Cool & Rainy Rest of the Week

FastCast—Wednesday, Dec. 7 to Friday, Dec. 9:

The FastCast is back! What a crazy past week, with super localized snow that caused lots of problems for lots of people, but never a widespread event! Thanks to all of you who followed along on my blog and Twitter during this event. We have transitioned back to a “normal,” albeit cold, pattern. It will be a typical pattern for the rest of the week. A system will impact the area from late Wednesday through Thursday, bringing lowland rain, mountain snow, and breezy conditions. Expect 0.2-0.4 inches of rain for the lowlands, 4-8 inches of snow at the passes, and winds gusting up to 30-35 mph, except up to 45 mph around Admiralty Inlet and Whatcom/San Juan Counties. Areas of showers will continue through Thursday and Friday. By late Friday, rain will total 0.5-1 inch in the lowlands (most near Everett), 1-3 inches on the coast, and 0.9-1.25 inches from Olympia south. Highs will be on the chilly side, only reaching the low to mid 40s through Friday, with lows in the mid to upper 30s. Some forecasts are beginning to show another bout of colder weather next week, so stay tuned.

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Continue reading the full blog below!

After a cold and snowy past week (for most) we have transitioned back to a typical winter pattern, but on the chillier side. Below is the European model forecast for total rain through 10 PM Friday.

Expect rain to begin late Wednesday, becoming showery on Thursday, with showers continuing on Friday. Totals for the lowlands will be 0.5-1 inch, most near Everett, with 1-3 inches on the coast and 0.9-1.25 inches from Olympia southward. Eastern Washington will pick up 0.1-0.5 inches, but most of this will be in the form of snow (especially north of I-90) as temperatures remain chilly.

Next, we’ll look at expected mountain snow through Thursday evening from the HRRR model.

The HRRR shows that the passes will get 4-8 inches through Thursday evening, so be prepared for delays when crossing the state. Additionally, Eastern Washington will receive a trace to inch of snow (except in the Lower Columbia Basin), and 1-6 inches north of US-2.

Below is the European model forecast for Wednesday’s highs. Wednesday is expected to be the warmest day of the week for the lowlands.

As you can see, “warmest” is used loosely. Highs across Western Washington will struggle to hit 45º, with Eastern Washington will reach the low 40s in the south and get very close to or just above freezing in the north.

Now, let’s take a look at the extended temperature and precipitation probabilities from the NWS Climate Prediction Center.

Below is the temperature probability outlook for December 12-16.

The CPC shows a 40-70% probability of below average temperatures for Washington, with the highest probability for the eastern tier of the state.

Next, the precipitation probability outlook for December 12-16.

This outlook shows a 33-40% probability of above average precipitation for most of Washington state into mid-December. This isn’t a very high probability, so precipitation near normal is a good expectation.

Overall, chillier and slightly wetter weather is expected through mid-December. Stay tuned!