Sunday: Skies will eventually clear out enough to get us into the upper 70s late this afternoon, despite cooler north breezes at 5-15 mph. Tonight will clear and cool with lows in the low 50s.
Extended: Hot and humid air will likely make an extended stay, beginning Wednesday. There is some discrepency in the models as to whether or not a weak cool front will interrupt the heat for a day or two. But the consensus suggests otherwise ... with the hottest airmass of the season so far coming in time for the Memorial Day weekend.
And by the way, April 2012 was the 5th warmest April on record globally, completing the warmest 12-month period in 117 years. And the trend continues ...