San Antonio Sizzles Under Heat Advisory as Pop-Up Storms Crash Afternoon

San Antonio is starting Thursday with clear skies and temperatures around 80 degrees, but the relatively calm morning will give way to another triple-digit afternoon. A Heat Advisory remains in effect as the city heads toward a high near 101, with a chance of showers and thunderstorms arriving after lunch.

According to the National Weather Service Austin/San Antonio, heat-index values could reach 105 degrees in the city and up to 110 across the broader advisory area. The alert covers Bexar County through 7 p.m. Thursday, when hot temperatures and humidity could raise the risk of heat illness.

This is a sharper turn from Wednesday's forecast, which focused mostly on uninterrupted heat. Thursday brings the first meaningful storm window in several days, although the rain will be spotty rather than a citywide washout.

Storm Chances Arrive After Lunch

Rain chances increase after 1 p.m., with a 30% chance of showers and thunderstorms through the afternoon and evening. Stronger storms could produce gusty winds and locally heavy rainfall, though widespread severe weather is not expected.

Thursday night will remain warm, with a low near 79 and a chance of storms before 10 p.m., followed by a smaller chance through about 1 a.m. Skies should become partly cloudy overnight, but the evening may still feel sticky, with heat-index values reaching as high as 101.

Friday Offers Only A Small Break

Friday will be mostly sunny and slightly cooler, with a high near 100 and a 20% chance of afternoon showers or thunderstorms. The heat index could still reach 104, while Friday night falls only to around 78.

A slight chance of storms lingers before 7 p.m. Friday, then mostly clear skies return. By Saturday, the forecast turns mainly dry and sunny, with highs near 98, followed by 99 degrees Sunday and another run of near-99-degree afternoons Monday through Wednesday.

Heat Safety Remains The Main Concern

Residents should drink plenty of fluids, stay in air conditioning or shade when possible and limit strenuous outdoor activity during the afternoon. Lightweight clothing, frequent cooling breaks and checks on older adults, neighbors, children and pets are especially important while the advisory is in effect.

Anyone showing signs of heat exhaustion should be moved to a cool place and given immediate attention. Heat stroke is an emergency, so call 911 if symptoms become severe.