Stormchaserchuck1

The 12z NAM was really strong with the -PNA/SE ridge

Oct 30-Nov 15: 60 day correlation to 500mb Nov 15-30: 40-45 day correlation to 500mb Dec 1-31: 30-40 day correlation to 500mb Jan 1-31: 20-30 day correlation to 500mb Feb 1-28: 15-25 day correlation to 500mb. etc. They aren't common, as these are anomalies vs the climo-norm. Here's a graph. Or maybe I'm misunderstanding your question? I'm really impressed with the predictable lead time of D+15 in this 10mb warming to +600dm -NAO. Pretty classic.

Stratosphere is warming again. This is a pretty severe warming. There is a 10-15 day lag at this time of the year with 500mb NAO correlation. It's been a nonstop 10mb warm phase since February 15 (15-28). What's interesting is that I had another and unrelated factor which is a -NAO signal until March 19th (3.9-19): This year-to-year change has been hitting pretty hard in verification for 2 years. These are two really strong factors. If the -NAO really lifts out the 10th/11, it will say to me that it doesn't have any staying power at this time, which is what I theorized because the Pacific always had an opposite correlation to EC cold when the NAO was negative/positive-cold. I also think there is a high bust-potential, (vs model verification accuracy) that/for -NAO conditions March 11-19. I also think this gravity could slightly make our storm have colder stay power on model trend, but I don't like what happens in the Pacific after March 11. The Pacific may equalize it out, and when that High leaves Alaska, it's game over as far as our snow chances goes.

Yeah, the SE ridge is strong in spite of the Pacific.

I can't believe the low is cutting into Canada with a near +600dm -NAO. What a good setup for a HECS v. The Pacific is already favorable here. I'd worry about last second warming with the coastal if it happens after the 11th.

I thought you guys would be pumping the 300hr panel, it finally shows a vortex/trough moving across our region. I wouldn't expect snow in this pattern at all. The High up top is the only thing really fundamental for a snowstorm, they always trend toward a GOA low. Once that -EPO/west -NAO moves out, it should be a flood of warm air(on the current model).

Oh wow. Look at this in the LR.

Really lost that Aleutian ridge to the north of Hawaii trough at 18z. The models will adjust. It's a below average temperature pattern. We aren't going to hold all three of those conditions: +PNA, -NAO, SE ridge. Only if the Aleutian island High strengthens back.

That first wave will moisten up, and like brooklynwx posted, it's a below average temperature pattern while several waves move through. :)

Strongest -NAO yet, this is a +500dm block now on the 18z GFS ensembles. Pacific trended more +PNA today in the MR. I like the idea of that WC trough as it moves east.

They couldn't take the ECMWF's domination. Had to even it out with ensembles. They seem like 0.40 correlated with initial conditions that day.

It's a really bad model though. It might just be running with the likelihood of a scenario.

Like I expected, we're always trending toward a GOA low

I'll slow it down

Upper latitudes will probably adjust.

There's a lot of moisture in the STJ

What do you guys think of this? 3 areas of low pressure in the west going into a healthy -NAO?

This is the Pacific pattern change

Boy did this storm weaken

It's a >500dm Aleutian block on the 6z gfs ensemble mean, 3 closed 500mb low contours on the mean. I've noticed that recently in snowstorms, everytime models want to put a GOA low, and sometimes it's a serious trend. I would say that, that is our window, when they show GOA low's, but the cold air might lift out/pattern less favorable in that case. With that -300dm trough under the N. Pacific ridge, I don't think it will be trending south a lot, so we might be safe for a good overrunning storm, unless a GOA low pops and it morphs into something extreme at 500mb. I think a lot can change with now that look in the Pacific, but I just wanted to make a point that the pattern trended more extreme at 6z. I'm curious to see how it plays out. There aren't many analogs of a +500dm -PNA/>+300-NAO in March. Most -PNA's happened with +NAO going back to 1948..

courtesy of brooklywx.. ridge over Greenland to ridge over Aleutian islands.. check ^lots of 50/50 low energy around..

Wow, awesome

^ Actually, that's straight HECS setup. The ridge is so big into Alaska, that there isn't enough normal variance for us to not get snow. I've seen the High jump to just the Aleutian islands maybe 1/10 times (sometimes we are the anti-snow magnet). Biggest risk is the pattern drying up.

It's definitely going to snow. The pattern is too wet for us to miss the window. Every 3 days we get a storm/precip or something if the jet stream is going straight w->e. We have like a 5-10 day window, maybe less(3?). I'm afraid it's probably +AO/+EPO after that. edit: both storms fizzled out compared to what they were showing a few days on models, under the fast jet-through Canada +EPO pattern (like I thought they would- that's what happens. Models always underestimate Alaska). That's going to change/flip, so I think we are building potential energy the right way.

That 573+dm -EPO block is a new development. Models had started trending south to -PNA, weakness cutting through Alaska yesterday. It's a wet STJ too.