059
FXUS64 KBMX 191838
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
138 PM CDT Wed Aug 19 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Issued at 137 PM CDT WED AUG 19 2026

- Heat: Major HeatRisk is expected to persist through the end of
  the workweek, with heat indices are forecast between 103 to 108
  degrees. A Heat Advisory is now in effect for portions of
  central Alabama through Thursday

- Thunderstorms: Scattered to isolated afternoon thunderstorms
  will remain in the forecast through Saturday. Rain chances will
  increase this weekend.

- Severe: Isolated severe thunderstorms are possible today and
  Thursday with damaging wind the main threat. The greatest
  chances for severe thunderstorms will be in the western part of
  the state today, and the entire state on Thursday.

&&

.DISCUSSION...
(This afternoon through Tuesday)
Issued at 137 PM CDT WED AUG 19 2026

Today, high pressure will remain to the south and west of the
area, with flow over the state out of the northwest. A shortwave
moving around the high will cause enough lift for scattered to
isolated showers and thunderstorms through the late afternoon and
evening. Instability is decent, with DCAPE values between
1300 and 1500 J/kg. Steep low level lapse rates, drier air in the
mid levels, and weak winds will all contribute to a threat for
evaporative cooling aloft and dense cold air providing
downdraft/microburst potential in any stronger storm. These
parameters are strongest in the western part of the state, and
with that shortwave, would keep most of the severe threat west of
I65...though there is enough heating for isolated activity to
develop along and just east of the I65 through the afternoon and
weaken after sunset. Heat indices will remain around 105 degrees
or slightly higher, so will keep the Heat Advisory going through
tonight.

Tonight, a low pressure over the Great Lakes will move to the
northeast, with a frontal boundary around this low slowly moving
south through the TN River Valley and into the northern part of
the state Thursday afternoon. There should be enough lift and
instability for scattered showers and thunderstorms through the
afternoon Thursday and Thursday evening, weakening through the
early night. Parameters will be similar to Wednesday, though
coverage should be higher with the focus of that boundary
allowing scattered to more widespread activity. DCAPE remains
around 1500 J/kg with several thousand CAPE, weak winds through
the atmosphere and dry air in the midlevels. Damaging winds will
remain the main threat, with the most likely mode from downburst
winds after a storm collapses. With high moisture and warm
temperatures remaining, the Heat Advisory will continue through
Thursday night. Low temperatures at night in the 70s will
exacerbate the effects of heat.

By Friday, a trough east of the MS River will begin to deepen,
with flow over the state slowly transitioning to out of the
northwest and then west around this trough. The boundary that
moved into the north part of the state Thursday will continue to
move southward through the state, initiating diurnal convection
through the afternoon. Exact placement of where the focus of
storms will develop is dependent on that boundary, with the most
likely area between the I20 and I85 corridors. Parameters will be
similar to the those today and Thursday, with the chance for
downburst winds. Temperatures will be a couple of degrees lower
on Friday, though moisture should still remain high. Heat indices
will be in the triple digits for much of the area, with many
places currently forecast to reach the Heat Advisory criteria
around 105 degrees.

Saturday, there is uncertainty with the models how far the
boundary moves through the area. A few models show scattered to
widespread convection through the afternoon, with the boundary
and diurnal influences. More recent runs are showing the trough
moving into the state and northwest flow prevailing. A weak mid
level jet moving around this low could increase winds, especially
across the northern half of the area, gusting to 20-25 mph at
times through the afternoon. For now, will leave rain in the
forecast until more consistent model runs come in. With northwest
flow and cooler air advected into the state, the temperatures
should be several degrees cooler for Saturday and Sunday, with
heat indices for the first time in a week below 105 degrees,
though still in the triple digits.

High pressure moves back across the area briefly as a low
pressure develops and moves to the east across the AR/TN area.
This low will bring an increase in rain chances towards the end
of the extended. There is some uncertainty as to how quickly the
trough moves to the east and the low moves behind, and will
adjust as needed.

24

&&

.AVIATION...
(18Z TAFS)
Issued at 137 PM CDT WED AUG 19 2026

Scattered to isolated convection is expected through the
afternoon and evening today. The coverage should be greater in
the west and southwest, so left mention out of every TAF except
KTCL. Otherwise, northerly flow and high pressure will keep VFR
conditions at each TAF site through the rest of the TAF period.

Note: AMD NOT SKED for AUO due to a weather observation outage.

24

&&

.FIRE WEATHER...

MinRH values will generally range between 35 and 45% the next few
days, before slowly climbing into the weekend ahead of increasing
rain chances. Winds will remain light the next few days, before
increasing into the weekend as well. Fire weather concerns are
currently low, but they will start to increase by Monday no
meaningful rainfall occurs with this weekend`s system.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     74  97  73  94 /   0  20  40  50
Anniston    73  94  72  92 /   0  10  30  50
Birmingham  76  95  74  92 /   0  20  30  50
Tuscaloosa  76  99  75  96 /   0  20  30  50
Calera      75  95  73  93 /   0  30  30  50
Auburn      74  93  74  91 /   0  20  30  50
Montgomery  75  98  74  96 /   0  20  30  50
Troy        73  96  73  95 /   0  30  20  60

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM CDT Thursday for the following
counties: Autauga-Bibb-Chilton-Coosa-Dallas-Elmore-Fayette-
Greene-Hale-Jefferson-Lamar-Lowndes-Marengo-Marion-Montgomery-
Perry-Pickens-Shelby-Sumter-Tuscaloosa-Walker.

Heat Advisory from 9 PM this evening to 9 PM CDT Thursday for
the following counties: Barbour-Bullock-Macon-Pike.

&&

$$

DISCUSSION...24
AVIATION...24