UA5243 SBA-SFO today (April 12) is canceled "because of current or anticipated disruptions related to airspace and/or ground congestion"
It looks like it is quite windy at SFO today, but perhaps the weather issue is amplified by the closure of SFO 28L??
Yes, when the winds shift due to a storm (which is currently incoming), and they can't do takeoffs on the 1s, it's a problem.