HRRR simulated radar shows rain briefly mixing with and changing to snow in some areas Tuesday before ending.

The Arctic front predicted to set hundreds of cold records across the eastern United States will sweep through the Washington region early Tuesday, bringing a sudden and startling drop in temperatures. Enough moisture may even linger as cold air streams in for some wet snowflakes late Tuesday morning.

The drop in temperatures will be a bigger story than the snow. Considering the 70-degree temperatures on Monday, the sudden drop into the 30s on Tuesday will come as a shock, especially factoring in howling winds, gusting to around 30 mph.

By Tuesday night, temperatures plummet into the 20s, with wind chills dipping into the teens. The 24-hour change in temperature will be near 30 degrees and it will feel like a 40-degree change (factoring in the wind).

Twenty-four-hour predicted change in temperature between 10 p.m. Monday and 10 p.m. Tuesday from the NAM model.

The snow chance

If it snows late Tuesday morning, temperatures are unlikely to fall low enough for it to stick to roads, but some of our colder areas could see a quick coating on mulch, car tops and other cold, elevated surfaces.

The precipitation will start as rain during the predawn hours Tuesday and could mix with and/or change to snow in the mid- to late-morning hours as temperatures fall into the mid- to upper 30s. The rain and/or snow should end around early afternoon.

Forecast radar from the NAM model on Tuesday.

Snow is not a guarantee. If the precipitation ends before temperatures cool sufficiently, we may just see rain.

The cold

Irrespective of whether we see flakes, the shift to winterlike conditions will come on suddenly.

During the predawn hours Tuesday, temperatures will be in the 50s. But by dawn Tuesday morning, they’ll fall into the low to mid-40s. Then, by midday, they’ll drop into the mid- to upper 30s, where they’ll remain into the afternoon.

Forecast temperatures from the high-resolution NAM model between 4 a.m. Tuesday and 7 a.m. Wednesday.

After dark, temperatures really topple. By 10 p.m. Tuesday, most areas will have air temperatures between 25 and 30. And by Wednesday morning, lows bottom out between about 20 and 25.

Wind chills early Wednesday morning are likely to hover in the teens.

Forecast wind chills at 7 a.m. on Wednesday from the high-resolution NAM model.

High temperatures on Wednesday afternoon are then only forecast to reach the upper 30s.

Forecast highs on Wednesday from the National Weather Service.

While the intensity of the cold will ease starting Thursday, temperatures are forecast to remain below normal through the weekend, with highs mostly in the 40s — more typical of December than November.

Records

Temperatures on Wednesday may be low enough to challenge a few records:

• Dulles could approach the record low (minimum) of 21 set in 1963 and the record low maximum of 38 set in 1996.
• Baltimore and Washington could approach their record low (minimum) of 22 from 1911.
• The record low maximums of 31 and 32 in Washington and Baltimore, from 1911, are unlikely to be threatened.

If Washington’s high on Wednesday is 38 or lower, it will be the third-coldest high so early in the season on record, trailing 31 from the same date in 1911 and 35 on Nov. 11, 1987 (when 11.5 inches of snow fell).