A strong high pressure system, which has developed just to the east of Texas, is expected to linger near the state over the upcoming week. This weather system will have a “heat dome” effect, in which the stagnant high air pressure will keep hot air from rising, while also preventing cooler air from entering the area.
The result? Persistent near-average to above-average temperatures are expected across all of Texas this week, including in San Antonio. Temperatures may also build slightly by the weekend, as the center of high pressure moves closer to our region. Here’s what you can expect.
Monday will start with mild temperatures in the mid- to upper 70s under partly cloudy skies. Clouds will give way to mostly sunny skies after 9 a.m., allowing temperatures to rise into the lower 90s by noon. Hazy conditions are also expected, as a plume of Saharan dust is expected to push through South-Central Texas during the first half of the day.
The Saharan dust will lead to poor air quality in San Antonio, with concentrations of particulates in the air potentially reaching levels considered unhealthy for sensitive groups, including young children, older adults, and people with asthma or other respiratory problems. Those affected should limit time outdoors and avoid strenuous activity outside.
By late afternoon, temperatures in San Antonio are expected to peak at 95 or 96 degrees. While the Saharan dust will help keep humidity slightly lower, heat index values, or “feels like” temps, will still reach 99 or even 100 degrees.
Breezy weather will persist throughout the day, with sustained winds of 15 to 20 mph through the afternoon and evening. Gusts could be as strong as 30 mph.
High atmospheric pressure is expected to shift slightly to the east by the middle of the week. Even so, it will still have a major influence over Texas weather, keeping the days mostly dry and the temperatures steady over the region.
San Antonio temperatures are expected to top out at 94 or 95 degrees from Tuesday through Thursday, while morning temperatures are expected to start out in the mid-70s each day. Humidity levels will stay elevated, with heat index values expected near 100 degrees.
A few isolated showers and storms may also become possible across parts of Southeast Texas, with about a 20% to 30% chance of rain in places like Houston and Beaumont. Rain chances will be lower (around 10%) in San Antonio.
The high pressure system is expected to shift closer to South-Central Texas by Friday and Saturday, resulting in slightly warmer temperatures across the state. San Antonio temps are likely to reach 96 or 97 degrees, while many areas across North Texas will experience triple-digit temps.
If you have outdoor plans for the Fourth of July, the forecast is still looking favorable. Although a few isolated showers or thunderstorms can’t be ruled out, rain chances are expected to remain below 20%.
After the holiday, a weak system of low pressure could increase rain chances across the area July 5-7. However, the system will continue to contend with high pressure overhead, which should keep any rainfall scattered rather than widespread.