785
FXUS64 KEWX 171740
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1240 PM CDT Sat May 17 2025

...New AVIATION...

.SHORT TERM...
(Today through Sunday)
Issued at 1208 AM CDT Sat May 17 2025

Key Messages:

- Hot conditions continue today with elevated heat index values over
portions of South Central Texas.
- Low to medium chances for isolated or widely scattered strong to
severe thunderstorms this afternoon and evening.

Thunderstorm activity has ended early this morning with only some
lingering light showers in the west associated with the decaying
storms. Showers will end well before sunrise with dry conditions
expected the rest of the morning. Overcast skies have begun to build
over the area allowing for another morning of warm lows in the 70s
to right around 80 degrees for some locations along the Rio Grande.
A few locations may also see patchy fog, mainly along and east of
the I-35 corridor.

Not to sound like a broken record, but another hot day is in store
for this afternoon. Highs will peak in the mid to upper 90s for most
of the southern Edwards Plateau, Hill Country, I-35 corridor and
coastal plains. Along the Rio Grande, highs will likely be in the
triple digits from around 100 to 105 degrees. As with previous days,
dewpoints remain elevated allowing for heat indices from around 103-
107 over the I-35 corridor and coastal plains and up to 111 over the
Rio Grande Plains. Opted to go without a Heat Advisory given the
majority of locations look to stay below criteria, though would not
be surprised if some isolated spots hit their thresholds. Heat
safety measures should continue to be taken into early next week
given the forecast.

Additionally, this afternoon and evening there are low to medium
chances for strong to severe thunderstorms, mainly across the Rio
Grande, southern Edwards Plateau and Hill Country. Storms are
expected to form ahead of the dryline, but coverage could be
isolated or widely scattered for our area with decent model
uncertainty on exactly where they will form. That said, any storm
that does form could quickly become severe with large to very large
hail and damaging wind gusts the main hazards. Activity should drop
off with the loss of heating with drier conditions expected
overnight.

Lows tonight will depend on where storms form, but will generally be
on the warm side again. Highs Sunday will be similar to those of
today. Sunday afternoon should be mainly dry with only some low
precipitation chances in the far northern Hill Country.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 1208 AM CDT Sat May 17 2025

Key Messages:

- Record breaking heatwave and heat related impacts continues with
  additional temperature records likely being broken Monday and
  possibly Tuesday.

- Chances for showers and storms Tuesday with arrival of a cold
  front though confidence of timing and strength is low.

The early record breaking heat continues Monday though air temperatures
start slowly decreasing but the feels like remains in the 100-110
degree range through Tuesday. Several weak disturbances move into the
region thus possibly limiting just how high actual air temps can go
due to the increased moisture and abundant cloud cover. However, the
increased moisture could actually cause our heat indices to be even
warmer then what we have currently forecast, definitely something to
watch for. One of these disturbances will impact our area late
monday night as a shortwave moving through the southern Plains looks
to send the dry line back east into the Hill Country and I-35
corridor into Tuesday, with a cold front eventually overtaking it
Tuesday night. Confidence continues to remain low as models
generally have a difficult time with such small scale features. The
best chances still look to be along and West of the I-35 Corridor.

Regarding temperatures the cold front mentioned prior could bring
some temporary relief from the heat for Wednesday and Thursday,
however confidence in the strength and position is low at this time.
Regardless, temperatures will remain well above normal through the
end of the forecast period with high temperature records likely to be
tied or broken through Tuesday. Towards the end of the long term,
temperatures cool somewhat into the low 90s vs the upper 90s/100s
that we previously have been seeing. Please make sure you and your
loved ones have a way to stay cool during this early season heatwave.
Additional heat safety information and resources can be found at the
following websites:
www.heat.gov and www.weather.gov/safety/heat

&&

.AVIATION...
(18Z TAFS)
Issued at 1240 PM CDT Sat May 17 2025

Stratus continues to erode across the area, and remaining locations
at MVFR should become VFR over the next hour with scattered CU field
through the remainder of the day. Haze across the region is producing
visibilities around 6 miles.

Later this afternoon we will be watching for convective initiation
to the north and west, around 20Z. Initially isolated TSRA activity
is forecast to develop along and northwest of a DRT-AQO line,
becoming widely scattered 22Z-00Z through the Hill Country and along
the Rio Grande. Isolated severe storms, producing large hail and wind
gusts >50KT, are possible. This widely scattered activity could
reach the I-35 corridor, in a weakening state, 00Z-04Z, before
dissipating overnight. MVFR ceilings and visibilities re-develop
overnight and Sunday morning with stratus and haze

&&

.CLIMATE...
Issued at 236 PM CDT Fri May 16 2025

RECORD MAX TEMPERATURES SATURDAY THROUGH TUESDAY
(* TIED RECORD WITH MOST RECENT OCCURRENCE SHOWN)

         SAT       SUN       MONTUE
        05/17     05/18     05/19   05/20
----------------------------------------------
AUS    97/2018   97/2022   97/2006  99/2008
ATT    99/2022   98/2022   98/2022* 101/2008
SAT   100/2022  101/2022  101/1989 100/1996
DRT   105/2013  107/2024  108/2020 105/1973

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              75  97  75  97 /  20  10   0  20
Austin Bergstrom Intl Airport  74  97  75  97 /  20  10   0  20
New Braunfels Muni Airport     75  98  75  98 /  20   0   0  10
Burnet Muni Airport            73  95  73  93 /  20  20  10  30
Del Rio Intl Airport           78 103  78 104 /  20  10  20   0
Georgetown Muni Airport        73  96  73  95 /  20  10  10  30
Hondo Muni Airport             73 100  74 100 /  20   0  10  10
San Marcos Muni Airport        74  97  74  97 /  20   0   0  20
La Grange - Fayette Regional   76  95  76  94 /  10   0   0  10
San Antonio Intl Airport       75  98  76  98 /  20   0   0  10
Stinson Muni Airport           76  99  76 101 /  20   0   0  10

&&

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

&&

$$

Short-Term...27
Long-Term...CJM
Aviation...76