517
FXUS64 KSJT 230531
AFDSJT

Area Forecast Discussion
National Weather Service San Angelo TX
1231 AM CDT Mon Sep 23 2024

...New AVIATION...

.SHORT TERM...
(This evening through Monday)
Issued at 240 PM CDT Sun Sep 22 2024

...Thunderstorms and cooler temperatures on the way...

Early this afternoon, a cold front was moving south across
northwest Texas and the Texas High Plains. The front will push
south into the Big Country by mid afternoon and continue south
across the remainder of the area late this afternoon and evening.
Aloft, an upper low was located over eastern Colorado, with an
associated trough axis extending southwest across New Mexico.
Convection is already developing along and north of the front near
Lubbock and this trend will continue, with showers and
thunderstorms expected to increase in coverage across the Big
Country by mid to late afternoon as the front continues south. An
expansion southward is expected this evening and overnight with
the bulk of precipitation ending across southern sections by mid
to late morning tomorrow.

A very moist airmass remains in place across the region, with PW
values near 2 inches. As temperatures warm into the upper 80s and
lower 90s this afternoon, the airmass will continue to
destabilize, with MLCAPEs ranging between 1500 and 2000 J/kg. This
combined with deep layer shear between 30 and 40 knots will
support some strong to locally severe storms into the early
evening hours before the low levels stabilize. The main severe
hazard will be strong winds gusts over 60 mph and hail up to i
inch in diameter. In addition to the severe threat, heavy rainfall
and a threat for localized flooding will also be a concern.
Precipitation will gradually diminish late tonight, with some
lingering showers/isolated storms south of I-20 during the morning
hours. A cooler airmass, coupled with mostly cloudy skies, will
result in below normal temperatures tomorrow. Afternoon highs will
be mainly in the mid and upper 70s, although a few lower 80s are
possible along the I-10 corridor.

&&

.LONG TERM...
(Monday night through next Sunday)
Issued at 159 PM CDT Sun Sep 22 2024

...Cool and wet pattern through Wednesday with drier and warmer
conditions expected by the end of the work week...

Overnight Monday into Tuesday, the upper level shortwave trough
associated with the primary cold front will exit off to our
northeast, leaving our area in brief zonal flow. Some HREF members
are picking up on convection forming across our central counties
as an embedded shortwave impulse tracks across the area. Have
capped PoPs during this timeframe in the chance category as
certainty with this development is limited but still possible as
the earlier cold front is not expected to scour out any moisture
(as shown by forecasted PWats in the 1.4+ inches range). The
better chances for showers and storms look to come later in the
day on Tuesday into early Wednesday. An upper low is expected to
drop south out of the Northern Great Plains and into the Central
Plains/Mid Mississippi Valley. This will send another upper level
trough axis through the region. An attendant cold front is also
expected to swing south through the area during this Tuesday/early
Wednesday timeframe. The NAM and many of the European ensemble
members seem set on a potentially wet frontal passage with the GFS
ensemble members painting a much drier picture. Will keep with
the blended solution for now, showing chance PoPs mainly through
12Z Wednesday. Any convective activity looks to wane through the
day on Wednesday as the front continues to push well south and
east of our area. With the rain chances and continued high amounts
of moisture across the area, temperatures will remain fairly
consistent Tuesday and Wednesday with highs in the upper 70s to
mid 80s and lows in the upper 50s to mid 60s.

Models seem to be in good agreement that much drier air will
begin to filter in at the surface behind the cold front Wednesday,
leading to a dry pattern for the end of the work week and
weekend. Surface flow will generally stay out of the north through
this timeframe, limiting moisture return. The aforementioned
upper low is expected to become cut-off from the main flow during
this timeframe and will stay in the general vicinity of the
Southern Plains. How the track of the potential tropical system
across the gulf impacts this remains to be seen but consensus for
now is that we will stay to the west of the low in an area of weak
subsidence. High temperatures for the late week/weekend timeframe
will be on a steady upward trend as the 850 mb thermal ridge
begins to slowly work its way back into the area. Daytime highs
will approach 90 degrees again by the weekend. Overnight lows are
expected to be on the cool side in the mid 50s to low 60s.

&&

.AVIATION...
(06Z TAFS)
Issued at 1231 AM CDT Mon Sep 23 2024

SHRA and TSRA continue to affect the KABI area. Farther south,
much less coverage of SHRA with no TSRA currently. Will continue
at least VCSH for southern terminals, but confidence is lower in
better coverage of TSRA farther south given the current trends.
Still expect CIGs to deteriorate into MVFR, and likely IFR between
now and 12Z at all sites. Expect these ceilings to then improve
gradually throughout the day tomorrow, with most sites back in the
VFR category by 00Z or a couple hours earlier. Winds will be out
of the north at all sites within the next hour or so, and should
remain northerly at 10 knots or less through 00Z Monday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene     75  62  86  64 /  30  40  40  40
San Angelo  77  64  87  66 /  40  30  40  30
Junction    83  66  88  65 /  30  10  40  30
Brownwood   78  64  86  63 /  40  30  50  40
Sweetwater  75  63  86  65 /  30  30  30  30
Ozona       78  65  86  65 /  40  20  20  20
Brady       78  65  86  65 /  40  30  40  30

&&

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

$$

SHORT TERM...24
LONG TERM....50
AVIATION...20