10:40 a.m. update: The wind chill advisory has been upgraded to a wind chill warning for northern Fauquier, Loudoun, and Frederick counties for wind chills of -15 to -20, and isolated -30 wind chills at high elevations.
Counties outlined in yellow were just upgraded to wind chill warnings pic.twitter.com/CUdDxteAL2
— TerpWeather (@TerpWeather) January 6, 2014
6:45 a.m. update: A wind chill advisory has been issued for the entire area through Tuesday evening, starting at 6 p.m. today for our western suburbs and midnight tonight elsewhere. Forecast wind chills are from -5 to -15, with even lower readings possible in colder areas, such as Loudoun and Frederick counties.
FORECAST IN DETAIL
Today is awfully volatile. Early risers may find it mild but then the highly anticipated arctic front blasts into the area with a brief bout of morning rain and snow showers. Temperatures fall throughout the day, but the wicked cold waits until tonight. It’s then downright frigid through early Wednesday before a slow moderation in temperatures starts. Enough stale arctic air may linger into Thursday night for a wintry mix when the next storm system approaches. By the weekend, temperatures may be above normal, but it’s likely unsettled.
Today (Monday): Any early morning fog quickly dissolves as the arctic front moves into the region. Morning temperatures in the 40s (30s colder suburbs) fall back into the 30s as scattered rain showers, changing to snow showers, complement the frontal passage – mainly between 5 and 10 a.m. A brief dusting to coating of snow is possible, especially in the colder suburbs west of town, but the snow shouldn’t be a big deal.
We rapidly dry out midday, with temperatures from 30-36 as winds from the west increase to 15-25 mph. By dark, temperatures fall to 26-32, with wind chills dipping into the teens. Confidence: Medium
Tonight: It turns brutally cold in a hurry as temperatures tumble through the 20s and into the teens by between 10 p.m. and midnight. Wind chills sink into the single digits to near zero.
After midnight, many locations fall into the single digits, with sub-zero wind chills everywhere. Overnight lows range from near 0 in the colder suburbs to around 10 downtown. Wind chills go as low -10 to -15 inside the Beltway to -20 to -25 in some of the colder suburbs. Thee bitter winds are from the west at 15-25 mph, with gusts over 30 mph.
The record low of 5 at Reagan National from 1884 may be a challenge to match. But the records of 8 at BWI and Dulles (from 1988) will almost certainly be broken. Confidence: Medium-High
For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend…
Tomorrow (Tuesday): The coldest day we’ve had in years, if not two decades (look out for Ian Livingston’s post later today which will put this cold snap in perspective). Under mostly sunny skies, highs only reach the low-to-mid teens. Wind chills are sub-zero well into the afternoon. Winds are from the west at 15-20 mph in the morning, decreasing to 10-15 mph in the afternoon. The record low maximum temperatures of 18, 21, and 22 at Reagan National (from 1878), Dulles (last set in 1996), and BWI (last set in 1996) all have a good chance to be broken. Confidence: Medium-High
Tomorrow night: Winds diminish further (out of the west at 5-10 mph) but under clear skies temperatures plummet to near 0 in the colder suburbs to around 10-12 downtown. Confidence: Medium-High
A LOOK AHEAD
After a frigid morning, temperatures make admirable upward progress Wednesday, rising to a high of 25-30. Skies are mostly sunny, and – mercifully – there’s less wind. Some increasing high clouds at night, and not as cold, with lows 17-25 (suburbs-city). Confidence: Medium-High
Thursday into Friday are cool and unsettled. We bounce back above freezing but clouds increase, with highs Thursday around 40. Light snow or a wintry mix is possible Thursday night, with lows in the upper 20s to low 30s. Right now, this looks like a minor event, but is worth keeping an eye on. Any lingering snow or mixed precipitation changes to rain if it continues into Friday morning. Otherwise, Friday’s mostly cloudy with highs 40-45. Partial clearing Friday night, with lows 30-35 (suburbs-city). Confidence: Low-Medium
Flow from the south may return for the weekend, meaning milder weather. But it also may carry some moisture into the region, with a 30 percent chance of rain showers each day. Highs Saturday are 45-50, and by Sunday 50-55. Overnight lows are around 40. Confidence: Low-Medium