December 2022 Medium-Long Range Disco

[Ralph Wiggum]

4 hours ago, Always in Zugzwang said:

Hell at this point it's like a glorified occluded front passage!

Saw that myself. Not just the gfs. Past few Nina years have had plenty of these unfortunately. 

[CAPE]

The big 3 global means are all suggestive of one or more waves tracking from the the deep south up along the east coast between Dec 20-25, with cold air in place.

Same general favorable h5 look-

Go Canada!

[BristowWx]

^such a good look there…we need a little luck…a miracle perhaps.  

[CAPE]

3 minutes ago, BristowWx said:

^such a good look there…we need a little luck…a miracle perhaps.  

Miller A for Xmas! 

[Maestrobjwa]

21 minutes ago, CAPE said:

Miller A for Xmas! 

Miller A in a nina--now that WOULD be a literal Christmas miracle, lol I mean seriously

[CAPE]

1 minute ago, Maestrobjwa said:

Miller A in a nina--now that WOULD be a literal Christmas miracle, lol I mean seriously

It's possible. I am mostly just having a little fun with the labels. The advertised pattern would support a primary wave taking the southern route. There will certainly be pieces of energy in the NS with that look.

[BristowWx]

It looks cold. At least that seems better than a maybe.  

[CAPE]

3 minutes ago, BristowWx said:

It looks cold. At least that seems better than a maybe.  

Cold air in place ahead of a storm, with a favorable pattern, gives the MA lowlands the best opportunity for frozen. The late week deal has always looked convoluted and simply not enough cold around yet.

[Bob Chill]

19 minutes ago, CAPE said:

It's possible. I am mostly just having a little fun with the labels. The advertised pattern would support a primary wave taking the southern route. There will certainly be pieces of energy in the NS with that look.

Labels are muddy for sure. The majority of our big snows are a hybrid of some sort. Plenty lean on the Miller B side of things too. Each storm has it's own pros and cons. Miller As have the higher probability of missing us to the south than hybrids/b's with a big block. Such a "fun" latitude we live at. Lol

[Ralph Wiggum]

 

27 minutes ago, CAPE said:

It's possible. I am mostly just having a little fun with the labels. The advertised pattern would support a primary wave taking the southern route. There will certainly be pieces of energy in the NS with that look.

Dont stoke the fire. You know darn well how hard it is to get one of those that you labeled let alone get one during a Nina to come up the coast. Now half of these folks are going to be hunting for it and expecting it. Youre the devil at times I swear lol  

[CAPE]

7 minutes ago, Bob Chill said:

Labels are muddy for sure. The majority of our big snows are a hybrid of some sort. Plenty lean on the Miller B side of things too. Each storm has it's own pros and cons. Miller As have the higher probability of missing us to the south than hybrids/b's with a big block. Such a "fun" latitude we live at. Lol

Yep. Many of our good events are hybrids. Miller B gets associated too much with Ninas and failure. We have many failure modes lol.

[wxdude64]

4 minutes ago, CAPE said:

Yep. Many of our good events are hybrids. Miller B gets associated too much with Ninas and failure. We have many failure modes lol.

Sadly 'failure mode' outnumbers 'win mode' about 95 to 5 on 100 chances. And that is being generous. 

[Bob Chill]

8 minutes ago, wxdude64 said:

Sadly 'failure mode' outnumbers 'win mode' about 95 to 5 on 100 chances. And that is being generous. 

I always come back to simple math... met winter avgs around 10-12" of total precipitation through time. Good or great years are still usually only 20-25% frozen. Lol. Many sit quite comfortably in your math 

We need chances more than anything to have a good winter. The good years will have a handful of 1-4" snows peppered in the mix with a few nice events. Our 1-4" snows are usually streaky too. Fun when they line up

Eta: we usually do well when it's active and "close enough" to snow.  3-4 OK chances in a favorable period of any length usually produces something. How well "something" is received is quite personal lol

[Weather Will]

WB OZ EPS through Christmas.  Better % than historical averages but nothing honking yet.  Will post every couple days until Christmas.

[frd]

National temps on December 26 th using a blend of the GEPS, GEFS and EPS.  Brrr.....  

 

 

[Bob Chill]

23 minutes ago, CAPE said:

Yep. Many of our good events are hybrids. Miller B gets associated too much with Ninas and failure. We have many failure modes lol.

Our lowest stress coastals (imo only) are the ones that kill an 850 low over or just west of the apps south of harpers ferry. We debate these all the time. Hybrid is the only answer for me and slp does jump the coast. Even when the shortwave is pure southern stream it can still jump and screw just like our epic Nima fails lol. It's a bit subjective. 

Eta: I'll clarify "lowest stress".  A good column and 850 track along or just west of the apps sets our entire area in the crosshairs of WAA snowfall. Often from winterwxluvrs yard to Cape's.  Things can get tricky with the coastal but it's already snowed a good bit by then and it was easy to track. I like that. Lol

[nj2va]

9 minutes ago, Bob Chill said:

I always come back to simple math... met winter avgs around 10-12" of total precipitation through time. Good or great years are still usually only 20-25% frozen. Lol. Many sit quite comfortably in your math 

We need chances more than anything to have a good winter. The good years will have a handful of 1-4" snows peppered in the mix with a few nice events. Our 1-4" snows are usually streaky too. Fun when they line up

Eta: we usually do well when it's active and "close enough" to snow.  3-4 OK chances in a favorable period of any length usually produces something. How well "something" is received is quite personal lol

Yep, its rare that we score flush hits on every opportunity - usually if there are 4 chances in a good pattern, we’ll eventually score on the 3rd or 4th especially once the pattern has established and the cold is in place.  The good news is we’ll have cold in place.

[Weather Will]

WB EPS.  Ingredient number 1 will be in place the week leading up to Christmas….more than half the the battle most years…now we see if a discreet threat appears over the next week to track.

[frd]

Very active pattern weather pattern coming up between December 20 th and Jan 15 th.  

Massive arctic airmass pooling in Western Canada by day 8 to 10 and disturbances focused near our area, mostly undercutting the block,  hybrid coastals and eventual clippers are possible.  The Pac improves as we move deeper in December.  Snowcover continues to expand South and East over time increasing the odds of min. temps falling to near 10 degrees at some point after the arctic passage(s)  later in the month.   

 

Blocking wants to recycle in the EPO and NAO domains.  We already achieved a statisical significant  - 4.0 AO SD to add to this continuaton of HL blocking. You can see that here:

https://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_nh_anim.shtml

 

 

[frd]

Nice animation and discussion by @griteater

 

 

[Ralph Wiggum]

12 minutes ago, frd said:

Nice animation and discussion by @griteater

 

 

Can anyone explain to me, umm i mean my 11 year old daughter, what EAMT is?

This is one of the atmo / geo physics things Ive read and tried to decipher but am struggling with understanding for the life of me. Explain it like youre talking to my 11 year old. 

[Scraff]

Cosgrove on board it would seem. Cosgrove = @CAPE? 

 

“With the instability of the various longer-term numerical models, I have to tread carefully here. If you follow the goings-on with the stratospheric vortex, splitting and reshuffling, the cold wave forecast to get entrenched in North America will be three to four weeks after the 10MB event. Which means I am about six days off from my original December 7-8 start phase time, but reasonably close to have some confidence in the prediction through the end of December and the first week of 2023. So on the idea that this winter weather event will verify (which means ignoring the operational GFS scheme form 18z and the latest CFS and ECMWF weeklies), it would be wise to focus on the two drivers to this pattern.

 

One is the prediction of a Hudson Bay vortex digging southward and phasing with the storm complex moving out of California and northern Mexico around December 19-20. The ensemble platforms, as a rule, endorse a three-way jet stream merger and seem to point out surface cyclogenesis near Galveston TX. That low pressure center would travel east, then north-northeast, along the U.S. shoreline in a manner typical of "Miller A" cyclones. Climatology would favor a conversion to frozen types in the south central U.S. away from the coast. But as more Arctic air gets entrained into low pressure moving up the coast (just prior to Christmas Day, though the timing is suspect), chances would increase for a substantial, if not heavy, snow event in Appalachia, the Lower Great Lakes and possibly the Eastern Seaboard. Following the snow threat would be substantial wind and perhaps three days of numbing cold from the High Plains to the Atlantic coastline.

 

There is also the matter of another disturbance arriving in the Golden State or Baja California in the hammock week between Christmas and New Year's Day. The extensive blocking signature following the Arctic Circle from Alaska to Greenland should hold through the first week of January, so there would be the chance for another round of snow and ice along and below 40 N Latitude just before 2022 makes its exit. I will hold on to my forecast of the January Thaw occurring roughly between the 10th and 22nd of next month. But if analog forecasts verify, major cold and frozen precipitation potential will cover the eastern two-thirds of North America from January 23 through February 28” 

[Bob Chill]

18 minutes ago, Ralph Wiggum said:

Can anyone explain to me, umm i mean my 11 year old daughter, what EAMT is?

This is one of the atmo / geo physics things Ive read and tried to decipher but am struggling with understanding for the life of me. Explain it like youre talking to my 11 year old. 

This is foggy memory stuff but iirc the principal is simple. Giant mountains create obstructions for upper level flow and can buckle the flow or "break an existing pattern". The most common times you'll hear people getting all torqued up is when the pac jet is at time travel speed aimed directly at the conus. Upstream torquing can cause downstream buckling. 

Disclaimer: everything above may be incorrect 

[CAPE]

25 minutes ago, Ralph Wiggum said:

Can anyone explain to me, umm i mean my 11 year old daughter, what EAMT is?

This is one of the atmo / geo physics things Ive read and tried to decipher but am struggling with understanding for the life of me. Explain it like youre talking to my 11 year old. 

Search Atmospheric Angular Momentum and EAMT. Plenty of technical papers on the topic. Complex large scale physics. Esoteric stuff.  General idea- The atmosphere is a fluid moving relative to the rotating earth. Big mountains (ie in east Asia)represent obstructions/disturbances to the flow, and act like a 'lever arm' in a sense, imparting a force relative to the earth's rotation, and can influence jet stream configuration. 

[poolz1]

 Who would have thought we would be looking at a PAC and Arctic that looks like this as we near the end of Dec? Appears pretty stable at the end of the runs as well. +QBO, -PDO, Nina   

[IronTy]

54 minutes ago, CAPE said:

Search Atmospheric Angular Momentum and EAMT. Plenty of technical papers on the topic. Complex large scale physics. Esoteric stuff.  General idea- The atmosphere is a fluid moving relative to the rotating earth. Big mountains (ie in east Asia)represent obstructions/disturbances to the flow, and act like a 'lever arm' in a sense, imparting a force relative to the earth's rotation, and can influence jet stream configuration. 

The ole cross product.   

[Bob Chill]

Late Dec 83 & 89 analogs keep peppering the lists. Those are the 2 coldest holiday years in the last 40 years.  Doubt records are going down but it makes things interesting. More warmth in the oceans and more moisture in the air nowadays...

[jacindc]

1 hour ago, Bob Chill said:

Late Dec 83 & 89 analogs keep peppering the lists. Those are the 2 coldest holiday years in the last 40 years.  Doubt records are going down but it makes things interesting. More warmth in the oceans and more moisture in the air nowadays...

I was just talking with my family about Christmas '83 last night. We had driven up to NYC with another family to see a matinee, and hit quite a snowstorm on the northern Jersey Turnpike on the way back, a huge traffic jam of cars getting stuck on snow and ice. My dad and his friend had gotten out to push the car, having my 20-year-old brother take over the driving, and once the car got going, my brother didn't want to stop, leaving my dad and his friend screaming at him, and in the midst of that an 18-wheeler started sliding and jack-knifing right next to us, and brother managed to thread the needle between that and the cars in the other lane. Happy holidays, indeed!

[frd]

 

1 hour ago, poolz1 said:

 Who would have thought we would be looking at a PAC and Arctic that looks like this as we near the end of Dec? Appears pretty stable at the end of the runs as well. +QBO, -PDO, Nina   

 

 

The AO is trending more negative further out in time. Looks really nice up top. 

 

[frd]

 

Improvements out West really showing up on the modeling.  The looks might continue to improve in the days ahead. 

Real winter weather in the East is fast approaching.