10:15 a.m. - Winter storm warning issued for much of region Thursday and Thursday night

The National Weather Service has issued a winter storm warning for much of the region, except Calvert and St. Mary’s counties, which are under a winter weather advisory. The warning is in effect from 3 a.m. Thursday to 6 a.m. Friday.

The Weather Service expects 3 to 6 inches of snow and up to a quarter inch of ice from Thursday’s storm. “Travel could be nearly impossible,” the Weather Service writes. “The hazardous conditions could impact the morning or evening commute.”

We’ll have a new, detailed briefing on the storm published between midday and early afternoon.

Original forecast from 5 a.m.

Today’s daily digit

A somewhat subjective rating of the day’s weather, on a scale of 0 to 10.

5/10: After morning wind chills in the teens, a somewhat nicer afternoon with partial sun and 30s. Anyone else ready for spring?

Express forecast

  • Today: Partly sunny, colder, a.m. wind chills in teens. Highs: Mid- to upper 30s.
  • Tonight: Snow developing before dawn. Lows: Mid- to upper 20s.
  • Tomorrow: A.m. snow/sleet, p.m. sleet/freezing rain. Highs: Upper 20s to low 30s.

Forecast in detail

After a break yesterday and today, the parade of storms continues late tonight through tomorrow night, with what could be our most impactful storm of the winter so far due to the combination of cold temperatures, ample moisture and the weekday timing. We should dry out by Friday afternoon, but then turning frigid Friday night and remaining cold through the weekend.

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Today (Wednesday): Temperatures trend colder today as cold high pressure settles in over the Mid-Atlantic. Morning readings rise through the 20s to near 30, with a 10-15 mph breeze from the northwest keeping wind chills in the teens. The wind should lighten by afternoon with highs only in the mid- to upper 30s under partly sunny skies. Confidence: High

Tonight: Clouds increase this evening with snow moving in from the southwest around 2 to 5 a.m. Could be mixed with some sleet. Roads and sidewalks should have a coating by sunrise as temperatures fall to the mid- to upper 20s. Confidence: Medium-High

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Tomorrow (Thursday): Cancellations of in-person activities are likely as snow, possibly mixed with sleet, continues during the morning. With cold temperatures in the 20s, accumulation is expected on both untreated and treated surfaces. We do expect the precipitation to change to all sleet from south to north around 9 a.m. to noon, as warmer air moves in at the mid-levels of the atmosphere. We may see a lull in the steady precipitation midafternoon into early evening as temperatures remain at or below freezing. Confidence: Medium

Below is our current thinking for snow/sleet accumulations. We may or may not tweak this as new model data comes in this morning into midday...

Tomorrow night: Lighter sleet and freezing rain could pick up again during the evening and overnight, with temperatures in the upper 20s to around freezing. Generally speaking, we should see colder temperatures and more sleet north and west of D.C., versus warmer temperatures and more freezing rain from D.C. to the south and east. Confidence: Low-Medium

A look ahead

Light sleet or freezing rain could linger into early Friday morning, especially east of the District and Interstate 95. But we should dry out by late morning into the afternoon, with some peeks of sun and highs near 40, as winds turn breezy from the northwest. Becoming mostly clear and very cold Friday night with lows in the midteens to mid-20s. Confidence: Medium-High

Plenty of sun this weekend, but starting off with a cold and breezy Saturday, as highs only reach the low to mid-30s after those chilly overnight lows. Saturday night lows drop back into the frigid teens area-wide. We’re a bit more comfortable by Sunday afternoon, with highs in the mid-30s to near 40 and light winds. Confidence: Medium-High

Snow potential index

A daily assessment of the potential for at least one inch of snow in the next week, on a 0-10 scale.

8/10 (↑): Looking good for at least a couple of inches of snow (or a combo of snow and sleet) early Thursday before changing over to mostly sleet and freezing rain.