799
FXUS64 KEWX 081147
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
647 AM CDT Wed May 8 2024

...New AVIATION...

.SHORT TERM...
(Today through Thursday)
Issued at 236 AM CDT Wed May 8 2024

Temperatures will warm to well above normal today across all of
south central Texas with highs ranging from 100 to 105 degrees along
the Rio Grande with 90s elsewhere. Our current forecast calls for
103 degrees at Del Rio, which would tie the existing high
temperature record. Heat Index values across our coastal plains
counties may briefly approach 108 degrees in a few spots this
afternoon. We will opt to issue a Special Weather Statement for our
coastal plains counties from Atascosa eastward to Lavaca county to
cover the elevated heat index values today. With this heat coming a
little early in the season, it will be important to practice heat
safety precautions today. The other item of concern for today is the
potential for isolated storms to develop across portions of the Hill
Country into the nearby I-35 corridor, mainly from Burnet county
eastward into Williamson county. Forecast soundings generally show
the mid-level capping inversion will remain strong today thus
limiting the potential for storms to develop. In addition, models
keep a fair amount of high clouds today and this may limit heating
as the dryline mixes eastward. If storms manage to break the cap,
they would likely be severe given adequate shear and impressive
instability. We will keep some low pops in the forecast, but below
mentionable values. If 12Z guidance trends weaker with the cap, the
forecast will need to be updated to mention thunderstorm chances
over portions of the Hill Country and adjacent I-35 corridor. The
dryline retreats westward tonight keeping most of the region in a
warm and humid air mass. Expect warm overnight lows in the upper 60s
to upper 70s.

On Thursday, the pattern is expected to become active as the dryline
mixes eastward during the afternoon and interacts with a cold front
moving southward across north Texas. Daytime heating along with some
weak upper disturbances embedded in the southwest flow aloft should
be enough to initiate convection in the vicinity of the dryline and
front intersection, with hi-res guidance favoring initial
development across San Saba/Mason/Llano counties during the late
afternoon. Convection will then likely continue to develop along the
southward moving cold front across the remainder of the Hill Country
and I-35 counties, mainly near/north of San Antonio through the
early evening hours. Large to very large hail and damaging winds are
the main severe weather concerns. SPC has upgraded the severe threat
to Enhanced (level 3 of 5) for areas along and north of a Llano to
Austin line. The Slight to Marginal risk areas extends farther south
to near a Rocksprings to San Antonio to Hallettsville line. It will
be very warm again on Thursday, especially out west along the Rio
Grande behind the dryline where highs of 103 to 106 degrees are
forecast. The record high for Del Rio will likely be met or
exceeded. We will need to keep an eye on San Antonio as well, but
will likely end up a couple degrees shy of the record. Austin looks
safe as record highs were set back in the heat wave of 2011.

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 236 AM CDT Wed May 8 2024

Synopsis:

On Thursday night, storms should have come to an end, but
it`s possible some lingering strong to severe storms may still be
around after sunset Thursday. An upper level low situated over the
Four Corners will remain in place through the first half of the
weekend, eventually ejecting out over the southern Plains on Sunday.
Once this storm system moves out over the Plains, we should see some
drier and warmer weather return by the beginning to middle of next
week.

Thursday Night-Friday:

A strong cold front by early May standards will move through South
Central Texas Thursday night, bringing cooler and drier air into the
region after several abnormally hot and humid days. Winds may be
quite gusty at times, but a wind advisory is not expected. Winds
will remain northeasterly through the day Friday, keeping
temperatures some 5-10 degrees below normal for early May, and
falling some 10-20 degrees from highs on Wednesday and Thursday.

Saturday-Sunday:

The upper-level trough ejects out over the southern CONUS late
Saturday, and with easterly surface flow resulting in rapid
moistening of the overall atmospheric profile, showers and
thunderstorms are expected to develop late Saturday and persist
through Sunday afternoon before moving eastward by Monday afternoon.
Sunday will likely be the coolest day of the week, with highs in the
lower 70s over the Hill Country and portions of the I-35 corridor.
As far as the severe threat goes, severe storms are not anticipated,
however, continue to monitor the forecast over the next several days
for any possible changes.

Monday-Wednesday:

A steady warming trend is expected as we edge closer to normal highs
for early to mid May. Uncertainty in the overall upper-level pattern
will lead to low end PoPs through the remainder of the long term
period.

&&

.AVIATION...
(12Z TAFS)
Issued at 641 AM CDT Wed May 8 2024

Low clouds continue with IFR to continue along I-35 for the next
several hours, with upper end MVFR at DRT. Rapid improvement is
expected at DRT after 15Z as dry, northwest winds move in and begin
to mix out the shallow cloud deck. MVFR cigs will linger through the
morning and into early afternoon along I-35. We do expect clouds to
lift and scatter back to VFR between 18-19Z. Low clouds will develop
once again by late evening with MVFR returning to the I-35 sites
between 04-05Z. We will not mention any return of MVFR at DRT just
yet as there is any chance for cigs may be very late in the current
forecast period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              93  74  90  68 /   0   0  30  10
Austin Bergstrom Intl Airport  91  73  90  68 /   0   0  30  10
New Braunfels Muni Airport     95  73  93  69 /  10   0  20  10
Burnet Muni Airport            91  70  87  65 /  10   0  30  10
Del Rio Intl Airport          104  72 106  72 /   0   0   0  10
Georgetown Muni Airport        90  72  88  66 /  10   0  30  10
Hondo Muni Airport             98  70  98  69 /   0   0  10   0
San Marcos Muni Airport        92  72  91  68 /   0   0  20  10
La Grange - Fayette Regional   91  74  90  70 /   0  10  20  10
San Antonio Intl Airport       95  74  94  70 /   0   0  10  10
Stinson Muni Airport           97  74  95  71 /   0   0  10  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Short-Term...Platt
Long-Term...MMM
Aviation...Platt