textproduct: Austin/San Antonio

KEY MESSAGES

Updated at 1205 PM CDT Thu Sep 3 2026

- Low to medium (10-50%) rain/storm chances across portions of the region today thru Saturday with isolated PoPs most days going into next week.

- Above average temperatures continue with elevated afternoon heat indices, along and east of the I-35 corridor into the Rio Grande Plains.

SHORT TERM

(Tonight through Friday night) Issued at 1205 PM CDT Thu Sep 3 2026

A TUTT low over the Central Gulf is fusing into the weakening remnants of Edouard, allowing for some of the mid level dynamics to be preserved while the lower level features to continue dissolving over North TX. The mid level features, as depicted in the H7 and H5 maps are stretching into a N-S oval shape, running generally from Dallas to Houston. This shear axis is drifting SW today as the TUTT low continues drifting west. This puts Central TX in the cross-hairs of some of the best rain chances associated from the remnant low. That only means our forecast PoPs are bumped to 50 percent, but considering our rain forecasts from a few days ago, that's certainly a welcome trend for areas that are beginning to show more vulnerability to wildfires.

Todays rain chances are being locally suppressed by an abundance of mid to high cloudiness over Central TX, leading to lower temperatures and a weak convergence zone that is drifting out and away from a large core of moderate to heavy rain under the center of circulation. That convergence zone will eventually get away from the cloud canopy over Austin, and we think that will lead to more deep convection forming near the Austin metro area late today into the evening hours. PWat values are already exceeding 2 inches and the GFS/NAM PWat fields for 00Z Friday suggest a few pockets of PWat values up to 2.4 inches. This plus, a slow expected storm motion should provide a favorable setup for locally heavy rain amounts up to 3 inches late today into tonight, mainly along and NE of a line from Llano to New Braunfels to Hallettsville. Overall QPF values in the forecast are quite low and this is intentional. While the 3 inch rain potential could be problematic for flooding, the coverage of the higher rainfall amounts is expected to be isolated. The early morning core rain potential should be severely reduced, possibly non-existent as MRMS estimated rainfall over a small area between Fairfield and Buffalo topped out at only 7 inches, as compared to the 17+ inch bulls-eye that occurred the prior night. So even if a small core rain were to be possible tonight there's a good chance it would fall just east of the forecast area.

Fridays rainfall chances will continue trending west and south closer to the I-10 corridor From Junction to San Antonio to La Grange. The H7 to H5 pattern is expected to unravel a bit faster, so the concentration of better rain chances will be more uncertain, leading to more broad rain chances but lower potential for heavy downpours. As we saw over Central TX today, there should still be a fair amount of cloud cover, so the best news is that we should get a nice break from the oppressive near 100 degree temperature streak that's carried over from August. Highs should be capped at the mid 90s for the I-35 corridor, and a few areas of the Hill County could fail to even reach 90. Sadly, the heat index values will not chance a whole lot due to the pooling of higher dew point temperatures that will not mix out in the daytime as easily.

Friday night's rain chances will probably be more rooted in the evening and pre-dawn periods as reduced moisture pooling and mid- level shear leads us back to more diurnally driven rain chances.

LONG TERM

(Saturday through next Thursday) Issued at 1205 PM CDT Thu Sep 3 2026

Despite the dissolving of Edouard's moisture and shear aloft by Saturday, the trailing TUTT Low is moving onshore into Deep South TX and the Coastal Bend by this time to bring one more day of slightly elevated rain chances. Pooled moisture in the mid levels (PWat values near 2.2 inches) and some more weak mid-upper level shear might be just enough to bring one more day of low CHC category PoPs at least in the daytime. This also should curb high temperatures, but probably not as much as we expect it to on Friday. Sunday's rain prospects look even more isolated, because by then, the TUTT circulation will have passed to the SW into Mexico, leaving only the moist easterly mid level winds. High temperatures will continue trending back toward triple digits, but our blended guidances continue to show the I-35 corridor remaining below triple digits. By Monday, the upper ridging should further isolate rain chances, but not completely eliminate them. The ridge center over Arkansas means a deep onshore wind extends up to the H5 level and that pattern is expected to hold up through the middle of next week. So with compliments from Edouard, the season of triple digit heat wave have come to an end for all but the Rio Grande Plains. The elevated heat indices are not expected to go away as quietly, and some 100-105 values each day will be in consideration throughout the next 7 days.

AVIATION

(18Z TAFS) Issued at 1203 PM CDT Thu Sep 3 2026

There is better confidence scattered showers and thunderstorms could move over KAUS this afternoon/early evening and a TEMPO group has been included in this update. Some guidance, although not the majority, have isolated convection as far south as KSAT/KSSF but there is not high enough confidence to add to the forecast. Otherwise, southerly wind will mainly remain around 10 knots with gusts to 20 knots this afternoon. A period of higher gusts is included this evening for sites, with wind decreasing during the overnight hours. MVFR ceilings seem likely over the I-35 corridor tonight developing sometime around 08-09Z.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 76 94 75 96 / 40 40 10 20 Austin Bergstrom Intl Airport 76 94 75 96 / 30 40 10 20 New Braunfels Muni Airport 75 95 74 96 / 10 30 10 20 Burnet Muni Airport 75 90 73 94 / 30 40 10 10 Del Rio Intl Airport 79 101 77 98 / 0 0 10 20 Georgetown Muni Airport 75 92 74 95 / 50 40 10 10 Hondo Muni Airport 74 97 73 96 / 0 10 10 30 San Marcos Muni Airport 76 94 74 96 / 20 30 10 20 La Grange - Fayette Regional 77 94 75 95 / 30 40 10 30 San Antonio Intl Airport 78 95 76 96 / 10 20 10 30 Stinson Muni Airport 78 98 76 98 / 0 20 10 30

EWX WATCHES/WARNINGS/ADVISORIES

None.