Several Hours of Heavy Snow Possible

Tuesday, January 7th, 5AM

A small, but energy-packed storm system will cross the region later today bringing a period of moderate to heavy snow during the afternoon and early evening.  Expect clouds to increase this morning and rain or a rain/snow mix to develop around 1PM across central MD.  There will likely be shallow layer of warm air right at the surface, and you may even say to yourself that it’s too warm to snow, but once the precipitation becomes steady, cold air just above the surface will mix down causing rain to change to snow.

Models are pretty consistent that the snow will be moderate to heavy at times between 2 and 6PM, so even if temperatures are slightly above freezing, the snow rates will probably overcome road temps and bring dangerous slushy and snow-covered conditions.  The gfs model has BWI airport around 33* during the heaviest precipitation, so areas to the west of that will be at least that cold, and maybe even at or below freezing.  Either way, driving this afternoon and evening will be a headache.  Once the sun sets, all areas from 95 and points west will likely fall below freezing until tomorrow morning.

The snow should end quickly this evening, exiting the area by about 8PM with total accumulations from a coating to an inch along the bay, 1 – 2″ along and just west of 95, and 2 – 3″ in the normally colder areas to further west and north of I 70.  Most counties west of the bay are under a Winter Weather Advisory beginning at noon with the exception of those bordering the Chesapeake Bay where there may be a longer period of mixed precip which will reduce impacts (AA, PG, Charles, Calvert, St. Mary’s counties).  But even in those areas, there will likely be a period of all snow this evening.

Be careful this afternoon, and if there are any changes, I’ll update around lunchtime.