Severe Thunderstorm Warning 43, NWS Austin/San Antonio, TX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
726 PM CDT Sat Apr 18 2026

...New AVIATION...

.KEY MESSAGES...

- Scattered showers across South-Central Texas through Sunday
  morning, mostly light but with a few isolated thunderstorms
  mainly late afternoon today into the overnight hours.

- Gusty conditions will gradually lessen tonight.

- Cool weather continues into mid-week with moderate chances for
  rain through Wednesday.

&&

.SHORT TERM...
(Tonight through Sunday night)
Issued at 143 PM CDT Sat Apr 18 2026

A strong mid-April cold front has now swept across the entirety of
South-Central Texas, with temperatures cooling substantially on a
breezy north wind. Most have avoided measurable precip so far, but
areas will start to fill in with mostly light stratiform showers
today. We expect to see an uptick in convective activity with some
lightning in the late afternoon into the evening as mid-level ascent
ripples north to south through the area. A stronger storm or two
could be capable of producing some small hail as temperatures aloft
cool, but most of these deeper storms will be non-severe and mainly
pose an intermittent lightning risk to outdoor activities with
that risk peaking in the evening and early part of the night. The
area of showers and storms will gradually ease tonight with most
activity clearing out by sunrise Sunday. Overall rainfall amounts
will tend to be light relative to coverage given the high-based,
cooler nature of the rains... from a few hundredths of an inch to
about a quarter inch for most, and some isolated pockets of a 1/2
to 1 inch. Those marginally higher amounts are more likely over
the Coastal Plains.

Temperatures will continue to fall throughout the day into the
night. Residual post-frontal cloudiness will prevent more aggressive
cooling, but lows tonight should settle into the mid-40s to low-50s
with the coldest temperatures in the northern Hill Country and north
of the Austin area. Winds will gradually ease through the night with
gusts dropping below 25 mph for most, but it won't be until Sunday
afternoon that the enhanced post-frontal winds settle down more
fully.

Sunday is shaping up to be a tale of two halves of the region. For
areas generally north of I-10 or east of I-37, the day trends
sunnier and drier, allowing highs to reach the low 70s. To the west
and south across the Rio Grande Plains, a resurgent flow of
southerly winds aloft forces mid-level moisture back into the area.
This will keep an overcast in place along with light showers and
sprinkles, with a low chance of some rumbles of thunder. Those
clouds will also keep temperatures along the Rio Grande in the upper
50s to mid 60s Sunday afternoon. The area of light rains should inch
closer to the US-281 and I-35 corridors Sunday evening and
overnight. Lows Sunday night into Monday morning are forecast to be
in the 50s throughout South-Central Texas.

&&

.LONG TERM...
(Monday through next Saturday)
Issued at 143 PM CDT Sat Apr 18 2026

Despite the presence of a broader upper-level ridge moving over
Texas during the first half of the upcoming workweek, a mid-level
shortwave disturbance is forecast to slowly drift out of Mexico on
Monday before slowly making its way about Texas through Wednesday.
This keeps rain chances in the area during the first half of the
week. The best chances are probably on Tuesday, when the disturbance
is most favorably positioned to drag moisture across the region.
Chances for rain are most favored in South Texas and along the
Coastal Plains, especially if a coastal low or trough materializes
as indicated in the synoptic global models, though the latest
ensembles carry chances for rain across most of South-Central Texas
Monday and Tuesday with activity limited to mainly east of the I-35
corridor on Wednesday. The return of southerly winds at the surface
on Tuesday should help increase low-level instability, opening up
the potential for thunderstorms and a heavier rain.

Temperatures will be slow to warm up during the week with the
continued rain chances and cloudiness, staying well below average
Monday and Tuesday. Del Rio may see a few daily record cool high
temperatures with afternoon temperatures staying as much as 25
degrees below average. These cool anomalies aren't as dramatic to
the east, but are still 10-15 degrees below late-April norms. As
conditions start to clear up west-to-east on Wednesday with warmer
air aloft, temperatures should return to seasonably warm levels with
highs in the 80s and lows in the 60s. A pair of troughs over the
Rockies and Intermountain West late in the week may influence
conditions over our area Thursday to Saturday, possibly with some
dryline-related thunderstorm activity. However, those disturbances
won't reach the western US coast until midweek.

&&

.AVIATION...
(00Z TAFS)
Issued at 725 PM CDT Sat Apr 18 2026

Mostly VFR CIGs are associated with the overrunning pattern this
evening, but areas that have a fair amount of convection nearby
may see some MVFR CIGs and some RW that could drop the VSBY to
about 3-4 SM The strongest of cells have frequent lightning and
perhaps hail as big as pennies. and one such cluster could impact
AUS in about 30-50 minutes. Low confidence among the rapid refresh
solutions on what convective trends may appear overnight so we'll
wait until the 03Z updates are issued to change the outlook if
needed. For now, we just have winds gusting less after midnight
and continued VFR skies for AUS/DRT, but a return to MVFR from 08Z
to 12Z at SAT/SSF.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              52  75  55  70 /  60   0  20  50
Austin Bergstrom Intl Airport  52  74  54  68 /  60   0  20  50
New Braunfels Muni Airport     52  73  54  68 /  70  10  30  60
Burnet Muni Airport            48  72  53  66 /  30   0  20  50
Del Rio Intl Airport           56  66  54  64 /  30  30  40  40
Georgetown Muni Airport        48  73  54  67 /  50   0  20  40
Hondo Muni Airport             53  67  53  62 /  70  10  50  60
San Marcos Muni Airport        52  73  55  67 /  70  10  30  60
La Grange - Fayette Regional   53  74  55  72 /  70  10  10  40
San Antonio Intl Airport       53  71  55  66 /  80  10  40  70
Stinson Muni Airport           54  70  56  66 /  80  10  40  70

&&

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

SHORT TERM...Tran
LONG TERM....Tran
AVIATION...18

Special Weather Statement
National Weather Service Austin/San Antonio TX
551 PM CDT Sat Apr 18 2026

TXZ187-189>191-204>206-182345-
Comal TX-Bexar TX-Blanco TX-Medina TX-Hays TX-Bandera TX-Kendall TX-
551 PM CDT Sat Apr 18 2026

...A strong thunderstorm will impact portions of eastern Medina,
southeastern Bandera, southwestern Hays, south central Blanco,
southeastern Kendall, northwestern Bexar and Comal Counties through
645 PM CDT...

At 551 PM CDT, Doppler radar was tracking a strong thunderstorm over
Cross Mountain, or 10 miles south of Boerne, moving northeast at 25
mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
San Antonio, New Braunfels, San Marcos, Boerne, Wimberley, Canyon
Lake Dam, Canyon Lake, Helotes, Fair Oaks Ranch, Bulverde, Shavano
Park, Cross Mountain, Woodcreek, Guadalupe River State Park, Smithson
Valley, Bandera Falls, The Dominion, Kreutzberg, Spring Branch, and
Government Canyon State Natural Area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 2985 9789 2979 9796 2950 9881 2967 9899
      3015 9821
TIME...MOT...LOC 2251Z 237DEG 23KT 2964 9869

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

MO

Special Weather Statement
National Weather Service Austin/San Antonio TX
721 PM CDT Sat Apr 18 2026

TXZ173-191-192-190100-
Williamson TX-Hays TX-Travis TX-
721 PM CDT Sat Apr 18 2026

...A strong thunderstorm will impact portions of southwestern
Williamson, northwestern Hays and central Travis Counties through 800
PM CDT...

At 720 PM CDT, Doppler radar was tracking a strong thunderstorm over
Bee Cave, or 9 miles northeast of Dripping Springs, moving northeast
at 45 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Austin, Round Rock, Cedar Park, Georgetown, Pflugerville, Taylor,
Dripping Springs, Anderson Mill, Serenada, Windemere, Leander, Hutto,
Lakeway, Lago Vista, Bee Cave, West Lake Hills, Hudson Bend, The
Hills, Liberty Hill, and Rollingwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3071 9749 3051 9739 3005 9804 3020 9823
      3023 9822 3074 9786
TIME...MOT...LOC 0020Z 218DEG 39KT 3031 9797

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

MO

Special Weather Statement
National Weather Service Austin/San Antonio TX
723 PM CDT Sat Apr 18 2026

TXZ191>193-208-190115-
Caldwell TX-Bastrop TX-Hays TX-Travis TX-
723 PM CDT Sat Apr 18 2026

...A strong thunderstorm will impact portions of northwestern
Caldwell, central Hays, southeastern Travis and southwestern Bastrop
Counties through 815 PM CDT...

At 723 PM CDT, Doppler radar was tracking a strong thunderstorm near
Martindale, or near San Marcos, moving northeast at 35 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Austin, San Marcos, Kyle, Buda, Lockhart, Wimberley, Tanglewood
Forest, Austin Bergstrom Int Airport, Martindale, Uhland, Mustang
Ridge, Niederwald, Onion Creek, Cedar Creek, Wyldwood, Shady Hollow,
Hornsby Bend, Manchaca, Mountain City, and San Leanna.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 2981 9784 2983 9784 2985 9786 2985 9788
      2982 9793 2998 9814 3031 9764 2998 9730
TIME...MOT...LOC 0023Z 245DEG 31KT 2991 9787

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

MO

Special Weather Statement
National Weather Service Austin/San Antonio TX
741 PM CDT Sat Apr 18 2026

TXZ193-208-209-190115-
Caldwell TX-Bastrop TX-Fayette TX-
741 PM CDT Sat Apr 18 2026

...A strong thunderstorm will impact portions of southeastern
Caldwell, southeastern Bastrop and west central Fayette Counties
through 815 PM CDT...

At 741 PM CDT, Doppler radar was tracking a strong thunderstorm 11
miles southeast of Lockhart, moving northeast at 40 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Smithville, Cistern, Rosanky, Upton, Brownsboro, Delhi, Hills
Prairie, Joliet, Tilmon, Togo, String Prairie, Watterson, Alum Creek,
McNeil, Red Rock, McMahan, Buescher State Park, Jeddo, Kovar, and
West Point.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 2988 9696 2977 9731 2978 9732 2976 9736
      2968 9762 2979 9770 3015 9718
TIME...MOT...LOC 0041Z 238DEG 34KT 2981 9751

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

MO

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