A (mostly) sunny week will get colder
Looks like we will have a very pleasant and unseasonably mild start to this week, with a high near 50 degrees today and in the mid-50s on Tuesday. But a cold front is due to pass by late on Tuesday, dropping daytime temperatures into the low 40s by Wednesday - about 5 degrees below normal for BWI at this time of year. The lows will sink into the near-normal mid-20s.
The good news is that skies will remain sunny for pretty nearly the entire week, if the forecast holds up. The only smudge on the forecast is the "mostly cloudy" forecast for Tuesday as the front passes. But there is no rain at all expected from the frontal passage, or right through the weekend.
And that will be a nice break, indeed. Baltimore-Washington International Thurgood Marshall Airport has recorded 51.86 inches of precipitation so far this year. That is nearly 10 inches of surplus beyond the 41.94-inch average for an entire year. (The surplus is the dark green area in the chart). It is very close to becoming the fourth-wettest year in the past 30 years at BWI.
2003: 62.66 inches
1979: 58.98 inches
1996: 58.31 inches
1989: 51.88 inches
2009 (to date): 51.86 inches
Average (full year): 41.94 inches
Average (to Dec. 14): 39.96 inches