Thursday, January 11, 2024

Thursday Night Winter Weather Update

A significant cold weather outbreak has begun to impact the Pacific Northwest. A modified arctic front has brought a dusting to 1" of snow to areas of the lowlands, except 2-6" from Port Angeles to Southern Whidbey Island. Scattered snow showers will continue through early Friday morning, mainly from Seattle southward and along the western Strait of Juan de Fuca. 

One potential hazard is a flash freeze, where temperatures rapidly cool, causing black ice and any snow on roads to freeze. This can cause treacherous conditions, especially on side streets. Be aware when driving on Friday.

Now, let's take a look at the extreme cold temperatures, starting with lows on Friday morning, from the European model.


In the lowlands from Everett south, expect lows in the mid teens to low 20s. From Everett northward, lows will drop to the mid single digits to low teens (coldest in Whatcom County). Eastern Washington will drop to the mid single digits to mid teens, except -5° to -15° for Spokane, Pullman, and NE Washington.

Next, let's take a look at the European model forecast for high temperatures on Friday.


Highs will only reach the low to mid 20s in the lowlands, and the mid teens in Whatcom County. Eastern Washington will have highs of -5° to 10°, except up to the upper teens in the lower Columbia Basin. These will be some of the coldest high temperatures in recent years for Western Washington.

As of now, it looks like Saturday morning will be even colder than Friday morning. Below is the European model forecast.


The European model forecast shows very cold lows in the low to mid teens for the entirety of Western Washington on Saturday morning, with some areas from Everett northward dropping to the mid single digits. Eastern Washington will drop to -15° to 5°, coldest outside the Columbia Basin. 

One of the most important factors of this cold snap will be the wind chill. The wind chills across the state will be extremely cold for the next few days. Let's start by taking a look at the wind chill forecast for Friday at 10 AM.


On Friday morning, the European model shows wind chills dropping to 0-10° across Western Washington, except -5° to -15° for Whatcom and San Juan Counties. Eastern Washington is another story, with wind chills dropping to 0 to -30°, coldest for areas downwind of the Okanogan River Valley and around Spokane and Pullman. Wind chills below -5° can cause frostbite in 30 minutes or less.

Stay tuned for more wind chill information.

Winds themselves will be very cold, biting, and gusty. Below is the NAM high-resolution forecast for wind gusts on Friday morning.


On Friday morning, expect continued strong winds out of the Fraser River Valley, impacting Whatcom and San Juan Counties with gusts of 40-55 mph. The rest of Western Washington will be impacted by brisk north winds gusting 10-20 mph, which brings the extreme cold wind chills.

There is a chance of strong cross-Cascade gap winds on Saturday, impacting areas such as North Bend and Enumclaw, plus the Columbia River Gorge. Stay tuned for more information on this possibility.

Finally, let's take a look at the next storm system, which will move into Northern Oregon and SW Washington. Below is the European model forecast for precipitation Friday night.


This forecast shows the boundary of precipitation being between Grand Mound and Centralia, with snow impacting SW Washington and the Northern Willamette Valley, and potential freezing rain from the southern Portland metro toward Eugene.

Let's compare this to the GFS forecast, also for precipitation on Friday evening.


The GFS shows a similar outlook, with precipitation ending around the Lewis/Cowlitz County line. This forecast shows mostly snow for Northern Oregon and SW Washington, with some isolated areas of freezing rain south of Portland and on the Oregon coast.

This storm will likely bring an impactful 4-8" of snow from Southwest Washington into the Northern Willamette Valley, with potential for an ice storm in the Central and Southern Willamette Valley. For more information, check the NWS Portland website.

Stay tuned for another update Friday night on the continued impactful winter weather.

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