Area Forecast Discussion
Issued by NWS San Angelo, TX

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FXUS64 KSJT 191131 AAA
AFDSJT

Area Forecast Discussion...UPDATED
National Weather Service San Angelo TX
631 AM CDT Fri Apr 19 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 259 AM CDT Fri Apr 19 2024

In the wake of yesterday and early last night`s cold frontal
passage, temperatures will be much cooler today with considerable
cloudiness and northeast winds. Numerical guidance differs with the
highs today by 10-14 degrees across much of our area. Leaning toward
the cooler side of guidance and going with highs in the lower to mid
60s across the Big Country, 65-70 in our central counties, and in
the lower to mid 70s for the southern part of our area.

An upper shortwave trough will approach the Desert Southwest today,
with some indication of an embedded wave ahead of it moving into the
Big Bend area this evening. The approach of this initial wave
will bring may bring a low chance of showers and thunderstorms to
the southwest part of our area (mainly the Northern Edwards Plateau)
late this afternoon and evening.

The primary shortwave trough will move east to the Arizona/New
Mexico border by daybreak Saturday, with the possibility of the
initial wave overspreading our area overnight. The bulk of our
area will have a low to medium chance (30-40 percent) of showers
and thunderstorms early tonight, but the main focus looks to be in
the northern third to half of our area overnight. With isentropic
lift and precipitable water values increasing to 1 to 1.5 inches,
some of the hi-res models indicate elevated convection developing
and quickly increasing in coverage over the northern third to
half of our area late tonight. The main thunderstorm threat will
be lightning, but small hail will also be possible with some of
the storms. Heavy rain will be possible and some areas may
receive over an inch of rainfall by 7 AM Saturday. Cloud cover
will be widespread tonight and overnight lows are expected to
range from the upper 40s to lower 50s in the Big Country, to the
lower 60s south of I-10 and in our far southeastern counties.

&&

.LONG TERM...
(Saturday through Thursday)
Issued at 551 AM CDT Fri Apr 19 2024

...Heavy Rainfall Possible Saturday and Saturday Night...

The main concern in the medium term is the heavy rain possible
for parts of the area on Saturday. A cooler airmass will be well
established across west central Texas with temperatures in the
50s. Plenty of moisture should advect in from the Gulf of Mexico
and overrun the cooler airmass in place. Meanwhile, a mid-level
trough will move in from the Desert Southwest and provide
additional lift to support more widespread showers and
thunderstorms. PWAT values look to be between 1 and 1.5 inches.
The latest QPF from WPC shows anywhere from a half-inch of rain to
around one and a half inches. The heaviest rainfall amounts look
to be across the Big Country, where mid-level moisture is likely
to be in phase with the 700mb trough axis. Some elevated
instability will exist, which would result in strong thunderstorms
that could produce locally heavier rainfall. As a result, WPC has
placed much of west-central Texas in a Marginal to Slight Risk
for Excessive rainfall for Saturday through Saturday night.

By Sunday morning, the mid-level trough axis will have pushed
through the area to east Texas.  This should bring rain chances to
an end, although cloud cover and cool conditions should still remain
in place as a surface high settles in.  For Monday and Tuesday of
next week, the surface high will move eastward and generate
southerly return flow.  Skies will clear out and temperatures should
warm back up into the 70s and 80s through Wednesday.

By mid-week, models show the potential for another frontal boundary,
this one much weaker, to drop into north Texas.  This could generate
more chances for localized showers and thunderstorms north of I-20.
However, this could end up stalling north of the region due to an
upper-level ridge attempting to build in at the same time, so
these features will be monitored over the weekend.

&&

.AVIATION...
(12Z TAFS)
Issued at 630 AM CDT Fri Apr 19 2024

Low cloud cover has become widespread over our area early this
morning, with MVFR ceilings. Considerable cloud cover will persist
through the day today, but ceilings should climb above 3000ft by
late morning or early afternoon. Winds will be mainly from the
northeast at 10-15 knots this morning, decreasing to 7-10 knots
during the afternoon. For early tonight, the area will have a
chance of showers and thunderstorms, but confidence in the
occurrence at any particular TAF site is too low to include
at this time. Late tonight, showers and thunderstorms are
expected to develop and quickly increase in coverage across the
northern third to half of our area. The KABI site is the most
likely to be affected, but the convection may extend as far south
as San Angelo. Carrying VCTS at KABI after 09Z, with VCSH at our
other TAF sites overnight. Outside of the convection, low cloud
cover is expected to develop and expand in coverage overnight.
Generally expecting IFR ceilings. Visibility reductions will be
possible where locally heavy rain occurs.

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene     66  53  58  44 /  10  70 100  80
San Angelo  70  58  66  46 /  10  50 100  60
Junction    75  61  74  48 /  10  40  90  70
Brownwood   68  58  64  46 /   0  70 100  90
Sweetwater  63  51  56  44 /  10  80 100  70
Ozona       71  60  68  47 /  20  50  90  50
Brady       71  60  67  47 /  10  50 100  90

&&

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

$$

SHORT TERM...19
LONG TERM....SK
AVIATION...19


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