Today and Saturday will be mostly sunny with highs in the mid-80s. A much stronger storm system will move out of the Rockies and cross Texas on Sunday. Thunderstorms are likely Sunday afternoon and night, and some storms could be severe. Much cooler air will arrive Tuesday and drop temperatures 10 to 15 degrees. Lows will be in the upper 40s to mid-50s and highs in the upper 60s to mid-70s Tuesday through Thursday.