We're in for a drippy day today in Central Maryland as we wait for the next cold front to move through late this afternoon. And once it finally gets by us, we're in for some of the first really nippy temperatures of the season.

The National Weather Service forecasters at Sterling have posted a Freeze Watch for the early hours of Friday morning, from Allegany County across Maryland's northern tier of counties to northern Baltimore County and Harford (dark blue on the map). The city and southern Baltimore County are not included. The forecast low for BWI tonight is 38 degrees.

Low temperatures in the watch zone will reach the low 30s, forecasters say. "A Freeze Watch means sub-freezing temperatures are possible. These conditions could kill crops and other sensitive vegetation."

Friday still looks good, with sunny skies. But daytime highs will only reach the low 50s. And the forecast from there goes downhill again.

Another low pressure system arrives from the Carolinas late Friday and Saturday just as a new surge of cold air moves through the region. Forecasters expect a cold and rainy coastal storm to develop, with Saturday's highs only in the 40s at BWI, and an 80 percent chance of rain.

"Hate to mention it," this morning's forecast discussion adds, "but precipitation initially falling into a rather chilly air mass ... which will only be enhanced by evaporative/diurnal/dynamic cooling processes. Thus, need to consider elevation-dependent snow or snow/rain mix during the late night/early morning hours. ... Changing to snow around 1,500 feet."

For Central Maryland, AccuWeather.com puts the rain/snow line well to our north, somewhere around Philadelphia. They also add some storm-track uncertainties. Here's their discussion of the Saturday storm possibilities.

Whatever, looks like a good day for a book and a fire in the fireplace. Or a pub.