Winter 2024-25 Medium/Long Range Discussion

[DocATL]

There’s a very small window of opportunity for a legitimate thread the needle chance, leading into the expected significant Eastern US/Canada troughing.

We’ve seen countless opportunities similar that have fallen apart well in advance or just don’t produce. So, I wouldn’t put down any money that it’ll happen, but there’s at least a chance. The OP Euro modeled evolution is essentially the perfect/best case scenario…with the GFS not far off.

Is this because this is just not a pattern that typically produces? Seems like the southeast, east coast, and LES regions are in the crosshairs. Maybe we get more legitimate chances late January?

[RogueWaves]

3 hours ago, DocATL said:

Is this because this is just not a pattern that typically produces? Seems like the southeast, east coast, and LES regions are in the crosshairs. Maybe we get more legitimate chances late January?

CPC with a slight risk of a heavy snow swath on their 8-14 day map. That's as high as you can go for now. As posted, these windows have flashed before and didn't work out. Have to give it some time to trend better or join the scrap heap of prior fails. 

[HillsdaleMIWeather]

Surprised noone has commented on the 18Z GFS, we might actually have some events soon gentlemen 

[OHweather]

5 hours ago, DocATL said:

Is this because this is just not a pattern that typically produces? Seems like the southeast, east coast, and LES regions are in the crosshairs. Maybe we get more legitimate chances late January?

That type of setup CAN produce. The issue is there’s a lot that can go wrong. If the trough along the east coast is deeper or farther west, there’s less space for the storm in question to amplify and produce. Also, that kind of  setup is quite dependent on the shortwave phasing and amplifying early enough for those who want more impactful snow farther west. So as Chicago Storm said, with that many moving parts at this distance it can easily fall apart. 

[nvck]

I mean, this is just ridiculous. Yeah, this is a couple weeks out, but temps down into the negative teens in Tennessee is crazy. Obviously, I don't think that this will come anywhere near verifying, but wow...

[Maxim]

1 hour ago, nvck said:

I mean, this is just ridiculous. Yeah, this is a couple weeks out, but temps down into the negative teens in Tennessee is crazy. Obviously, I don't think that this will come anywhere near verifying, but wow...

Def overdone, but first half of Jan looks like it will be colder than average unfortunately. Seeing signs of a much warmer second half, however.

[ILSNOW]

As stated by the pros probably not going to happen but

 

 

[A-L-E-K]

At least a reason to look at model runs again 

[IWXwx]

8 hours ago, OHweather said:

That type of setup CAN produce. The issue is there’s a lot that can go wrong. If the trough along the east coast is deeper or farther west, there’s less space for the storm in question to amplify and produce. Also, that kind of  setup is quite dependent on the shortwave phasing and amplifying early enough for those who want more impactful snow farther west. So as Chicago Storm said, with that many moving parts at this distance it can easily fall apart. 

As Rocky told Bullwinkle in the old cartoon, "That trick never works." At least it never seems to.

[hawkeye_wx]

It's still a week out, but, for the first time, the 06z GFS has joined the Euro in showing a much more amped wave moving into the pacNW, which then leads to a big event for the midwest.

[A-L-E-K]

Gefs p good, warm lake should help with any marginal miss south

[Chicago916]

Definitely some better trends lately for a snowy next couple of weeks? Seems like the mean trough position has shifted slightly west putting the GL and Midwest into a more favorable position. I'm not putting much faith in a large storm before the Arctic blast though, too much ptsd from the last time we saw that in modeling and got blizzard warnings for a glorified cold front. We'll see though, tons of moving parts.

[RCNYILWX]

The expected phase change back to a strong +PNA after the potential event next weekend caught my attention, thinking back to the Superbowl 2015 storm.

It's not a perfect match but seeing some similar pieces in the Pacific pattern progression, when comparing the ECMWF ERA5 data on weather.us to the 500 mb anomaly forecast from the 00z EPS.

A deep trough into the Aleutians forced a ridge spike off the west coast, dislodging what would become our main wave into the Rockies, while a deep trough also was in place over northeast NOAM and moving off the coast. This enabled height rises in between into the Midwest. Finally, a northern stream wave was able to dig in and at least partially phase in with the main wave for the deepening surface low we saw on 2/1-2.

One of the biggest differences in the loading pattern was that the NAO was positive back in 2015 while it's forecast to be strongly negative in our timeframe of interest. That I think lends even moreso to the thread the needle aspect with the importance of a proper phase with the northern stream wave. If the phase is missed, the downstream blocking would suppress an overall weaker system.

Back in 2015, the main wave being quite juiced and the lack of downstream blocking likely would've resulted in the good WAA thump that played out even without the phase for the prolonged high ratio deformation snow portion of that event.

Overall, the analysis from [mention=525]Chicago Storm[/mention] and [mention=525]OHweather[/mention] is spot on in that the pieces could plausibly come together for a nice event, but with so many moving parts, things could certainly go wrong.

[hawkeye_wx]

Booya!  The 12z GFS has fully joined the Euro.  A major wave moves into the pacNW, the eastern trough exits, but leaves cold air in place across the north, and we get a big snowstorm in the midwest.

[DocATL]

Canadian looking to suppress with a southern slider and a frigid northwest flow for us. Unfortunately this look has popped up intermittently on model runs and is a very plausible solution. It would mean hoping for a clipper.

[DocATL]

Other concern is that GFS basically puts us in the shredder after the Jan 5/6 system. We will be in purgatory for a bit.


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[nwohweather]

16 hours ago, HillsdaleMIWeather said:

Surprised noone has commented on the 18Z GFS, we might actually have some events soon gentlemen 

I think Fort Wayne to Detroit stands to get a nice shot there on Tuesday evening

[ILSNOW]

12z Euro has a nice little snowstorm for North Carolina.

[Chicago Storm]

Other concern is that GFS basically puts us in the shredder after the Jan 5/6 system. We will be in purgatory for a bit.


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Whether or not there’s a storm system in the timeframe in question, that’s happening either way after.

This is a one and done shot.

[roardog]

This pattern coming up will be good for getting the Great Lakes more ice covered than we've seen in years, that's for sure.

[hawkeye_wx]

A change in the flow over the upper midwest on the latest op Euro appears to lead to the potential storm being weaker and well south of previous runs.

[mimillman]

Going to be a lot of back and forth with a system this far out. Euro ensembles have a good mix out major hits. Potential is there

[DocATL]

Canadian and Euro with similar solutions. So much run to run variance.


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[ChiTownSnow]

2 hours ago, hawkeye_wx said:

A change in the flow over the upper midwest on the latest op Euro appears to lead to the potential storm being weaker and well south of previous runs.

the difference from my untrained eye is that the wave ahead of it is a bit stronger, and gets a bit cut off which keeps the east coast trough deeper and further west long enough,  which supresses the headline storm as it cannot amplify 

[Baum]

I've learned not to get too excited until we get into NAM range.

[sbnwx85]

4 hours ago, Baum said:

I've learned not to get too excited until we get into NAM range.

No sarcasm here when I say the models should have a good grasp on this storm by Friday.

[Malacka11]

Not to suggest that it matters, but didn't GHDII spend most of the medium range chilling largely south of where it ended up in reality?

[sbnwx85]

32 minutes ago, Malacka11 said:

Not to suggest that it matters, but didn't GHDII spend most of the medium range chilling largely south of where it ended up in reality?

I’m starting to go back and look through that thread. It’s funny how the models haven’t improved much in ten years… and in some cases gotten a little worse. GHDII hit on a Sunday, as well. Models struggled 6-8 days out with most going south. The Tuesday before the storm, the GFS really honed in on the potential beast and track of the blizzard. It’s fun to go back and read everyone’s posts. 

IIRC, last January Euro and GFS showed a major snowstorm/blizzard for much of the subforum five days before 1/13… and backed off to a “run-of-the-mill” snowstorm.

Just a reminder not to get too high or too low run-to-run until about Friday

[sbnwx85]

GFS is a great hit for IA, WI, MI, N IL, N IN. South of there it’s nasty sleet/ice storm.

Canadian moves a low along the Gulf Coast… so take that for what it’s worth.

[HillsdaleMIWeather]

Euro is pretty juicy