High temperatures nearly 20 degrees above normal are in the forecast Monday and Tuesday, before starting to fade on Wednesday and moving into more seasonable weather. Beyond that, forecasters looking at the long-range see hints of colder weather ahead.
Highs could approach 70 degrees early this week. Normal highs are in the upper 40s to around 50 this time of year, and we are expected to return to that sort of weather Thursday through the weekend.
Monday was the warmest December day at BWI since 2006, when the airport reached 72 on Dec. 18 and 75 on Dec. 1, according to the National Weather Service.
The warmth isn't necessarily a harbinger of weather to come, forecasters said.
December 2010 started with a 62-degree high, but things quickly turned frigid. All but one day out of the month dipped below freezing at BWI Marshall Airport, and the average temperature of 32.4 degrees was 4.3 degrees below normal.
On the other hand, December 2009 started with three days in the 50s and 60s but ended with an average temperature of 34.8 degrees, 1.9 degrees below normal.
Seven days during last December reached 60 or above, building up an average temperature of 42.2 degrees, 5.5 degrees above normal.
Forecasters don't expect a repeat of that, given larger snowpack and more frigid air building across Canada relative to last December. Both Foot's Forecast and AccuWeather.com's Henry Margusity expect a threat of a winter storm some time in the middle of December.
Speaking of snow -- make your guess for this winter's snowfall at BWI. Typical snowfall is about 20 inches, though it wouldn't take much to beat last winter's paltry 1.8 inches.
Have a weather question? E-mail me at firstname.lastname@example.org or tweet to @MdWeather.
Warm-up to last into Wednesday
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