806
FXUS64 KEWX 180122
AFDEWX

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

...New UPDATE...

.UPDATE...
Issued at 816 PM CDT Sat May 17 2025

The Severe Thunderstorm Watch has been cancelled for most locations
except for the counties immediately along the Rio Grande where
storms across Mexico may still try to make a run for the border. No
additional development is expected elsewhere. I have adjusted the
PoPS according to the latest trends. There is still a low end rain
chance that could reach into as far east as Bexar and Atascosa
counties later tonight with any possible anvil remnants.

&&

.SHORT TERM...
(Tonight through Sunday night)
Issued at 125 PM CDT Sat May 17 2025

Key Messages:

- Level 1 to 2 out of 5 risk for isolated to widely scattered severe storms
  this afternoon and evening across the Rio Grande, southern Edwards
  Plateau, Hill Country, and portions of the I-35 corridor

- Hot and humid conditions continue through Sunday with elevated heat
  index values

Hot and humid conditions will continue through the short term. A
dampening mid and upper level shortwave in the southwest flow aloft
will assist with convective initiation this afternoon along the dry
line. We have recently seen this briefly take place in the higher
terrain of Mexico as well as just north of the region across the
Edwards Plateau. Discrete convection should continue to sustain
itself once peak heating is reached 2-4 PM, with isolated supercells
possible and some indications of splitting supercells along the Rio
Grande by HREF members. Some smaller clusters of storms are
indicated to develop into the late afternoon and early evening hours
across the Rio Grande and Winter Garden, southern Edwards Plateau,
Hill Country and Central Texas. Instability and shear parameters are
favorable for isolated severe storms capable of producing very large
hail through these regions along with damaging wind gusts. SPC has
placed these regions in a Level 2 out of 5 risk for severe storms.
There are some uncertainties on how quickly weakening will take
place after sunset as the widely scattered storms approach the I-35
corridor and convective inhibition begins to increase. This
uncertainty is realized in the spread of coverage and intensity
solutions in the HREF members. There is currently a Level 1 out of 5
risk for severe storms for the I-35 corridor this evening.

Eventually storms should weaken and dissipate late evening, with
stratus re-developing overnight. In addition, like this morning we
could see some haze around again Sunday morning. This is associated
with the agricultural burning going on in Mexico that is typical for
this time of year. Tomorrow`s convective focus along the dry line
should be mainly just north of the area, although a isolated, tail-
end storm could clip the northern Hill Country and souther Edwards
Plateau. Continued hot and humid.


&&

.LONG TERM...
(Monday through Saturday)
Issued at 125 PM CDT Sat May 17 2025

Key Message:

- Rain potential trending down in the medium range, a couple milder
  weather days are in store for mid-week.

Tuesday was shown as another potential storm day in earlier model
cycles, but has since trended with the better chances farther east.
Thus have cropped back to our eastern border for Tuesday as the
latest NBM suggests. Tuesday`s winds are still shown as light post-
frontal with some downsloping, so the cool front will not have much
potential to ease of the temperatures, but cold at least lower the
evening RH for some light relief. Wednesday will get a better crack
at the high temperatures with the low overnight dewpoints allowing
the day to start off with min temps in the low to mid 60s over the
northern half of the area. The southern tier of counties may not
experience as much moderation on the maxes Wednesday, but they should
at least get the heat index back "down" to the mid 90s to 102. A
continental NE low level wind will continue through Wednesday,
leading to another pleasant morning low temp near the seasonal
normal. Unfortunately the dry air intrusion, while making the weather
more pleasant, comes at a bad time, because there will be some weak
vorticity coming over TX in weak zonal flow for late Wednesday into
Thursday. Some isolated PoPs are peppered in for the period Wednesday
night through Thursday evening, but we could be looking at some
light elevated or virga type activity. A building shortwave ridge
aloft moves back into TX suppress convection by the time the Gulf
moisture fetch becomes established Friday into next weekend.

&&

.AVIATION...
(00Z TAFS)
Issued at 609 PM CDT Sat May 17 2025

The latest observation trends show that anvil rain, and perhaps a
storm could impact KDRT the first few hours of the TAF period. The
probabilities for storm activity at the other sites has lowered and
confidence doesn`t remain enough to keep the PROB30 groups. Some
anvil rain and clouds may spread to near KSAT and KSSF from around
02Z to 06Z. Otherwise, low clouds with MVFR to IFR ceilings will
develop overnight and continue into Sunday morning. VFR conditions
return to all sites by the afternoon. Breezy south-southeasterly
winds establish at the I-35 terminals (KAUS, KSAT, and KSSF) with
gusts into the 25 to 30 kt range. Winds will trend lighter and more
east-southeasterly at KDRT with closer proximity to the dryline.

&&

.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              76  95  76  96 /  10  10  10  20
Austin Bergstrom Intl Airport  76  96  76  97 /  10  10  10  20
New Braunfels Muni Airport     76  96  76  97 /  10  10   0  10
Burnet Muni Airport            73  93  73  93 /  10  30  10  30
Del Rio Intl Airport           79 102  80 104 /  20  10  10   0
Georgetown Muni Airport        75  95  75  95 /  10  20  10  30
Hondo Muni Airport             75  98  76 101 /  20  10  10  10
San Marcos Muni Airport        76  96  76  97 /  10  10   0  20
La Grange - Fayette Regional   77  94  77  93 /  10   0   0  10
San Antonio Intl Airport       77  97  77  99 /  20  10  10  10
Stinson Muni Airport           78  98  78 100 /  20  10   0  10

&&

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

$$

Short-Term...Brady
Long-Term...18
Aviation...Brady