PM Update: Coldest March night in decades ahead, remaining cold on Tuesday

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Temperature Map

Temperatures: Latest D.C. area temperature map. See interactive map on our Weather Wall.

The snow is over, and the dig out phase is underway. If it wasn’t for highs in the mid-and-upper 30s around midnight, daytime temperatures today would have matched readings about as cold as we’ve ever recorded in March. Those temperatures, sitting in the teens to low 20s most spots late this afternoon, drop off markedly overnight. On the heels of today’s  extraordinarily cold readings, tonight’s temperatures are likely the coldest in decades in March.

Through Tonight: Skies continue to clear, maybe setting up a decent sunset across the area? Winds still blow around 10 mph — with higher gusts — into the evening, but they tend to wane overnight. Clearing skies, lighter winds, and a fresh snow pack mixed with brutal arctic air all combine to create extra cold lows. Temperatures dip to near-record territory for the date and month, ranging from around zero in the coldest spots north and west to perhaps the upper single digits or around 10 in the warmest spots like downtown.

These temperature will cause everything to freeze over and will be a challenge for crews to treat as salt/chemicals lose effectiveness below 10-15 degrees.  Be extremely careful on untreated roads and sidewalks overnight tonight through Tuesday morning.

Tomorrow (Tuesday): After a start that would be cold even by January standards, we don’t move past freezing. Sunshine at times feels good, but it’s often veiled by high clouds. Highs in the upper 20s to around 30 in most spots won’t promote too much melting. Still, you’ll probably notice some if we get enough sunshine. Winds are quite light, around 5 mph from the east, and maybe flipping to the south late.

See Jason Samenow’s forecast through the weekend. And if you haven’t already, join us on Facebook and follow us on Twitter . For related traffic news, check out Dr. Gridlock.

Tonight’s cold benchmarks: For D.C. and Baltimore, even though it’s going to be really cold tonight, it has some difficult temperatures to exceed in order to make history — as March 4 holds the record for the all-time coldest temperatures for the month. In D.C., meeting or besting the record is a long shot, and even Baltimore may be challenged to get there. The numbers to reach are 4 degrees in D.C., and 5 degrees in Baltimore, each set in 1873. At Dulles, where the historical record is only about half as long, the daily benchmark of 6 degrees in 1980 is certainly in play, and the monthly record of -1 degree set in 1993 may also fall.

12z GFS forecast lows for Tuesday morning. They're probably a little cold in spots. (Weatherbell.com)

12z GFS forecast lows for Tuesday morning. They’re probably a little cold in spots. (Weatherbell.com)

Back to D.C., anything lower than 14 degrees will be the coldest on record for March at Reagan National. 14 degrees was last reached as recently as 2009 (after March snow that year). If we get down to 10 degrees or lower in D.C., it’ll be something we haven’t seen in March since the late 1800s.

SchoolCast

2.5 apples: Widespread delays likely, and a good number may close for yet another day.

FedCast

2 domes: 50/50 chance of unscheduled leave policy. Delay less likely, and shutdown unlikely.

Airport snow totals: Reagan National got 3.8″, Dulles got 4.9″, and BWI got 3.8″.  These amounts were generally on the low-end of other reports around the region, in the 4-7″ range.

Also on Capital Weather Gang

D.C. area forecast: Snow concludes, but frigid tonight