AbbyJr

It's still a long ways out but it will be quite remarkable if the PNW can win another cold blast with the upcoming SSW. It used to be that SSW's mostly dropped the cold back east but it seems like in recent years that it's almost a given that the PNW gets at least some of the cold. Just wow.

I'd like to hope for another round of cold and snow but I'm just not seeing any strong evidence for a -PNA pattern.

The two cases where I recall March performing exceptionally well in the PNW were 1951 and 2002. Both were cold neutral. I'd be very surprised to see a cold March in the PNW during a strong El Niño even with a SSW/PV split.

Yay I'm learning. Thanks Phil.

This, however, is a PV split, correct me if I'm wrong? By the way, I'm not saying this is likely to verify. Just pointing out the raw data.

Even if we only make it to neutral, that can still work out well for the PNW if the QBO goes positive. The 1990/91 winter was a neutral/+QBO and produced multiple top tier arctic blasts in the PNW. I've always understood that during neutral years, the ENSO doesn't really play a big role in the upper level pattern. Therefore, such winters can be full of wild swings. Do you think there is a good chance the QBO will go positive by next winter?

Could something similar to February 2018 be a possible solution for mid February in the PNW?

The good news is that we don't need a top tier arctic blast from a PV lobe in order to get cold and snow down to the lower elevations in SWBC. February 2017 was one example of how a medicre outflow event still produced a very snowy pattern in the low elevations. In fact, Abbotsford recorded its highest snow depth since December 2008 during that event. While temperatures were marginal, many areas saw significant snowfall as a low pressure system stalled off the Washington coast and interacted with a modified arctic airmass. Run of the mill cold but top tier snowfall was the outcome.

It's possible but there have been many La Niña events that did not feature an arctic outbreak in the PNW.

Trends? 12Z Today: 00Z Last Night: 12Z Yesterday:

There is a good chance the PNW could get chilly in mid to late February but I'd be surprised to see any legit arctic air.

Agreed. But I think next winter has a lot of potential if we do end up crashing back into La Niña and the QBO goes westerly. La Niña/+QBO is usually a good combo for PNW cold.

It’s extremely rare but March has sometimes performed in the PNW. 1951 and 2002 are a couple examples. Though they were both cold neutral. This year we have a strong El Niño making a cold outcome much less likely.

At least North America was able to score mid January with that SSW event. Back to El Niño.

The big thaw is happening here too. We are all in this together.

No problem Phil, thanks for your explanation. It's all good. While I don't always understand your acronyms, I get the gist of what you are saying. Do you think there is a solid chance the IOD could go negative by next winter so as to avoid a 1999/00 outcome?

When I said "like 2016/17" I was referring to the persistent cold and snowy pattern. December had an early lengthy cold wave with multiple low elevations snows. January had a few arctic outflow events, and then there was a major snowy pattern in early February with several days of heavy snow. Even March had a low elevation snowfall here in SWBC. The winter seemed to be dominated by high latitude blocking and western troughing. Perhaps I misunderstood you but a while back I recall you mentioned that the sudden crash from the super El Niño in 2015/16 to La Niña was one of the reasons the PNW did so well cold and snow wise in the 2016/17 winter. Since we might crash back into La Niña, I wondered if a similar outcome could unfold. I'm not sure how one could say it wasn't a La Niña winter when the SST's in the Nino 3.4 region were below normal.

@Phil If we crash back into La Niña by next winter and the QBO goes westerly, do you think the outcome could be similar to 2016/17 for the PNW?

March 1951 repeat? Probably not but check out the 500mb pattern on March 5th that year:

I don't remember the last time I've seen this much snow modelled on the RGEM within 70hrs. Might not verify at that intensity bit still. Huge potential.

Hopefully it verifies. Models seem to be coming into agreement so its a realistic possibility now but still far from a lock.

Fair enough. Do you think the PNW is done with the arctic air for January as well once the PV lobe shifts east?

Well it may very well be east focused.

@Phil If I recall correctly, a while back you said that February is a write off for PNW cold. However, do you still think so or has your opinion changed since we are now expecting another SSW event?

Maybe another cold period in the PNW around that time then. One can hope. It can still get cold here in February. I remember February 2018 was quite cold and there was a region wide snowstorm up here in SWBC late month.