A strong low pressure system and associated frontal boundaries are forecast to approach the Pacific Northwest from the northwest producing heavy precipitation and windy conditions throughout the region. Travel is expected to be difficult Monday evening through Wednesday with Cascade and Blue Mountain highways possibly being impassible at times.
This system has prompted National Weather Service offices throughout the Pacific Northwest issue alerts for wind in lower elevations and widespread blizzard warnings in mountainous areas.
Precipitation is likely to start in the Cascades Monday morning but intensify overnight Monday night as the cold front passes through. Winds pick up during the frontal passage with wind gusts in the mountains possibly reaching 65 mph (105 km/h).
The blizzard warning for the Cascades is preceded in most places by a winter storm warning with alerts running through Wednesday morning. Snow levels down to about 2000 ft (600 m) are expected with blizzard conditions ranging from above 2000 feet (600 m) in the Snoqualmie Pass area to above 3500 feet (1000 m) down toward the Three Sisters west of Bend.
Snow totals in the mountains will likely exceed one foot (30 cm) and may reach four feet (120 cm) by Wednesday morning. Snow will be heavy at times with whiteout conditions. It will be difficult for WSDOT and ODOT to keep roads clear both due to the weather and because of vehicle crashes including spinouts.
Blizzard conditions are also forecast along I-84 in the Blue Mountains. Light snow is possible on the Palouse, in the north end of the Columbia Basin, and around Spokane. Some snowflakes may be observed in higher elevation neighborhoods around the Tri-Cities and Yakima.
A wind advisory is in place for the Tri-Cities, Yakima, and Walla Walla from 04:00 Tuesday to 10:00 Wednesday for winds of 30 to 40 mph (50 to 65 km/h) gusting to 55 mph (90 km/h). Winds will likely be stronger around Pendleton and Goldendale where a high wind warning is in place from 01:00 Tuesday to 13:00 Wednesday for gusts to 65 mph (105 km/h).
Rain is likely in and around the Tri-Cities Monday evening with showers possible through Tuesday. Strong winds may produce power outages and blow around outdoor objects that aren’t secured such as trampolines. Drifting tumbleweeds may accumulate in some areas on the edge and outside of towns in the Columbia Basin.
The weather alert map for the Pacific Northwest is lit up like a Christmas tree as a result of this dynamic system. On top of the alerts covered above, there is also a blizzard warning for the Olympic Mountains, a winter storm watch for Southern Oregon, a winter weather advisory for Spokane, and a wind advisory for Portland just to name a few. Strong winds and heavy rain will occur in the Columbia River Gorge but I-84 from Portland to Pendleton should remain snow free.
An active weather pattern continues beyond Wednesday for periodic heavy snow in the mountains and chances of rain in the Columbia Basin. Remember to check travel conditions before heading out and if you need to cross the passes it is a good idea to be prepared to be stuck in snow and/or traffic for several hours.
Weather models continue to favor a cooler weather pattern beginning toward the end of this week but uncertainty remains. Snow levels should remain low, but just how low still hasn’t been resolved.
The featured image for this post is NWS alerts as of 16:00 Sunday presented by the GIS Surfer tool.
1 Comment
Well that should help the snow pack situation.