Capital Weather Gang from The Washington Post

Daily forecast for the Washington area

D.C.-area forecast: Heavy snow and mixed precipitation to sweep through metro Monday night into Tuesday

snow-forecast-map-Mar13- 2017v2b

* Winter storm warning for areas along and west of Interstate 95 in D.C. area, including the District, 7 p.m. Monday to 2 p.m. Tuesday *

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

5/10: Much of the day is quiet and chilly before the siege of snow and wintry mix tonight.

EXPRESS FORECAST

Today: Increasing clouds. Highs: 40-45.
Tonight: Snow and mixed precipitation, heavy at times. Lows: 29-33.
Tomorrow: Morning snow then afternoon snow showers, blustery. Highs: 33-37.

View the current weather conditions at The Washington Post headquarters.

FORECAST IN DETAIL

Today we brace for a major late-winter storm set to begin this evening and continue into Tuesday. Depending on where you live, moderate to heavy amounts of snow could fall or a sloppy mix of snow, sleet and rain. The heaviest snowfall is expected to occur in our far western and northern areas, but the storm will likely will prove disruptive for much of the region through at least Tuesday morning.

We want to stress that this forecast is extremely complex and we have lower confidence in predicted snow amounts than usual. This is especially true along and east of the Interstate 95 corridor where we have reduced our predicted snowfall amounts some.

Starting Wednesday, in the wake of the storm, the region is locked into a winterlike regime with colder-than-normal temperatures through the weekend.

Programming note: We will post a new, detailed update on the storm threat late morning at washingtonpost.com/capitalweathergang

Today (Monday): Through at least midday we expect partly to mostly sunny skies. Clouds increase this afternoon but we should stay dry through at least 5 p.m. or so. Temperatures are chilly, but slightly milder than they were over the weekend, with highs 40-45. Winds are light at around 5-10 mph, initially from the northeast and then backing to out of the southeast. Confidence: Medium-High

Tonight: Light snow or mixed precipitation, especially around the District and to the south and east, begins between 5 and 10 p.m., from south to north. When the precipitation begins, it should be light and temperatures will be well above freezing. In other words, we don’t expect slick roads for the commute home.

Between 8 p.m. and midnight, precipitation should starting picking up in intensity while temperatures edge close to freezing. In our colder areas toward Loudoun County and northern Maryland, snow accumulation may begin. Elsewhere, snow or mixed precipitation may not accumulate much in this window.

The best chance for accumulating snow will occur after midnight and toward the pre-dawn hours. Along and to the east and southeast of Interstate 95, the snow may alternate and mix with sleet and rain, limiting accumulations some. Across the entire region, the precipitation may be quite heavy, and temperatures should fall into the upper 20s in our coldest areas to the low 30s elsewhere. Confidence: Low-Medium

Follow us on Facebook, Twitter, and Instagram for the latest updates. For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend …

High-resolution NAM model simulated radar at 5 a.m. Tuesday.

Tomorrow (Tuesday): Snow is likely through at least midmorning, affecting the commute. It could continue steadily through midday in our northern areas. In most of the region, any mixed precipitation should become all or mostly snow during the morning as the storm winds up and draws in colder air. Especially early on, there may be areas of heavy snow. Into the afternoon, steady, accumulating snow is likely over in most spots and skies should brighten, but occasional snow showers could continue to cycle in from the north. It’s blustery and cold with highs only in the mid-30s.

Total snow accumulations may vary substantially over short distances, but we expect generally around 3-6 inches inside the Beltway, with the potential for more north and west, and less south and east. Small changes in the storm track and strength could easily lead to lower or higher totals. Confidence: Low-Medium

Tomorrow night: Intermittent and scattered snow showers are possible through much of the night, but become less frequent toward morning. Widespread additional accumulation is not expected, but pockets of the region may experience an additional dusting to an inch. Any slush from the earlier snow will likely refreeze as lows dip into the low-to-mid 20s. Confidence: Medium

A LOOK AHEAD

Believe it or not, a few snow flurries or snow showers could linger into Wednesday morning. Skies should finally become partly sunny in the afternoon, but it’s windy and unseasonably cold, with highs only near freezing. Clearing and bitter cold at night, with lows 15-20, possibly colder in areas with extensive snow cover. Confidence: Medium

Finally some tranquility Thursday and Friday, but it’s still much colder than normal. Under partly to mostly sunny skies, highs are in the mid-to-upper 30s on Thursday, moderating into the low-to-mid 40s on Friday. Thursday night is another very cold one, with lows in the upper teens to mid-20s. Confidence: Medium-High

Cold weather will continue Friday night into the weekend and, at some point — most likely Saturday, a disturbance will pass through. Yes, it could bring more snow or rain showers. It probably won’t be a big deal, but it may prompt some folks to start begging to have spring back. Highs are generally near 40 with lows in the 20s to near 30. Confidence: Low-Medium

SNOW POTENTIAL INDEX
A daily assessment of the potential for at least 1 inch of snow in the next week, on a 0-10 scale.

9.5/10 (↑): While some parts of the region could see two inches and others more than ten, we think it’s pretty much assured everyone will see some Monday night into Tuesday.

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