Chilly, Rainy, and High Mountain Snow Through Monday

FastCast—Sunday, June 18 to Wednesday, June 21:

An abnormal few days are ahead for Western Washington, with cool and rainy conditions through Tuesday. Expect showers, heavy at times, with a total of 0.2-0.7” of rain across the lowlands. However, areas from Tacoma to Everett and from the Kitsap Peninsula into the foothills will be favored by the Convergence Zone, with higher rain totals of 0.5-1.5” possible, highest in the foothills. Additionally, snow levels will crash to 4,500 feet through late Monday. Areas above 4,500 feet, including Chinook/Cayuse Passes, Paradise, and White Pass, could receive a trace to 3” of snow. Higher peaks and some backcountry areas could receive even more snow. In the lowlands, temperatures will be much colder than average. From Sunday to Tuesday, expect highs in the mid 50s to low 60s and lows in the mid 40s to low 50s. On Wednesday, temperatures will increase as clouds decrease, with highs increasing to the upper 60s to low 70s.

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Continue reading the full blog below!

A colder and wetter pattern is ahead through Tuesday for Western Washington. Let’s take a look at the details!

First, the NAM high-resolution rain forecast through late Monday. 

Notice the potential for higher rain totals in the Convergence Zone between Everett and Tacoma. These areas will receive 0.4-1.25”, while all other areas will receive 0.1-0.5”. Most areas in the Cascades will receive 0.75-2”, unless they receive snow.

Now, we’ll look at the European model, which will show a longer forecast, through late Tuesday.

Essentially, the European model shows that there will be an additional round of rain in addition to what is forecast by the NAM. By late Tuesday, most of Western Washington will receive 0.3-0.75”, with isolated higher totals around the area. Areas of Eastern Washington will receive 0.1-0.3” of rain, except in the mountains. 

Snow levels will crash as this colder and wetter pattern arrives. Forecasts show that snow levels will drop to around 4,500 feet by early Sunday, remaining there through late Monday. Let’s take a look at snow forecasts below.

First, the NAM high-resolution forecast for snow through early Tuesday morning.

This forecast shows up to 3-5” of snow at 4,500-6,000 feet, with higher amounts at higher peaks (though this forecast is likely overdone).

Let’s compare this to the HRRR model’s high-resolution forecast, seen below.

The HRRR shows a similar forecast that is also a bit overdone. The key message to take away here is that elevations of 4,500 feet will likely see snow, and much higher peaks and backcountry areas will receive more snow.

Finally, let’s take a look at high temperatures. Below is the NAM forecast for highs on Sunday.

Highs in the lowlands will only reach the upper 50s to low 60s, with the coast only reaching the mid 50s, and Eastern Washington only in the mid 60s to low 70s. Some record low maximum temperatures are possible.

As seen below, similar conditions are expected on Monday.

On Monday, highs will be nearly identical to Sunday, only reaching the upper 50s to low 60s in the lowlands, in the mid 50s on the coast, and in the low 60s to low 70s in Eastern Washington.

This is an abnormal pattern for June…but there are indications that warming is expected next week! Stay tuned!