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December 2019 Med/Long Range Disco


Bob Chill
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1 hour ago, showmethesnow said:

To say we have seen improvements in these last few days in regards to the pv (500 mb) migrating westward would be an understatement. My fear of possibly seeing that feature plant itself for a period of time close to Alaska now seem unwarranted. As it stands now we are looking at only a short period of a CONUS wide warmup as PAC air floods NA on the pvs initial move westward. And even that looks to be mitigated in the NE US  as we are seeing decent troughing induced by the higher heights/ridging in the NAO domain backing the flow. Though we might struggle with climo temps with the pv located on the other side of the globe in the extended the look being presented now is a far more forgiving look then what was being offered up several days ago.

By 144 hrs an argument could be made that the SPV is being pinched and has 2 centers but the GFS ens seems to recover quickly so much so by 180 hours has one strong center anchoring near the Kara Sea while anti cyclonic flow strengthens over AK and W Canada. TPV remains banged up but the only negative takeaway I had this cycle was by 240 the TPV has consolidated (for the most part) near old Russia. Granted, the charts are more smoothed out the longer the lead time and this is the day 10 prog chart, so there's that. 

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18 minutes ago, Ralph Wiggum said:

By 144 hrs an argument could be made that the SPV is being pinched and has 2 centers but the GFS ens seems to recover quickly so much so by 180 hours has one strong center anchoring near the Kara Sea while anti cyclonic flow strengthens over AK and W Canada. TPV remains banged up but the only negative takeaway I had this cycle was by 240 the TPV has consolidated (for the most part) near old Russia. Granted, the charts are more smoothed out the longer the lead time and this is the day 10 prog chart, so there's that. 

 

I like a weakened and perturbed vortex, but one concern I have,  is the eventually outcome should we get a SSWE or a split.  

I prefer a deep long lasting -AO regime.  I have been following SSWE for many years and sometimes we do not benefit here. 

The eventual target zone is hard to pin down and the science is still evolving.  Sure weaken the vortex , makes it easier to move around but then as you mention it could reform and get stronger in an area that may not be as conducive for our backyard. You know all this, I am just explaining my concerns.     

Here are a couple interesting things  I came across this morning. Personally I love the depiction in Anthony's post. 

 

 

 

 

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Good to keep in mind regarding the strat vortex split/warming/disruption is that last years was advertised and steadily pushed back for awhile, but it did happen eventually. And it doesn’t say at all how it will impact the troposphere on our side of the pole.

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Well, that is interesting, get an early- season SSW , ( absorbing type vortex split ) and then without coupling the vortex recovers and gets very strong. 

Simon mentions it was a non-downward propagating event.  Didn't HM mention something the other day about a bottoms-up event.   

 

 

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16 hours ago, C.A.P.E. said:

That was a seriously fun winter. Lots of luck involved, but hey sometimes things just go our way. The frozen inland waters and even large parts of the bay was awesome too. Love that stuff.

eta- I think that was the winter that featured the epic poetry thread. lol fun times.

I think the poetry thread happened in 2015 before the switch flipped but I'm old and memory and stuff...

Like I said before, "favorite" anything in this hobby is 100% subjective but one of the metrics I use to rate a winter is how much dead space and how interesting it was. 09-10 is no doubt the king of snow totals. It was basically ridiculous. But between the Dec event and late Jan sneaky slider there was a lot of thumb twiddling. The last week of Jan through the second Feb storm was the greatest 2 week tracking period ever and there isn't a close second. But being honest, missing out on the late Feb storm did bum me out more than a little. The lack of any real winter wx from the 2nd Feb storm on was a let down to me as was the speed that 50" of snow melted. The way the Dec storm got washed down the sewer on Christmas was a little depressing also. 

13-14 had me glued start to finish. It was never boring and dead space was limited. I pulled off over 16" with the Feb storm so there was a "KU" in my yard and the barrage of arctic air and cold snow was remarkable.  We had some ice that year to complete the buffet. I distinctly remembering in late March (after 16 events stretching from 11/27 to 3/30) being worn the F out from tracking and was actually looking forward to the door closing on that winter. For those reasons 13-14 takes the top spot in my book but our "books" are very personal. 

 

 

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Euro model has a strong trough moving through the region around the D9 timeframe but not quite the look I'm looking for if we want decent wintry precip. Ridge a little too strong in the NW and not quite in the most favorable spot, and the SW over California will have a tough time transferring energy to the trough in the east in that location. In general I think late Nov - early December timeframe will have multiple opportunities after the pattern shuffle warm up.

500h_anom.na.png

 

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15 minutes ago, JakkelWx said:

Euro model has a strong trough moving through the region around the D9 timeframe but not quite the look I'm looking for if we want decent wintry precip. Ridge a little too strong in the NW and not quite in the most favorable spot, and the SW over California will have a tough time transferring energy to the trough in the east in that location. In general I think late Nov - early December timeframe will have multiple opportunities after the pattern shuffle warm up.

500h_anom.na.png

 

That could be a pattern that lets clippers go under us.  Could be...

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1 minute ago, Ralph Wiggum said:

Urging cautious optimism. Let us never forget the LR ens winter 2018-19. Agreed tho, if it holds then that's a solid look going forward.

This time is different in that the current potential -NAO never showed up on weekly or seasonal guidance. It appears to have snuck in under the radar which should be expected because long range  nao forecasting and accuracy doesn't exist. We're at 7 day leads right now. Still not close enough to go all in but close enough to believe some sort of -nao is happening. How long it lasts and how it affects our wx will be discussed under the microscope for the next week straight. Worse things to discusss in Nov I suppose

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1 hour ago, JakkelWx said:

Snow cover continues to advance at record levels. Some relaxation in the extent is likely as the pattern turns milder.

image.thumb.png.8ce856c5256c96e700bb5b045d820574.png

 

This is one time where the rapid delivery of snow cover to our far North and Northwest contributed to the very anomalous cold air mass here, setting all sorts of records. 

Nicely put by Maue in a weather related post of all things :-)

We also had the air mass originate at the pole as well. Pretty awesome ! There was even cross-polar flow as well. 

Regardless of snow cover and the SAI theory having a robust NA snow cover really helped in the arctic discharge this go around 

Imagine if we do this again in some form, or fashion in the next 4 to 8 weeks,  it will be truly brutal.    

 

 

 

 

 

 

 

 

 

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5 minutes ago, Daniel Boone said:

Verbatim, that has snow threats written all over it, depending on how much cold is available of course. 

Based on that posted snow cover map we should be in decent shape.  But we are getting ahead of ourselves I believe.  The pattern upcoming looks favorable for at least seasonal conditions based on the current ensemble guidance all subject to change. 

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