Stormchaserchuck1

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

Trend has been really strong for the last 7 years that we have a Feb-March -PNA. At the flip of the month, it's doing it again this year. Late blooming La Nina also enhances the SE ridge probability late Winter, and +QBO has been helping 10mb stay very cold this Winter, disallowing Stratosphere warmings. For the last few years, our cold late Winter has come from Stratosphere warmings, but that is looking less likely to occur this year. I would say we veer toward a -PNA/SE ridge pattern through March, but the 2-month period of cold late November through mid January was really uniform and solid.. those type of patterns usually come back at some point later in the Winter. So a bit of a conflicting forces.. I'd probably go with slightly above average late Feb through March, +EPO being less likely and a Winter trend of -EPO/-WPO probably means that I would wait until April to plant.

Yeah we really flipped from +AAM earlier in the Winter to -AAM now. This is a completely different pattern happening: 12z GFS ensembles go wild with RNA in the long range. It's a brutal pattern for snow in the Northeast with +NAO and -PNA, maybe until mid-February..

I just think it's a really strong signal on the mean for being so far out. I think the mean is approaching +300dm south of the Aleutian islands. It's been going back and forth a lot this Winter, I've seen -PNA patterns dissolve and move into -EPO domain in future time this Winter. If the EPS isn't aligned that's a little cause for less confidence.

Pattern's probably underestimated right now for how warm it can get here.