Major Storm Bringing Blizzard Conditions, Strong Winds, and Heavy Rain

For the first time since December 2012, NWS offices in Seattle, Portland, Pendleton, and Spokane have issued Blizzard Warnings for the Cascades, Olympics, and Blue Mountains. 

A significant mountain snow event is ahead as a multi-faceted storm impacts the region. Let's take a look at the forecast, starting with the European model forecast for snow through Tuesday night.

This forecast shows 15-30 inches of snow for the Cascades through Tuesday night. Snow will start Monday morning, continuing through late Tuesday, but becoming showery. Snoqualmie Pass will switch over to rain sometime late Monday night or early Tuesday morning ahead of the cold front, before dropping below freezing again on Tuesday.

Also, notice the potential for 0.5-2" of snow for the Bellingham and Vancouver BC areas, plus 1-4" of snow for most of Eastern WA except the lower Columbia Basin. The European model also shows a weak system bringing a potential 1-3" of snow to the Portland & SW WA regions on Wednesday morning.

Let's compare this to the high-resolution NAM forecast for snow through Tuesday night.

This forecast shows 12-18" of snow at the passes, with 2-3" of snow for Spokane and Pullman, plus a chance of a trace to 2" of snow for Northern Whatcom County and Vancouver BC.

Finally, let's zoom into the Cascades and take a look at total snow through Tuesday night from the ultra high-resolution UW WRF forecast.

This forecast shows 16-24" of snow at the passes, with additional areas of snow on the Eastern slopes of the Cascades, Northern Whatcom County, and along I-5 south of Olympia.

By itself, 1-2 feet of heavy snow is impactful, but when you add in strong winds, it becomes a dangerous and impactful winter storm. This storm will cast a strong pressure gradient across Washington state, bringing windy conditions to the entire region. Below is the European model forecast for peak winds (in knots) for Washington, through late Tuesday.

Expect winds gusting 40-50 mph in the lowlands and 50-60 mph on the coast, peaking Tuesday. A strong westerly wind surge down the Strait of Juan de Fuca will likely bring damaging 60-65 mph gusts to west-facing shorelines of Whidbey and Fidalgo Islands on Tuesday afternoon. Note that winds across the Cascades, Olympics, and Blue Mountains will likely gust 45-60 mph (higher at higher elevations), which could cause blizzard conditions (more on this below). Eastern WA will also gust 35-45 mph on Tuesday.

Next, let's take a look at the HRRR high-resolution forecast for peak winds.

This forecast shows stronger winds for the entire region, with the lowlands gusting 45-55 mph, the coast gusting 50-65 mph, and a westerly surge bringing gusts of 55-65 mph to Whidbey Island, with the entire Strait hitting 50-60 mph in this forecast. Eastern Washington will gust 40-60 mph in this forecast, strongest from the Tri-Cities to Spokane. The mountains will gust 50-65 mph in this forecast, strongest at higher elevations.

Due to the combination of a major snow event and a windstorm, blizzard conditions are expected in the Cascades, Olympics, and Blue Mountains. The map below from NWS Seattle shows where the Blizzard Warning is in effect (red).

A Blizzard Warning is in effect for most of the Cascades and all of the Olympics. This is the first time since December 2012 that a Blizzard Warning has been issued for the western slopes of the Cascades and the Olympics. Snow will be heaviest late Monday night through Tuesday, with winds strongest from early Tuesday through the evening. A "blizzard" is defined as winds of 35+ mph and visibility of 1/4 mile or less for 3+ hours during a snowstorm. While blizzard conditions will not be happening everywhere in the warning area at all times, those conditions are expected in the Cascades, Olympics, and Blue Mountains.

Finally, let's take a look at the rain forecast through Tuesday night. Below is the European model forecast for rain through Tuesday.

In the lowlands, expect 1-2" of rain through Tuesday night, most from Tacoma south. The coast will receive 2-3". All of this will be snow in the mountains.

Lastly, here is the GFS (American) model forecast for rain through Tuesday.

This forecast, while slightly drier, shows 1-1.5" for the lowlands with a rain shadow over Whidbey Island. The coast could get 1.5-2.5" of rain out of this system.

Overall, a very dynamic storm system is ahead for the Pacific Northwest. Stay tuned for more updates on my Twitter and on Michael Snyder's Pacific Northwest Weather Watch YouTube channel for daily briefings. Stay safe out there!

Next System Arrives Friday, Look at Extended Forecast

 FastCast—Friday, Jan. 5 to Sunday, Jan. 7:

More rain and mountain snow are ahead as a system impacts the Northwest on Friday and Saturday. In the lowlands, expect 0.5-1.2” of rain through Sunday morning. Snow levels will remain around 2,000 feet, bringing 10-15” of snow to the passes through Saturday morning. This will bring impacts to the passes, especially from Friday night into Saturday. Be very aware of conditions when traveling across the state. In the lowlands, expect highs on Friday in the mid to upper 40s, decreasing to the low to mid 40s this weekend. Lows will reach the mid to upper 30s, coldest by Sunday. Additionally, expect winds gusting 30-35 mph for the lowlands and 35-40 mph for the North Sound (up to 45 mph on the coast). Winds will be strongest from late Friday through early Saturday.

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Continue reading the full blog below!

Active weather is expected through this weekend for the region, with the main impacts being mountain snow and rain. Let’s take a look at the forecast!

We’ll start with the mountain snow forecast from the European model through early Sunday morning.

This forecast shows a total of 10-20” of snow at the passes. This will likely bring travel impacts, especially from Friday afternoon through Saturday.

Let’s compare this to the GFS forecast, also showing snow through Sunday morning.

This forecast shows similar snow amounts for the passes, with 10-20” expected. One notable difference is the much higher snow (3-6”) for the Spokane area. With the Euro showing 1-3” for Spokane and the GFS showing 3-6”, 2-4” is a good estimate. 

Now, let’s take a look at the rain forecast through Sunday morning, starting with the European model.

This forecast shows 0.6-1.4” of rain for the lowlands and 1-1.5” for the coast. Most rain would fall from midday Friday through Saturday morning.

Now, let’s take a look at the GFS forecast for the same timeframe.

This forecast is a bit less wet, showing a total of 0.4-0.9” for the lowlands and 1-1.3” for the coast. 

Now, for the most interesting part of the forecast…a brief look at the extended forecast. Extended forecast models have been predicting a potential arctic air intrusion late next week. Let’s take a look at the European model ensemble forecast (which shows the substantial uncertainty) for temperatures in Seattle. 

This forecast’s average shows highs in Seattle dropping to near freezing late next week, with potential lows into the mid 20s. However, note the faint gray and blue lines by the potential temperatures. This shows a huge spread in potential temperatures, indicating that uncertainty is still quite high. 

However, the potential for arctic air has been increasing over the next few days. In the next blog (this weekend), we will likely begin taking a look at what is possible. Remember…just because your weather app shows very cold temperatures and possible lowland snow does NOT mean it will happen. Weather apps don’t have human input to communicate uncertainty.

Stay tuned!!

Pattern Change & Active Weather to Start the Year

 FastCast—Wednesday, Jan. 3 to Friday, Jan. 5:

An active start to 2024 is expected for the Pacific Northwest, with a pattern change bringing an increase in rain and mountain snow. On Wednesday, expect showers across the lowlands, up to 0.2”, with an exact repeat on Thursday. Friday looks to start off dry, with a potentially more impactful system moving in later in the day, with details still uncertain. For the lowlands, expect highs in the mid to upper 40s, with lows in the upper 30s to low 40s. In the mountains, the passes will receive up 8-12” of snow through Friday, with a potential for multiple feet of snow in the mountains over the coming weeks…so stay tuned for more information!

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Continue reading the full blog below!

Active weather will impact the Pacific Northwest to begin 2024, so let’s dive in and take a look at the forecast.

Below is the European model forecast for rain through Friday.

Through Friday (including some rain that fell on Tuesday afternoon), the lowlands will receive 0.4-0.8” of rain. The coast will get 0.8-1.5” of rain in this time, with Eastern WA getting 0.3-0.6” for the western half and 0-0.2” for the eastern half. 

Let’s compare this to the American (GFS) forecast for rain through Friday, seen below.

The GFS forecast shows a rain shadow from Seattle to Bellingham, with 0.1-0.4” of rain for that area. The rest of the coast and lowlands will get 0.4-0.7” through Friday. Eastern Washington will get less rain in this forecast, only getting 0.1-0.3”.

Now, let’s take a look at the snow forecasts for the mountains. We’re in desperate need of an increase in snowpack. First, the European model forecast for snow through Friday.

This forecast shows 10-14” of snow at the passes through Friday, including some snow that already fell on Tuesday. The Spokane area will get up to 1”, with the eastern slopes (including Wenatchee and Ellensburg) getting up to 4”. 

Let’s compare this to the GFS forecast, also showing snow through Friday.

This forecast shows 6-10” for the passes, up to 3” for the eastern slopes, and 1-2” for the Spokane area, plus a dusting for parts of the Palouse. 

Now, let’s take a look at some extended outlooks from the NWS Climate Prediction Center (CPC) for January 8-12 (next week).

First, the temperature outlook, seen below.

This outlook shows a 40-50% probability of below average temperatures for Washington through January 12th.

Now, let’s take a look at the precipitation outlook for this same time (January 8-12).

This outlook shows a 33-50% probability of above average precipitation for Washington.

As you would expect with below average temperatures and above average precipitation, the mountains across the Pacific Northwest will likely receive large amounts of snow over the next few weeks. Below is the European EPS forecast for snow at Stampede Pass (near Snoqualmie Pass) through mid-January.

This graphic shows all 50 ensemble “members” (slightly different forecasts), with snow accumulating from left to right (days and times on bottom). The big bar at the bottom is the average of all the ensemble members. Through mid January, the average is around 44” of snow, with most ensemble members showing 30-60”! Keep in mind, this station is only at 3,700 feet, so higher areas could have much more snow.

Stay tuned over the coming days as an active start to 2024 continues!