textproduct: Austin/San Antonio

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.