Stormchaserchuck1

A lot of the long range factors were unfavorable for cold/snowy though.. it's important to keep that in mind when looking ahead to the long range, the QBO is still record positive, which with a Weak Nina favors cold 10mb conditions, or at least not a Major Stratosphere warming. People can freak out about the 10mb PV being split, but it's very close to a near neutral anomaly, so the best that is, imo, is a "not super +AO". -PDO, west-based Nina, etc... If the MJO can stay strong going into Phase 8 late February, maybe that is something to watch, but I've seen this Scandinavian ridging trying to break that NAO in the long range before, and it seems to be something just runs with more -PNA. We'll see I guess.

I've just seen the look models before.. it's a difficult one to change. If you really want to get down to it, we have a Weak Nina right now.. even during the late Nov - mid Jan cold period there was +OLR and +SOI, and other things Weak Nina-like, especially during the end. In late December the subsurface ENSO went from Neutral to pretty moderately Negative. I've researched this, and run numbers, and a negative anomaly in the central-ENSO-subsurface region at 150-200m correlates to -PNA conditions. Because it didn't happening immediately when the cold pool flared up and was a bit lagged, I feel it may stick around longer now. I've seen this time of year -PNA... after Jan 27th, the coldest day of the year, it's like a switch flips, and we go -PNA for whatever reason. Because it's aligned with the warming/cooling cycles of the Hemisphere, it seems to be somewhat of a permanent pattern. I think you agree that the snow prospects are slim for the next 15 days. If the pattern goes more -EPO like the EPS has, that favors maybe some ice, but models are pretty consistent on having an East Coast/mid atlantic ridge at least through day 15. Beyond there, you seem to be bullish on it getting cold again, but I've seen these LR ridges try to change a -PNA in the long range, by overtaking the NAO or whatever, and they don't work out as well in verification as you would think.. the RNA pattern is a stubborn one and can be difficult to change. I do think we could see some breaks, but probably not the late Nov - mid January cold that we just experienced. It's hard to pattern change. That doesn't mean that it can't happen, it's just a little lower confidence right now on the Day 16+.

This ridge from Californina to Russia is a good example of what a cold 10mb (Stratosphere) looks like near the surface, as the effect of a stronger Polar Vortex at the Pole speeds up, and makes it down like the funnel of a tornado at 0-time. On its edges, in the midlatitudes a ridge is flexed. Below you see the down atmospheric effects of a cold/fast 10mb level, which is centered over western Greenland and the Davis Strait currently. Cold Stratosphere correlates to 500mb at 0-time. Warm Stratosphere corrleates to 500 at +15-45 days.

EPS has mostly a -EPO.. It's very different from the GEFS which is about 1000 miles south with the Pacific High pressure. EPS is legit Alaskan block.. GEFS has not been showing this and has had -PNA for 3+ days. The two are very different right now.

what's aldie doing. nam is warm

February DCA _ NYC _ BOS __ ORD _ ATL _ IAH __ DEN _ PHX _ SEA 4.0 3.9 3.2 2.8 5.8 5.2 0.9 1.0 -4.7

AI isn't a very good model. GEFS has a strong, sustained, stable -PNA Hrs240-384.. +300dm in the long range is about as extreme as it gets on the ensemble mean. https://www.meteo.psu.edu/ewall/ENSHGTAVGNH_18z/ensloopmref.html

Hopefully you guys will learn the importance of upper latitude 500mb patterns.

That's not a 50/50 low. It's north.. It's a +NAO

GEFS continues to look different.. that low pressure SE of Greenland with N. Pacific High pressure is -AAM, which is a global negative angular momentum state that usually takes some time to change I'm still going with no snow for 15+ days

0z EPS has more -EPO in the long range... that's definitely the colder scenario. GEFS holds the -PNA.

GFS trend.. It will be interesting too see if the long range does this, or if the H5 shifts away from a pretty far south -PNA in the Pacific https://ibb.co/BVGSHXvY

That we're seeing another strong February RNA is just insane, here's the last 7 consecutive years! The trend has often carried into March, although not as strong as Feb

Ok.. I'm saying the Pacific, if it looks like this with the highest anomaly ridge this far south, is a warm pattern.. Maybe in future runs it will show the H further north or over Alaska.. that will get you colder at the surface. I've seen that kind of change happen in the last few days. But beyond Day 10 on 18z GEFS, the Pacific -PNA ridge is pretty far south, and would verify as an above normal temp pattern most likely.

^See, these are the two biggest regions for downstream East Coast troughs/ridges (-PNA/+NAO)

I just can't see 500mb High between Aleutian islands and Hawaii at +300dm, and southern Greenland having negative 500mb and it not being above average.. maybe the 500mb pattern will change in future runs, it has been going back and forth a little the last few days.

Part of it could be that the Pacific ridge extends into Alaska.. that is colder at the surface in the US. The other part may actually be model error, as they are maybe coming off a really cold period and running that forward? Save those maps, I bet in verification it will either be warmer, or the H5 will adjust differently to match the colder surface. It's a pretty strong -PNA/+NAO happening in the long range.. that usually trends warmer to the day of.

In the long range, you want to look at what's happening over the index regions.. That's a big +NAO/-PNA, the odds of snow in that pattern are slim to none. The hope maybe is that future models change on the H5 pattern, but there is a lot of adjustment that would need to happen.

Monster -PNA ridge Days 10+ on the 18z GEFS. Unfortunately, a +300dm mean isn't likely to reverse in time for verification time. We could be waiting until after mid-February for snow.. Does late Feb get colder? The MJO if it stays strong may go through favorable phases then, but I think the late blooming Nina is having somewhat of an impact and this may carry into the end of the month. -EPO tendency this Winter has been strong, but I almost feel like we are becoming "due" for a +EPO period going into the start of March. They say the uniform +PNA we saw late Nov - mid January is something that comes back, but we seem to be doing just as an extreme -PNA catch up now, somewhat neutralizing the probability for what happens next..

Surprising, because the 18z GEFS has a really strong -PNA/+NAO from hour 252->. Really, really rare to get snow at all in that pattern.

I mean, models were showing -PNA/+EPO/+NAO for a long time.. You would think with that upper latitude pattern, Chicago would hit 60, but the downstream projected pattern didn't show that. It makes you think.. is index forecasting a better way to go? In the last few years on here I have made model error bias calls, particularly with -PNA leading to less/no snow in the Mid-Atlantic, and it has been working out. Surprisingly, the downstream effect of index-patterns isn't completely factored in the models in the medium/long range..

I said yesterday the EPS was probably closer. It's probably not going to snow for the next 15+ days though.. 64 in DC today.. -PNA patterns overperform for warmth here.. that's my point

This is a big time -AAM, which means the pattern has staying power

LR GFS, but at least we know it's not a snowy pattern: >5800dm south of the Aleutian islands (-PNA) and 4700s dm over the Baffin Island (+NAO). >5700dms going north of Chicago. Day 15-16, but that's quite a pattern.

I still have pretty good snowcover.. this was taken 5 minutes ago Love where I live, it's a little bit of a microclimate