This will be a relatively brief post because it’s a sunny, warm autumn weekend in the Pacific Northwest, and I don’t want to spend too much time inside on such a rare occasion!
Let’s start with some obligatory eye-candy from the GOES-17. Besides being a huge asset to the scientific community, the GOES-17 has been a boon to weather bloggers everywhere and has done wonders for our social media traffic. I don’t always approve of U.S. government spending, but I believe these were some tax dollars well appropriated!
Our calm and tranquil weather today is courtesy of a ridge of high pressure just offshore. If you look closely in the aforementioned eye-candy above, you can see some high cirrus clouds outlining the northern periphery of this ridge as they approach the Washington Coast before moving into drier air aloft and disintegrating.
NASA’s AQUA satellite below, which has even higher-res images than the GOES-17 but orbits the poles instead of hovering over the equator (and can only give us one image a day as a result), shows convection occurring over the warm land but not the cool water… always a cool thing to see.
This ridge will strengthen tonight/tomorrow morning and give us a truly spectacular day tomorrow. Temperatures will be about average for this time of the year – low 70s for the Willamette Valley and low-mid 60s for Western Washington – but they’ll definitely feel above-average given our chilly weather as of late. Any patchy morning fog will quickly burn off after sunrise, and the I-5 corridor south of Tacoma will see blazing sunshine for the afternoon, with just a few high clouds to the north. It will be a wonderful day for a hike, and that’s what I plan to do!
But our wonderful weather will come to an end midday Monday as a cold upper-level trough (shown above as the threatening blob of purple over Alaska and the Yukon) moves through, bringing a little rain Monday afternoon-Tuesday along much colder temperatures, especially on Tuesday. In fact, the UW WRF model below shows accumulating snow down to 3,000 feet, meaning Snoqualmie Pass would see its first snow of the season!
While I doubt such minor snow would cause any travel difficulties, it will probably help sell some season’s passes for our local ski resorts! As an avid meteorologist and passionate penny-pincher, I feel obligated to say that an early October snowfall is not a reliable harbinger of an epic ski season and shouldn’t influence your decision in whether or not to buy a seasons pass. Still, sometimes the excitement of seeing snow at the resorts is enough to make us do it anyway!
Our cold spell will only be a transient curse, with low 60s and partly cloudy skies next Wednesday giving way to mostly sunny conditions Friday/Saturday and temperatures once again flirting with 70. But by next week, the models show an increasing chance of rain, and climatology tells us that they are probably right.
Enjoy your beautiful weekend, watch for “teaser” mountain snow early next week, and savor those last few sunny days towards the tail end of next week. Once we get past mid-October, sunshine becomes a rare commodity indeed!
Charlie
