486
FXUS64 KBMX 150558
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
1258 AM CDT Wed May 15 2024

...New AVIATION...

.SHORT TERM...
(Tonight through Thursday)
Issued at 909 PM CDT TUE MAY 14 2024

Updated the forecast to adjust timing and magnitude of POPs across
the northern counties the rest of the evening. I think categorical
POPs (80%+) justified for areas downstream of ongoing convection.
And we needed to keep the higher POPs in the northeast a bit
longer than previously forecast. Didn`t make any changes to
temperatures, or any other sensible weather elements.

/61/

Previous short-term discussion:
(This afternoon through Wednesday)
Issued at 1156 AM CDT TUE MAY 14 2024

A low pressure system will continue to move to the east across
the TN Valley this afternoon through tonight. Winds will be from
the southwest through the day, transitioning to the west tonight,
and then the northwest early Wednesday morning. This afternoon,
scattered showers and thunderstorms are possible across the entire
area. CAMs are trying to show a greater coverage for activity
across areas along and north of I20 where instability values are
between 2000 and 2500 J/kg, though instabilities south of I20 will
be between 2500 and 3000 J/kg in the south and east. Would expect
greater forcing in the north, with greater diurnal effects in the
south for this afternoon and evening. Instability will be between
30-40 kts throughout the afternoon, with PW values near 90th
percentile for this time of year. Though scattered thunderstorms
are expected across the entire area, only a few are expected to be
strong to possibly severe if those storms can tap into the
instability and shear properly. Skies have been partly cloudy in
the southern half of the state, with temperatures much warmer and
highs anticipated in the low to mid 80s. In areas of the north
where cloud cover has been persistent this morning, high temperatures
will be in the mid to upper 70s.

Overnight tonight, as flow shifts to out of the west, drier and
cooler air will begin to advect into the state with activity
decreasing from west to east shortly before midnight. By early
morning, most activity should be east of the state, with clouds
beginning to clear from west to east. As the low pressure
continues it`s eastward trek, wraparound moisture and forcing
could cause isolated weak thunderstorms in the far northeastern
counties Wednesday afternoon during the day`s peak heating.

24

&&

.LONG TERM...
(Wednesday night through next Monday)
Issued at 250 PM CDT TUE MAY 14 2024

Beginning of extended, Wed night through Thu evening, this will
hold a break between upper shortwaves as wave number 1 exits to
the E off of the Atlantic coast. Wave number 2 will move across as
an open wave on the lee side of the Rockies Thu evening. Model
solutions differ as to the strength of the upper low/shortwave #2
as it progresses NEWD Fri/ Fri evening and then slides EWD over
ERN Conus over the weekend. We should see the best chances of
showers and thunderstorms on Fri/Fri night when wave #2 is
closest to AL (over OK-MO), before it moves off to the NE toward
the Atlantic coast leaving dry weather for the end of the
extended.

08

Previous long-term discussion:
(Thursday through next Monday)
Issued at 309 AM CDT TUE MAY 14 2024

A shortwave ridge will be on an easterly transit across the area on
Thursday, behind a trough departing into the western Atlantic.
Central Alabama will be rain-free and warm, with highs in the 80s
to near 90 in some southern locations.

An upper-level disturbance is progged to advance from the Southern
Plains toward the Mid Mississippi Valley Friday morning. This will
coincide with a broad zone of southerly to southwesterly low-level
flow overspreading the Gulf Coast and Deep South. As such,
isentropic ascent will be present leading to increasing clouds and
rain chances from west-to-east. Widespread showers and embedded
thunderstorms are forecast by Friday afternoon with locally heavy
rainfall possible along and south of I-20 (latest QPF is 2-4" in
these areas). This scenario is not too dissimilar from our recent
weather event. Flow aloft is west-southwesterly overspreading much
of the Gulf Coast baroclinic zone. It appears the quasi-stationary
front will struggle to advance northward, and this leads to a
tendency for thunderstorms/higher QPF to dwell closer to the I-10
corridor. While we`ll maintain some messaging for locally heavy
rainfall/flooding Friday, there`s no current concerns for severe
weather given the scenario and the differing solutions still
present in medium-range guidance. Regardless, some convection is
forecast to linger Friday night into Saturday morning, gradually
drifting to the east with time. Drier, warmer conditions prevail
at the end of the period with a transition to northwesterly deep-
layer flow.

40/Sizemore

&&

.AVIATION...
(06Z TAFS)
Issued at 1255 AM CDT WED MAY 15 2024

The upper low is beginning to swing into the the area. Two areas
of showers and storms continue as of this hour. The northern band
is dissipating while the second one in the south is developing.
Added in some tempo thunder at MGM and TOI. Convection should be
done by 10z. Patchy fog at TOI, MGM and TCL through sunrise. Winds
pick up late morning to around 10 kts from the northwest.
Will need to monitor the afternoon for convection at ANB/ASN but
right now it appears to be to the north of them.

16

&&

.FIRE WEATHER...

Isolated to scattered thunderstorms are possible through this
evening, with a chance of showers across the northeast counties on
Wednesday. This coincides with elevated moisture values this
afternoon and southwesterly 20 foot winds at 5 to 10 mph. A
transition to westerly and northwesterly 20 ft winds is forecast
Wednesday and Thursday, with overall drier conditions Thursday.
Additional wetting rains are forecast on Friday with thunderstorms
and locally heavy rainfall possible.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     80  57  86  61 /  20   0   0  20
Anniston    79  59  86  64 /  20   0   0  20
Birmingham  80  60  87  67 /  10   0   0  30
Tuscaloosa  82  61  88  67 /   0   0   0  40
Calera      80  61  87  66 /   0   0   0  30
Auburn      80  62  86  66 /   0   0   0  10
Montgomery  83  61  87  67 /   0   0   0  20
Troy        84  61  87  66 /   0   0   0  20

&&

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

$$

SHORT TERM...61
LONG TERM....08
AVIATION...16