textproduct: Austin/San Antonio

KEY MESSAGES

- Unseasonably warm and humid weather forecast to continue through Sunday afternoon.

- A strong cold front likely arrives Sunday evening, bringing gusty winds and much cooler temperatures by Monday morning.

- Low chances for showers accompanying the cold front Sunday night mainly east of I-35.

- Freezing temperatures possible Tuesday and Wednesday, followed by a gradual warming trend.

SHORT TERM

(Tonight through Sunday night) Issued at 1204 PM CST Sat Dec 27 2025

With the past week's strong ridge now shifting east of the local area, the eastern fringes of an upper-trough and its flanking subtropical jet are beginning to push into the Central US. The primary zones of ascent remain well to our north, so we don't expect much considerable change in the weather tonight or during the afternoon Sunday. Tonight's low-level jet does strengthen to about 20-30 kt over our area in response, so a moderate breeze should persist especially at higher elevations and coverage of fog will likely be reduced compared to previous mornings. The intensified LLJ will also stream more moisture into the area for Sunday, leading to more cloud cover sticking around during the daytime. That may shave off a few degrees for highs, though warm southwest flow should continue to support another warm day with highs in the upper 70s to low 80s.

Our week of unseasonably warm and muggy weather should come to an abrupt end Sunday night with the arrival of a strong polar cold front. With the frontal passage now in range of the higher resolution models, the timing has trended slightly sooner, and the front could arrive at the northern Hill Country as early as about 6 PM CST tomorrow evening. The front should move speedily through the area thanks to its robust density current speed and supportive northerly flow at 850mb, likely reaching US-90/I-10 by 10 PM CST and exiting the Coastal Plains and Rio Grande Plains by about midnight Monday. Some spots could see a quick 10-degree drop within the first hour of the frontal passage. Model soundings have remained consistent in showing a decently mixed boundary layer up to about 2000 ft AGL, which could transfer strong gusts to the surface. The HREF ensemble members show widespread north winds of 15-25 mph across the vast majority of South-Central Texas Sunday evening into the overnight. Mean boundary layer winds of 30-35 kt are depicted in the latest RAP13 and NAM12 models, which supports the 40-45 mph gusts exhibited in the REFS ensemble. These winds should develop quickly Sunday night and continue into Monday morning. It'll be a good idea to secure loose outdoor objects and holiday decorations. A thin line of showers is possible along the front mainly along and east of I-35 Sunday evening. However, the dry and windy post-frontal air, unsupportive thermodynamics aloft, and speed of the front will curtail rain amounts to mostly a few hundredths of an inch of rain.

LONG TERM

(Monday through next Saturday) Issued at 1204 PM CST Sat Dec 27 2025

Monday morning will be quite the drastic change from previous muggy mornings. The much colder air arriving behind the overnight cold front is expected to push lows into the 30s and 40s across South- Central Texas. Coupled with a 20 mph wind and gusts of at least 30 mph for many locations, wind chills may be in the upper 20s and low 30s for portions of the southern Edwards Plateau and Hill Country. Strong cold air advection during the day and residual post-frontal stratus will likely keep temperatures low throughout Monday with highs in the 40s and 50s. Much drier post-frontal air and gusty winds will likely produce at least elevated fire weather conditions across the area Monday afternoon. Winds should be at their strongest Monday morning but gradually taper during the day to a more ordinary breeze by around sunset.

The cold post-frontal airmass sticks around until about midweek. Lows Tuesday and Wednesday morning are forecast to be in the 30s to low 40s across South-Central Texas, with light morning freezes possible mainly north of I-10. A gradual warming trend should return midweek heading into 2026 as mid-level ridging passes overhead. New Year's Eve looks seasonably cool and New Year's Day a touch milder with highs in the 60s to low 70s. Aside from Sunday/Monday's front, rain is kept out of the forecast for next week. That said, the subtropical jet stream may be in flux over the eastern Pacific and southwestern US during the week, which could send a weak disturbance or two worth monitoring for low rain chances middle to late next week.

AVIATION

(00Z TAFS) Issued at 604 PM CST Sat Dec 27 2025

VFR conditions through the evening hours across South-Central Texas. Stratus will gradually re-develop 04Z-08Z across the Coastal Plains, I-35 corridor, and Hill Country. The stratus is expected to spread westward into the Rio Grande 09Z-13Z. We continue to forecast closer to a persistence ceiling/visibility forecast from recent nights at AUS and SAT given the elevated winds and mixing overnight. We expect a mix of IFR and MVFR ceilings along the I-35 corridor, including SAT and AUS, developing overnight through morning. LIFR ceilings are more likely to occur between HDO-DRT. Conditions are forecast to gradually improve 15Z-20Z Sunday.

A strong cold front is forecast to move through the region between 00Z-06Z Monday, bringing north winds with gusts initially around 25-30 KT at AUS and SAT, increasing 06Z-12Z Monday to 30-35 KT.

CLIMATE

Issued at 1204 PM CST Sat Dec 27 2025

Record High Temperatures

12-27 12-28 Austin Bergstrom 82 (2024) 85 (2016) Austin Camp Mabry 79 (2021/1954) 83 (2016) San Antonio 82 (2005) 83 (2024) Del Rio 84 (2005) 83 (2024)

Record High Minimum Temperatures 12-27 12-28 Austin Bergstrom 68 (1971) 66 (1946) Austin Camp Mabry 67 (2021) 67 (1984) San Antonio 68 (1971) 68 (1984) Del Rio 65 (2019) 63 (1984)

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 82 67 79 41 / 0 0 0 20 Austin Bergstrom Intl Airport 82 66 80 41 / 0 0 0 30 New Braunfels Muni Airport 82 65 79 43 / 0 0 0 30 Burnet Muni Airport 79 65 78 38 / 0 0 0 10 Del Rio Intl Airport 82 64 81 46 / 0 0 0 0 Georgetown Muni Airport 79 65 79 39 / 0 0 0 10 Hondo Muni Airport 81 63 78 43 / 0 0 0 10 San Marcos Muni Airport 82 65 80 41 / 0 0 0 30 La Grange - Fayette Regional 83 66 82 43 / 0 0 0 30 San Antonio Intl Airport 80 66 78 44 / 0 0 0 20 Stinson Muni Airport 83 67 80 46 / 0 0 0 20

EWX WATCHES/WARNINGS/ADVISORIES

None.