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Feb To Forget? - 2020 Discussion

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The 2/1-2/3 weekend looks extremely chaotic in the upper level pattern.  The 12z and 18z GFS operational runs show the chaotic underbelly of the pattern ahead at least for the 8-12 day period.  The ensembles are showing a favorable pattern setting up in the 11-15 days range.  Now the transition period could lead to a superstorm like the 12z GFS showed around hour 252.  The GFS is chaotic with several trough/Ridge patterns moving through the flow, short wave ridges and troughs.  This is not a permanent pattern.

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16 minutes ago, Baroclinic Zone said:

Yeah, stick with what we’ve had.

Yeah... we’ve found a number of creative ways not to snow this winter so I’m sticking with persistence until it’s right on the doorstep 

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10 minutes ago, Ginx snewx said:

You should start a thread.....

Perhaps we can reverse curse if we have a thread of "all the reasons why the Feb.3 system will be no more than a Day-10 fantasy".  Every post needs to focus on things going wrong and why needles won't be threaded.

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If there is one thing that seems to be going for next weekend it's the evolution of the pattern across the eastern PAC into the western U.S. The signal is there for not only somewhat substantial ridging across the western U.S. but the structure of the ridge doesn't look bad...would favor deep troughing in the east and they key here is where the trough axis becomes positioned. Even looks like some very weak but noticeable ridging (or at least higher heights) poking into the Arctic. 

As long as models aren't very off with the development of the ridge to the west we're in a good spot. As far as any worries about the airmass...as long as the track is off-shore the majority of the region should be fine. Looking at 850 temp anomalies can be very misleading given the time of year we're in...sure they may be above-average but we're still talking about -10C's 850's in southeast Canada. 

 

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There's like 3 shortwaves in the flow and a transient ridge out in the mountain west....this has a long ways to go before t becomes interesting. 

Airmass is better than this weekend but still not very deep cold so there wouldn't be a lot of wiggle room. We'll see if it's still a threat in 4 days. 

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Out in the longer range, the death vortex up north is taking a beating at least. Hopefully that gives more credibility to change in February. 

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Just now, ORH_wxman said:

Out in the longer range, the death vortex up north is taking a beating at least. Hopefully that gives more credibility to change in February. 

This is something I'm trying to read up on and learn more about. What are good signals to focus on for this process? Is it escalated or driven by series of strong s/w's crashing into the vortex and strong heat flux transport from the tropics? 

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25 minutes ago, ORH_wxman said:

Out in the longer range, the death vortex up north is taking a beating at least. Hopefully that gives more credibility to change in February. 

Well the climo clock is about to start ticking soon so something better change quick. 

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Just now, HIPPYVALLEY said:

OT  but what is up with the air quality alert in SW NH?  Wood stove smoke from an inversion? 

yup

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1 minute ago, HIPPYVALLEY said:

OT  but what is up with the air quality alert in SW NH?  Wood stove smoke from an inversion? 

decomposing chicken poop 

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1 hour ago, weatherwiz said:

This is something I'm trying to read up on and learn more about. What are good signals to focus on for this process? Is it escalated or driven by series of strong s/w's crashing into the vortex and strong heat flux transport from the tropics? 

Pick your indicator. What I like to do is establish a conceptualization of how the atmosphere will evolve in the preseason based upon seasonal factors, such as the QBO, and keep a vigil on the stratosphere, as well as guidance for confirmation as the winter progresses. I think if you look to  guidance to develop your ideology, then you have it backwards and can end up chasing your tail, so to speak.

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5 minutes ago, 40/70 Benchmark said:

Pick your indicator. What I like to do is establish a conceptualization of how the atmosphere will evolve in the preseason based upon seasonal factors, such as the QBO, and keep a vigil on the stratosphere, as well as guidance for confirmation as the winter progresses. I think if you look to  guidance to develop your ideology, then you have it backwards and can end up chasing your tail, so to speak.

I agree...but I think we're talking about different aspects here...you're referring to long-term forecasting where I'm talking about medium-range signals. 

The PV has been quite strong all winter...and while perhaps from an evaluation of pre-season indicators you could assume weakening based on several factors (such as descending QBO as you mentioned)...we can also see models in the 10-15 day period just start to weaken the PV and then all of a sudden inside of D10 or D8 that signal vanishes...once it becomes apparent that there indeed be direct impacts on the PV the initial forecasts really mean nothing. 

My understanding is that one way to weaken it is to keep pelting it with Rossby wave after Rossby wave...and strong Rossby waves. Let's say you have a 4-5 week stretch of horrific winter weather...and you think it may never end...if there is a constant flux of Rossby waves pelting the PV...that can give you a very strong indication that within the next 3-4 weeks big changes will result. 

Anyways...perhaps through pre-season guidance you can put a wager on these changes happening...but until you actually spot those potential developments within guidance the preseason guidance doesn't hold a whole heck of alot of merit. 

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1 minute ago, weatherwiz said:

I agree...but I think we're talking about different aspects here...you're referring to long-term forecasting where I'm talking about medium-range signals. 

The PV has been quite strong all winter...and while perhaps from an evaluation of pre-season indicators you could assume weakening based on several factors (such as descending QBO as you mentioned)...we can also see models in the 10-15 day period just start to weaken the PV and then all of a sudden inside of D10 or D8 that signal vanishes...once it becomes apparent that there indeed be direct impacts on the PV the initial forecasts really mean nothing. 

My understanding is that one way to weaken it is to keep pelting it with Rossby wave after Rossby wave...and strong Rossby waves. Let's say you have a 4-5 week stretch of horrific winter weather...and you think it may never end...if there is a constant flux of Rossby waves pelting the PV...that can give you a very strong indication that within the next 3-4 weeks big changes will result. 

Anyways...perhaps through pre-season guidance you can put a wager on these changes happening...but until you actually spot those potential developments within guidance the preseason guidance doesn't hold a whole heck of alot of merit. 

Yeah....the things you want to look for are evidence on guidance that the PV is actually taking hits. Scott posted some good 50mb Euro maps (which unfortunately aren't widely available) that showed the PV getting very elongated and stretched out....that is a bullish signal that it's taking big hits and could split....or displace. Either one is bullish for blocking. We don't really see it though until later in the ensemble run though....like after D11-12. But if it's actually true, then we'd expect to see the arctic pattern become a lot more favorable by the 2nd week of February or so.

This site has 12z Euro OP runs out to D10....not overly useful for stuff beyond 7-8 days, but if it looks like the event is getting closer, then these will become useful:

https://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

 

You can check out some of the GFS/GEFS products here....but they aren't great IMHO

https://www.cpc.ncep.noaa.gov/products/stratosphere/SSW/

 

 

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8 minutes ago, ORH_wxman said:

Yeah....the things you want to look for are evidence on guidance that the PV is actually taking hits. Scott posted some good 50mb Euro maps (which unfortunately aren't widely available) that showed the PV getting very elongated and stretched out....that is a bullish signal that it's taking big hits and could split....or displace. Either one is bullish for blocking. We don't really see it though until later in the ensemble run though....like after D11-12. But if it's actually true, then we'd expect to see the arctic pattern become a lot more favorable by the 2nd week of February or so.

This site has 12z Euro OP runs out to D10....not overly useful for stuff beyond 7-8 days, but if it looks like the event is getting closer, then these will become useful:

https://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

 

You can check out some of the GFS/GEFS products here....but they aren't great IMHO

https://www.cpc.ncep.noaa.gov/products/stratosphere/SSW/

 

 

This is a great site with stratosphere products

stratobserve.com 

You can see that the PV does look to elongate by around 228-hr...but then towards the end of the run it becomes more compact..I would assume though we would want it to become more displaced on our side of the hemisphere

gfs_nh-vort3d_20200124_f252_rot000.png

 

I'm glad I have that notion correct about the PV taking hits. 

One thing noticeable too (wish I could do this in animation) but around 228-hr there is a reversal of the zonal winds aloft...they become westerly 

gfs_nh-uzm-epfluxes_latprs-xsect_20200124_f276.png

 

Quite a bit of heat flux too

gfs_nh-ehf-hgt_lonprs-xsect_20200124_f252.png

 

Again though...seems like all of this is happening on the wrong side of the globe?

 

(Of course this is based off the GFS)

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