The National Weather Service has issued a *Winter Storm Warning* that goes into effect at Midnight tonight through Monday Evening.
Timing:
Rain showers will develop between 5 PM and 7 PM this evening.
Rain will mix with Sleet between 7 PM and 10 PM.
Rain will change to a Wintry Mix of Snow and Sleet between 10 PM and Midnight.
Wintry Mix will change to Heavy Snow during the overnight hours.
Snow will continue, heavy at times through the afternoon rush hour.
Snow will taper off and end during the evening on Monday.
Temperatures:
Falling to freezing late this evening then into the mid to upper 20s by Monday morning.
Temperatures will then fall during the afternoon on Monday from the middle 20s into the 10s.
DC Storms 
I hope we get the period of sleet. That will put a nice foundation on the roadways, so we shouldn’t have our normal March sticking problems, even before the big temperature drop.