CAPE

The primary issue is the next trough digging in out west is right on the heels and additional shortwave energy from that is influencing the shortwave in front. The 'good' runs had more separation/little interaction. The GFS has consistently depicted the trough diving in closer behind(plus NS interaction with the Hudson vort) which causes the shortwave to take on a neutral/negative tilt sooner and track further NW. Last few runs of the Euro have trended towards more interaction with the next trough. That wave needs to be 'left alone' in order to take a more southerly track. Current Euro run compared to 4 runs ago- I'm not sure minor improvements to our NE(increased confluence) will help that much at our latitude. If there are more significant changes in that area then it could encourage a secondary coastal low to form further south. Otherwise we need to see more separation between the wave and the upper level energy coming in behind.

A -PNA during a Nino has a somewhat different(less hostile) character because we don't see the persistent Aleutian ridge like in a Nina. Much more workable esp with a prominent STJ.

We really need a run of Ninos. More likely to have a +PDO. Less hostile Pacific overall gives NA blocking a better chance to do what it normally(historically) does.

The Aleutian ridge/-PNA combo is the blocking pattern that wins. Unless that relaxes the NAO will probably keep losing that battle.

The orientation of the EPO ridge matters. That amped positively tilted ridge is going to bury a trough out west. I think that is a Nina/TNH tendency. Maybe PSU has some thoughts. Either way, until I see that Aleutian ridge die off and the PNA head towards positive, I doubt we will do any better towards mid month. The -PNA and SER are still there in the LR, then way out there we see the oft promised change, then it fades and never materializes. That h5 ens map WW posted above is just more of the same.

Yes it is definitely 'busy' in the NS, and subtle differences in wave timing/interactions are going to potentially make big differences in the outcome. It is almost always the case that the one result we want requires so much to go right with these wave interactions. As you often say, we need some luck.

There are definite differences in the character of the ridge across Greenland at that point. If you read my somewhat rambling post yesterday about all the interactions between waves over time, it is nearly impossible to discern cause and effect. In this case I think 'in phase' interaction with NS energy will tend to pull the low further NW.

Some key differences influencing the track of the storm between the GFS, and Euro/CMC: GFS- Has more interaction with NS energy rotating down around the vort near Hudson, as well as energy digging in behind associated with the next trough. Euro/CMC- Most of the NS energy near Hudson is shifting eastward out ahead, and also more separation from the digging trough out west with more of a ridge between.

My wag at this point is that this will end up favorably, although maybe not all snow, for places inland and further NW in our region. For the lowlands it looks more problematic because of the marginal temps. Given the advertised lack of HP to the north on guidance, even a track along/just off the coast would be iffy for eastern areas. This has been a notable issue in recent winters in marginal cold situations.

I am not predicting it will be. I just thought the most likely way we fail would again be a NW track. The setup is clearly better than what we have had, but the block is just getting established. The location and timing of the NS vorticity across southern Canada is going to influence the track of the wave and there are still differences there, and then there is the next western trough with additional upper level energy digging in behind, also impacting the track. Always issues. We still can't know yet.

These poor people. Snow on the ground continuously since early Dec. Never get a break! They never salt the roads there though- just scrape it every other day and continue on. No bother.

Atmospheric wave interactions are so complex and interesting. Just sitting here (a little high) animating and analyzing the differences in the pattern evolution that lead to the different outcomes between the GFS and Euro. There are many (rather subtle) interactions that can be visually identified that lead to significant differences later, but determining the exact initiating 'causes' are literally impossible, as waves are constantly interacting and upstream/downstream is relative in a hemispheric longwave pattern. Then there is the matter of how far back you want to look in time to try to identify what features (and differences in their character) may be influencing any differences in the ultimate outcome later on. Fascinating stuff and yes I do this as an exercise a lot during winter lol. Probably a good one for weather weenies trying to gain an intuitive understanding of a complex process.

(Predicts Ralph will like this post)

That vorticity lobe over the southern end of Hudson Bay needs to pivot eastward sooner. It is in phase with the ejecting southern wave then digs in behind and tugs it north.

I could never do PBP. I have WB.

Somehow it lost its way after HH Thursday. This will be the run where the GFS gets its mind right again.

Come on Americans.. you can do it.

Yeah the CMC ens was beautiful.

lol how sad. Same here.

Snow on the beaches again. Just looked at Rehoboth Beach Cam. Coming down good there.

Basically just snow tv here. Had a period with some decent sized flakes and it started to stick in shaded areas, then went back to super light stuff. Radar doesn't look too encouraging, unless further south.

Some seriously perfect timing wrt to the NS energy overtop. Not too behind like the GFS to tug it NW, or out in front. Just right to let it track underneath, with enough space to not dampen the wave. Not very cold, but the thermals are likely going to be an issue for this period.

Sold. Close the curtains on winter after that.

Some small flakes in the air here now. 34.

See my previous post. Too broad-brush to say the 'NAO/50-50' are causing suppression, when it is really the timing/location of a specific piece of energy associated with what's going out west that is the primary problem.