frd

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?

Only this year, and in this new warmer background state, does a deep - AO and -NAO produce no significant snowfall for us. Source region concerns continue, and even though the +EAMT events are helping with the -NAO they are also bringing in copious warmth to Alaska . At our latitude we need perfection and it is just not there. The fast flow and uncooperative Pac is over-powering the - AO and -NAO. How long this lasts is still uncertain , but hopefully by mid month the Pac changes up a bit. At the moment the really cold air is in Asia, as you have read about the very strong high pressure areas there.

We need at @Isotherm to come in here and do a little updating. I believe according to his seasonal forecast , January held the highest probabilities of colder with normal to above normal snowfall for our area.

Goes to show, both humans and models still possess debatable value beyond a certain point.

Ark like rains here , warnings flying across the radios and TVs, Rudolph is wearing scuba gear.

Hard to be a believer after a run like that.

EPS at 360 hours has an awesome Greenland block in the Davis Straights with another incoming +EAMT event. Maybe spur a +PNA . Mid to late Jan. could rock.

Donald Sutherland did some posting about the CFS last winter, and its accuracy for the month ahead. What he found was it really gets into its wheelhouse of accuracy around this time of the month for the month ahead. So, it would appear you can place a little more faith on the CFS at this time.

Hearing about concerns related to source regions from several mets. This went in the wrong direction, hopefully by mid Jan this looks much different. CFS progression makes sense, so it is not out there alone with bringing improvements in the EPO region.

This is a long range thread ? Gathering unique, useful data and weighing it for long range outcomes is the fun part of long range forecasting.

7 x more likely. Good odds. @SimonLeeWx Replying to @SimonLeeWx The Arctic High regime is ~7x more likely to occur if the lower-strat vortex is weak than strong (https://doi.org/10.1029/2019GL085592…) - and that's certainly consistent with this forecast. Suggests that the accuracy of the stratospheric forecast may be important here for the regime forecast. Wintertime North American Weather Regimes and the Arctic Stratospheric Polar Vortex agupubs.onlinelibrary.wiley.com

Overall probability is reassuring that the Greenland blocking regime is indeed real. @SimonLeeWx Tropospheric-led but then subsequently likely reinforced by the weakened stratospheric vortex, the GEFS 35-day shows an unusually strong signal for the Arctic High regime (Greenland blocking) to dominate the North American regime space over the coming few weeks. 11:12 AM · Dec 23, 2020·Twitter

Progression could be cuter, cuter. Mid Atlantic snowstorm then clipper, then classic Miller A third week of Jan. It fits evolution of NAO block retro and then Pac improvement based on forcing moving into more favorable area / +EAMT events and then a rise off of a deep -NAO sort of similar to a HA event.

Damn !!!! I like!!! Eric Webb @webberweather This is the composite of Jan-Febs that had late Dec-Jan SSWEs & whose tropospheric pattern in the 3 weeks leading up to the SSWE bears some semblance to this yr (+WPO/+EPO/-NAO/-AO/+SCAND). Very NINO heavy composite as you'd probably expect given the deep, precursor Aleutian Low 11:42 AM · Dec 23, 2020

Hasn't the GEFS out-schooled the EPS, or is it my imagination? Thought a couple mets commented on that last week.

He probably did jump the gun, but the pattern that he spoke about may very well develop in time. The Nao and the Arctic oscillation point to the possibility of winter storm threats in the East at some point in January.

There has been a tendency for Inland Runners and Coastal huggers but the Dynamics of the block have to fully mature, the best chances most likely after the 7th of January.

Looking forward to the next update, but this is rather impressive and starts in only a few days,

Member count continues to increase.

Seems as though there will be multiple +EAMT events upcoming. Hopefully, this provides a few +PNA intervals, coinciding with a storm threat for us in January.

OMG, spit my sugar smacks out. At least your odds are 10 % , I am at zero.

The long range GFS matches the new CFS for Jan. 2021 , which according to the date today of the 22 nd should be entering its period of higher verification for the next 30 day period. I like ! We track ! @psuhoffman you think ridge bridge way out there possible.