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000
FXUS64 KBMX 171216
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
716 AM CDT Wed Apr 17 2024

...New AVIATION...

.SHORT TERM...
(Today through Thursday)
Issued at 422 AM CDT WED APR 17 2024

Satellite is indicating AL covered with thick mid and upper clouds.
Upon first glance at the GWX and BMX radars, there looks to be more
weather going on than there actually is. While there is a broken
line/area of showers extending from C TN into N MS, just about all
of the rest of the returns that you see on GWX/BMX radars in E/S AL
and S MS are mid level cloudiness. Most of the observations, unless
augmented by human observers are reporting CLR (clear below 12KFT).
This will change as we progress through the day.  This AM in the
upper levels, a low is present over the NC US with WSW flow into C
AL. This low is expected to continue to swing ENE past the Great
Lakes  into ERN Canada getting absorbed into the main parent low
over C Canada by late Thu. Across C AL, we will have a zonal to WSW
flow in the upper levels as the low progresses, with some
perturbations traversing through this flow. We will see rain return
to the area during the day today as low level moisture continues to
increase and showers begin to precipitate to the ground with these
perturbations. The best chances continue to be in the NRN half to
2/3 of C AL closer to the main system. Thunderstorms are expected as
we heat up during the day. Although an isolated strong storm during
the late afternoon heat chance isn`t zero, thinking that generally
storms are expected to remain sub-severe with the better energy and
instability to stay well to the N. Activity tapers down tonight.
Lower storm chances are possible for Thursday but still an isolated
to scattered afternoon storm or two is possible related to these
waves for Thursday afternoon as well.

08

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 335 AM CDT WED APR 17 2024

An active subtropical jet will bring westerly 500 mb flow and
unsettled weather conditions to the region for Friday through
Sunday. The first disturbance is expected to move across the
eastward from the Mississippi Valley Thursday night supporting
moist 20-30kt southwesterly flow at 850 mb. As the associated
weak front approaches from the northwest, scattered showers and
perhaps a few thunderstorms could affect our northern half
Thursday night into Friday.

The split flow pattern and associated upper-level confluence will
support strong high pressure from western Canada southward into the
Plains and Southeast CONUS. This shallow cool airmass will move
southward into Alabama on Saturday ahead of a shortwave moving out
of Texas. As a result, isentropic lift is expected to overspread
the region over the weekend, potentially leading to widespread
rain and embedded thunderstorms.

With the passage of the shortwave trough, dry conditions should
return for Monday and Tuesday.

87/Grantham

&&

.AVIATION...
(12Z TAFS)
Issued at 646 AM CDT WED APR 17 2024

TAFs/obs are mainly VFR except for TCL where the MVFR cigs have
arrived ahead of our next area of rain. This will last for the
next few hours ahead of SHRA/TSRA that will approach from the W.
There is a small chance that these stratus clouds could propagate
as far E as BHM/EET this morning, but thinking that the MVFR cigs
should stay just W of them this morning. Convection should be
mainly across the NW part of AL and not affect the C AL TAFs
through early afternoon. By ~ 21z, I do mention some PROB30s for
all but MGM/TOI. At this time, I don`t think that the convection
will make it that far S. SHRA chances continue into the evening
hours, but left out TS mention for now as those chances are lower.
Winds will be S-SW 5-10KTS with a few gusts possible with general
TS convection this afternoon. MVFR conditions cigs/vsbys do
develop after late in the period 8-10z after the shower end with
lots of residual low level moisture. Have a mention possible for
TCL/BHM/EET.

08

&&

.FIRE WEATHER...

RH values will increase significantly today ahead of an approaching
front. A band of showers and a few thunderstorms will impact
northern portions of the area today. Southwesterly 20 foot winds
should range from 6 to 10 mph. Much of the area will remain dry
on Thursday in between weather systems with RH values above 40
percent. 20 foot winds should be from the south at 8 mph or less.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     79  59  86  62 /  60  40  20  50
Anniston    81  60  86  63 /  40  40  20  40
Birmingham  79  62  86  65 /  50  40  20  40
Tuscaloosa  80  63  85  65 /  50  30  20  30
Calera      80  62  85  65 /  40  30  20  30
Auburn      81  63  84  65 /  10  20  10  20
Montgomery  84  64  86  65 /  10  10  10  10
Troy        84  63  86  64 /  10  10  10  10

&&

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

$$

SHORT TERM...08
LONG TERM....87/Grantham
AVIATION...08