358
FXUS64 KBMX 152139
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
439 PM CDT Wed May 15 2024

...New LONG TERM...

.SHORT TERM...
(This evening through Thursday)
Issued at 1230 PM CDT WED MAY 15 2024

Low pressure will continue to the northeast through the afternoon
with flow around the low bringing showers and a chance for brief
thunderstorms to the northeastern corner of the area.
Instabilities are enough with PW values lingering close to the
75th percentile for scattered development this afternoon. Winds
will be gusting today as the high pressure and weak pressure
gradient continue to move east, but winds should weaken after
sunset.

Dry air will filter into the area in the evening, with
activity expected to decrease as the sun sets. Skies should clear
through the night, with patchy fog possible in a few locations.
Winds should be weakening through the night, so how quickly those
winds weaken may determine where and how much fog develops.
Thursday, high pressure moves across the southeast US with dry
weather and mid level flow shifting from the northeast in the
morning to the southwest by the evening.

High temperatures today will be near normal in the upper 70s to
mid 80s. Lows tonight will be in the upper 50s and lower 60s due
to that northwest flow, and with mostly clear skies on Thursday,
highs will be a couple of degrees above normal in the mid to upper
80s.

24

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 412 PM CDT WED MAY 15 2024

The beginning of the extended will be wet and unsettled for
Thursday night through Saturday evening as a second upper shortwave
over OK/TX is expected to move NEWD across the Mid MS River Valley
and TWD WV/VA by Sun morning. Model solutions continue to differ
as to the strength of the positive tilted upper low/shortwave as
it progresses across the ERN half of Conus. Instability ramps up
as the morning progresses with the best severe chances in the
afternoon and evening on Friday helped also by a low level jet.
The extent of which will depend somewhat on the morning`s rains
and recovery time afterwards. PWs are high with this event, and
this will help to have some very effective rain producers. The
highest amounts expected will be across the SRN half of the state.
From early Fri through late Sat, anywhere from 1-3 inches of rain
may be noted across the NRN half of C AL and 3-5 inches across
the SRN half (with isolated locally higher amounts). Will be
watching for some flash flooding and possible rises on area rivers
over the weekend.

08

Previous long-term discussion:
(Friday through next Tuesday)
Issued at 349 AM CDT WED MAY 15 2024

A zone of west-southwesterly flow aloft is progged to stretch from
the Texas Gulf Coast through the Southern Appalachians by Friday
morning. This is associated with a positively-tilted upper-level
trough that extends into the Great Lakes with an embedded
disturbance/low nearing the ArkLaTex. While less clear in the low-
levels, latest guidance has trended farther north with a warm
sector, many of which depict an accompanying low-level jet
overspreading the Lower Mississippi and Tennessee Valleys Friday
morning, gradually shifting eastward during the afternoon. This
would place Central Alabama in a favorable parameter space for
strong to severe thunderstorms considering low-level and deep-
layer shear with modest mid-level lapse rates. Various forecast
soundings now suggest MLCAPE <2,500 J/kg west of I-65. Hodographs
suggest supercellular storm modes are also possible.

However, there`s still much uncertainty about how things near the
surface evolve. There`s indication that morning convection could
disrupt the northward expansion of the warm sector, or at least
delay its recovery past peak heating, especially if convection
lingers across the I-10 corridor. There`s also uncertainty
regarding placement of surface boundaries and their respective
orientations. It`s for this reason that it`s also hard to clearly
define placement of flooding potential, though highest PWs and
soil moisture remain across the southern half of the area (thus
higher QPF there for now).

All things considered, and while I hate to say it, there is growing
concern for all severe weather hazards on Friday, with flooding
potential to boot.

In some capacity, lingering convection is forecast across southeast
Central Alabama into Saturday morning, though threats will have
diminished by then. The trough is progged to accelerate to the east
during this time along with the low-level jet. PoPs decrease quickly
west-to-east as a result. Deep-layer ridging is depicted in medium-
range & ensembles thereafter, which supports a period of dry,
warm weather that appears to extend into early next week. Highs in
the 90s could be possible by then.

40/Sizemore

&&

.AVIATION...
(18Z TAFS)
Issued at 1230 PM CDT WED MAY 15 2024

Scattered showers are moving across the northeastern part of the
area, with mainly KANB and KASN affected. Due to low confidence on
exact timing and coverage, have included VCSH at these two sites
for now. Otherwise, VFR conditions are expected with clearing
skies through the night tonight. High pressure will move through
the area tomorrow with VFR conditions through the end of the TAF
period.

24

&&

.FIRE WEATHER...

Only a few rain showers will be possible across the northeast
portions of Alabama through the afternoon. Drier, warmer conditions
return to the area on Thursday with light northwesterly 20 ft winds.
Our next weather system moves into the area on Friday. This will
feature widespread rains and thunderstorms that will persist into
Saturday morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     56  87  62  78 /   0   0  20  80
Anniston    58  86  65  80 /   0   0  20  70
Birmingham  60  87  65  79 /   0   0  30  80
Tuscaloosa  60  88  65  81 /   0   0  40  90
Calera      60  87  66  80 /   0   0  40  80
Auburn      62  85  67  80 /   0   0  20  60
Montgomery  61  87  67  83 /   0   0  30  80
Troy        61  88  67  83 /   0   0  20  70

&&

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

$$

SHORT TERM...24
LONG TERM....08/40/Sizemore
AVIATION...24