Snow develops Thursday evening, peaks overnight, and tapers Friday morning into midday. Snow levels during active precipitation generally hold from near 0 to about 1,800 feet, so upper-mountain terrain stays mostly snow while some lower bases flirt with mixed periods. Snow quality should be mostly moderate/fair with SLRs around 10-15, with denser 8-10 pockets where mixing intrudes.
From late Saturday night through Sunday, guidance is converging on timing and warmer snow levels but diverging on intensity and ridge-top wind magnitude, with the most consistent signal for light snowfall in the northern and central ranges and limited coverage farther south. Most mountains should stay in the low single digits for accumulation during this first push, with favored terrain near the Continental Divide able to approach around 4 inches by Sunday evening.
Guidance is most aligned on a moderate midweek refresh, strongest in central Honshu, where many mountains should pick up 10 cm-35 cm, with the wettest favored terrain closer to 25 cm-45 cm.
Right now, forecast models are split. Some keep the storm far enough out to sea to spare New York City from snowfall but others show snow reaching coastal New Jersey and Long Island late Saturday into Sunday. A shift of just 50 to 100 miles in either direction could change everything, from rain versus snow to whether the city sees accumulation at all.
There will be a little wintry intrigue early this week, though. A fast-moving clipper system is expected to slide through tonight into Tuesday, bringing a brief burst of snow across parts of the state. Upstate and higher-elevation regions could see some accumulation, especially east of Lake Ontario, in the Tug Hill Plateau and the Adirondacks, where several inches are possible.
WeatherLight to modest early week snow refreshes the Washington and Oregon Cascades, with the biggest boost focused on Mount Baker, before a quieter midweek and a warmer, wetter pattern building late in the period. A weak system Monday night into Tuesday drops a few inches of mid-density snow on the northern Washington crest and around an inch or so elsewhere, with snow levels generally near 3,000 to 4,000 feet and all featured resorts remaining closed and quietly building base.
The forecaster has warned that an icy northerly wind means temperatures in some parts of the country could drop to -10C as the first cold snap of the season takes hold. In London, temperatures will remain at around 5C through the day until Friday, with colder conditions at night. The capital felt significantly colder throughout Monday despite sunny spells throughout the day.
