Back in the WeatherBlog Blockhouse this morning after working up a sweat in the sunshine, in a jacket and tie, while over at University of Maryland Medical Center on assignment. Bright sunshine and summer-like highs in the 80s will make today and tomorrow seem more like October in L.A.

But forecasters at the National Weather Service forecast office in Sterling, Va. caution that this can’t last, as another pesky autumn cold front lurks off to our north and west.

The specifics are a bit uncertain. Forecast models don’t agree well on this one. But it seems likely we’ll see some chance for rain by tomorrow night, with temperatures knocked back by 20 degrees or so on Thursday.

We can thank a big high-pressure system off the Carolina coast for the mild weather. Highs circulate in a clockwise direction. That means this one is pumping warm air our way out of the Deep South.

The forecast highs of 82 or 83 for today and tomorrow are at least 10 degrees above the long-term average for this time of year in Baltimore. But they’re well short of the record highs, which are still in the 90s.

But it’s autumn, and that means periodic intrusions by increasingly cold air to our north. The next one will advance on us behind a cold front, triggering rain along the frontal boundary. Daytime highs will only reach the mid-60s from Thursday into the weekend.