102
FXUS64 KBMX 271747
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
1247 PM CDT Thu Jun 27 2024

...New SHORT TERM, AVIATION...

.SHORT TERM...
(This afternoon through Friday)
Issued at 1144 AM CDT THU JUN 27 2024

An area of low pressure will meander over western Alabama through
the afternoon, weakening through the evening and early night. Flow
will be from the west and southwest this afternoon, with plenty of
low level moisture advecting into the southern half of the area.
Instabilities will be around 1500 to 2000 J/kg though shear is
fairly weak. With high PW values and weak shear, would expect
strong storms to form with localized flooding possible in any
storms that can train over the same area. Chances of stronger
storms will be in the southeastern third of the area where
instabilities and PW values will be the highest. The northwestern
two thirds of the area could see more isolated showers and
thunderstorms.

Overnight, high pressure tries to develop over the area. Flow
will remain from the south as the high pressure strengthens. PW
values will remain high Friday, values well over 2" expected, with
scattered, mainly diurnal, convection expected again.
Instabilities appear lower, around 1000 J/kg at most.
Temperatures will be lower today with the cloud cover expected to
remain through the afternoon. As the low pressure weakens, clouds
could begin clearing, though only the mid to upper 80s are
expected this afternoon for high temps. Tonight should see lows in
the low 70s, and with the high pressure expected tomorrow,
temperatures in the low 90s are possible.


24

&&

.LONG TERM...
(Friday night through next Wednesday)
Issued at 332 AM CDT THU JUN 27 2024

Key message:

- Oppressively hot and humid conditions are expected this weekend,
  with dangerous heat possible on Sunday as heat indices rise
  above 105 degrees. A multi-day heat wave is expected to
  continue through much of next week. Best rain chances will exist
  Saturday through Sunday, with scattered showers and storms
  possible each afternoon through the end of the forecast period.

Another prolonged period of oppressive heat will begin this weekend
as the 500mb ridge begins to build and broaden from Texas all the
way east through the Deep South. The big difference in this heat
wave compared to the one we`ve recently experienced will be the
addition of more tropical low-level moisture with dewpoints expected
to remain in the 70s during the afternoon hours. Rain chances on
Saturday will remain across the eastern and southeastern portions of
Central Alabama, with higher PWATs and deeper 700mb moisture
transport from the southwest. Although shower and storm coverage is
expected to be scattered to numerous, temperatures aloft due to the
500mb ridge strengthening to 597 decameters will be quite warm.
Therefore strong to severe storms are not expected at this time.
Where it doesn`t happen to rain, heat indices will rise between 100
and 105 degrees Saturday afternoon as highs top out in the low to
mid 90s. So, even though we may escape Saturday without issuing a
Heat Advisory, all bets will be off on Sunday.

As the ridge continues to strengthen but slightly retrograde off to
our west, a shortwave trough is expected to move through the Great
Lakes states Sunday morning. A cold front will be moving southward
into northern Arkansas and Tennessee during that time, along with
synoptic lift in the form of a 500mb vort max within the
northwesterly flow. Convective development will be likely with
strong surface instability as temperatures rise into the mid to
upper 90s with dewpoints holding in the low to mid 70s. A Heat
Advisory will be needed if current guidance trends hold, but
widespread convective development (potentially in the form of an
MCS) may throw a wrench in those trends if storms move through a bit
earlier. As of now, heat indices Sunday afternoon should easily rise
between 105 and 110 degrees for just about everyone.

The cold front is currently progged to move southward on Monday,
with a fresh fetch of dry air moving in from the north at 700mb. How
far south the dry air at the surface can move southward is still in
question, which will affect locations that may need another Heat
Advisory Monday afternoon. For now, those locations appear to be
along the U.S. 80/I-85 corridors and points southward with plenty of
moisture pooling out ahead of the surface front. Scattered to
numerous showers and storms can also be expected across the southern
half of Central Alabama. The 500mb ridge is currently advertised to
build back in over Deep South through Thursday, with isolated to
scattered showers and storms possible during the peak heating of the
day. As highs top out in the upper 90s each day, we could enter into
a prolonged period where Heat Advisories may be needed for several
days in a row. With this being said, we`ll also have to start
keeping an eye on the dreaded Drought Monitor, with significant rain
chances staying out of reach likely through the end of next week.

56/GDG

&&

.AVIATION...
(18Z TAFS)
Issued at 1144 AM CDT THU JUN 27 2024

Scattered showers and thunderstorms are possible across the entire
area, with the greatest chances around KMGM. VCSH was included in
every TAF except KMGM due to uncertainty in timing and coverage of
any thunder, and will amend as needed. KMGM has VCTS to account
for the scattered nature of the convection. Skies should begin to
clear this evening as the low pressure weakens, with plenty of
low level moisture bringing MVFR and IFR ceilings through the
early morning. Scattered convection is possible again Friday.

24

&&

.FIRE WEATHER...

Scattered to numerous showers and storms can be expected today
across much of Central Alabama, but widespread wetting rains are
not expected. Min RH values this afternoon will be much higher
than previous days, in the 55 to 65 percent range. Transport winds
will remain light and variable at times through the afternoon
today. Fortunately, we`re not expecting much in the way of gusty
erratic winds with showers and storms today like what was observed
on Wednesday. Scattered showers and storms will remain in the
forecast for Friday, confined more to the southern half of Central
Alabama. Transport winds are expected to increase out of the
southwest between 10 and 15mph by Friday afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     87  70  91  72 /  80  20  40  20
Anniston    87  71  91  74 /  70  20  50  20
Birmingham  88  73  92  75 /  90  20  40  20
Tuscaloosa  89  73  92  75 /  50  20  40  10
Calera      89  72  93  75 /  80  20  40  20
Auburn      86  72  89  74 /  80  40  60  20
Montgomery  89  73  91  74 /  70  30  60  20
Troy        86  73  90  73 /  70  30  70  20

&&

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

$$

SHORT TERM...24
LONG TERM....56
AVIATION...24