South Texas is facing a dangerous heat day before the forecast shifts toward a possible storm threat late Friday into Saturday. Heat index values could climb near 110 degrees today, while the next round of rain chances depends on how storms develop to the north.
Heat index to soar today
After a brief period of morning cloud cover, full afternoon sunshine is expected to push temperatures into the upper 90s. Thick humidity will make it feel even hotter, with heat index values topping 100 degrees by noon and possibly reaching 110 degrees or higher at peak heating.
Excessive Heat Warnings are in effect today, according to KSAT meteorologists. The combination of strong sunshine, hot temperatures, and heavy humidity is driving the most intense heat of the stretch.
Friday brings a limited storm chance
On Friday, a few storms may move in from the northwest before dawn, but they are expected to stay north of San Antonio. Added cloud cover should trim temperatures slightly, though it will still be hot and humid and heat index values may again rise above 100 degrees.
Outflow boundaries from storms farther north could help spark new storms Friday evening and Friday night. KSAT notes that these boundaries will be the deciding factor in where any storms form, which makes the late-day forecast highly dependent on how the atmosphere evolves.
Saturday keeps the storm threat in play
Rain chances continue into Saturday, with a 50% chance through the afternoon. It will not rain all day, but some areas could see heavy rainfall if storms develop in the right places.
The overall pattern stays unsettled because the placement of storms will still hinge on outflow boundaries. Quieter weather is expected on Sunday for Father’s Day, offering a calmer end to the stretch after the heat and scattered storm threat.
KSAT meteorologists say the forecast remains changeable, especially for Friday evening through Saturday, when storm coverage could vary sharply across the region.
