Strong sunshine and warm, humid air straight out of Dixie could push Baltimore's temperatures into the 90s again today, with enough humidity to make it feel downright summery.
"Enjoy it while it lasts," said Jeff Warner, a meteorologist with Penn State Weather Communications. "If you want fall to come, though, it's tough right now, I guess."
Four days into autumn, the temperature in Caribou, Maine, was 82 degrees yesterday afternoon. It was 95 in Huntington, W.Va., and 90 at Baltimore's Inner Harbor and at BWI Marshall Airport.
Boston and Baltimore are both expecting highs near 92 degrees today. Neither would set a record for the date. The Sept. 26 record for Baltimore is 95 degrees, set in 1970.
If the thermometer reaches 92 at BWI today, it will be the warmest Sept. 26 here in 21 years.
"It's a little unusual, not something you do every year. But we've certainly done it before," Warner said.
There are several factors behind the early autumn heat, he said. The first has been a strong high-pressure system parked over the eastern United States, providing clear skies and lots of sunshine.
"It started as a Canadian high, and we had some crisp nights and sunny, mild days," Warner said. "Now it's moved off the coast ... a pattern not all that dissimilar from what we see in summer - a big high that's morphed into a 'Bermuda high.'"
That means the clockwise flow around the offshore high is bringing warm, humid air up from the Deep South.
"Now the humidities are coming up, and it feels quite muggy," Warner said. With more moisture in the air, it will be harder for the atmosphere to give up its heat at night, putting a temporary end to our crisp nights in the 50s or lower. Lows tonight and tomorrow night will be in the mid-60s.
But hot weather at this time of year can't last. There's a cold front headed our way that brings a fair chance for showers and thunderstorms tomorrow.
Once the front has passed, Friday will dawn somewhat cooler, though well above seasonal averages. And for the weekend, Marylanders will once again enjoy sunny skies and dry, breezy weather with daytime highs in the 70s and lows in the 50s.
"Even farther into next week it stays relatively mild, in the 70s, maybe 80 degrees," Warner said. "I don't see any chilly weather soon."