Area Forecast Discussion
Issued by NWS San Angelo, TX

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432
FXUS64 KSJT 021918
AFDSJT

Area Forecast Discussion
National Weather Service San Angelo TX
218 PM CDT Thu May 2 2024

...New SHORT TERM...

.SHORT TERM...
(This evening through Friday)
Issued at 217 PM CDT Thu May 2 2024

...Severe weather possible today and tomorrow...

A surface low is currently located just to our northwest, with a dry
line across out western most counties and a cold front moving in
from the north. Storms are expected to form later this afternoon and
evening near the low, where the dry line and front interact. Most
models have storms developing in the Big Country starting around 4
this afternoon and continuing overnight. We are seeing some cumulus
development in Nolan County, which could be a precursor for
thunderstorms in the next couple of hours. The majority of models
show most of the activity staying in the Big Country, Heartland, and
northern Concho Valley, with a few storms finding their way into the
our southern counties. Instability will be very high this afternoon
(4000+ J/Kg possible) and wind shear values will be sufficient for
severe development. With the instability as high as it is, storms
could very quickly become severe once they develop and outflow
boundary`s could trigger new storms. The main threat today will be
large hail (2+ inches), but damaging winds and an isolated tornado
are also possible. Localized flooding will also be possible with
these storms, as rain amounts could exceed 2 inches under isolated
storms.

Tomorrow will be slightly cooler for the Big Country, as the cold
front keeps winds from the north and east for the start of Friday.
Winds will return back to the southeast for much of the area and the
dry line will retreat westward again, leaving us with dewpoints in
the 60s and 70s. CAPE values could be in excess of 3000 J/Kg by the
late afternoon. Weak convergence on any residual boundaries and an
upper level disturbance aloft could be enough to produce storms in
the late afternoon. CAMs are differing on coverage for tomorrow. The
HRRR is bringing much more widespread activity, with storms
developing to the west and moving into the area. With the large
instability and sufficient shear, any storm that develops could
produce very large hail, strong winds, and possibly a tornado.&&

.LONG TERM...
(Friday through Wednesday)
Issued at 343 AM CDT Thu May 2 2024

Friday could see another round of dryline development. With our
area in continued southwest flow aloft and on the fringe of the
southern stream jet, guidance is indicating the potential for a
shortwave to pass overhead during the afternoon hours. This would
likely provide enough upper level support to see development off
of a quasi-dryline likely somewhere near our western CWA border.
Southeasterly surface winds through the day will help to moisten
the boundary layer across the area leading to MLCAPE values
between 2500-3500 J/kg. Shear will be similar to previous days in
the 25-35 kt range with mid level lapse rates right around 8 deg
C/km. SPC has the Day 2 Marginal ending just north of our area in
the Caprock, if guidance continues to trend the way it has with
the shortwave passage, would not be surprised if this is extended
further south in future updates. The main threats would likely be
large hail and damaging winds. Current indications are that these
storms would move off to the east fairly quickly with the threat
tapering off after midnight.

By Saturday, a frontal boundary is expected to stall just north
of our area. Storms will be possible along the front earlier in
the day, keeping rain/storm chances in play for northern areas of
the Big Country Saturday morning. However, as the boundary layer
heats up and destabilizes through the day, more diurnal activity
is expected to develop across the area with yet another potential
shortwave passing overhead. Later in the day, an easterly low
level jet is expected to develop, helping shower and storm
activity to become more widespread, potentially developing into an
MCS type feature. With ample instability in place and steep lapse
rates, some storms could become severe, especially across the Big
Country and western Concho Valley where the Day 3 Marginal Risk
for severe storms is located. As activity becomes more widespread
Saturday afternoon through Sunday morning, this looks to be the
best timeframe to see heavy rainfall leading to flash flooding. As
such, WPC has put the Big Country, Concho Valley, and Heartland
in their Slight Risk (Level 2 of 4) for excessive rainfall with
the rest of the area in Marginal (Level 1 of 4). The highest
rainfall totals will likely be in the Big Country, closer to the
frontal boundary. With the weak frontal boundary still in the
region for Sunday and southwest flow continuing aloft, we will see
continued chances for showers and storms through the day before
coming to an end overnight into Monday morning. High temperatures
through the weekend will generally stay in the upper 70s to 80s.

A large upper trough is expected to move north of our area during
the day on Monday. As a dryline pushes east into our area during
the day, upper level support may be strong enough to warrant a
chance of showers and storms across our northeastern counties
between 18-00Z. Better chances will stay well to our north though,
closer to the negatively tilted trough axis. Behind the dryline,
skies will begin to clear and winds will pick up out of the west.
This dry, downsloping air will help to warm temperatures into the
lower 90s for the Concho Valley and Northern Edwards Plateau.
Elsewhere should see highs in the mid to upper 80s. The dryline is
overall expected to make little retreat to the west overnight and
will push even further east on Tuesday and Wednesday. This should
keep our area dry and allow for temperatures to reach well above
average into the 90s, even the mid and upper 90s for areas south
of the I-20 corridor. CPC has our area highlighted in their 8-14
day Slight Risk for Excessive Heat for May 9-11 so unfortunately
it looks like the heat will be sticking around through the end of
next week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1232 PM CDT Thu May 2 2024

Skies are clearing from west to east, lifting MVFR CIGs to VFR
over the next hour or so. Storms are possible later this afternoon
and overnight. Exact location of the storms is uncertain, KABI has
the best chance of seeing storms this evening, but the other sites
could have a nearby thunderstorm as well. Gusty winds, lighting,
and hail will likely accompany these storms. Low clouds will move
in overnight, dropping CIGs to MVFR and IFR.

&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene     63  82  64  81 /  40  40  40  70
San Angelo  64  90  64  87 /  10  40  30  60
Junction    67  90  66  89 /  20  30  20  40
Brownwood   63  83  66  81 /  50  30  40  60
Sweetwater  62  84  63  80 /  20  40  40  80
Ozona       66  89  64  84 /  10  40  30  40
Brady       64  84  66  83 /  30  30  30  50

&&

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

$$

SHORT TERM...AP
LONG TERM....50
AVIATION...AP