CAPE

The 0z GEFS was already moving in the direction of a further south coastal low development. EPS as well.

A GFS op run at range, but not out of the realm of possibility. I would hold off though..

No one should pay any attention to the 6z GFS.

On the 0z runs the GEFS and CMC ens trend the PNA to neutral/slightly positive by the 20th. EPS keeps it somewhat negative.

Looking at the advertised evolution of the pattern mid month and beyond, with h5 +height anomalies in both the EPO and NAO space, through wave interactions (specifically the amplifying EPO upper ridge) the models are once again indicating a TPV lobe cutting off underneath and becoming displaced southward over Hudson Bay. There have been hints of this on recent runs, but it's more prominent on the 0z GEFS. That's in a good spot and sets up the possibility of a more classic sustained NAO block with colder air on our doorstep.

Pretty good odds out that way there will be multiple snow chances leading up to and including Xmas, given how the currently depicted pattern looks. Whatever falls should mostly be able to stick around during that period.

Wasn't that the year where it snowed for Thanksgiving(more SE of I-95), Dec was super cold, the Bay froze, then by mid Jan winter was over?

If the 18z GFS simulation were to come to fruition, a quick chase up to central PA might be considered for late next week.

A snowman19 sock seemingly- this moron has also been around shitting up threads for years.

Also has a more legit looking -NAO.

Yeah, there are issues in any pattern, even ones we identify as favorable overall. The orientation/character of the EPO ridge makes a difference as to how much cold can make it eastward. The -PNA tendency needs to be kept in check. A -NAO will help encourage more favorable storm tracks and inhibit eastern ridging. Details we just can't know yet.

Looks like there will be at least some help in the NAO domain, but need the PNA to hang around neutral. Always a fight in a Nina.

Impressive -EPO across guidance now, so it appears we will have the mechanism to deliver some pretty legit cold beyond mid month. Seeing hints on the ens means of possible waves tracking along the boundary to our south, but no clear signal at this range.

We got us another one.

Foggy here too. Was worse last evening.

The 'new favorable pattern' concept over the last few runs on the means, from mid month forward-- a solidly -AO, a bit stronger -EPO, a little less -NAO. I'll take the slight tradeoff that tilts a bit more towards a favorable Pacific in a Nina. Looks colder too. Just don't want the EPO ridge to become too positively tilted, esp if the -NAO weakens.

Can't really compare a smoothed/course mean to a high resolution op run extrapolated out 15 days. Load h5 on the 6z op run, put it on animate, squint a little, and notice all the red in the high latitudes with vortices flying around all over the midlatitudes. That's the general look we want. The interactions and timing among these features will change significantly from run to run and result in wildly different outcomes.

A -AO/-NAO/-EPO trifecta can get some decent cold into Canada, then into the central and eastern US. In that setup, a slightly negative to neutral PNA can facilitate disturbances entering the west coast further south, instead of exclusively relying on waves coming over the top with a stacked -EPO/+PNA ridge. That could be dry-ish.

The GEFS h5 pattern over the last few runs has trended to a better overall look across the top for the period beyond mid month. Good sign.

Are these 2 statements related? LSD cloud seeding?

0.70" of rain here. Looks like a mild and murky day ahead.

This doesn't always work. The NAO will technically be negative, but not a true block. That chance is evaporating as we speak with a lobe of the Okhotsk TPV digging south and absorbing the vortex over Canada. Ruined by typical Nina wave interactions.

As it looks now, the colder air will come in behind the mid month storm, which at this point looks like a mild rainstorm. Still a week out and there are hints on the ops and ens that it could morph into something a bit more favorable, but most likely outcome is rain for our region, with upslope snow for the western highlands on the backside. Once the colder air is in place and the the thermal boundary is south of the area, there should be some trackable waves leading up to Xmas. For all the reasons we have discussed over the past couple days with the pattern evolution, the airmass- at least initially- will likely be somewhat colder than average for the EC. The Canadian model is probably too cold- it has a stronger more classic -NAO look for a time beyond mid month, quite different from the EPS and GEFS. Good news is snow climo is improving the last third of the month. Personally I am rooting for something simple- a more modest wave tracking along the boundary vs something that amps up. The key to a favorable pattern for the last half of December imo lies on the PAC side at this point. We need a -EPO, and at least a neutral PNA period. The NAO will initially be quite negative, although probably never close to the true block of our hopes and dreams, but trending towards neutral by the end of the month.

Sticking with Canada.