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@poolz1 pretty neat

I love this animation, really hope the GEFS has the right idea. Its beautiful ! The GEFS has been doing well overall, so hopefully this wave retrogression is correct.

Euro pretty firm on Jan 5 th. Getting closer.

Coming soon to CAPE's backyard.

Today there is increased consensus on keeping the AO negative near - 3 SD for an extended period of time, possibly even lower towards mid Jan.

Hopefully the last cutter for a while afterwards, if the GEFS is correct. Then, we track the various impulses moving under the block as the pattern continues to improve. Looks like exciting tracking opportunities from mid Jan into Feb. I would speculate, as you ,mentioned, real threats for our area start near the 14 th or 15 th. In the past there have been multiple times when we scored with a so so Pac, but a stellar -AO and - NAO.

Hmmm......

I like the sound of this, a huge player for sure.

HL becoming more negative as indicated by the blue colors, this increases over time. A very positive factor for eventual cold and snow in the East.

NAM state improving.

If you want to play voodoo outcomes, lets say the SSWE officially triggers on the 5 th of Jan, ( per the Euro ) the cold would not become evident in the East until near January 25 th to Feb 1 st. The map above is only January 8th. Also, keep in mind if the Urals High re-builds we will continue to get +EAMT events.

Euro has official wind reversal much sooner than the GFS. GLOSea supports the Euro. Faster official SSWE would mean effects time line moved up. @SimonLeeWx Replying to @SimonLeeWx GEFS & CFSv2 have 64 vertical levels, while ECMWF's ensemble has 91 and more of those are in the stratosphere (38 above 100 hPa vs. 24 in CFS). So, I anticipate ECMWF is on the right lines, as models with greater vertical resolution perform better (https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD030920…) [2/2] The ensemble-means of ECMWF extended, GEFS 35-day & CFSv2 all produce a major SSW during January - but they are really predicting different events, since while ECMWF reverses ~Jan 5, GEFS (Jan 12) & CFS (Jan 22) reverse much later! Which will be correct? [1/2]

Do you still feel the Pac will improve in late Jan? I mean beyond periodic + PNA intervals. This area is another area of various conflicting views from mets and pros.

Looking at 500 certainly makes you think that NA gets the benefits of the SSWE. And speculation would suggest the cold air continues to gather and deepen past this time frame. Also, some off the climo charts possibilities exist down the road, with the incredible low pressure storm system in the North Pac and a possible world breaking high pressure reading yesterday.

Seems like conflicting views and opinions, even from various well respected mets regarding the - NAO/block/ AN heights near and around Greenland. Some say what tombo stated, others are gung-ho about real storminess and snow prospects in the East.

Great thread. Worth a read. Way more to.it than what I posted. Anthony Masiello @antmasiello · 1h A tradition of sorts: to take the ECMWF zonal wind anomaly charts during a SSW and show the zero-line descend through the stratosphere. GIF @antmasiello · 1h **correction, that is not a zonal wind anomaly but mean zonal @antmasiello Replying to @antmasiello the mean zero-wind line determines the level at which future waves break (RW can only upwell through westerly flow) and deposit their easterly momentum. The descent in this one seems quicker than usual, but I do not have numbers to back that up. 12:06 PM · Dec 28, 2020·Twitter Web App @webberweather · 1h Replying to @antmasiello JRA-55 SSWE compendium composite shows the zonal wind reversal propagating from the stratopause to ~20mb in a matter of 3 days (ish) during major sudden warming. Looks about right to me @antmasiello · 1h thanks for the composite, and your conclusion is probably right, but that doesn't show the zero-line reaching the 50-100mb depth, probably from event smoothing.

No time for greater detail but, wow to the new AO and NAO ensemble forecasts. Really diving down, looking better and better for a SECS based solely on those 2 indicates moving forward into January.

The Ural blocking has diminished by hour 576 ( accept at own risk ) which was responsible for the East Asian Mountain torque. Hopefully models go to a more robust + PNA , and post the SSWE we may get the vortex to settle further South in time. May seed areas to our NW with a very cold air mass by the third week of Jan.

Crazy look here with the Pac and the height distribution from Greenland to the US SE Coast. A week beyond this date is when things might start shifting. On a unrelated note, Ocean temp off Southern New Jersey according to Magic Seaweed is 55 degrees F. If correct rather mild for this time of year.

Some feel the opposite of this view. Yet, as mentioned, we may still get some good events. As griteater posted earlier, mid to late Jan for an improved Pac. That seems to be the trend during the last couple of days. Anxious to see if the modeling does a big change for the better in the next several days, as it possibly could latch on to the time period and evolution of the SSWE. Of course the outcomes doesn't have to be one of colder, however, I am hoping for improved looks in the PNA domain. David Gold @dgoldwx2112 Replying to @antmasiello I think in the winter mean the tropical heat source will be situated well west of where it typically aids in setting up the kind of pattern that eastern winter weenies love. That of course doesn’t preclude some good events. 5:05 PM · Dec 26, 2020

Agreed, wondering if in the end our savings grace will be the very thing that was an obstacle. Hopefully we score when the Pac improves and we take advantage of the active pattern.

All and all we are in trouble. Blocks mean little, folks neglect temps. This winter the new player is source region, damn I missed that one.

Excellent info, thanks.

Last thing, if we have a favorable SSWE for example whether it be a displacement event, or a split, of combination is it possible that under certain circumstances it can create its own regime, over-powering say even the Pac influences or is that not a valid possibility ? I ask because HM alluded that the strat may be able to create its own regime under certain circumstances in a recent post several days ago. Thanks

Tom, in your view, can there be too much of a +EAMT event? Meaning, having multiple events is it a net plus or minus to a desired Eastern cold state in time?