Arctic Outbreak Possible For Western Washington

[Cumulonimbus]

W13:

Except for Bellingham and even that is a maybe there will NOT be arctic air in western WA nor will there be snow for at least another week. The snow level will be lower but not at sea level. As usual the GFS again made a last second MAJOR pattern change regarding cold air into western WA and joined the FAR superior ECMWF in dropping down a low OFFSHORE of Washington keeping us in a SOUTHERLY wind flow aloft on the east side of the low. Yes..a tiny bit of cooler air will barely ooze into western WA but that is it. Even the forecast discussion says 9 out of 10 arctic airmasses stay EAST OF THE ROCKIES!

In order to get a true arctic front through western WA and deep into Oregon you need a "mega high" of 1050 mbs or higher chugging south southeast into British Columbia to FORCE the air south down the west side of the Cascades. That is what the GFS showed a week ago. Now it is down to a "very weak" 1025 mb high. The ETA is a better model of choice for cold air or check out the MM5 from the UW website in Seattle.
Check out the daily weather maps(now online) from January 1969 or Dec 1968. Critical week of Dec 23-31 is missing but due to be put online next month. You will see an intense high which had a strong ridge right through BC and which forced the cold air south well into western Oregon.If you want to look at the maps send me a reply and I will give you the website address for the daily weather maps from 1875 to present.

More interesting weather MIGHT be ahead, IF the ECMWF comes close to verifying in about a week to 10 days. It shows a better chance of colder air further south and west and the 10 day map looks like a better chance of lowland snow for western WA.

I don't mean to burst your bubble. I too am very frustrated by being "cheated" time after time after time. I would LOVE to see an INTENSE La Nina occur but I guess with global warming that is never going to happen. So our choice is to go up to the mountains or move east of the Cascades and east of the Rockies. Keep watching the ECMWF, it shows a much more realistic trend in the pattern..at least for western WA.

[W13]

W13:

Except for Bellingham and even that is a maybe there will NOT be arctic air in western WA nor will there be snow for at least another week. The snow level will be lower but not at sea level. As usual the GFS again made a last second MAJOR pattern change regarding cold air into western WA and joined the FAR superior ECMWF in dropping down a low OFFSHORE of Washington keeping us in a SOUTHERLY wind flow aloft on the east side of the low. Yes..a tiny bit of cooler air will barely ooze into western WA but that is it. Even the forecast discussion says 9 out of 10 arctic airmasses stay EAST OF THE ROCKIES!

In order to get a true arctic front through western WA and deep into Oregon you need a "mega high" of 1050 mbs or higher chugging south southeast into British Columbia to FORCE the air south down the west side of the Cascades. That is what the GFS showed a week ago. Now it is down to a "very weak" 1025 mb high. The ETA is a better model of choice for cold air or check out the MM5 from the UW website in Seattle.
Check out the daily weather maps(now online) from January 1969 or Dec 1968. Critical week of Dec 23-31 is missing but due to be put online next month. You will see an intense high which had a strong ridge right through BC and which forced the cold air south well into western Oregon.If you want to look at the maps send me a reply and I will give you the website address for the daily weather maps from 1875 to present.

More interesting weather MIGHT be ahead, IF the ECMWF comes close to verifying in about a week to 10 days. It shows a better chance of colder air further south and west and the 10 day map looks like a better chance of lowland snow for western WA.

I don't mean to burst your bubble. I too am very frustrated by being "cheated" time after time after time. I would LOVE to see an INTENSE La Nina occur but I guess with global warming that is never going to happen. So our choice is to go up to the mountains or move east of the Cascades and east of the Rockies. Keep watching the ECMWF, it shows a much more realistic trend in the pattern..at least for western WA.

Well, when you say we aren't going to get any snow anytime soon, well then I have to tell you that you will be wrong in saying that.

On Saturday Night into Sunday, there will still be a ton of showers around the area, and those will ALL turn over to snow showers at or before (looks like it will be well before) midnight. Even NWS says that snow showers are likely on Sunday, and has even since issued a Special Weather Statement, stating that 1-2" are possible, throughout Western Washington. Now, we are still two days away from this occuring, and current thought among people on other weather forums, as well as the Farmer's Almanac forums, lead to heavier accumulations.

Next, we have a good chance for some snow on Tuesday Night into early Wednesday Morning, as well. It is too early to tell if it will stay snow, but from what I have seen it will at least remain snow through Tuesday Night and very early Wednesday Morning (whatever is left later on in the day on Wednesday, might turn back over to rain). But again, it is far to early to make estimate on accumulations and if it will stay snow all the way through Wednesday.

Lastly, looking at the current GFS Models (18z, 00z comes out in a few hours), it looks like we will have a TRUE shot of Arctic air around the 30-31 of December. Also, it looks like precipitation will accompany this shot of very cold Arctic air.

Finally, I think that you should realize that what the GFS has been saying today, could just be a computer error. I mean seriously, lets take a minute and examine what happened. Yesterday (and since about five days before that, for that matter), forecasted a strong shot of Arctic air for Sunday, and lasting throughout most of next week. Now, as the models went along (up to last nights models, even), it looked great for the previously mentioned snow event on Saturday Night into Sunday Morning, but it also had a MAJOR snow storm for this coming Tuesday. Then, all of a sudden this morning the GFS completely flip flopped, much like it did with regards to the possibilities of Southeast chances of snow this holiday weekend. Now, if you look at the latest Euro and even Canadian models, they still show a great chance of snow, and cold temperatures all the way through the entire next week.

Overall, I believe that we will be recieveing some snow on Saturday Night into Sunday Morning, and I believe that the cold will be much worse than the GFS is showing. The cold temperatures will stick around through at leats Wednesday, before another shot of sharply colder air invades Western Washington on either Thursday or Friday. This sets up the strong probability of all the precipitation on Tuesday and all the way through Wednesday as falling as snow.

I will be gone until either Saturday Night or Sunday Morning, so I will not be able to reply to this thread until that time frame. I think that we should know a little more about what will happen next week, by then.

[Aslkahuna]

Flip flops in the extended period and the GFS go hand in hand almost to the point where it is a characteristic of the model. The question then becomes one of which is correct-the flip or the flop or neither the latter case often being the true state of affairs. On a scale of 1 to 10 with ten being the best, I would rate the GFS at any point beyond 120 hours as -5. The European has been shown to be a far superior model to the GFS in the medium range.

Steve

[Cumulonimbus]

Steve
I agree. The old MRF seemed to be a much better model regarding weather 7 days or less. In 1998 the MRF forecast arctic air in here beginning 7 days out and showed that for each day right up to the event and it was almost right on the money. I know advances have made the forecasting easier, and it is great to be able to look out beyond 5-7 days but we all know that relying on any model beyond 120 hours will have errors just because of the time element itself.
The ECMWF just seems to have a lot more consistancy. Not that it is the model of choice, it just maintains or adjusts the patterns better in the extended.

Alex

[W13]

From the looks of things, Saturday night-Wednesday morning has significant potential. My gut feeling is the last two runs from the GFS were mere hiccups and that next week will generally see highs in the 30s. With a significant storm approaching Tuesday night/Wednesday morning, I still see the possibility for a major over-running event, esp. in northern counties. We'll have to wait and see. Can't wait for the latest GFS model. Another thing that's interesting is a possible Puget Sound Covergence Zone Saturday night/Sunday morning. When there's cold air in place, Everett/Lynnwood usually gets small accumulation. Anyone remember the big snowstorm of 1990? I think it was December 18 to be exact. All that snow from Everett to South Seattle was from a STRONG Puget Sound Covergence Zone. Maybe that will happen again!! lol.