D.C. area forecast: Cold with big winter storm likely looming for Wednesday night into Thursday

** Winter storm watch Wednesday night and Thursday **

5:10 a.m. update: Overnight modeling holds steady with our impending storm. The European model nudged the mixed risks slightly to the right and less into the District for Thursday morning. But no big surprises.

Today’s Daily Digit

A somewhat subjective rating of the day’s weather, on a scale of 1 to 10.

6
Still cold, but thankfully more sunshine today (compared to yesterday)

Express Forecast

Today: Mostly sunny. Highs: 28-32.

Tonight: Some clouds. Lows: 10-20.

Tomorrow: Clouds increase. Highs: 28-32.

FORECAST IN DETAIL

Temperature Map

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

It may be difficult to focus on today and tomorrow when we have potentially the biggest snowstorm of the season looming by tomorrow night, so I’ll do my best to keep the pre-storm details to a concise minimum.   It’s cold and sunny today, dark tonight, and cloudier tomorrow. Then we watch as a powerful storm system cranks up the Eastern Seaboard.

The first flakes could begin between 8 p.m. and midnight tomorrow night.  Snow may be heavy at times overnight Wednesday into Thursday though it may mix with sleet or even rain from the District to points east and south by Thursday morning.  Any mixed precipitation should change back to snow before ending.

Accumulation potential could land this storm as our biggest of the season, but watch for our official first projection midday.  Beyond that, the upcoming holiday weekend looks mostly cold with a couple chances of snow showers.

Today (Tuesday): More sun, less breeze helps the situation marginally, but most areas continue to be confined below freezing as highs only top out in the upper 20s to low 30s.  Light winds at 5-10 mph from the north.  Confidence: High

Tonight: Just a few clouds around with light winds from the north as lows drop into the low teens in the outer suburbs to the upper teens in the city.  Confidence: High

For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend…

Tomorrow (Wednesday):  Increasing clouds throughout the day with cold highs again in the upper 20s to low 30s.  Light winds from the east.  Confidence: High

Tomorrow night: Snow starting between 8 p.m. and midnight for much of the area initially at light to moderate levels.  However, the timing at night combined with the cold weather of the last several days means that this snow will start accumulating immediately on nearly all surfaces that are untreated. The intensity of snow gradually increases overnight and could become heavy at times towards morning.   Winds from the north at 10 to 15 mph. Confidence: Medium

A LOOK AHEAD

Snow Potential Index

A daily assessment of the potential for at least ~1″ of snow in the next week, on a 0-10 scale.

8/10 + (↑) Reasonably good model consistency suggests a Wednesday night/Thursday pasting.

Thursday should feature the coastal low pressure area making its closest approach to D.C. by mid-to-late morning with a risk that some areas right in the District and points east/south mix with sleet or even rain at times.  Otherwise, moderate to heavy snow during the morning rush into the later morning hours translates to reduced visibility and tricky travel.  Windy weather creates a nasty wind chill and makes visibility even more challenging.

Here are our latest snowfall forecast probabilities:

Probability of 1″+: DC/Balt/Fredericksburg: 80%, Frederick/Loudoun/Warrenton 85%
Probability of 4″+ DC/Balt/Fredericksburg: 60%​, Frederick/Loudoun/Warrenton 70%
Probability of 8″+ DC/Balt/Fredericksburg: 45%​, Frederick/Loudoun/Warrenton 55%

(Note: we’ll issue a map-based accumulation forecast between mid-morning and mid-afternoon.)

Highs should range from the upper 20s to low 30s, but areas from the city eastward could briefly spike up higher into the 30s to near 40F depending on how close the low pressure briefly gets.  Afternoon precipitation should trend lighter with time with maybe some drizzle mixed in by mid-to-late afternoon in milder areas, but gusty winds from the northeast continue.  Thursday night could still see some snow showers, particularly in the evening, but winds trend lower and skies become partly cloudy as lows drop into the 20s. Confidence: Low-Medium

Friday is dig-out day as temperatures rise into the upper 30s to low 40s for highs under partly cloudy skies.  A disturbance Friday night into early Saturday threatens some snow showers, but no significant accumulation concerns as lows range from the upper 20s to low 30s.  Confidence: Medium-High

The holiday weekend looks to see seasonal to colder than normal temperatures with highs in the upper 30s to low 40s and lows in the 20s to near 30.   Saturday should be partly cloudy, Saturday night may see an increase of clouds with snow showers late that linger into Sunday morning, while the balance of Sunday looks mostly cloudy.   A partly cloudy Sunday night opens up to a partly sunny potential for President’s Day.  Confidence: Medium

(Note: Forecast prepared overnight)

Also on Capital Weather Gang

Update: Major East Coast storm late Wednesday into Thursday