Cold front is expected to bring rain to the region
The record hot summer San Antonio experienced has now carried over into the first month of meteorological fall.
July was the second hottest ever recorded in San Antonio. We followed that up with the hottest August ever recorded. And now, September is in the books as the hottest September the Alamo City has ever seen since records began in 1885.
The average high temperature during September was 98.2 degrees, beating the old record of 96.5 degrees set in 2019. That is actually quite a wide margin to set a monthly record. To put it in a bit more perspective, had the high temperature risen only to 46 degrees on Saturday, the monthly record still would have been set.
The top four warmest Septembers of all time have come in the last 20 years.
The September heat was relentless. Temperatures reached at least 90 degrees every single day, only the third time that’s ever happened in September. Temps also reached at least 100 degrees 11 times, which was the most San Antonio has ever recorded in the month.
Big shift in weather pattern
The overall weather pattern this week will open the San Antonio area up to chances of rain and thunderstorms that could bring the risk of localized flooding.
Today brings about the first decent round of thunderstorms, particularly for the evening commute east of San Antonio. An advancing trough of low atmospheric pressure will create a moisture-rich environment with air pulled in from the Gulf of Mexico. Weather forecast model guidance suggests that scattered thunderstorms will push into the region by late this afternoon.
What can you expect as you head home from work today? Scattered downpours are possible and could force you to put the windshield wipers on high, with rainfall totals likely to land near half an inch. Some areas could see higher rainfall totals, especially as the week progresses.
Temperatures today likely will be the warmest of the week, with highs generally in the low 90s after starting the day in the low 70s.
Widespread rain likely
Wednesday and Thursday both bring the risk of widespread and potentially heavy rainfall and even the risk of flooding.
A cold front will be pushing deeper into the Lone Star State by
Wednesday. Ahead of the front, an opposing warm air mass carried by southeasterly winds will set the stage for numerous showers and thunderstorms. Scattered storms will be possible as early as Wednesday morning, so it may be a good idea to prepare for the possibility of a slower commute to work, especially along and east of Interstate 37 and Interstate 10.
Widespread downpours will be likely by Wednesday evening, so make sure to keep the rain gear with you in the next couple of days. Heavy rain could lead to some flash flooding, especially north of San Antonio.
Rainfall could total at least an inch, or even more in localized pockets, across South Texas. Meanwhile, areas in Central and North Texas will be most at risk for some small stream flooding. Widespread flooding is not expected as stream flows are either low or nonexistent, according to the National Weather Service.
As the cold front approaches San Antonio Thursday morning, storm chances will linger. Thursday will not be a total washout, with chances of rain most likely early and later in the day. The cold front is forecast to push through San Antonio by Thursday evening, bringing with it a line of potentially strong thunderstorms.
The exact timing of the front is still uncertain, but if storms come through during the late afternoon, they’ll have unstable air to nurture them. Severe weather does not look likely, but a few of the strongest cells may bring damaging winds and large hail.
Temperatures drop Wednesday into Thursday, with highs generally in the upper 80s expected. Nighttime low temperatures will be in the lower to middle 70s under mostly cloudy skies.