Wednesday will start partly cloudy with light south winds and temperatures near 80 degrees. By lunchtime, the clouds will give way to plenty of sunshine, and temperatures will quickly climb. Expect readings around 91 degrees by noon, but with humidity factored in, it could feel closer to 101 degrees. In other words, it may not be the best time for that post-lunch walk around the block.
The afternoon will be hot and humid, with dew points remaining in the low 70s, which is a temperature threshold that can feel oppressive across South Texas. That humidity will push heat index values into the low 100s. A few spotty showers could develop during the afternoon with rain chances near 20%.
Not much change is expected on Thursday, with a warm and humid morning followed by a hot, sunny and humid afternoon. Temperatures will climb into the upper 90s, with heat index values between 99 and 102 degrees.
In the short term, as the strong upper-level ridge of high pressure, or heat dome, eventually breaks down, it will still drive Texas’ weather. Southerly winds will continue to funnel hot, moist air into South Texas.
The extreme heat won’t likely end this week or even into next week, as the forecast calls for temperatures hovering between 97 and 100 degrees, with heat index values a few degrees higher. The National Weather Service’s Heat Risk Index has most of Texas under a level 2 to level 4 risk, ranging from moderate to extreme, for heat-related effects over a 24-hour period.
As of Monday, this is officially the fourth-warmest start to September on record, with an average temperature of 87.9 degrees.
Here are the top five warm starts of September:
• 2000: 90.0 degrees
• 2023: 89.3 degrees
• 2013: 88.4 degrees
• 2026: 87.9 degrees
• 1989: 87.9 degrees
The warmest temperature so far this month was 100 degrees, recorded Sept. 2 and Sept. 3. For comparison, the average high temperature for September is 92 degrees.