Crepuscular rays (or sunbeams) at the Iwo Jima memorial. By Brian Moulton via Flickr. (Brian Moulton)

* Frost advisory for immediate D.C. metro area 12 a.m. to 10 a.m. Monday | Freeze warning southwest of Fairfax County, and in effect for Loudoun, Frederick, and western Montgomery counties *

9:30 p.m. - Freezing warning expanded to the north

The Weather Service expanded the freeze warning, previously in effect just for areas southwest of Fairfax County, to the north. It now includes Loudoun, western Montgomery and Frederick counties. In all of these locations, the temperature may fall to near or slightly below freezing tonight, ending the growing season. You’d be wise to cover or bring in sensitive plants.

Locations under frost advisories and freeze warnings. (National Weather Service)

Original post from late Sunday afternoon

First the wind, and then the cold. The first act, featuring strong gusts, will end over the next few hours. The second act will probably result in the coldest night for the region since late April, with temperatures falling close to the freezing mark in our colder areas. Make sure to bring your plants inside tonight, and if you have a household like mine, also ensure that they are protected from cats that like to chew on plant stems and leaves.

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Through tonight: Mostly sunny and cool, with temperatures in the upper 40s to low 50s for the remainder of the afternoon. Winds and gusts will gradually subside by sunset. Clear conditions and light winds will allow temperatures to drop off rather efficiently overnight. As such, a frost advisory is in place for much of the metro area where lows are expected to fall into the mid-30s. Right around downtown, frost is less likely with lows in the upper 30s. In our southwest areas, including Fauquier and Prince William counties, winds are expected to go calm, which may allow some spots to dip into the low 30s, prompting a freeze warning.

View the current weather at The Washington Post.

Tomorrow (Monday): It will be a cold start, but temperatures will recover nicely as the day progresses. With high pressure firmly in place, skies will be mostly clear with a light south wind at 5 to 10 mph. Afternoon highs will top out in the upper 50s to around 60 degrees. Partly cloudy tomorrow night, and not nearly as cold, with lows from the upper 30s to low 40s.

See Brian Jackson’s forecast through next weekend. And if you haven’t already, join us on Facebook, and follow us on Twitter and Instagram. For related traffic news, check out Gridlock.

Saturday night wind: Things went from calm to quite windy in a matter of minutes Saturday night, as a potent cold front swept through the region a bit earlier than forecast. Most of us experienced gusts from 35 to 45 mph, with some higher values over the Chesapeake Bay. The gusty winds resulted in 34 reports of downed trees and branches, mainly in the elevated areas north and west of the District. The full list of wind gusts can be found here.

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