Medium Range-Long Range thread

[tombo82685]

GEM also has stronger clipper more suppresive set-up at hr 144

I'm not sure which one is the gfs storm on the GEM. The tuesday timestamp the gfs ha,s the gem has a storm that looks more like the euro. Dominant northern stream that develops the low over sne. The following one on thursday looks more like the gfs depiction. 

[HM]

Wouldn't that give the opposite signal that the mjo is showing, which is trof in the east?

 

Not exactly.

 

The North Pacific is a function of-->

 

1. What the stratosphere is doing?

2. Retrograding or a progressive tendency on height anomalies?

3. AAM and AAM tendency propagation and GLAAM background

4. PDO / ENSO background state

5. Internal waves from mountains or snow cover (Asia...related to 1 and 3)?

6. Tropical forcing (related to 3)...what will be the dominate forcing signal (stagnant-walker, KW, MJO etc.)?

 

The MJO has shifted the upper level subtropical anticyclone to the dateline with an extended Pacific Jet giving birth to low anomalies in the NW PAC and Aleutians. 

[RowanBrandon]

Thats not the issue. The issue is that primary goes into western PA before dying and the secondary takes over south of us. The southerly push from the primary does it.

You're right, I didn't look at the hours prior.

[Rainshadow]

I sort of like the warmth getting into the Plains, but then perhaps having a tough time in the east..at least  for a time anyways. The euro ensembles in the 11-15 day basically Kid 'N Play flat top our nice ridge in NW Canada and the cutoff over the SW (which may be a bias?) pumps up the SE ridge. The GEFS and even Canadian don't completely agree at all.

 

I know for at least P8, not sure of the others, but the highest JFM correlations between the MJO and cold are in New England, so this goes hand in hand.

[Rainshadow]

The 12z gefs are further south than the 6z ones and further south than the operational, which isn't surprising . Keep up your negativity its working. Where is Colin when you need him?

 

I thought shooting a low score was the key to snow, all I have to do is post I expect rain....  Colin move over...

[chubbs]

I'm not sure which one is the gfs storm on the GEM. The tuesday timestamp the gfs ha,s the gem has a storm that looks more like the euro. Dominant northern stream that develops the low over sne. The following one on thursday looks more like the gfs depiction. 

trend in the east is in line with the GFS. Looks like its splitting the western system and introducing a little more southern stream.

[CoastalWx]

Well regardless, kind of a stormy signal post 2/10 with the srn stream perhaps getting involved. Persistent low pressure in the Gulf on the MSLP fields are probably a good signal for that.

[tombo82685]

I thought shooting a low score was the key to snow, all I have to do is post I expect rain....  Colin move over...

As is usually the case with the gefs, they are all over the place. Some have a driving rain storm, some have a monster.

[chubbs]

Now that run is available on e-wall, GEM ends up similar to GFS with southward shift in D7 system 

[winterymix]

2/5 is the new 12/5

[tombo82685]

euro continues to be not so enthused with the clipper on friday like the other models. Though it did trend towards digging the energy better.

[tombo82685]

well the euro looks nothing like the gfs for the tuesday storm. Its basically a low that goes into maine and a cold front that has limited moisture with it. Though, it may be keying on another feature like the gem has. There is another disturbance coming down from the north with what looks like some potential southern moisture to tap...lets see.

[HM]

well the euro looks nothing like the gfs for the tuesday storm. Its basically a low that goes into maine and a cold front that has limited moisture with it. Though, it may be keying on another feature like the gem has. There is another disturbance coming down from the north with what looks like some potential southern moisture to tap...lets see.

 

I haven't seen the euro yet but this is just a straight up mess...

[NaoPos]

the difference is the mean ridge axis between the two. Euro keeps it off shore and less amplification/digging of the northern stream. The GFS has it over the inter mountain west states. Also of note, is the preceeding clipper(our 50-50) is much weaker on the euro compared to the GFS.

[tombo82685]

the difference is the mean ridge axis between the two. Euro keeps it off shore and less amplification/digging of the northern stream. The GFS has it over the inter mountain west states. Also of note, is the preceeding clipper(our 50-50) is much weaker on the euro compared to the GFS.

the clipper strength is what tony was saying how the gfs has been over zealous in that.

[tombo82685]

well the euro looks nothing like the gfs for the tuesday storm. Its basically a low that goes into maine and a cold front that has limited moisture with it. Though, it may be keying on another feature like the gem has. There is another disturbance coming down from the north with what looks like some potential southern moisture to tap...lets see.

The other disturbance digs down nicely but it just falls apart. The whole trof ridge axis doesn't scream a storm up the coast rather than offshore. The amplication though is there.

[NaoPos]

the clipper strength is what tony was saying how the gfs has been over zealous in that.

Yea, that was a great & worrisome point he made. It's hard not to lean to the euro at this point.

[tombo82685]

I haven't seen the euro yet but this is just a straight up mess...

yea the biggest difference i see between the two is the position and strength of the pac ridge. The gfs is amplified moreso and further west which allows the northern stream to dig more. The euro is less amplified and good bit further west.

[tombo82685]

Im not sure the clipper strength is the issue on the euro. Both the euro and gfs blow it up below 990mb and pretty much in the same spot. Its the ridge axis that's the issue imho.

[tombo82685]

It's pretty funny looking at the euro post hr 180. The Aleutian low forms and its like an amoeba, just sucks all the cold air right to it. Also, the euro is dominated by all northern stream disturbances. Its like groundhog day over and over again with last friday's and the next tuesday's system with a northern low and somewhat of southern low. It does however develop a huge n atl ridge that pushes into greenland. It's like the proverbial middle finger pointing right at us

[NaoPos]

The euro laughs @ any return of the southern stream.

[Quakertown needs snow]

well at least the euro has something at 240hr

[HM]

The only real difference between the GFS and ECMWF, on a large scale, is the North Pacific situation. GFS has a robust wave that amplifies and closes off in the GOA day 4-5-6 which acts to pump up the ridge a bit more into western North America. The ECMWF, on the other hand, has only 1 closed low near Aleutians (the main vortex) and just keeps the GOA system an open wave.

[NaoPos]

The only real difference between the GFS and ECMWF, on a large scale, is the North Pacific situation. GFS has a robust wave that amplifies and closes off in the GOA day 4-5-6 which acts to pump up the ridge a bit more into western North America. The ECMWF, on the other hand, has only 1 closed low near Aleutians (the main vortex) and just keeps the GOA system an open wave.

Any reason why the euro doesn't seem too enthused with the STJ?

[CoastalWx]

Euro ensembles continue ugly in the 11-15 day.

[am19psu]

P1 is warm

[CoastalWx]

P1 is warm

 

Yeah the difference in handling the tropics can be seen.

[tombo82685]

P1 is warm

what are the cold phases for February 2-3?

[tombo82685]

what are the cold phases for February 2-3?

nevermind i found it

 

[NJwinter23]

The WPO is essentially a function of AAM and tropical forcing but it has a meaningful correlation in this "causal step ladder." It basically is a poleward advancement of the Aleutian Low pattern/hybrid +AO pattern, cutting off the Canadian Pipeline and flooding the CONUS with Pacific Air (with all else being equal) as low heights develop over the Chukchi and Bering Sea.

 

 

 

Yes,  it can make any winter lover sick but is this the correct forecast?

 

I could make an argument that it isn't and a hybrid style of this with more PNA and more east-based -NAO stuff going on would be more correct. Also, with the bombing 2/5 low and a possible quicker migration of the PAC wave, you got yourself another coastal storm setup.

 

 

Just to further elaborate on this as well, notice the correlation for warmth in a +WPO is greatest in the chinook regions of Western Canada where the Pacific Air downslopes off the rockies, but not as great across far eastern North America. In fact, the correlation is less than 0.6 in the mid-atlantic which is a benchmark for a clear statistical correlation. Now I’m not trying to say that a +WPO means jack **** for us, because it does cut off the Canadian cold supply as HM stated, but this does imply that being further away from the WPO regions versus say the EPO region allows for more wiggle room, perhaps in the form of a +PNA team up keeping the warm ups more muted..

 

This is what the gefs try to imply, however, the euro ensembles continue to trend worse and worse (closer and closer to Alaska with the gathering the vortex with less of a +PNA) on every run . Today’s 12z ens are an all out torch by day 11-15 and the worst run yet. I know it is not the only tool out there, but damn, since Friday its been a toaster bath with that model’s trends.