609
FXUS64 KSJT 212334
AFDSJT

Area Forecast Discussion
National Weather Service San Angelo TX
634 PM CDT Sat Sep 21 2024

...New AVIATION...

.SHORT TERM...
(This evening through Sunday)
Issued at 246 PM CDT Sat Sep 21 2024

...Cold front arrives tomorrow afternoon and evening, with showers
and thunderstorms developing...

The main item of interest the next 24 hours will be the arrival
of a weak cold front later tomorrow afternoon and evening and
increasing rain chances. An upper level shortwave will be
situated across the central and southern Rockies by tomorrow
morning and will track east into the Plains by tomorrow afternoon.
At the surface, an associated cold front will drop south across
the area tomorrow afternoon and evening. Showers and thunderstorms
are expected to develop along the front as it tracks south across
the area, with the best chance for rainfall tomorrow afternoon
from the Concho Valley northward into the Big Country. The airmass
will be plenty moist, with precipitable water values near 2
inches, which will contribute to heavy downpours and a threat for
localized flooding. As was previously mentioned, widespread
severe weather is not anticipated, but marginal instability and
shear will support a few strong to locally severe storms capable
of producing damaging winds and large hail during the afternoon
and early evening hours. Temperatures will be mild tonight,
along with some low clouds develop towards daybreak, with
overnight lows in the low to mid 70s. Highs tomorrow will be in
the upper 80s and lower 90s, although cooler temperatures will
begin filtering in behind the front across the Big Country by
late afternoon.

&&

.LONG TERM...
(Sunday night through next Saturday)
Issued at 153 PM CDT Sat Sep 21 2024

...Rain chances and cool temperatures to continue through
Wednesday. Drier with a slow warming trend expected Thursday into
the weekend...

An upper low over Colorado is expected to open into a trough as it
moves into the Central Great Plains late Sunday into Monday. This
will put our area in the troughing regime with an upper high
generally located to our southeast along the Texas Gulf Coast. At
the surface, a cold front will be pushing into our area with showers
and storms ongoing by 00Z Monday. The front will progress through
most of the area by 12Z Monday. There is expected to be a lull in
activity for much of day on Monday as the front slowly retreats back
to the north and zonal flow aloft prevails. Isolated to scattered
chances for precipitation remains as an embedded shortwave impulse
aloft cannot be ruled out. Convective activity begins to ramp back
up Tuesday as a weak secondary trough is expected to develop just to
our north and west with the frontal boundary still in our general
area. Moisture will still be abundant with above normal pWats across
the area in the 1.4+ inch range. This activity will not be as
focused along the front (as compared to Sunday) and is expected to
be more scattered in nature leading to widespread chance PoPs
through early Wednesday. As the surface forcing begins to weaken
across our area with the front pushing south, activity will become
more nebulous and should eventually come to an end by late
Wednesday. Temperatures during this timeframe will be well below
normal for this time of year with highs Monday and Wednesday being
the coolest in the mid 70s to low 80s. Highs Tuesday will be a bit
warmer with the front drifting back north in the low to mid 80s.
Overnight lows will be cool in the upper 50s to mid 60s.

Uncertainty in the upper pattern begins to take shape later in the
week. Mid range models tend to agree that an upper low will drop out
of the Upper Plains and Midwest by late Wednesday into Thursday and
should stall out. Where exactly the low stalls out remains a point
of contention. The general consensus though is that much drier air
will filter in behind the cold front Wednesday and that West Central
Texas will be on the backside of this upper low in an area of
greater subsidence. Most ensemble members of both the GFS and ECMWF
keep our area free of precipitation from Thursday through next
weekend. We will see a gradual warming trend, largely due to the 850
mb thermal ridge slowly working its way back into our area as we
will still be seeing a dry northerly wind at the surface. Highs will
be in the low to mid 80s with overnight lows getting slightly cooler
in the mid 50s to low 60s.

&&

.AVIATION...
(00Z TAFS)
Issued at 623 PM CDT Sat Sep 21 2024

MVFR stratus returns to KJCT and KSOA late tonight and spreads
north to KSJT and KBBD towards morning, Thunderstorms possible
Sunday afternoon at KABI and KSJT as a cold front approaches. KSJT
will see thunderstorms potential mainly after 21Z. Storms may
briefly produce IFR visibilites/MVFR ceilings in heavy rainfall
and strong winds as they move through.


&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene     73  89  58  77 /   0  60  70  20
San Angelo  73  91  61  78 /   0  50  80  30
Junction    70  91  65  83 /   0  10  40  30
Brownwood   71  92  63  80 /   0  20  50  30
Sweetwater  74  87  58  77 /  10  70  70  20
Ozona       72  88  63  78 /   0  30  70  40
Brady       70  91  64  79 /   0  20  50  30

&&

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

$$

SHORT TERM...24
LONG TERM....50
AVIATION...04