textproduct: Austin/San Antonio

KEY MESSAGES

- Low to medium chance of patchy showers and isolated thunderstorms Wednesday, with an isolated strong to marginally severe storm possible.

- Unsettled weather pattern develops mid week with rain and storm chances through early next week. Stronger storms and locally heavy rain are possible.

- Well above average temperatures continue this week, trending slightly cooler this weekend into early next week.

SHORT TERM

(Tonight through Wednesday night) Issued at 1154 AM CST Tue Mar 3 2026

Closer to the surface, a warm low-level airmass presides over Texas and continues to bring unseasonably warm temperatures. We remain on track to breach today's daily record highs for our Austin climate sites this afternoon.

While the surface synoptic situation should continue to support warm and humid conditions this week, changes are taking shape aloft. Water vapor imagery and this morning's sounding from Del Rio depict a shift in mid-level flow to southwesterly, a sign of amplifying troughing over the western US and our first signal of a coming change in the weather pattern. An initial shortwave trough will move across the Central Plains Wednesday, accompanied by a front which will stall just north of our area by Wednesday evening. Southerly flow ahead of the front will pipe in a steady stream of moisture over South-Central Texas, resulting in a deep warm moist layer.

Patchy warm advection sprinkles and showers are depicted in most of the hi-res simulated reflectivity guidance during the day tomorrow, mainly for the Coastal Plains and I-35 corridor. The best forcing for ascent ahead of the shortwave and along the front is focused north of our area, which will be a limiter on the coverage of more robust rains Wednesday. Gradual height falls aloft will encourage a broad low- to mid-level ascent of air over our area, but whether this is sufficient to fully erode the capping inversion being supplied by a warm southwesterly Z700 flow is the main question. Models are split in showing the development of thunderstorms (and most of the operational CAMs do not), though coverage overall looks isolated in agreement with the weak forcing in play. Given that the cap needs to erode first, chances for storms would mainly be towards the late afternoon to evening. Two potential zones for initial development include the Hill Country and Austin area where capping is slightly weaker, and over the Rio Grande Plains where daytime temperatures imply less effort required to overcome the cap. Should thunderstorms materialize, the presence of 1500 J/kg MLCAPE and modest 20 kt effective bulk shear could support a stronger to marginally severe storm with large hail and a heavy downpour the main hazards. For these reasons, the SPC has a marginal (level 1 of 5) risk for severe weather highlighted for these areas extending east to the I-35 corridor. However, most of South- Central Texas will likely miss out on more substantial rains Wednesday.

Temperatures Wednesday should rise into the 80s again for most with highs around 90 in the Rio Grande Plains. Mild and humid conditions persist Wednesday night as onshore Gulf flow continues.

LONG TERM

(Thursday through next Tuesday) Issued at 1154 AM CST Tue Mar 3 2026

Unseasonable warmth continues through the week, with dew points remaining at or above the 90th percentile keeping overnight temperatures mild. Wednesday's trough quickly departs from the Plains and its attendant front lifts north and wanes in the face of strong southerly flow, reducing forcing in our area and bringing down rain chances Thursday. However, persistent warm and humid air, gradually upslope southerly flow, and the possibility of some boundaries left over by activity Wednesday mean an isolated thunderstorm can't be ruled out for Thursday.

As we move towards the end of the week, a stronger trough will push into the Intermountain West. Models remain consistent in the trough separating into two primary lobes of energy, with a shortwave continuing to advance into the Central Plains and a cut-off low dropping southwest towards the Baja California. The lead shortwave sends a cold front into Texas which may stall across our region Saturday night. The lagging cutoff low will set up an extended plume of moisture from the eastern Pacific to Texas, with the subtropical jet providing opportunities for spokes of energy to spin off the cut- off low and track over Texas. This is a favorable setup for periods of showers and thunderstorms beginning Friday and continuing into early next week, with the end of this wetter period hinging by whenever the cutoff low rejoins the upper-level westerlies... recent models have delayed this passage until midweek next week, which could prolong this timeframe. The latest model blend continues to show about a 50-75% chance for at least 1 inch rainfall across most of our area this weekend with potential for multiple inches for some areas. Deep moisture should in ample supply, so heavier downpours could be supported. Moderate instability and shear may allow for a few strong to severe storms, though continued cloud cover over time should drive a gradual decrease in instability over time. Temperatures are expected to stay warm with muggy nights, though weak cold advection behind the front, cloudiness, and the rains may provide slightly cooler temperatures this weekend into early next week.

AVIATION

(18Z TAFS) Issued at 1154 AM CST Tue Mar 3 2026

VFR conditions are forecast for the I-35 terminals through late this evening. Currently the MVFR cigs at KDRT may last for one more hour, however, VFR conditions are anticipated by 19Z. A moderate southeast flow of 10 to 15 knots with gusts up to 25 knots is in place and forecast to remain through early this evening. MVFR cigs return overnight across the I-35 terminals and close to 10Z Wednesday for KDRT. There is a low chance for IFR cigs for the Austin and San Antonio airports by late overnight and day break, but due to low confidence and wind speeds staying up, mentioned just here. The southerly winds continue Wednesday with VFR conditions returning by 18Z Wednesday.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 68 83 67 85 / 10 40 30 30 Austin Bergstrom Intl Airport 67 84 66 86 / 0 40 30 30 New Braunfels Muni Airport 66 84 66 85 / 10 50 30 30 Burnet Muni Airport 67 80 65 82 / 0 40 40 30 Del Rio Intl Airport 67 86 67 87 / 10 20 20 30 Georgetown Muni Airport 67 82 65 85 / 0 40 30 30 Hondo Muni Airport 65 87 64 88 / 10 20 40 30 San Marcos Muni Airport 67 84 65 86 / 10 50 30 30 La Grange - Fayette Regional 68 84 67 85 / 0 40 20 10 San Antonio Intl Airport 68 84 67 86 / 20 40 40 30 Stinson Muni Airport 68 87 68 87 / 10 40 30 30

EWX WATCHES/WARNINGS/ADVISORIES

None.