172
FXUS64 KSJT 221759
AFDSJT

Area Forecast Discussion
National Weather Service San Angelo TX
1259 PM CDT Sun Sep 22 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 342 AM CDT Sun Sep 22 2024

...Thunderstorms expected this afternoon through tonight...

Currently, an upper level low is located over CO, with southwest
flow over west central Texas. This low is expected to open into a
wave while slowly moving east into the central and southern plains
by Monday morning. This will maintain southwesterly flow over our
area. At the surface, a cold front is expected to move south into
our CWA by this afternoon, making its way through the rest of the
area by late tonight. Scattered to widespread thunderstorms are
expected to develop along and ahead of the cold front this
afternoon, and continue through most of the overnight hours.

With temperatures warming well into the 80s to lower 90s this
afternoon, combined with plentiful low level moisture
(precipitable water values near 2 inches), low levels will
destabilize ahead of the front. Mixed layer CAPE values are
forecast to be in the 500 to 1500 J/kg range during peak heating
hours. Deep layer shear values of 40 to 50 knots over the area,
combined with the instability will allow some of the storms to
become strong, with a few storms possibly severe. The main concern
with the storms will be wind gusts over 60 mph, but hail up to
the size of quarters will also be possible. After sunset,
instability will wane, and although storms may continue, the
concern for severe weather will diminish. The other concern will
be heavy rain and localized flooding with precipitable water
values near 2 inches.

Storms are expected to develop first over the Big Country along
the front, then spread southward over the rest of the area during
the afternoon and overnight hours as the front moves south.
Overall coverage should diminish late tonight, but isolated to
scattered activity will still be possible after midnight, mainly
south of Interstate 20.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 449 AM CDT Sun Sep 22 2024

An upper level low pressure system will move north of our area
and then proceed east across the Plains on Monday. Then, another
strong low pressure system will move across the eastern portions
of the Great Plains on Wednesday. This will swing another cold
front into the area, which will keep temperatures a bit cooler for
the remainder of the work week. High temperatures look to be in
the upper 70s to middle 80s. This same system and the attendant
frontal boundary will also be supportive of another round of
rainfall across the area on Tuesday and Wednesday ahead of the
front. The Weather Prediction Center has placed west Central Texas
into another Marginal Risk (5% chance) of excessive rainfall
leading to flash flooding on Tuesday and Tuesday night. Rainfall
totals may be near 0.5" to 1" during this time frame with locally
higher amounts remaining possible. We will have to keep an eye on
this scenario for changes in the next day or two.

&&

.AVIATION...
(18Z TAFS)
Issued at 1256 PM CDT Sun Sep 22 2024

Ceilings have lifted to VFR across the terminals early this
afternoon. Still expecting a cold front to move south across
the terminals late this afternoon and evening, with FROPA at KABI
around 22Z, KSJT around 00Z and the far southern terminals by mid
to late evening. Showers and thunderstorms are expected to
develop along and behind the front, and will include TEMPO groups
for TS this forecast cycle. Precipitation is expected to end
across the far southern terminals by mid to late morning tomorrow.
Also, ceilings are expected to lower to IFR overnight, and
persist through at least the mid morning hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene     59  75  62  85 /  80  30  40  40
San Angelo  62  76  64  86 /  80  40  30  30
Junction    66  82  66  88 /  40  40  10  30
Brownwood   64  78  64  85 /  60  40  30  40
Sweetwater  59  75  63  85 /  70  20  30  40
Ozona       63  77  65  86 /  70  40  20  20
Brady       64  78  65  85 /  50  40  30  30

&&

.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...20
LONG TERM....41
AVIATION...24