Febuary 9-11 threat

[earthlight]

Hopefully we see some positive trends over the next few days...the one thing that's worrisome is the progressive trend with the blocking over Northern Greenland. Most guidance had this feature building far enough south to bring the effect of high latitude blocking into the pattern. The PV was shoved further south and west and the pattern slowed enough to allow for some amplification. Now we're seeing a sudden fast trend with the southern stream..the PV is much more suppressive and further south..and the blocking has been significantly reduced to nearly the northern 1/4 of Greenland.

[earthlight]

What is your thinking about the pattern breakdown in mid-February? Do we have a true torch or just a couple days in the 40s? The 0z ECM seems to want to build an east-based NAO block with an increasingly -AO by February 16th, with some cold air from the PV left over Eastern Canada, so that might mitigate the warm-up. With the MJO moving towards Phase 6, we're likely to see a moderation, but then the MJO goes towards Phase 7/8 and the blocking looks to return. Could we see a wintry period from February 20th through early March?

Pacific ridge breakdowns are always ugly..so if it does happen that way it's going to be hard to dig our way out of it. When you flood the country with Pacific air the models are usually a beat too fast in redeveloping the blocking. Take tonights 00z GEFS as an example..they try multiple times in the long range to build the block back towards Greenland but it remains progressive. If that does happen..it's going to be until March that we see any rebound towards a supportive snow pattern. I don't buy into this, yet...but I have seen some absolute abortions when it comes to Pacific ridges breaking down to the east across the CONUS. It's a long process in redeveloping the pattern once the ridge breaks down over the top of everything...it can take multiple storms to redevelop the block and rebuild it towards Greenland...and we don't have that much time unless you're talking late March/April snowstorms.

[earthlight]

Getting these historic snowfall amounts can be really tough for a reason, there's a reason they are historic. Regarding pattern changes..I enjoy watching them unfold, but for anybody hoping to smash records..you need to hope for the storm next week to work out..and then throw up a hail mary for the end of February. Watching a pattern change unfold in November is much different than watching one unfold in Late February...when there's 2:00 on the game clock.

[SnowGoose69]

Pacific ridge breakdowns are always ugly..so if it does happen that way it's going to be hard to dig our way out of it. When you flood the country with Pacific air the models are usually a beat too fast in redeveloping the blocking. Take tonights 00z GEFS as an example..they try multiple times in the long range to build the block back towards Greenland but it remains progressive. If that does happen..it's going to be until March that we see any rebound towards a supportive snow pattern. I don't buy into this, yet...but I have seen some absolute abortions when it comes to Pacific ridges breaking down to the east across the CONUS. It's a long process in redeveloping the pattern once the ridge breaks down over the top of everything...it can take multiple storms to redevelop the block and rebuild it towards Greenland...and we don't have that much time unless you're talking late March/April snowstorms.

When you look back at the number of Decembers andJanuarys to both have double digit snowfall at Central Park its somewhat surprising how poor many of the ensuing Februarys were...2003-2004 being the most recent example.

[Dsnowx53]

This is a case where not having a "good" -NAO can really hurt you. The PVs are often a lot more potent in +NAOs. Although the PVs are further south in -NAOs, they are also weaker, and often positioned much better where they can work very well with a developing storm, instead of being a storm squasher.

The flow is just way too fast/progressive in the NW Atlantic right now.

The blocking helps to push the PV further SW and thus buckle the pattern. We do not have that. It also leaves more room for amplification because the downstream NW Atlantic pattern is much slower/not progressive, and the height field is not progressive. How is anything going to amplify given how insanely fast the flow is in the Atlantic with this kind of pattern?

There are so many great things that blocking provides that we just do not have right now. Things can obviously change given that it's 5 days out. But the current pattern certainly does not support a snowstorm.

[earthlight]

This is a case where not having a "good" -NAO can really hurt you. The PVs are often a lot more potent in +NAOs. Although the PVs are further south in -NAOs, they are also weaker, and often positioned much better where they can work very well with a developing storm, instead of being a storm squasher.

The flow is just way too fast/progressive in the NW Atlantic right now.

The blocking helps to push the PV further SW and thus buckle the pattern. We do not have that. It also leaves more room for amplification because the downstream NW Atlantic pattern is much slower/not progressive, and the height field is not progressive. How is anything going to amplify given how insanely fast the flow is in the Atlantic with this kind of pattern?

There are so many great things that blocking provides that we just do not have right now. Things can obviously change given that it's 5 days out. But the current pattern certainly does not support a snowstorm.

Yeah, agreed pretty much on all counts. Also, drawing on my earlier post..check out the 03z SREFs at 81 hours. Obviously we're stretching into their longer range here, but this illustrates the problem on a synoptic level as well. That's a huge northern stream/piece of the Polar Vortex which is both poorly positioned and poorly timed in relation to the southern stream. You aren't going to get a storm up the east coast with this upper air pattern.

[Dsnowx53]

Even though the center of the PV is not that far south, it's just such a freaking huge PV (because of the +NAO...and yes, to me it's positive, I don't care what the index number says it is) that there are low enough heights on the south side of it to be a very suppressive PV. And given how fast the flow is, you are not going to buckle the pattern. The blocking helps to push the PV further southwest which buckles the pattern and actually helps to make the NW Atlantic flow much less progressive, and leads to a better chance of a northern stream/southern stream phase.

Or the PV could move out of the way entirely.

[Dsnowx53]

Yeah, agreed pretty much on all counts. Also, drawing on my earlier post..check out the 03z SREFs at 81 hours. Obviously we're stretching into their longer range here, but this illustrates the problem on a synoptic level as well. That's a huge northern stream/piece of the Polar Vortex which is both poorly positioned and poorly timed in relation to the southern stream. You aren't going to get a storm up the east coast with this upper air pattern.

Yeah, exactly. The PV is in the worst position possible...if you move it eastward from where it is now, you have less initial confluence in SE Canada which might actually help the southern stream wave to amplify. If you move it westward from where it is now, you make the NW Atlantic less progressive, and it helps to buckle the flow.

But right now, it's in the exact position where it provides neither of the positives, and all of the negatives.

[SnowGoose69]

http://www.meteo.psu.edu/~gadomski/NARR/1988/us0106.php

The setup over the NE is somewhat similar as well as the southern Plains here minus the west coast ridge...ultimately a system did eventually come up the East Coast on 1/8 and it was a relatively bastardized version of a low that more or less was fueled by a strong high...its a similar scenario to what the GFS has been showing although the low came well further north.

[nzucker]

Getting these historic snowfall amounts can be really tough for a reason, there's a reason they are historic. Regarding pattern changes..I enjoy watching them unfold, but for anybody hoping to smash records..you need to hope for the storm next week to work out..and then throw up a hail mary for the end of February. Watching a pattern change unfold in November is much different than watching one unfold in Late February...when there's 2:00 on the game clock.

I'm not thinking this milder pattern is going to last that long; this winter attempted to moderate over New Year's but got snuffed out by the 1/8 snowstorm and ensuing arctic air. This last week has been an attempt to moderate towards a more typical La Niña pattern with low pressure tracking through the Plains but ultimately hasn't been that warm and will be snuffed out by the arctic front Tuesday. We've seen a pattern where we have short intrusions of milder airmasses but they don't really detract from the overall wintry regime we've been in. I think you may be playing the "time is running out" card too early; Central Park only needs two 8" storms to break the 95-96 record, and that's entirely possible given we have two threats this coming week and then a redeveloping NAO by 2/20. Even with a moderate snowfall Monday night and nothing on Thursday, I'd think NYC is a favorite to break the record.

La Niña winters tend to have a much colder/stromier March than El Niños....we saw this in 1956 when the KU occurred, in 1960 when the Nor'easter that month dumped 30"+ in the NYC suburbs, in 1967 when we had 70" of snow here by the end of the season despite a putrid Dec/Jan, etc. So the winter isn't over even if we do get a week of warmer weather in mid-February; having a mid-winter thaw is just climo for this area, so we should expect it. There are already signs on the models that a block will be building; the 0z ECM has the NAO becoming increasingly west-based by 2/16, the GEFS are trying to get some blocking in, and we have some sneaky cold sitting over Quebec/Labrador that might keep the Northeast relatively cool compared to the rest of the CONUS.

Yeah, agreed pretty much on all counts. Also, drawing on my earlier post..check out the 03z SREFs at 81 hours. Obviously we're stretching into their longer range here, but this illustrates the problem on a synoptic level as well. That's a huge northern stream/piece of the Polar Vortex which is both poorly positioned and poorly timed in relation to the southern stream. You aren't going to get a storm up the east coast with this upper air pattern.

Can't we get a piece of the PV to phase into the southern stream, and thus promote amplification? If the PV trends a bit further west, wouldn't we see a big phase that forces the storm up the coast?

[nzucker]

Getting these historic snowfall amounts can be really tough for a reason, there's a reason they are historic. Regarding pattern changes..I enjoy watching them unfold, but for anybody hoping to smash records..you need to hope for the storm next week to work out..and then throw up a hail mary for the end of February. Watching a pattern change unfold in November is much different than watching one unfold in Late February...when there's 2:00 on the game clock.

It isn't happening in late February though...the warm-up seems to be centered around Valentine's Day with the return to a winter regime by 2/20.

[nzucker]

6z NAM looks very interesting at 84 hours with regards to the Thursday threat...note the deeper amplification of the southern stream shortwave and higher heights...this should come up the coast:

You can see the difference at 500mb compared to the 0z GFS at 90 hours, in which the southern s/w was dampened out and the northern stream was in a much less favorable position for amplification of the system:

[IsentropicLift]

If the system on tuesday pans out the odds of thursday are greatly increased. Regarding the long range the pattern changes back near hr 360 after an extended period of ridging over the east on the 0z gfs and I think that sounds like a good bet

[Alpha5]

NAM looking a lot better in terms of the PV orientation.

[Edge Weather]

At 84 hrs on the NAM the precip shield has already reached extreme SW PA.

[EasternLI]

I don't think there's any reason to panic yet. Whatever happens with the first system will have some say in what happens with this system. Until that one gets resolved, we'll continue to see models shifting everything around. I'd be more concerned if we were seeing consistant hits in this long lead time.

[NEG NAO]

I don't think there's any reason to panic yet. Whatever happens with the first system will have some say in what happens with this system. Until that one gets resolved, we'll continue to see models shifting everything around. I'd be more concerned if we were seeing consistant hits in this long lead time.

This storm is being suppressed by the northern stream - this setup is completely different then the previous snow events - lack of a -Nao and the other players being in the wrong position is forcing this solution - OTS and its not going change - anyone hanging on with the theory that the models all winter corrected themselves 2 days before the storm to the more amplified phasing solution are going to be disappointed and wrong this time around...........

[RUNNAWAYICEBERG]

This storm is being suppressed by the northern stream - this setup is completely different then the previous snow events - lack of a -Nao and the other players being in the wrong position is forcing this solution - OTS and its not going change - anyone hanging on with the theory that the models all winter corrected themselves 2 days before the storm to the more amplified phasing solution are going to be disappointed and wrong this time around...........

that is incorrect.

[IsentropicLift]

I don't see anything that gives this thing hope unless tuesdays event somehow completely phases and bombs out leading to a better orientation of the PV I would say this has about a 20% chance now of being a significant event.

[EasternLI]

This storm is being suppressed by the northern stream - this setup is completely different then the previous snow events - lack of a -Nao and the other players being in the wrong position is forcing this solution - OTS and its not going change - anyone hanging on with the theory that the models all winter corrected themselves 2 days before the storm to the more amplified phasing solution are going to be disappointed and wrong this time around...........

Maybe so, but I can't even tell you how many times I've already heard those exact statements already this season.

[NEG NAO]

Maybe so, but I can't even tell you how many times I've already heard those exact statements already this season.

You have heard in previous statements that there is no -NAO ???? The NAO has been negative with all the previous snow events....

[isnice]

I don't see anything that gives this thing hope unless tuesdays event somehow completely phases and bombs out leading to a better orientation of the PV I would say this has about a 20% chance now of being a significant event.

This may be a first, but I do actually agree with you! lol

[EasternLI]

You have heard in previous statements that there is no -NAO ???? The NAO has been negative with all the previous snow events....

I wasn't talking about that. You said this is going OTS period. Correct me if I'm wrong, but it's still over 100 hrs out. I admit the 12Z GFS was a step in the wrong direction. You seem to be suggesting that there is NO chance of a storm without a -NAO which is just not true.

[Storm At Sea]

It's not looking good at this point.

[Juliancolton]

It's not looking good at this point.

Agreed. A major shift in the whole synoptic pattern is looking increasingly unlikely. At least it wasn't a disappointing long-tracker that bailed ship under 48 hours.

[LongIslandWx]

Let's give it until 00z Tuesday to stick a fork in this potential event.

[SACRUS]

It's not looking good at this point.

GGEM matches the GFS. Amazing trend from the fear of a cutter to an OTS convergence on the models. We'll see if the euro follows suit, suspect it will but there is time for trends the other way.

[NEG NAO]

that is incorrect.

If you are going to say someone is incorrect - prove it ......

[NEG NAO]

I wasn't talking about that. You said this is going OTS period. Correct me if I'm wrong, but it's still over 100 hrs out. I admit the 12Z GFS was a step in the wrong direction. You seem to be suggesting that there is NO chance of a storm without a -NAO which is just not true.

Yes Period - and in this case a -NAO in the right position would probably do the trick.......

[IsentropicLift]

The problem with this event is that it would take much more than a quick fix to fix this one. We need alot of things to change in the near term to have a chance which is why this is becoming unlikely our fate should be sealed in 72 hrs.