wpostServer: http://css.washingtonpost.com/wpost

The Post Most: Local

Posted at 07:40 AM ET, 03/18/2013

D.C. area forecast: Wintry and wet today with snow to rain; then mostly cold, dry rest of week

* Winter weather advisory western Va., mountains (map) | Snow totals *

7:40 a.m. update: The snow band which produced light to moderate snow in Fairfax county and to the west and southwest is collapsing as it hits drier air around the District and northern suburbs. So just expect light snow and/or flurries in the region for the next hour or so before it ends with little or no accumulation (where no snow has fallen). I expect National Weather Service will discontinue winter weather advisories shortly. We should have a break in the precipitation before rain develops later today.

7:20 a.m. update: Band of light to moderate snow covers eastern Loudoun and much of Fairfax county and will move into District and northern suburbs in next 30 minutes or so. Per update below, it will move through quickly, but lower visibilities and probably coat grassy areas. There are reports of some slick roads around South Riding west of town, and particularly well to the southwest in Fauquier, Stafford, and northern Prince William counties. In these areas, conditions should improve quickly - though - as snow is moving out.

6:30 a.m. update: The area of snow moving through will come and go fairly quickly. We expect it to wind down from southwest to northeast between 8 and 10 a.m. A steadier burst of snow (already affecting locations to the southwest), which will reduce visibilities, is likely in the immediate metro area between around 7:00 and 8:30 a.m. Please take this into consideration for your commute and allow extra time.

5:50 a.m. update: Good morning. There’s light snow/flurries around, with the steadiest activity west and south of the District. There’s a bit of a hole in the precip north of town, but that should fill in a bit in the next hour.

We don’t expect snow amount to much because it’s so light and temperatures are mostly above freezing (in the mid-to-upper 30s). Most likely snow accumulations should range from none to an inch on grassy areas. Highest amounts should be southwest of town.

The National Weather Service has scaled back the winter weather advisories north and northeast of town. They have been discontinued in Montgomery and Howard counties, but remain in effect in Fairfax, Prince William, Loudoun, Frederick counties and to the west and southwest.

EXPRESS FORECAST

Today: Snow/mix to rain. 36-41. | Tonight: Rainy. 34-40. | Tomorrow: Becoming partly sunny, breezy. 49-54.

TODAY'S DAILY DIGIT

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


A cold mix of snow and rain? That’s pretty miserable. Get the Digit on Twitter| Discuss on Facebook

SNOW POTENTIAL INDEX

A daily assessment of the potential for *accumulating* snow for the next week on a 0-10 scale. More info


SPI: 6 (↑) - Better than even chances someone in region gets at least a coating today. Get the SPI on Twitter | Discuss on Facebook

FORECAST IN DETAIL


We awaken to areas of snow and mixed precipitation, so allow extra time for the morning commute. Then the precipitation transitions to a cold rain. By Tuesday midday we dry out and the weather is mostly tranquil for the remainder of the week. But it’s unseasonably chilly with high temperatures mostly in the 40s Wednesday through Sunday.

Today (Monday): Patchy areas of snow and mixed rain/sleet/snow (from the District and south and east) are likely through mid-morning, before tapering off and changing to light rain/drizzle. We may see a bit of a lull in the precip during the afternoon, but it’s overcast and raw, with highs only in the upper 30s (colder suburbs) to low 40s. Winds are from the east around 5 to 10 mph. Total snow accumulation, before any changeover to rain, is most likely around 1 inch in the colder suburbs to a coating or less in the city and elsewhere (see our post from last night for more detailed snowfall probabilities). Confidence: Medium

Tonight: Another batch of rain moves in during the evening which may be moderate for a time. Rain continues intermittently through the night with temperatures mostly steady from the mid-30s in the colder suburbs to near 40 downtown. Rainfall amounts of around 0.25-0.5 inch are possible. Confidence: Medium

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

Tomorrow (Tuesday): A few showers are possible early in the morning followed by partial clearing and breezy conditions by late morning into the afternoon. Highs rebound into the upper 40s (in the colder suburbs) to the mid-50s (south of town), but it’s breezy with winds from the west at 10-20 mph with some higher gusts. Confidence: Medium-High

Tomorrow night: Clear skies with a light breeze and cold. Lows range from the upper 20s in the colder suburbs to the low 30s downtown. Winds are from the west at 5-10 mph. Confidence: Medium-High

A LOOK AHEAD

A big dip in the jet stream over the eastern U.S. means considerably colder than normal conditions Wednesday through Sunday. We’ll have to watch a couple disturbances in the flow that could trigger a few snow flurries or rain showers - mainly Wednesday into Thursday and, perhaps, late in the weekend. But, by and large, it’s partly cloudy and dry. Highs are mainly in the 40s. Overnight lows range from the mid-20s in the colder suburbs to the low 30s downtown. Confidence: Medium

By  |  07:40 AM ET, 03/18/2013

Categories:  Forecasts

 
Read what others are saying
     

    © 2011 The Washington Post Company