Before that, the region will see primarily rain, although our colder locations may see a very brief wintry mix on the storm’s front end Thursday morning. Winter weather advisories have been issued for western Loudoun and Frederick counties, as well as locations west of that for the potential of less than 1 inch of snow and a light coating of ice.
The rain could be heavy at times, prompting a flood watch from the National Weather Service from Thursday morning to Thursday night.
After the soaking rain on Thursday will come a wintry shock. A mega-cold front will blast the region Friday morning causing temperatures near 40 to plummet toward the teens by evening. This Arctic assault will set up the region’s most frigid December weather since at least 2004 and the coldest Christmas since 1989.
Here’s what to expect into the weekend:
- This is a long-duration event, including heavy rain Thursday followed by a rapid drop in temperatures Friday and frigid weather over the weekend.
- Slick spots are possible Thursday morning, primarily well west and north of the city.
- Rain will fall most of Thursday and will be heavy at times midday through the evening.
- A major cold front will pass through Friday morning, sending temperatures backward 35 to 40 degrees in 24 hours, and possibly leading to snow showers and a flash freeze.
- It will be the coldest two-day Christmas holiday since 1989, with wind chills near zero Christmas Eve morning.
Most of the precipitation Thursday will be rain. Rainfall totals of about 1.5 inches should be common across the D.C. area, with some spots near 2 inches.
4 a.m. to 7 a.m. Thursday: Precipitation should begin to arrive from the west, moving into areas mainly west of Interstate 95. A very light glaze of ice is possible, mainly in elevated areas far west and north of the Beltway, perhaps following a coating of snow.
7 a.m. to 1 p.m. Thursday: Rain should overtake the rest of the area, with some spotty freezing rain west. It may take until late morning to get temperatures above 32 degrees west of Route 15 (from Warrenton to Leesburg to Frederick). Temperatures are expected to rise through the 30s elsewhere, with rain increasing in coverage and intensity through early afternoon.
1 p.m. to 7 p.m. Thursday: Frequent periods of rain should persist, heavy at times. There could be a rumble of thunder. Temperatures are expected to rise to near 40 degrees in our colder areas to the northwest to the mid-50s to the south and southeast. There may be strong winds, with gusts of 40 mph.
7 p.m. Thursday to 7 a.m. Friday: It’s expected to turn showery late evening, and winds should ease slightly. Much of the overnight could be dry, but showers are a growing risk toward dawn. Temperatures should remain mild into the overnight before cooling toward 40 degrees by sunrise.
We’ll likely awaken to temperatures near 40 degrees on Friday, and that may be as high as they get for a while. Between about 7 a.m. and 10 a.m., an Arctic front will sweep through, with increasing winds and plummeting temperatures.
“Onset of strong winds with the front’s arrival could be quite sudden and dramatic,” Capital Weather Gang severe weather expert Jeff Halverson said. “With the ground very wet from the rain, isolated treefalls and spotty power outages are possible.”
During the transition, some snow or mixed precipitation may fall. Any lingering wet spots on paved surfaces could ice over.
“Weather models have been advertising the potential for snow showers behind the front,” said Wes Junker, CWG winter weather expert. “Even without any snows showers, puddles on roads are likely to freeze, so there could be slick spots.”
If there is any snow as the front passes, the chance for icy roads increases, Junker said. If the front comes through without precipitation, strong winds could help dry out pavements before they have the chance to freeze.
By early afternoon, wind chills should plunge to the single digits and teens in most areas because of wind gusts between 40 and 50 mph. Temperatures will rapidly drop through the 20s during the afternoon.
Gusts should ease somewhat into evening but still blow around 25 mph to 35 mph through Friday night, leading to wind chills near zero. Wind chills into the minus-teens to minus-30s are likely in the mountains to the west.
If you must travel Friday, consider carrying emergency supplies such as blankets, food and water in case of delays.
A frigid Christmas weekend
Under clear skies, lows on Christmas Eve morning are expected to range from about 10 to 15 degrees (maybe a little warmer downtown). Expect afternoon highs of only 20 to 25 degrees with wind chills no higher than the teens.
On Christmas Day, lows will range from the single digits to midteens. Afternoon highs may end up milder than Saturday’s but still only reach the mid- and upper 20s.
It’s close to a guarantee that this will be the coldest two-day Christmas holiday 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 fall.
If the low temperature dips to at least 16 degrees either Saturday or Sunday, it will match the coldest of 2022.
If it dips to 15 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.