This year there are 2 dbl regionals in the SOWDIV, both put on by TX region. One has held in January at MSRC (south of Ft. Worth) - the first time SCCA ever raced there. It was wet with freezing temperatures but the race went on. You had scrape ice off your windshield just to get from the hotel to the track!
The next dbl regional is at TMS (north of Ft. Worth) on 9/1-2 which is a good one. For the most part, SOWDIV is a national division.