Before that, the region will see mostly rain, though our colder locations may see a very short wintry mix on the front of the storm Thursday morning. Winter weather advisories have been issued for western Loudoun and Frederick counties, as well as locations west of them, due to the potential of less than an inch of snow and a light layer of ice.
The rain can be heavy at times, prompting a National Weather Service flood watch from Thursday morning through Thursday evening.
Winter storm to cause dangerous blizzards, high winds and arctic cold
After Thursday’s soaking wet rain, a winter shock follows. A mega-cold front will blow up the region Friday morning, dropping temperatures near 40 degrees by evening. This Arctic onslaught will bring the region’s frigidest December weather since at least 2004 and the coldest Christmas since 1989.
Here’s what to expect over the weekend:
- This is a long-lasting event, including heavy rain on Thursday followed by a rapid drop in temperatures on Friday and frigid weather over the weekend.
- Slippery patches are possible Thursday morning, mainly west and north of the city.
- Rain will fall for most of Thursday and will be heavy at times from afternoon to evening.
- A large cold front will pass through Friday morning, dropping temperatures to 35 to 40 degrees in 24 hours, possibly leading to snow showers and a flash freeze.
- It will be the coldest two-day Christmas break since 1989, with chills hovering around zero on Christmas Eve morning.
Most precipitation falls in the form of rain on Thursday. Rainfall totals of about 1.5 inches should be normal in the DC area, with some spots near 2 inches.
4 a.m. to 7 a.m. Thursday: Precipitation should start coming in from the west, mainly west of Interstate 95. A very light ice cover is possible, mainly in higher elevations in the far west and north of the Beltway, perhaps after a dusting of snow.
Thursday from 7 a.m. to 1 p.m.: Rain should catch up with the rest of the area, with some spotty freezing rain in the west. It can take until late morning for the temperature to rise above 32 degrees west of Route 15 (from Warrenton to Leesburg to Frederick). Temperatures elsewhere are expected to climb into the 30s, with rain increasing in coverage and intensity in the early afternoon.
Thursday 13:00 to 19:00: Frequent downpours should continue, sometimes heavy. There may be a clap of thunder. Temperatures are expected to rise to nearly 40 degrees in our colder areas in the Northwest to the mid 50s in the South and Southeast. There can be strong winds, with gusts of 40 mph.
Thursday 7:00 PM to Friday 7:00 AM: It is expected that it will rain late in the evening and that the wind will decrease slightly. Much of the night may be dry, but showers pose a growing risk towards dawn. Temperatures should remain mild at night before cooling to 40 degrees by sunrise.
Friday we will probably wake up with temperatures around 40 degrees, and that can be that high for a while. Between about 7 a.m. and 10 a.m., an Arctic front will move through, with winds increasing and temperatures dropping.
“The onset of strong winds with the arrival of the front can be quite sudden and dramatic,” said Jeff Halverson, a severe weather expert for the Capital Weather Gang. “Now that the ground is very wet from the rain, isolated tree falls and spotty power outages are possible.”
Some snow or mixed precipitation may fall during the transition. Persistent wet spots on paved surfaces can freeze.
“Weather models advertise the possibility of snow showers behind the front,” said Wes Junker, CWG winter weather expert. “Even without snowfall, puddles on roads are likely to freeze, so there may be slippery spots.”
If there is snow when the front passes, the chances of icy roads increase, Junker said. If the front comes through without precipitation, strong winds can help dry out sidewalks before they have a chance to freeze.
By early afternoon, wind chills should drop to single digits and teens in most areas due to gusts between 40 and 50 mph. The temperature drops quickly in the course of the afternoon to around 20 degrees.
Gusts should ease a bit by evening, but are still blowing around 25 mph to 35 mph through Friday evening, leading to wind chills around zero. Chills in the minus teens to minus 30s are likely in the mountains to the west.
If you must travel on Friday, consider bringing emergency supplies such as blankets, food and water in case of delays.
An icy Christmas weekend
Under clear skies, Christmas Eve morning lows are expected to range from about 10 to 15 degrees (perhaps a little warmer in the center). Expect afternoon highs of just 20 to 25 degrees with chills no higher than the teens.
On Christmas Day, lows range from single digits to midteens. Afternoon highs may be milder than Saturday’s, but still only reach the mid and above 20s.
This is almost guaranteed to be the coldest two-day Christmas break since 1989. That year, the high was 23 with a low of 10 on Christmas Eve, and the high was 29 with a low of 11 on Christmas Day. A few cold records in the region could be broken.
If the low temperature drops at least 16 degrees on Saturday or Sunday, that will correspond to the coldest of 2022.
If it drops to 15 degrees or lower, it would be the coldest since January 2019. Since 2000, only three December days have seen temperatures of 15 degrees or lower, most recently in 2004.
Jason Samenow and Dan Stillman contributed to this report.