wpostServer: http://css.washingtonpost.com/wpost2

Most Read: Local

Posted at 05:00 AM ET, 02/11/2012

Forecast: Arctic front threatens heavy snow showers, brings some of winter’s coldest air

* Winter Weather Advisory for northern Maryland (including Frederick and Carroll counties) until 7 p.m. Saturday *

2:25 p.m. update: The snow squalls are advancing toward the D.C. area and should impact sometime around or after 3 p.m. Reports of some thunder have come in with this activity (see vid). This is a brief but heavy burst of snow (possibly mixed with rain D.C. and east) that will mainly cause some light grassy accumulation as it passes.

1:00 p.m. update: A wind advisory has been issued for the area from 7 p.m. tonight through 7 a.m. tomorrow. This means winds sustained between 25-35 mph and gusts near 50. That’ll help wind chills dip well into the teens and even into the single digits overnight. Meanwhile, snow squalls associated with the Arctic cold front are advancing toward the area and should begin to impact western suburbs (Loudoun county, etc) during the next 30-60 minutes. These squalls could drop briefly heavy snow and cause visibility problems. The good news is they’re coming in somewhat early, and temperatures are currently above freezing, though they should fall back once the squalls move in.

7:45 a.m. update: Snow accumulation on the order of about 1/4” to 1”+ fell overnight across some of the north and west suburbs, with the highest totals generally in places like northern MoCo, parts of Frederick and into Loudoun counties. Reports indicate most or all of the snow stuck to everything but roads, though we can’t rule out an isolated slick spot this morning far to the north and west of the city. Other than that, we’re looking at a bit of a lull as the first batch of precipitation moves east. The Arctic front is now moving through West Virginia and is still on target to reach here this afternoon.

Today's Daily Digit
 
A somewhat subjective rating of the
day's weather, on a scale of 0 to 10.

 
Lots of clouds. Snow showers & squalls possible, especially p.m. Turning windy and much colder.
 
Get the 'Digit' on Twitter
EXPRESS FORECAST

Today: Mostly cloudy, rain and snow showers possible. Afternoon snow squalls. Near 40. | Tonight: Evening snow showers possible, then clearing. Windy. Near 20 to mid-20s. | Sunday: Partly-to-mostly sunny, breezy. Low-to-mid 30s. | Get Express Forecast by E-mail

FORECAST IN DETAIL

Some of us are waking up to white ground this morning after light snow targeted mainly the north and west suburbs overnight. That snow may melt off today as temperatures climb back up a bit ahead of the Arctic front that’s inbound. You’ll know it’s here by one of three ways, and perhaps all three: increasing wind from the northwest, falling temperatures, and snow showers or squalls. While the most intense snow squalls may be hit-or-miss, any place they hit could pick up light accumulation rather quickly.

Snow Potential Index: 5 (→) - PM snow squalls could pack a punch and whiten the ground in spots.
 
The SPI is a daily assessment of the potential for accumulating snow for the next week on a 0-10 scale. Get the 'SPI' on Twitter
 

Today (Saturday): The overnight precipitation should be headed out, but some light snow and rain transitioning to snow could persist for a short time. We’ll end up with a lull in precipitation during a portion of the morning at least, though a few showers (snow or rain) may pop up here and there into the midday. The Arctic cold front approaches and passes during the afternoon, and it may be accompanied by heavy snow squalls (think of it like a summer line of storms but in winter). These squalls could be hit-or-miss, but in places they hit they can cause low visibility and accumulation of snow (up to about 0.5”).

Highs rise to the near 40 to mid-40s range before the front sends temperatures tumbling backward with increasing northwest winds. Those winds push toward 30 mph, sustained, by evening. Confidence: Medium

Tonight: We might have remnant snow showers into the evening, and the potential for a few slick spots on roads as temperatures plummet. Actually, this is probably a good one for dinner and movies at home, unless you really like to brave the cold. Winds will be rockin’ into the first half of the night, sustained around 30 mph at times with gusts past 40 mph possible. Temperatures tumble, reaching near 20 in the colder suburbs to the low-or-mid 20s downtown by sunrise. That means a lot of wind chills at least into the teens and some into the single digits. Confidence: Medium-High

Keep reading for the forecast through the beginning of next week...

Tomorrow (Sunday): Wind chills remain very low — teens and single digits early — into the morning and don’t moderate much during the day. Thankfully, sun looks to return in a big way, though with so much cold air overhead, it’s hard to completely rule out some periods of clouds. There could even be a stray flurry. Winds are still up, but lighter than overnight, perhaps around 20 mph sustained (gusts past 30 mph) and dropping late in the day. High temperatures are considerably below average for the date, down in the chilly low-and-mid 30s. Confidence: Medium-High

Tomorrow night: It’s still breezy, though compared to the 24 hours prior, not too bad. Skies are mostly clear and lows should range from near 20 to the mid-20s. Confidence: Medium-High

A LOOK AHEAD

The cold weather begins to ease on Monday, and it should be sunny and rather tranquil overall. Even with what would still be below average highs in the low-and-mid 40s, that sun feels pretty good as its strength continues to grow. Confidence: Medium

Clouds may come wandering back to the area by Tuesday, and there’s even a shot at a few isolated to scattered showers across the area. Nothing to really worry about, but we’ll keep an eye on it. Despite the clouds, afternoon readings should nudge up to at least the mid-40s areawide with maybe some upper 40s too. Confidence: Low-Medium

By  |  05:00 AM ET, 02/11/2012

Categories:  Forecasts

 
Read what others are saying
     

    © 2011 The Washington Post Company