CAPE

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.

@mappy Here is your storm.

I looked at both MJO and Pacific jet configuration and the latter stood out as the bigger difference between the EPS/GEPS and the GEFS, and a possible reason for the disparity between the advertised patterns in the EPO/PNA space. eta- I have read his threads on EAMT and he seems very knowledgeable on the subject. All complicated stuff. My observations are via my untrained eye.

I looked at the NPAC jet on all 3 global means this morning and the EPS and GEPS were similar(more extended). Looks like GEFS may be playing catchup this time.

Seeing +Height anomalies in the HL regions(not the norm) is always better than the inverse. We have something to work with.

Go Canada!

Looking more EPS like.

Imagine what Ji is going through.

I suppose "delayed" in the sense that we won't have a more favorable pattern in place until later than guidance was previously suggesting. But you are right, we won't be getting that same pattern, because there was significant model simulation error in the interaction between important features that resulted in that outcome. That happens a lot in the LR, as we all know.

I have said this before, but in recent ENSO neutral/Nina/weak ass Nino winters, since 2016, the -NAO periods(mostly bootleg) have generally been too marginal (with stale/ Pacific origin cold) to get it to snow in the MA lowlands. Best outcomes have been in more progressive patterns during periods where the PAC was more favorable, mostly -EPO, with real deal cold air delivery. More of a thread the needle situation but it seems to work out better esp in a Nina. Need cold first! HL blocking during a CP moderate Nino has been gold- maybe we get that combo next winter, and we can see if that still works.

The Pacific is always a battle, but I also don't like the look of the NAO on the latest runs. It seems to evolve from a full lat ridge resulting from the western trough, then it tilts neg into GL, but it isn't so much a ridge at that point as it is a blob of higher +heights sitting there. Looking at the height lines they look flat, with little indication of a true -NAO dipole as we were seeing on previous runs, and ofc the TPV has exited stage left. As for getting legit cold air, I think it will probably have to come from a -EPO period..

I just looked at that. It might. In general the forcing looks weak regardless of phase. Not an expert on that stuff but that's gotta be better than having persistent convection near the MC.

Fwiw the GEFSX does get the h5 pattern very close to the look on the EPS, but later. Delayed not denied.

I just took a quick look at the Pacific basin on the means, centered around the 20th of Dec. Indication of more precip(convection) in the Western Pac on the EPS and GEPS, with not much going on in that region on the GEFS. The N Pacific Jet configuration on the EPS and GEPS is notably more extended than on the GEFS to my eye. This explains at least in part the differences we are seeing in the advertised h5 patterns. The base state in a Nina is usually hostile to our goals, so it's always a fight. The other problem with the latest GEFS runs is the -NAO looks a bit wonky and weaker, and if that is close to reality it won't do much to mitigate an unfavorable Pacific.

It won't happen now with Lamar out for a week or 2. Beyond that there will be 3 games left and a change might not make much difference. There will be plenty of offseason drama with this team.

The bottom line is having a mechanism for delivery of anomalous cold, especially in December. The currently advertised pattern on the EPS would get it done, as would the CMC ens(actually looks unrealistically cold given the h5 look). EPS has the best/coldest look at h5 with a -EPO/slightly +PNA from mid month onward. GEFS has improved in recent runs, but doesn't quite get the NPAC sorted- has a slightly -EPO/neutral PNA look towards D15. Root for the EPS, although as @WxUSAF said, the pattern progression it has been depicting looks more Nino than Nina, and it has trended towards the GEFS in recent weeks moving from the LR to MR.

If only he had the balls to get rid of the actual problem.

I'll wait until it actually materializes before I start getting 'concerned' it might not last. Besides, Chuck told us all a ++NAO is where it's at.

lol ninja'd

Latest edition of the Weeklies. That h5 look should bring some decent cold for the end of the month heading into Jan.

Super frosty this morning. Almost looks like a coating of snow.

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