textproduct: Austin/San Antonio

KEY MESSAGES

- Pockets of heavy rain and isolated to scattered instances of flash flooding possible Sunday into Tuesday morning with medium to high rain and storm chances

- Monitoring any lingering spin associated with the Mexico tropical disturbance through mid to late week and a disturbance over Texas panhandle from Friday into Saturday that could continue the rain chances

- Warm and humid conditions persist with elevated heat indices this weekend and during the second half of next week

SHORT TERM

(Tonight through Sunday night) Issued at 133 PM CDT Sat Jun 13 2026

A few brief light streamer showers and sprinkles occurred this morning but they were less prevalent compared to yesterday as the morning dew points and precipitable water values were slightly lower. An outflow boundary, associated with the outer influence of the tropical disturbance over the western Bay of Campeche nearing the Tamaulipas coast, moved through the Corpus Christi region. This boundary is the leading edge of higher precipitable water values and will be the source for isolated to scattered showers and storms through the afternoon for locations mainly to the south and east of the I-35 corridor. This activity dissipates entering the early evening and should provide a dry evening into the overnight period for most locations. Overnight tonight into Sunday morning may again see some brief light steamer showers or sprinkles, otherwise the usual overnight into morning low stratus will develop.

Moisture associated with the tropical disturbance moving inland into Mexico will increase from Sunday through Sunday night. Precipitable water values will climb into the 90 to 99 percentile range. This promotes better coverage (40-60%) for shower and storm activity from the afternoon onward into Sunday night. Any heavier storms could be able to produce efficient tropical downpours with a quick inch or more, occasional to frequent lightning, and gusty winds. An isolated flooding instance could be possible and WPC highlights the entirety of the region within a level 1 of 4 risk for excessive rainfall.

Warm and humid conditions maintain with afternoon highs reaching the upper 80s and low to mid 90s for most with higher heat indices. The heat indices look to be slightly higher Sunday afternoon compared to this afternoon where areas along and east of the I-35 corridor peak in the 102 to 108 degree range.

LONG TERM

(Monday through next Saturday) Issued at 133 PM CDT Sat Jun 13 2026

Monday into Tuesday is forecast to the be most active period during the forecast for now as a late season front slides south into our region. We will be rich with tropical moisture with precipitable water values above the 99th percentile for this time of year as the tropical disturbance alluded to in the short term meanders inland across Mexico. Numerous to widespread showers and storms will be expected across the region, with the highest coverage favoring Monday afternoon through Tuesday morning. Average rainfall Monday through Tuesday across the region will run from about 0.75 to near the 2 to 2.5 inch range with the highest totals running generally along and south of the I-10/US highway 90 corridor. Isolated higher bullseye amounts in excess of 5 inches may be possible and this is supported by the 84 hr RRFS and REFS guidance. This would lend into the potential for isolated to scattered instances of flash flooding and excessive runoff into local creeks and rivers. WPC highlights level 1 to 2 risk for excessive rainfall as a result. If additional short term higher resolution guidance trickles in within the next 24 hours or so with similar output as the RRFS/REFS, then a Flood Watch could be considered in future forecast cycles. Beyond this rain during this period, the daytime high temperatures are expected to slightly lower with widespread clouds, rain-cooled air, and the modest northeasterly flow that arrives behind the front. Overnight lows don't budge much and remain very humid.

The rain chances shift more southeastward primarily toward and into the coastal plains from late Tuesday into Wednesday. However, the uncertainty regarding some leftover vorticity with the tropical disturbance across Mexico remains for mid to late week. Majority of the guidance gradually lifts the leftover spin of this disturbance northeastward, perhaps paralleling near or along the Texas coast. This would keep rain and storm chances across our coastal plain counties for much of Wednesday through Friday. If the leftover spin advances farther inland and more on a northerly progression than a northeasterly one, then rain and storm chances would spike across our region with more concern for additional heavy rainfall and flooding.

Another wrinkle in the forecast that a number of medium range model guidance has started to pick up would be a upper level disturbance within the northwesterly flow aloft across the Texas panhandle that could make its way towards and into Central Texas during the Friday into Saturday timeframe, helping to generate the potential of more scattered shower and storm chances across the region.

The prospect for dangerous heat mentioned in yesterday's discussion during the mid to late week time frame has lowered slightly as the result of weaker 700 and 500 mb heights with the presence of the disturbances mentioned above. However, with that said, it still remains hot and humid with heat indices in excess of 105 degrees in places, along and east of the I-35 corridor from Wednesday through Saturday. While the chances for the issuance of heat products may have lowered from yesterday's forecast, continue to practice and promote heat safety!

AVIATION

(00Z TAFS) Issued at 615 PM CDT Sat Jun 13 2026

Some isolated showers may continue for the next hour or so, but then will dissipate after sunset. Gusts from 20-25 knots may continue through 02Z at I-35 terminals and linger through 06Z along the Rio Grande. Ceilings will mainly be MVFR as they redevelop tonight, though local IFR conditions are also expected. Ceilings return to VFR between 15-17Z. A surge of moisture moves into the area tomorrow with showers and thunderstorms expected to develop in the afternoon. Included TEMPO groups at I-35 terminals but timing may need to be slightly adjusted.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 78 93 76 86 / 10 50 50 90 Austin Bergstrom Intl Airport 76 92 75 86 / 10 50 50 90 New Braunfels Muni Airport 77 91 75 86 / 10 60 50 90 Burnet Muni Airport 75 91 73 82 / 10 30 70 90 Del Rio Intl Airport 79 96 77 89 / 0 0 40 80 Georgetown Muni Airport 77 92 73 83 / 10 40 70 90 Hondo Muni Airport 76 91 76 87 / 10 30 50 90 San Marcos Muni Airport 76 91 75 86 / 10 60 60 90 La Grange - Fayette Regional 78 92 77 86 / 10 60 50 90 San Antonio Intl Airport 77 91 76 86 / 10 50 50 90 Stinson Muni Airport 77 91 76 87 / 10 50 50 90

EWX WATCHES/WARNINGS/ADVISORIES

None.