From Rusty Garrett:
A cold front is surging south, arriving in Central Texas overnight and early Friday. This front will bring temperatures down into the 70s Friday and below average Saturday.
Temperatures overnight cool into the upper 40s and lower 50s, depending on the speed of Friday's front. If the front arrives a bit slower, readings Friday morning may only drop into the lower and middle 50s. Winds shift to the west overnight, but will come more from the northwest Friday. Highs Friday should only reach the lower 70s. Once the sun goes down, temperatures will remain nearly 10° degrees below average in the middle 30s.
Although abundant sunshine is in the forecast during the day, Saturday's high temperatures will only reach the upper 50s and lower 60s. Temperatures should fall into the upper 30s and lower 40s Saturday night, but south winds return, allowing for warm air to move back in Sunday into early next week when scattered rain returns.