Two blasts of cold air blitz the region between today and late Sunday, with a mild interlude in between. The first cold surge is a shock to the system today, especially with the brutal winds. Before the cold becomes too entrenched, milder air arrives Saturday but not before a shot of snow and ice Friday night, which may make Saturday morning travel extremely slippery. Sunday actually starts off mild but turns rainy. Then the second cold blast smacks us by evening.
Today (Thursday): Lingering clouds quickly dissipate as winds from the northwest build across the area. Gusts could go as high as 40 mph. With temperatures hovering in the 20s much of the day, that means single digit wind chills. Bundle up big time if you have to be out and about. Confidence: Medium-High
Tonight: The wind only slowly loses potency with gusts from the northwest still up to 25 mph in the evening. Temps drop steadily under moonlit skies with frigid lows ranging from upper single digits to lower teens in the suburbs to the mid-to-upper teens downtown. Wind chills dip to near zero. Confidence: High
Tomorrow (Friday): The heart of the cold air is overhead, and the one saving grace is that it calms the winds. Sunshine quickly gives way to high clouds, which thicken through the afternoon. That makes highs mainly in the upper 20s still pretty painful. Confidence: Medium-High
Tomorrow night: The ongoing influx of moisture struggles to produce much in the dry air through the evening, but by late night, snowflakes are likely to finally start making it to the ground. Accumulations of a dusting to an inch seem most likely, with higher amounts in northern Maryland. The problem is that the warm air surging over the cold air at the surface is likely to quickly switch the snow to sleet and then freezing rain. This brings the likelihood of hazardous driving conditions during the pre-dawn and early morning hours. Lows range from the upper teens to mid-20s. Confidence: Medium
Saturday could start off with some lingering snow in the northern reaches of the area while a mix of freezing rain and sleet looks likely to dominate the rest of the region. Untreated roads and sidewalks may well be extremely slick, especially early on. Most models support a switch over to cold rain by mid-morning before tapering off by midday. Some lingering drizzle is possible in the afternoon as highs top out in the 40s and remain at those levels through the night with mostly dry conditions but plenty of clouds. Confidence: Low-Medium
Southerly winds get Sunday off to a mild start and, if it weren’t for the likely early arrival of showers, a high of 60 would be in the running. As it is, most areas should make the low-to-mid-50s. The next Arctic blast is not a patient one and should start to knock temperatures down by afternoon. If the showers are slow to end (which some models show) the rain could mix with sleet and snow during the evening. Drier air does eventually win out overnight, and the next round of strong northwest winds and cold moves in. Lows are expected to be in the 20s. Confidence: Low-Medium
Monday is expected to see calming winds with highs no better than lower 30s despite a return of the sun. Confidence: Medium
SNOW POTENTIAL INDEX
A daily assessment of the potential for at least 1 inch of snow in the next week, on a 0-10 scale.
4/10 (↑): We’ve got a shot to pick up a quick inch in the predawn hours Saturday before a changeover to ice and rain.