519
FXUS64 KBMX 210612
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
112 AM CDT Sat Sep 21 2024

...New AVIATION...

.SHORT TERM...
(This evening through Saturday)
Issued at 138 PM CDT FRI SEP 20 2024

This afternoon.

Broad mid-level ridging remains centered over South-Central Texas
today while troughing was evident over the Eastern Seaboard well
to our east. Surface high pressure extended from across Southeast
Canada southwest across the Northeast and Mid Atlantic Regions and
stretched further southwest across much of Tennessee and Lower
Mississippi River Valley Regions. The 20/12z BMX sounding
contained a strong radiation inversion just off the surface
followed by a fairly moist layer up to near 700 mb where a
significant subsidence inversion was evident.

Expect partly cloudy skies this afternoon as dry conditions
persist. Winds will be from the north at 4-8 mph. High
temperatures will range from near 90 in the higher terrain east to
the low 90s west and central.

Tonight.

Broad mid-level ridging will remain centered to our southwest
overnight while surface high pressure will continue to extend
southwest across the area overnight.

Mostly clear skies are forecast overnight with light north to
northeast winds from 2-4 mph. Low temperatures will range from the
low 60s northeast to the upper 60s south and west.

Saturday.

Broad mid-level ridging will become more elongated with time
through the day on Saturday as it extends further to the northeast
over the forecast area. Surface high pressure will continue to
extend into the area from the northeast.

Look for partly cloudy skies on Saturday with another dry day
across the area. Winds will be from northeast to east at 4-8 mph.
High temperatures will range from near 90 in the higher elevations
east to the mid 90s far west.

05

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 139 PM CDT FRI SEP 20 2024

A period of dry conditions thanks to upper level ridging and
surface high pressure will continue through early next week.
Temperatures will run 7-10 degrees above normal with highs in the
low to mid 90s. Some relief is expected overnight, with lows in
the mid 60s to lower 70s.

By mid week, the upper level ridge shifts to the east as troughing
amplifies over the central CONUS. Alot of model variation in how
that trough evolves and where/if an upper low closes off over the
southern Plains. Additionally, a disturbance in the southern Gulf
moves northward by the end of the week. So, an increase in rain
chances is warranted, although with alot of uncertainty, will keep
chances relatively low.

14

Previous long-term discussion:
(Saturday night through Thursday)
Issued at 349 AM CDT FRI SEP 20 2024

Status quo remains in the long term. Upper level ridging tries to
remain established across the southeast states into early next
week, keeping us in a rain free subsidence zone. By Tuesday, an
upper trough flattens the top of the southeast ridge a bit,
allowing some lift and slightly better low level moisture to get
into central Alabama. Will maintain slight chance to chance POPs
in our area through this time frame.

For Wednesday and beyond, forecast confidence really starts to
nosedive as model spread starts to really increase. And that
includes the tropical Caribbean and Gulf of Mexico. Got to chuckle
at least a little bit at the global model ensemble members that
individually have surface lows of varying strength (including
nothing at all) stretched across just about any position of the
Gulf by this time next week. Suffice to say now is not the time
to bite on any single run of any single model, regarding potential
tropical impacts for us next week.

/61/

&&

.AVIATION...
(06Z TAFS)
Issued at 112 AM CDT SAT SEP 21 2024

No impacts are expected to the TAF sites through the next 24
hours. VFR conditions will continue with light and variable winds
of 6 knots or less.

87/Grantham

&&

.FIRE WEATHER...

Rain chances will remain at zero through the weekend as high
pressure takes hold. With temperatures climbing back into the 90s
and a modestly dry airmass in place, RH values should range from
35 to 45 percent each afternoon through Sunday. 20 foot winds will
be variable, at less than 7 mph.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     92  67  92  66 /   0   0   0   0
Anniston    91  68  92  69 /   0   0   0   0
Birmingham  92  70  92  70 /   0   0   0   0
Tuscaloosa  93  69  93  70 /   0   0   0   0
Calera      91  71  92  71 /   0   0   0   0
Auburn      89  70  91  70 /   0   0   0   0
Montgomery  92  70  93  71 /   0   0   0   0
Troy        90  69  91  69 /   0   0   0   0

&&

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

$$

SHORT TERM...05
LONG TERM....14
AVIATION...87/Grantham