This is an archive intended for personal use, and of course for all to reference if they so please. This will be a post-by-post archive of every arctic blast to affect Seattle, WA. Yes this is Seattle centric, but there will be stats for BLI, OLY, PDX, and EUG as well. Arctic blasts I am defining by any weather pattern with a high below freezing. This is cold enough that it should weed out all but the chilliest inversion setups, and even then those such inversions are usually aided by backdoor easterlies of some kind. Each blast will get its own post, and will be ordered from most recent to oldest. Extended events like January 1950 with warm interludes will be analyzed by each individual dip, as well as in aggregate. The aggregate posts will be labeled as such. The posts will be organized as follows: -500mb height loop for the relevant timeframe, including the buildup and aftermath. -Min/Max / Min for the blast at each listed site -# Subfreezing highs at each site -Average temps at each site, including anomalies compared to average -# snow (in) at each site

The officials sabotaged their plane too right?

And to be fair, the 1917 freakishness works both ways. December 1917 is still the all-time warm champ in downtown Portland and places like Pendleton and Eugene. Across the airport era so far at least there has yet to be a warmer December in Oregon (1950 was a bit cooler).

Juneau has data from 1917 and 1933. The milder downtown location averaged 14.6 in 1917 and 13.1 in 1933. Those numbers aren't in any serious jeopardy of being challenged there this month.

Its going to get nasty here Thursday nite into Fri-morning what flash freeze looking very likely. NOAA: Frontal passage in the evening then opens the door for rapid cooling with 850mb temps dropping from 6C at 00Z, -2C at 06Z and -11C by 12Z. Residual water on roads may rapidly freeze as air temps quickly drop into the mid to upper 20s after dark. Additionally, the strong cold westerly winds will excite lake effect with bands of snow working east across lower MI. Still no real strong signal with low level convergence which would suggest higher confidence for any corridor to overachieve with lake effect bands setting up. Still, strong winds and snow overnight Thursday into Friday morning will offer a chance for brief snow squalls. Currently only thinking around a half inch of snow is most likely as mixing depths are topping out around 5kft. Though this does pass through the DGZ, it`s a bit shallower than we`d like to see for higher end lake effect.