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Winter 2019-20 Medium/Long Range Discussion

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1 hour ago, buckeye said:

if this is where we are 10 days from now....I'm not seeing a pattern change.   Same old craptastic, wavy, fast moving, cold air-lacking, hoping-for-a ---well- timed wobble to accidentally fall into some snow....    pattern.

eurocrap.JPG

Yeah, pacific driven after a quick real cold shot from a pacific screamer after the 18th. Fantasy range just loves to suppress heights to try and give it some lipstick. Then reality sets in(except for the GFS, it takes it a few days longer).

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On ‎1‎/‎9‎/‎2020 at 10:28 AM, DaveNay said:

Right now the Euro and the GFS are in strong disagreement over temps on Wed.

 

sfct.us_mw.png

 

sfct.us_mw.png

I'd say the Euro is one step closer, in getting out of the ALEK doghouse..

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1 hour ago, DAFF said:

I'd say the Euro is one step closer, in getting out of the ALEK doghouse..

Better with temps not so much overamped storms 

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I'm just here to spread false hope of a pattern change that'll never come ;) (though we're already setting things in motion this week with a brief -EPO that does dump a good amount of cold into Canada and the eastern half of the U.S.)...

I don't totally hate the odds of a storm/event around the 23rd-25th across a good portion of the sub forum, with fairly strong ensemble support for a decent shortwave to eject out of the southwest.  With some bootleg blocking across Hudson Bay, lower heights over the southeast, and surface ridging over the top ahead of this feature, I think there's a good shot it's wintry.  850mb temperatures are near normal (after being cold for a few days prior) and are workable with the ensemble mean 0C line south of the Ohio River ahead of this wave.  If it deepens too quickly it would still cut and change the Ohio Valley to rain (or perhaps simply give them mostly/all rain), but places like Iowa/Wisconsin/Michigan, Chicago, Detroit, and maybe even Indy/Toledo/Cleveland would probably see a half decent amount of snow if an organized system can eject in this time-frame.  Places like Pittsburgh and Columbus/Dayton/Cincinnati still can snow but would likely need to root for a more strung out system, as the "blocking" to the north isn't strong enough to stop a stronger system from cutting too early for them.

1381407890_eps500.thumb.png.48036e8f30cb6e3e705cba396caf1256.png

1404831038_EPSsfc.thumb.png.54ed3e1a3fe6ca257192828c752ae0f6.png

1351583919_EPS850.thumb.png.f2862b0a8e33cd67e66d0a8e300c81aa.png

As for the "pattern change", both the tropics and extra-tropics don't really say it should be here yet...I think the ensembles several days ago (and hence those of us rooting for a pattern change) rushed the change a bit, but things suggest it's probably still 10-15 days away from really being "there"...

The MJO is at an extremely strong amplitude in phase 5/by tomorrow 6...these are not cold phases, though do usually end up being cold within 2-3 weeks of their occurrence.

92980003_CFSMJO.gif.959b69b78877786c8d52196b2a7b0abb.gif

Here are lagged composites of what happens after a phase 6 MJO at an amplitude of 1 or greater...although the MJO accounts for something like 25% of the sub-seasonal variability observed over a large sample, this is a very strong MJO and will influence the pattern.  Each lag is 5 days.

2122696592_phase6lagged.thumb.png.f59c86fc071d3275f267a6ddb4583520.png

This does not suggest a more legitimate pattern change that dumps cold into the CONUS for another 10-15 days (though does suggest slightly faster high-latitude changes, which we are seeing).  Phase 7, which we'll reach in 5-7 days, leads to cold by lag 1 which is 5-10 days (and supports the timeline from a current phase 6) and is typically cold thereafter for quite a while.  Phase 8 is cold immediately and for quite a while.  Here is a link to these composites for anyone interested: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/LaggedComposites/

Basically, tropical forcing says we should not yet be cold and probably shouldn't be for another 10-15 days, so it's probably not that surprising that the mid-range guidance has delayed a persistent cold pattern but still shows one developing past day 10.  This should start moving up in time as the MJO keeps propagating.

219121766_GWOlast120.thumb.png.bd8b72f8a1d0e31d435bcb6812a8c575.png

Global angular momentum (GWO, AAM, GLAAM, whatever your acronym) will rise soon, but it hasn't yet.  A low AAM is more typical of a La Nina, supports a strong stratospheric polar vortex/+AO, and trough over the western U.S.  We have been gradually climbing towards a more persistently positive AAM since the middle of fall, but it's been a slow climb, and I think the AAM slipping negative for most of December (after a couple of positive attempts in November) contributed to the strong stratospheric PV and +AO we are dealing with right now.  It spiked at the end of December, but the tropospheric pattern was horrible with a PV over Alaska and the stratospheric PV was too strong for that spike to significantly disrupt it.

The strong MJO over the next two weeks, along with a fairly strong East Asian Mountain Torque (high pressure east of the mountains) will add a lot of momentum over the next two weeks, and we will see the strongest positive AAM spike of the fall/winter by far.  Here is the EPS sea level pressure anomaly forecast for hour 264 showing this strong mountain torque, along with the CFS AAM forecasts for the next month:

895398534_EPS264.png.94f4c7bde3ac8f7dc6253849979385df.png

492379120_CFSAAM.thumb.png.e1ab314c956337e40148c70e401b87e9.png

This added momentum will help fuel an already active sub-tropical jet, will support some jabs to the stratospheric PV, and the MJO moving through the western Pacific as a +East Asian MT occurs will support significant amplification in the EPO/PNA domains.

Basically, I understand it's frustrating waiting a bit longer after over a month of really unfavorable conditions for snow for most of the sub and that it may seem like the models are perpetually pushing cold back, but there are reasons we didn't flip as quickly as the models suggested..basically the drivers didn't support it yet...and there are numerous reasons to expect it to still change soon.  The combination of factors we will see the rest of this month is unlike anything we've seen so far this fall/winter and I would be flabbergasted if it didn't result in a shakeup in the pattern.  I think the trick will be figuring out if we go back to warm in mid-late February, or if it's a more prolonged change that carries us through the rest of winter.  I don't know the answer to that yet.

After the potential system around the 23rd-25th (that favors the northwestern 2/3rds of the sub) there may be a similar opportunity a few days later.  Thereafter individual threats become murkier, but it should stay active and I think we see the EPO drop more than the EPS suggests in the 10-15, which will eventually push the baroclinic zone far enough south to favor the Ohio Valley over the Great Lakes. 

 

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I'm just here to spread false hope of a pattern change that'll never come (though we're already setting things in motion this week with a brief -EPO that does dump a good amount of cold into Canada and the eastern half of the U.S.)...
I don't totally hate the odds of a storm/event around the 23rd-25th across a good portion of the sub forum, with fairly strong ensemble support for a decent shortwave to eject out of the southwest.  With some bootleg blocking across Hudson Bay, lower heights over the southeast, and surface ridging over the top ahead of this feature, I think there's a good shot it's wintry.  850mb temperatures are near normal (after being cold for a few days prior) and are workable with the ensemble mean 0C line south of the Ohio River ahead of this wave.  If it deepens too quickly it would still cut and change the Ohio Valley to rain (or perhaps simply give them mostly/all rain), but places like Iowa/Wisconsin/Michigan, Chicago, Detroit, and maybe even Indy/Toledo/Cleveland would probably see a half decent amount of snow if an organized system can eject in this time-frame.  Places like Pittsburgh and Columbus/Dayton/Cincinnati still can snow but would likely need to root for a more strung out system, as the "blocking" to the north isn't strong enough to stop a stronger system from cutting too early for them.
1381407890_eps500.thumb.png.48036e8f30cb6e3e705cba396caf1256.png
1404831038_EPSsfc.thumb.png.54ed3e1a3fe6ca257192828c752ae0f6.png
1351583919_EPS850.thumb.png.f2862b0a8e33cd67e66d0a8e300c81aa.png
As for the "pattern change", both the tropics and extra-tropics don't really say it should be here yet...I think the ensembles several days ago (and hence those of us rooting for a pattern change) rushed the change a bit, but things suggest it's probably still 10-15 days away from really being "there"...
The MJO is at an extremely strong amplitude in phase 5/by tomorrow 6...these are not cold phases, though do usually end up being cold within 2-3 weeks of their occurrence.
92980003_CFSMJO.gif.959b69b78877786c8d52196b2a7b0abb.gif
Here are lagged composites of what happens after a phase 6 MJO at an amplitude of 1 or greater...although the MJO accounts for something like 25% of the sub-seasonal variability observed over a large sample, this is a very strong MJO and will influence the pattern.  Each lag is 5 days.
2122696592_phase6lagged.thumb.png.f59c86fc071d3275f267a6ddb4583520.png
This does not suggest a more legitimate pattern change that dumps cold into the CONUS for another 10-15 days (though does suggest slightly faster high-latitude changes, which we are seeing).  Phase 7, which we'll reach in 5-7 days, leads to cold by lag 1 which is 5-10 days (and supports the timeline from a current phase 6) and is typically cold thereafter for quite a while.  Phase 8 is cold immediately and for quite a while.  Here is a link to these composites for anyone interested: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/LaggedComposites/
Basically, tropical forcing says we should not yet be cold and probably shouldn't be for another 10-15 days, so it's probably not that surprising that the mid-range guidance has delayed a persistent cold pattern but still shows one developing past day 10.  This should start moving up in time as the MJO keeps propagating.
219121766_GWOlast120.thumb.png.bd8b72f8a1d0e31d435bcb6812a8c575.png
Global angular momentum (GWO, AAM, GLAAM, whatever your acronym) will rise soon, but it hasn't yet.  A low AAM is more typical of a La Nina, supports a strong stratospheric polar vortex/+AO, and trough over the western U.S.  We have been gradually climbing towards a more persistently positive AAM since the middle of fall, but it's been a slow climb, and I think the AAM slipping negative for most of December (after a couple of positive attempts in November) contributed to the strong stratospheric PV and +AO we are dealing with right now.  It spiked at the end of December, but the tropospheric pattern was horrible with a PV over Alaska and the stratospheric PV was too strong for that spike to significantly disrupt it.
The strong MJO over the next two weeks, along with a fairly strong East Asian Mountain Torque (high pressure east of the mountains) will add a lot of momentum over the next two weeks, and we will see the strongest positive AAM spike of the fall/winter by far.  Here is the EPS sea level pressure anomaly forecast for hour 264 showing this strong mountain torque, along with the CFS AAM forecasts for the next month:
895398534_EPS264.png.94f4c7bde3ac8f7dc6253849979385df.png
492379120_CFSAAM.thumb.png.e1ab314c956337e40148c70e401b87e9.png
This added momentum will help fuel an already active sub-tropical jet, will support some jabs to the stratospheric PV, and the MJO moving through the western Pacific as a +East Asian MT occurs will support significant amplification in the EPO/PNA domains.
Basically, I understand it's frustrating waiting a bit longer after over a month of really unfavorable conditions for snow for most of the sub and that it may seem like the models are perpetually pushing cold back, but there are reasons we didn't flip as quickly as the models suggested..basically the drivers didn't support it yet...and there are numerous reasons to expect it to still change soon.  The combination of factors we will see the rest of this month is unlike anything we've seen so far this fall/winter and I would be flabbergasted if it didn't result in a shakeup in the pattern.  I think the trick will be figuring out if we go back to warm in mid-late February, or if it's a more prolonged change that carries us through the rest of winter.  I don't know the answer to that yet.
After the potential system around the 23rd-25th (that favors the northwestern 2/3rds of the sub) there may be a similar opportunity a few days later.  Thereafter individual threats become murkier, but it should stay active and I think we see the EPO drop more than the EPS suggests in the 10-15, which will eventually push the baroclinic zone far enough south to favor the Ohio Valley over the Great Lakes. 
 
Great, informative post. Have learned a lot about long range forecasting from reading your posts over the years.

Sent from my SM-G965U using Tapatalk

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The big takeaway from that post to me is the MJO, at the very least with a high amplitude wave, we are going to flush out the current pattern at the very least.

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37 minutes ago, Hoosier said:

Using the 16 day op GFS as a counterargument

Come on, man

c'mon, if it was showing the polar vortex over Cleveland it would fit nicely with the calls for the end of this garbage pattern and no one would say a thing.  The point is if anything is going to show a flip to cold....it's the long range gfs.   It was for awhile, and now those looks are becoming muted more and more.    

I've got other arguments as well.... have you seen the latest mjo?    What's the argument for the flip?

Trust me...i hope i'm eating crow a week from now... and yes, we'll definitely get a cold shot after the slop storm....but I'm just not seeing us leaving this repeated back and forth, garbage pattern.   

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120-168 hour GFS is a mess again. It distorts the arctic jet somehow south despite another pacific wave crashing on shore which means forecasters will have a mess on their hands revising temps up as the GFS corrects the error for next week. It really shouldn't be doing that in that range. I gotta wonder this PAC heavy pattern hasn't exposed a error in the last upgrade. Even crap models like Icon knows you can't do that.

Then a split flow pattern occurs which is like throwing paper up into the air and hoping it lands on your lap for the last week of the month lol.........

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As per the Euro, the cold air doesn't last long and by the 22nd, we're above freezing again. This is in part due to the jet cutting overtop of the region and a lack of blocking in the Pacific. It almost resembles a -PNA in the west. And instead of a 50/50 Low off the coast of Newfoundland, there's a massive ridge at 192 hrs. There's nothing amazing about this pattern or set-up. 

Edit: By 216hrs the entire nation is flooded with warm pacific air while the cold air retreats to the Arctic. 

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21 minutes ago, Snowstorms said:

As per the Euro, the cold air doesn't last long and by the 22nd, we're above freezing again. This is in part due to the jet cutting overtop of the region and a lack of blocking in the Pacific. It almost resembles a -PNA in the west. And instead of a 50/50 Low off the coast of Newfoundland, there's a massive ridge at 192 hrs. There's nothing amazing about this pattern or set-up. 

Edit: By 216hrs the entire nation is flooded with warm pacific air while the cold air retreats to the Arctic. 

brutal....   

eurooo.JPG

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24 minutes ago, Snowstorms said:

As per the Euro, the cold air doesn't last long and by the 22nd, we're above freezing again. This is in part due to the jet cutting overtop of the region and a lack of blocking in the Pacific. It almost resembles a -PNA in the west. And instead of a 50/50 Low off the coast of Newfoundland, there's a massive ridge at 192 hrs. There's nothing amazing about this pattern or set-up. 

Edit: By 216hrs the entire nation is flooded with warm pacific air while the cold air retreats to the Arctic. 

I was considering posting something about this after perusing the Euro, but didn't want to get flack from the optimists.  Although we are approaching a "pattern change", the sensible weather past day 6 doesn't look that much different.

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3 minutes ago, IWXwx said:

I was considering posting something about this after perusing the Euro, but didn't want to get flack from the optimists.  Although we are approaching a "pattern change", the sensible weather past day 6 doesn't look that much different.

This is where you need to refer to THE METEROLOGICAL CYA HANDBOOK by Joe Bastardi

Chapter 2 : What to say when the cold never comes

pg 127"....I still nailed the pattern at 500mb!"

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1 minute ago, buckeye said:

This is where you need to refer to THE METEROLOGICAL CYA HANDBOOK by Joe Bastardi

Chapter 2 : What to say when the cold never comes

pg 127"....I still nailed the pattern at 500mb!"

You forgot earlier on that same page "delayed but not denied" and then if that fails pivot to your answer.

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2 minutes ago, buckeye said:

This is where you need to refer to THE METEROLOGICAL CYA HANDBOOK by Joe Bastardi

Chapter 2 : What to say when the cold never comes

pg 127"....I still nailed the pattern at 500mb!"

That was 01-02 when he had that infamous line I think.  

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6 minutes ago, Hoosier said:

That was 01-02 when he had that infamous line I think.  

I feel like he said it last year 18-19 also

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Just now, Hoosier said:

That was 01-02 when he had that infamous line I think.  

I think that's right.  All through December he was calling for the potential of an all-time coldest January for much of the east.  Ended up being a record high month :lol:

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He did a pivot from 2014-2015 and is now claiming 65-66 is a top analog. WB has been pounding the table, just like 65-66 winter will come roaring the 2nd half of the season! It’s comical. 

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1 hour ago, Chambana said:

He did a pivot from 2014-2015 and is now claiming 65-66 is a top analog. WB has been pounding the table, just like 65-66 winter will come roaring the 2nd half of the season! It’s comical. 

God i hope not...65-66 was terrible here.

 

 Although jokes aside, the long range after next weekend's brief mild up is back to cold on all models, which naturally is to be taken with a grain of salt

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35 minutes ago, Angrysummons said:

65-66????? oooooooooooookkkkkkkkkkkkkkkkkkk.

this afternoon he made a post using January '78 as an example of a January that in spite of being remembered as a severe winter month, featured several warm/rain storms in the east.    

so now i'm excited....we are in the midst of January'78....we just don't know it yet!!!!!!

 

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