textproduct: Austin/San Antonio

KEY MESSAGES

- A very humid and unsettled weather pattern continues through the middle of next week with daily rain and thunderstorm chances.

- A line of storms is forecast over the southern Edwards Plateau and Hill Country Saturday night, with heavy downpours and isolated severe weather possible.

- The potential for strong to severe storms and locally heavy rainfall continues through the weekend into early next week.

SHORT TERM

(Today through Sunday) Issued at 1250 AM CDT Sat Apr 11 2026

A humid Gulf airmass persists across Texas this weekend, with moisture content forecast to rise towards the upper percentiles of the historical distribution for mid-April. Water vapor imagery and model analyses indicate a brief lull in mid-level vorticity for most of the day Saturday, which will limit the intensity of storms during the morning and afternoon hours. However, with warm and moist air continuing to funnel in from the Gulf, isolated thunderstorms similar in character to the last few days should once again make their way mostly over the Coastal Plains and I-35 corridor Saturday. The ample moisture will allow for a quick 1 to 3 inches of rain in the heavier showers in the afternoon, though most will start out with lighter amounts. Slightly higher wind shear may allow for a stronger storm with gustier winds, but severe activity will be limited during the daytime on Saturday.

Heading towards Saturday evening, a shortwave trough is forecast to swing northeast across the Big Bend area. This will prompt a more vigorous round of storms over West Texas, accompanied by a more concentrated area of moisture and stronger wind shear. The trough will guide these storms east/northeast, bringing them into the southern Edwards Plateau mostly after sunset. The enhanced shear provided by the trough and moderate instability supports an isolated severe risk, and the Storm Prediction Center (SPC) has highlighted a Level 2 of 5 risk (Slight) with these storms as they push into Val Verde County. The main severe threats are initially large hail and damaging winds, with a low threat for an isolated tornado. Given the anomalously high moisture, we'll also need to watch for heavier rains capable of localized flash flooding, with the Weather Prediction Center (WPC) indicating a Level 2 of 4 risk (Slight) of excessive rainfall over the southern Edwards Plateau. Most of the convective allowing models show the potential for a 4" or greater swath of rain totals, mainly over Val Verde and Edwards counties, before the intensity gradually lessens farther east. These rain rates are capable of causing localized flash flooding concerns. The AI-based QPF guidance and ensemble-based indices also highlight the southern Edwards Plateau as having a more elevated potential for heavier rains. Deeper into Saturday night, as the storms push farther east, models suggest an evolution towards more linear storms, shifting the severe threat to isolated damaging winds. The severe potential is expected to gradually decline Saturday night as conditions stabilize, but enough instability should be in place for a marginal severe threat to taper into the Hill Country and potentially as far east as the I-35 corridor. The primary uncertainty Saturday night will be how far north or south the storms extend, and how quickly storms will move east. Most of the high resolution models do take the storms across the southern Edwards Plateau and Hill Country, mainly north of US-90, perhaps reaching the Austin area just before dawn on Sunday. However, this storm direction is sensitive to minor changes in the flow aloft, so there could be shifts in the main threat areas for Saturday night once the position of the parent trough becomes better established.

The uncertainties inherent in the evolution of storms Saturday night introduces complexities to Sunday's setup. High amounts of moisture, again near the higher end of climatology for mid-April (pushing above the 98th percentile), will persist across South-Central Texas on Sunday with southerly flow still prevailing. Within this humid air, Saturday night's storms may leave behind a boundary over the region, which could be a focus for thunderstorms during the afternoon hours. This timeframe is only just starting to come into the range of the high resolution models, which vary widely and lead to low confidence in the timing and placement of Sunday's storms. The initial activity may be somewhat scattershot, due to a lack of well-defined mid-level energy aloft, but adequate wind shear and instability could support an isolated severe risk Sunday afternoon. The ample moisture will also allow for highly efficient rainmakers should storms develop, leading to an isolated flash flooding risk from heavy downpours. Later in the day Sunday, another shortwave trough, this time farther south, may trigger another round of storms over Mexico into South-Central Texas towards the late afternoon and evening hours with high instability (with 2000-3000 J/kg possible) and moderate shear draped over the Rio Grande Plains and southern Edwards Plateau. Taken altogether, the environment Sunday is supportive of some severe weather and heavy rain, but timing and location will be dependent on where Saturday's rains end up. Up to Level 2 (Slight) risks for both severe weather and excessive rainfall are depicted Sunday.

LONG TERM

(Sunday night through Friday) Issued at 1250 AM CDT Sat Apr 11 2026

The broad longwave trough over the Western US, responsible for sending the various impulses of energy our way this weekend, should persist over the western CONUS early next week. Slightly more southwesterly low-level wind vectors will support a slight decrease in some of the higher-end moisture levels, but ensembles still project precipitable water content to remain in the 85th-95th percentile range... high enough to support heavier downpours. Daily rain and storm chances continue with this air remaining in place, beneath continued troughing aloft. A brief respite in mid-level vorticity could offer a decrease in storm coverage on Monday, but an uptick is possible Tuesday and Wednesday as the broader longwave trough slowly shifts east. Isolated risks for severe weather and locally heavy rainfall persist through midweek as moist and unstable air stick around. The longer range risk areas will likely wobble day- to-day based on small changes to the weather pattern, so it would be wise to not get too caught up in minor variations to next week's risk areas at this forecast range. While ensembles indicate a good chunk of the broad trough will make it past our longitude by Thursday, with the potential of a Pacific front briefly clearing the air, an overall southwesterly flow persists on the GEFS and EPS ensemble means. Thus, our humid springtime pattern may continue through much of next week.

The damp and humid weather through the weekend into next week will keep temperatures warm, with highs generally in the 80s, and lows mild in the 60s to low 70s. The lack of a stronger front or cooler air aloft should generally minimize episodes of rain-cooled air.

Keep up with the forecast through the weekend into next week. Each day's rain chances and overall risk with severe weather or locally heavy rain may be contingent on how the day before plays out. Have multiple ways of receiving warning information!

AVIATION

(06Z TAFS) Issued at 1250 AM CDT Sat Apr 11 2026

IFR and MVFR conditions are occurring along the I-35 terminals as of the writing (06Z Sat). These conditions are forecast to remain through late Saturday morning. VFR conditions are forecast for Saturday afternoon into the early evening with the exception of the time block from 20Z to 23Z Saturday, where showers and storms are forecast to affect the I-35 sites (lower cigs/vsbys). For DRT, MVFR conditions are forecast to start around 08Z with good chances to lower to IFR around 13Z and back to MVFR late Saturday morning through the afternoon period. Southerly winds prevail across all local area sites through the forecast period. A line of strong to severe storms is forecast to push across the Rio Grande late Saturday evening and could impact DRT. More details on this in future aviation discussions as hires models provide information.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 82 69 79 69 / 50 60 70 60 Austin Bergstrom Intl Airport 82 68 79 68 / 50 50 70 60 New Braunfels Muni Airport 82 68 80 68 / 50 50 70 60 Burnet Muni Airport 80 66 78 67 / 50 70 70 50 Del Rio Intl Airport 82 68 85 69 / 50 90 40 30 Georgetown Muni Airport 81 67 78 67 / 50 60 70 60 Hondo Muni Airport 82 67 80 66 / 40 60 70 50 San Marcos Muni Airport 82 68 80 68 / 50 50 70 60 La Grange - Fayette Regional 82 69 81 70 / 50 30 70 50 San Antonio Intl Airport 82 69 80 69 / 50 50 70 50 Stinson Muni Airport 83 70 81 70 / 50 50 70 50

EWX WATCHES/WARNINGS/ADVISORIES

None.