textproduct: Houston/Galveston

KEY MESSAGES

- Hot conditions persist through the week with the hottest days Tuesday and Wednesday.

- A Heat Advisory is in effect from 11 AM - 8 PM Tuesday.

- Tropical Storm Bertha is forecast to weaken as it approaches southeast Texas late in the week. While forecast uncertainty remains fairly high, residents should monitor the latest forecasts and evolution of this system.

- Corresponding rain and temperature forecasts for the local area are subject to changes later in the week and highly dependent on the tropics.

DISCUSSION

Issued at 1231 AM CDT Tue Jul 21 2026

The weather this week remains divided between the heat through Thursday followed by what will likely be a weakening Bertha.

First, the heat. Ridging over the Rockies will build southeastward into the southern Plains and across much of Texas. This ridge will provide ample subsidence, which will keep rain chances very low and raise our temperatures. While may mix out our dew points some in the afternoon, it will still be humid enough for heat concerns. Most areas this afternoon will rise into the upper 90s with some pockets near 100. Only the immediate beaches will stay in the low to mid 90s. The humidity this afternoon will make it feel more like 107-112 in many areas, and the Heat Advisory remains in effect from 11 AM to 8 PM today. Wednesday looks to be even hotter with the ridge center positioned over Oklahoma and northern Texas. Many areas away from the coast will likely exceed 100 degrees for highs (mid 90s near the coast). That also means our heat index values could be even higher, perhaps in the 110-115 degree range. We'll likely need at least another Heat Advisory for Wednesday, but Extreme Heat Watches/Warnings could be possible should more widespread areas see their heat index climb to or above 113. We may eke out a couple showers or storms Wednesday and Thursday afternoons as a weak backdoor front moves into the area, but chances are rather low (30% or less).

Now, the latter half of the week will hinge on the track and evolution of Bertha. Our ridge that is bringing us the heat will be the primary steering mechanism, dragging Bertha to the west paralleling the Louisiana Gulf Coast. On its path, it will be battling dry air entrainment and wind shear, likely weakening Bertha on its approach. For more information on its potential impacts to southeast Texas, please see the tropical discussion below.

After what is left of Bertha passes the area, ridging looks to dominate as the pattern amplifies further across the Central US. This means the potential for more heat and continued low rain chances this weekend into early next week.

Young

AVIATION

(12Z TAF Issuance) Issued at 623 AM CDT Tue Jul 21 2026

MVFR and localized IFR conditions due to patchy fog being observed this morning, especially at KCXO and KLBX, similar to what has occurred the past few nights. By 14Z all terminals are anticipated to return to VFR. Winds are expected to vary between west and southwesterly flow throughout the day. Overnight we may have another round of patchy fog; however, an increasing dewpoint depression may inhibit dense fog. A few of the usual fog prone sites may drop to MVFR during the 10Z-14Z timeframe, otherwise expect VFR conditions to continue overnight. Light and variable winds are likely across all regions tomorrow night.

Davis/Wingo/Bailey

MARINE

Issued at 1231 AM CDT Tue Jul 21 2026

High pressure over the western Gulf continues to bring light to moderate west-southwest breezes over the waters with seas around 2 to 3 feet. This should continue through Wednesday before influence from Tropical Storm Bertha potentially begins. There remains high uncertainty in the forecast track and intensity of Bertha, though the official forecast calls for weakening back to a depression late in the week. Given this, significant impacts in our waters is not expected, but some impact to small craft is possible if higher winds and seas materialize, mainly offshore.

Young

TROPICAL

Issued at 1231 AM CDT Tue Jul 21 2026

As of 10 PM CT, the center of Tropical Storm Bertha continues to slowly drift northwestward south of the Florida Panhandle. This should gradually pick up speed and turn more toward the west late Tuesday into Wednesday. On its forecast track, Bertha will move near the Louisiana coast late Wednesday through Friday morning, then potentially approach Southeast Texas late Friday. However, on its journey westward, Bertha will be battling dry air entrainment as well as northerly wind shear. This will likely result in a weakening Bertha with convection displaced to the south of its center. The official forecast from the National Hurricane Center calls for Bertha to weaken back to a depression near southwest Louisiana and remain that way on its approach to southeast Texas, if it survives.

Of course, this has implications for our local impacts. Regardless of what form Bertha is in on its approach, it appears most of the shower and thunderstorm activity will be displaced to the south. If some of the outer bands can make it to the coast, then some locally heavy rainfall would be possible. As it stands, the 90th percentile, or reasonable high-end, for rain from the LREF (GFS, ECMWF, and Canadian ensembles) around around an inch through this weekend. Some breezy winds are also possible, mainly near coastal areas and offshore.

Due to the high uncertainty, continue to keep up to date with the latest forecasts for any changes in trends over the next couple days.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 98 78 101 81 / 0 0 0 0 Houston (IAH) 100 80 103 82 / 0 0 0 10 Galveston (GLS) 94 81 96 83 / 0 0 10 30

HGX WATCHES/WARNINGS/ADVISORIES

TX...Heat Advisory from 11 AM this morning to 8 PM CDT this evening for TXZ163-164-176>179-195>200-210>214-226-227-235>238-300- 313-335>338-436>439.

GM...None.