SNOHOMISH COUNTY, JAN. 17: The coldest weather of the season is on tap starting this holiday weekend and extending into next week.
Strong high pressure aloft has been steering Pacific weather systems away from Western Washington recently and is expected to continue to do so well into next week. This weather pattern has led to no significant rainfall since Jan. 10.
Paine Field Everett has had only 0.26 inches of rain so far this month, the driest January on record if little or no rainfall occurs by the end of Jan. 31. The driest January on record at Paine Field was in 2017 with only 0.35 inches of precipitation.
The strong upper-level high pressure also created a strong temperature inversion – much warmer temperatures aloft than near the surface, leading to high temperatures struggling to reach the lower 40s. The average high temperature in mid-January is in the mid and upper 40s.
For much of the Puget Sound region in recent days, the temperature inversion has left the morning clouds and fog intact throughout the day. Other parts of Western Washington including the Strait of Juan de Fuca, the coast and the mountains have had plenty of sunshine.
A very weak passing weather system to the north through Friday will help break up this temperature inversion and its associated clouds and fog heading into the weekend. Expect more sunshine, yet quite cool temperatures. With the clearing skies, nighttime temperatures will dip into the 20s to lower 30s, while highs will labor to reach 40 degrees.
The recent drier weather has put a pause on building the mountain snowpack. The Northwest Avalanche Center released its latest snowpack report on Jan. 15 revealing a range of 69 percent of normal at Hurricane Ridge to 129 percent at White Pass. Most other Cascade reports including Stevens Pass and Mt. Baker were in the 70 to 90 percent of average for mid-January.
For those planning to play in the mountain snow or drive across the Cascade passes this holiday weekend, expect lots of sunshine with freezing levels only between 1000 and 2000 feet. Have those sunglasses handy.
For those wondering will this cold weather lead to the possibility of lowland snow, one key element that is missing is moisture. Yes, it is cold enough for snow. Looking at longer range weather charts, the next source of moisture coming in from the Pacific Ocean is anticipated to be late next week. Yet, these longer range charts have considerable uncertainty. So for those who would like a snow day, there is hope. And for those who despise snow, there is also hope.
At some point, this period of cold dry weather will break down. It is not uncommon that during the transition back to warmer weather, lowland snow can fall in Western Washington. At this moment, prepare for colder than average temperatures and dry weather this holiday weekend. The cold weather will hold into next week. After that, stay tuned to learn when and how the transition to milder conditions will unfold.
