after sunset. A
potentially slower progression would maintain some shower activity
across at least the eastern third of the area into Thursday and
would also result in more cloud cover than currently forecast for
this issuance. Lows Wednesday morning will range from near 40 far
northwest to the mid 50s southeast followed by highs from the low
60s northwest to the low 70s far southeast. Low temperatures will be
cooler Thursday morning ranging from the upper 30s far northwest to
the mid 40s far southeast and highs from the low 60s far north to
the low 70s south.

05

&&

.AVIATION...
(06Z TAFS)
Issued at 1255 AM CDT FRI MAR 22 2024

VFR conditions through sunrise. Ceilings will slowly lower through
the morning, with even a few vicinity showers at TOI and MGM after
12z. The bulk of the rain should hold off with limited
restrictions in the MVFR category until 14 to 15z for MGM and TOI.
Add about 2 hours to those times for the northern sites, with the
highest chances after 18z for MVFR impacts. There is a potential
this afternoon for some brief IFR conditions and included a tempo
here. There will also be a window for thunderstorms across MGM and
TOI after 00z so included a prob30 here.

16

&&

.FIRE WEATHER...

Rain returns to the area this morning and will continue through
evening before exiting Saturday morning. 20 ft winds increase from
the east southeast today, at 10-15 mph. As a front moves through
the area on Saturday, winds become northerly at 12-18 mph. Minimum
RH values will remain above critical threshold through Saturday,
with values ranging from 30-40 percent Sunday afternoon. The next
wetting rains look to be Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     65  52  64  36 /  90  90  20   0
Anniston    62  54  65  37 /  90  90  30   0
Birmingham  63  54  64  39 /  90  90  20   0
Tuscaloosa  63  54  67  39 /  90  80  10   0
Calera      62  54  64  39 /  90  90  20   0
Auburn      61  56  67  41 /  90  90  30   0
Montgomery  64  57  69  41 /  90  80  20   0
Troy        65  57  69  44 /  90  80  20   0

&&

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

$$

SHORT TERM...16
LONG TERM....05
AVIATION...16


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