Re: Long Range Thread 29.0

[nutleyblizzard]

What a stunning turn of events. Just 10 days ago all signs were pointing towards winter being DOA. Then after an unexpected major pattern reversal in the Pacific, we’re in this fortuitous weather pattern. I’m still cautiously optimistic to see if this has staying power. We’ll find out in the coming days and weeks if it does, but thus far GEFS and EPS look great for December.

[dkodgis]

I thought a winter pattern was to be but then I got spooked and hid in shame. Now look. I had mentioned colder temps and I am pleasantly surprised to see models showing this. Will it stick? Will it stay?

[amugs]

GEFS some heavy hitter in there.

[Frank_Wx]

The Godzilla on the 18z GFS deserves the first MADONNE of the season

[CPcantmeasuresnow]

GEFS some heavy hitter in there.

For December 8th? Do we even care that far out? Come on Mugs that's fantasy to the tenth power. Show me the same output 9-10 days from now and I'll pay attention.

[amugs]

GEFS some heavy hitter in there.

For December 8th? Do we even care that far out? Come on Mugs that's fantasy to the tenth power. Show me the same output 9-10 days from now and I'll pay attention.

It shows 2 storms during this time frame on these stamps - Nov 29th and Dec 4th. Be as what it may it showing the potential of the pattern. Fingers croossed my bretheren.

[heehaw453]

Not much change IMO for Thanksgiving potential. The north Atlantic trough IMO is the key. If it is able to hold together and stop the ridge link to the NAO domain think more white than wet. If not heights will rise on the ES and this will be an inland runner and wet for most. We've seen these ridges in the south link to the HL, but the Atlantic waters have cooled with persistent troughing.

[rb924119]

The Thanksgiving potential is nowhere near as straightforward as this last event, I can tell you that much aha

[sroc4]

Not much change IMO for Thanksgiving potential. The north Atlantic trough IMO is the key. If it is able to hold together and stop the ridge link to the NAO domain think more white than wet. If not heights will rise on the ES and this will be an inland runner and wet for most. We've seen these ridges in the south link to the HL, but the Atlantic waters have cooled with persistent troughing.

I think it may be more complex than that. The reason that happens on the euro is your getting a phase too early. There are multiple moving parts in this one for sure.  That trough off the SW coast. The subtle riding into the WC of Canada, the ridge over W Alaska play a role in timing of the backside energy. The NAO ridge and the 50/50 low position all play a role in slowing down the flow all of which determine the timing strength and positioning of three pieces of energy that may or may not come together too early, progressive and weak, or somewhere in the middle. Multiple moving parts to our N&E as well as to the west and NW.

[rb924119]

Preliminary thinking is that the same areas that got snow with this last event will get it good again on Thanksgiving. So, coastal plain, I think you're going to be largely out of the game for that one. At face value, I think the GEPS (Canadian ensemble) look the best with how they are handling things, mainly in the PNA and 50/50 domains, though I also think that they are still a bit too warm overall. I think if you're north of about I-80 this will be a mostly snow event, as I see room for things to trend further south and east. Additionally, I expect corrections to the Euro and GFS suites in this same direction, though more pronounced.

With the above said, the period from about December 4th through approximately December 9th has my attention for something that could get the majority of this forum on the board for the '24-'25 snowfall season, if not the entirety of the forum.

I'll have more to say on this over the next couple of days once I sit and ponder a bit, but right now, that's where my head is at.

[rb924119]

Not much change IMO for Thanksgiving potential. The north Atlantic trough IMO is the key. If it is able to hold together and stop the ridge link to the NAO domain think more white than wet. If not heights will rise on the ES and this will be an inland runner and wet for most. We've seen these ridges in the south link to the HL, but the Atlantic waters have cooled with persistent troughing.

I think it may be more complex than that. The reason that happens on the euro is your getting a phase too early. There are multiple moving parts in this one for sure.  That trough off the SW coast. The subtle riding into the WC of Canada, the ridge over W Alaska play a role in timing of the backside energy. The NAO ridge and the 50/50 low position all play a role in slowing down the flow all of which determine the timing strength and positioning of three pieces of energy that may or may not come together too early, progressive and weak, or somewhere in the middle.   Multiple moving parts to our N&E as well as to the west and NW.

Get out of my head!!!! It's freakin' me out, man :p Seriously, you pegged every single thing that I was just analyzing and spinning my wheels on haha although we will still have the west-based NAO block, it's nowhere near as strong as it was for this last event, so it won't have the same effect. Similarly, the 50/50 low is transient, but I think the west-based NAO block will end up having just enough of an effect to slow down the progression of that 50/50 low long enough to keep the heights ever so slightly suppressed. In the Pacific domain, I don't think that the Euro suite is properly handling the shortwave trough near Alaska/B.C. - it tries to sever the connection between the ridging in the eastern Pacific and the WPO/EPO domains. This makes zero sense with the Gulf of Alaska trough AND trough northeast of Hawaii. That trough should shear out and come rocketing down the back side of the long wave trough. As a result, the height field should compress, and we should actually see more western ridging emerge in subsequent runs as result of the constructive interference between the right exit region of that jet and the left entrance region of the main jet across the Gulf Coast States enhancing subsidence/surface high pressure/return flow/warming across the Pacific Coast. Among other factors, I think the result ends up being an Apps runner that then gets to the latitude of about I-80, but is then forced to transfer to the coast near the NY Bight. Again, all preliminary, but yeah, we are definitely on the same page, Scott haha

[heehaw453]

Not much change IMO for Thanksgiving potential. The north Atlantic trough IMO is the key. If it is able to hold together and stop the ridge link to the NAO domain think more white than wet. If not heights will rise on the ES and this will be an inland runner and wet for most. We've seen these ridges in the south link to the HL, but the Atlantic waters have cooled with persistent troughing.

I think it may be more complex than that. The reason that happens on the euro is your getting a phase too early. There are multiple moving parts in this one for sure.  That trough off the SW coast. The subtle riding into the WC of Canada, the ridge over W Alaska play a role in timing of the backside energy. The NAO ridge and the 50/50 low position all play a role in slowing down the flow all of which determine the timing strength and positioning of three pieces of energy that may or may not come together too early, progressive and weak, or somewhere in the middle.   Multiple moving parts to our N&E as well as to the west and NW.

Good points. The Euro drops the n/s into the storm which spins it up too quickly, and that looks to me due to the western ridge placement. And I guess you could argue the Atlantic ridge is allowed to poke through as a consequence of the early strengthening forcing more height rise on the EC.

[jmanley32]

Being its turkey day and I gotta travel I am okay with not getting snow but bring on Dec. 5th! Though that's like 300 hrs out, so to even be looking at that other than patterns does not make sense to me at this time as 1000 runs will put out so many things like yesterdays 18z GFS.

[sroc4]

I’m mobile this am but a quick rough and tumble analysis for the end of week threat shows what little ridging we had up and down the WC of Canada and NW CONUS we shifted west a bit. Same with the low off the SW coast. This seems to me be leading to a more progressive flow across the conus overall so our primary energy trajectory is a tad further north through the mid west and the northern energy isn’t allowed to dig much if at all. In addition on the euro the NAO ridge is weaker and a tad west also allowing the escape of the 50/50 energy faster. Result is a flatter more progressive track to our low, and a weaker soln re the mslp, with no real mechanism to inject cold air.  Latitude and altitude seem to be the only beneficiaries

[heehaw453]

^^^ true sroc

Even that being the case as no injection of cold air there's not much currently in Quebec to begin with as I've stated before. The cross polar injection to our west has to ooze down the cold. This year we will have that in December last year no such possibility as cold air was bottled up coupled with very warm eastern CA.  We wait IMO until post December 4th for chances.

Maybe the very highest elevations squeak out something from this setup?

The cold air coming for early December...


no High established in Quebec and even then it anomalously warm air in eastern CA. Also the Atlantic trough is giving way to a ridge. Flow is not compressed aiding to warming

[sroc4]

^^^ true sroc

Even that being the case as no injection of cold air there's not much currently in Quebec to begin with as I've stated before. The cross polar injection to our west has to ooze down the cold. This year we will have that in December last year no such possibility as cold air was bottled up coupled with very warm eastern CA.  We wait IMO until post December 4th for chances.

Maybe the very highest elevations squeak out something from this setup?

The cold air coming for early December...


no High established in Quebec and even then it anomalously warm air in eastern CA. Also the Atlantic trough is giving way to a ridge. Flow is not compressed aiding to warming

Couldn’t agree more on the “bleeding” of the truly cold air mass. The pattern just isnt there…yet. If you look at our system on approach like you pointed out despite a “semi blocky” NAtla tic the source region for eastern Canada is still off the Atlantic leading to this anomalously warm eastern Canada. Looking back west though you can def see the pattern taking shape for early December with the WPO and EPO regions blocky driving that attic and polar air into western and central Canada.  Pay attention to the trough just SW of the Aleutian Islands in the first image though. As it sits verbatim it’s a tad too far West.



When you look to the ensemble means there does seem to be the establishment of a solid entrenched south of the Aleutian island trough which consequently pumps the ridge along the WC of NA. If this truly sets up shop for more than a minute this will then push that cold air we are talking about into the East for sure and we as well as E Canada will reap the rewards. First with a real cold air source, and then we can hopefully time out the shortwaves coming out of the SW with the ones digging in from the NW. if that ridging along the WC is real it will effectively cutoff the dreaded pacific air mass from mixing with Canadas polar air. This has been the Bain of our winter existence over the last few years. Every time we’ve had a ridge out west a poorly timed s/w crashes the WC just as a system approaches the EC ruining everything.

The means are encouraging regarding this but it’s still a ways out. Too many times we’ve seen the LR evolve against us so I’ll remain cautiously optimistic for now. (PS sorry for the horrible graphics. I have to use my fat fingers on a screen shot on my phone. Lol)

[rb924119]

Good analysis by the two of you. Scott, I’d caution against using the Euro suite here, though, as I don’t think it’s handling the Pacific side of things well at all. I think the GEPS are much better, and the changes from yesterday’s 12z to today’s 00z were exactly what I mentioned last night. I would not be at all surprised to see the Euro and GFS come back to a stronger, more impactful system in upcoming runs. We should have more PNA domain ridging than either of those suites are currently indicating, in my opinion.

[sroc4]

Good analysis by the two of you. Scott, I’d caution against using the Euro suite here, though, as I don’t think it’s handling the Pacific side of things well at all. I think the GEPS are much better, and the changes from yesterday’s 12z to today’s 00z were exactly what I mentioned last night. I would not be at all surprised to see the Euro and GFS come back to a stronger, more impactful system in upcoming runs. We should have more PNA domain ridging than either of those suites are currently indicating, in my opinion.

Fair enough. But again I’m mobile. There is only so much I can/want to do. Lol. I was merely pointing out the latest trend overnight. Not necessarily what will be. We are still 5 days out. The time where models “experiment “ with the soln, before getting serious again and zeroing in on the final details.

[heehaw453]

We'll have to see but damn this early December jet on the EPS is so dramatically different than what we had December 2023. Nice split flow with western ridge helping ooze cold air to ES. If this keeps up have to like December for a snow event right to coast.

[heehaw453]

And as the h5 trough swings through next Sunday hopefully a bit of s/w action to provide a very minor snowfall next Sunday. Models definitely hinting at that and it makes sense to me with cold air in no short supply! A little snowfall for Christmas spirit would be awesome.

[weatherwatchermom]

And as the h5 trough swings through next Sunday hopefully a bit of s/w action to provide a very minor snowfall next Sunday. Models definitely hinting at that and it makes sense to me with cold air in no short supply! A little snowfall for Christmas spirit would be awesome.

Oh boy not so sure about that...every college kid will be heading back to school and people heading home from their holidays.... That would be a mess..right now Amtrak completely sold out on Sunday...can you imagine rescheduling.. ..also if you did not make your reservations months ago a round trip ticket from Prov to NJ is 750 dollars... absolutely nuts ..

[docstox12]

And as the h5 trough swings through next Sunday hopefully a bit of s/w action to provide a very minor snowfall next Sunday. Models definitely hinting at that and it makes sense to me with cold air in no short supply! A little snowfall for Christmas spirit would be awesome.

Oh boy not so sure about that...every college kid will be heading back to school and people heading home from their holidays.... That would be a mess..right now Amtrak completely sold out on Sunday...can you imagine rescheduling.. ..also if you did not make your reservations months ago a round trip ticket from Prov to NJ is 750 dollars... absolutely nuts ..

So far NWS Mom has just showers Thursday and Thursday night.
Glad to see Amtrak getting good business but the price of that ticket is high.

[Frank_Wx]

Thanksgiving Day storm has lots of model variability at the moment. EURO = lots of rain again with minimal changeover to the snow even for N&W regions. GFS = weaker system due to lack of upper energy consolidation with more of a casual low and snow to N&W.

https://x.com/tomniziol/status/1860798036026249426?s=46&t=khIuo-joMGhpKcLk0g9Y4g

Both models are indicating it might be a little too warm for NYC metro. For NYC to see snow, the GFS scenario has to play out but with a better timed phase which would drag the cold air down through the coast. We’re not seeing many model runs showing that right now.

[rb924119]

Overall, I have to say, I really like the presentation on the Euro AI the best yet again for the Thanksgiving storm.

[rb924119]

Overall, I have to say, I really like the presentation on the Euro AI the best yet again for the Thanksgiving storm.

Long-range NAM and RGEM look good as well with respect to my thinking.

[amugs]

Global look at D15 on 00z EPS Notice 3 main longwaves that suggest the colder pattern will likely extend well into Dec The sub-Aleutian low persistent Yesterdays EC46 showed that sub-Aleutian low feature remains in place most of Dec Thus the western NA ridge may be around awhile pic.twitter.com/AYu2CfvjeT

— Allan Huffman (@RaleighWx) November 25, 2024

The many factors that hurt us the past 3 years seem to have been jolted and are no more favorable for us. MJO is low frequency and we have a warming PDO and a cooling Kirisho Current off Japan that is helping quell and split the flow of the PAC JET Extension along with the Ido Pacific. I see a 2013-14 vibe and look pattern wise IMO

[amugs]

YIKES!! Get out the thermals!

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