textproduct: Austin/San Antonio

KEY MESSAGES

- Soggy weather continuing for portions of the I-35 corridor and Coastal Plains.

- Trending towards warmer and drier weather for the second half of the week.

SHORT TERM

(Tonight through Wednesday night) Issued at 129 PM CDT Tue Apr 21 2026

Much like yesterday, an axis of moist convergence led to a stationary band of persistent rain this morning, this time between Burnet and Lee counties. Continued moisture influx on its southwestern flanks should continue to produce rain today, but decreasing trends in rainfall rates have been noted, and the boundary looks less coherent than earlier. As divergence aloft swings east, this will gradually reduce the tendency for rainbanding and shift most activity east, with precipitable water also falling generally below the 90th percentile for the most impacted areas (about 1.4" PW). However, there is still a weak but humid low- to mid-level southerly flow especially along and east of the I-35 corridor. Thus, scattered south-to-north moving showers will continue today mainly over the I-35 corridor and Coastal Plains, but with a gradual declining trend in strength and coverage tonight. Overall additional rain amounts are more likely to be in the 1/4 to 1-inch range between the afternoon and overnight. Keep in mind that our recent soaking rains have reduced the ability for soils to take on more water, so even lowered rain rates could still cause some ponding and isolated nuisance flooding in some of the more saturated areas such as the northern part of the San Antonio metro and north of the Austin/Highland Lakes areas.

After a prolonged stretch of somewhat unusual north or east winds for the region, south winds are expected to return on Wednesday. This will restore the usual combination of warm and humid more typical of April in South-Central Texas. However, the depth of returning moisture will be much shallower with mid-level moisture vacating the area. There is a medium chance (up to about 40 percent) for afternoon and evening showers riding along the southerly flow over the Coastal Plains, but a lack of mid-level disturbances should greatly limit the extent of rains compared to the last few days. Otherwise, partly sunny conditions are forecast Wednesday afternoon, with highs returning to near-average values in the low 80s over most areas for the first time since last Friday.

LONG TERM

(Thursday through next Tuesday) Issued at 129 PM CDT Tue Apr 21 2026

Warm aloft moves off the Mexican plateau and over our area beginning Thursday. This will push daytime highs into the upper 80s to low 90s for some areas by Friday, with additional warmth likely over the weekend pushing more widespread highs in the 90s. Highs along the Rio Grande have about a 50 to 70 percent chance of topping 95F on Monday.

There are a few disturbances in the medium to long range which could produce some active weather over our area. However, the warm air aloft should maintain a strong cap, which increases uncertainty regarding rain chances especially since the bulk of the vorticity associated with those disturbances are projected to track well to our north. First, a weak shortwave trough tracking across Oklahoma brings with it a low chance (10-20 percent) for streamer showers over the Coastal Plains Friday afternoon/evening. More upper-level divergence and southwesterly flow aloft then arrives Saturday, accompanied by several small batches of passing vorticity through the weekend into Monday. This could generate some isolated thunderstorms mainly in the latter part of the days over the weekend, though ensemble trends have stayed low-profile regarding rain chances. That said, the continued humid south wind and warm temperatures will allow for fairly large amounts of conditional instability (2000-3000 J/kg SBCAPE on ensemble means) to remain in the area for storms to escalate if the capping strength trends weaker.

AVIATION

(18Z TAFS) Issued at 1217 PM CDT Tue Apr 21 2026

IFR to LIFR CIGs are expected to persist at AUS, SAT, and SSF terminals through tomorrow morning before lifting Wednesday afternoon. -RA is expected through late evening with lower end chances and VCSH used after 09Z at the three I-35 sites. Winds will remain between 5-10 kts out of 070 to 120 direction. Visibilities may become more of an issue after sunset this evening as low level moisture and light winds allow those visibilities to go down to the 1-2SM range. Improvement begins around 16-17Z Wednesday as sites climb back out of IFR ceilings.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 63 83 67 85 / 40 30 0 10 Austin Bergstrom Intl Airport 64 81 67 84 / 40 40 0 10 New Braunfels Muni Airport 64 83 66 85 / 40 40 0 10 Burnet Muni Airport 62 80 65 83 / 30 20 0 10 Del Rio Intl Airport 68 85 69 88 / 10 10 0 0 Georgetown Muni Airport 63 80 66 83 / 40 30 0 10 Hondo Muni Airport 65 80 65 84 / 30 20 0 0 San Marcos Muni Airport 65 81 66 84 / 40 40 0 10 La Grange - Fayette Regional 64 82 67 85 / 40 40 0 10 San Antonio Intl Airport 66 82 67 84 / 40 30 0 10 Stinson Muni Airport 67 82 67 86 / 30 30 0 0

EWX WATCHES/WARNINGS/ADVISORIES

None.