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December 2019 Med/Long Range Disco


Bob Chill
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Another reason not to get ahead of ourselves.. I recently read a tweet stating how warm Nov = warm winter and cold Nov = cold winter. What really matters is the upper hemispheric pattern teleconnections for the winter. A cold Nov means nothing if the ensuing pattern after the fact is garbage. There isn't much correlation IMO.

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1 minute ago, Wonderdog said:

GFS shows a coastal trying but failing to run up the coast.

Well we probably don’t want too much blocking.  I will take the cold and smile but snow is a much more delicate equation as everyone knows.   Still this ensemble display shows some promise.  We watch.  

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2 hours ago, JakkelWx said:

Another reason not to get ahead of ourselves.. I recently read a tweet stating how warm Nov = warm winter and cold Nov = cold winter. What really matters is the upper hemispheric pattern teleconnections for the winter. A cold Nov means nothing if the ensuing pattern after the fact is garbage. There isn't much correlation IMO.

I think the opposite happens more often, but that might be for enso years specifically.

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11 hours ago, BristowWx said:

Well we probably don’t want too much blocking.  I will take the cold and smile but snow is a much more delicate equation as everyone knows.   Still this ensemble display shows some promise.  We watch.  

I don't think too much blocking is even remotely a concern at this point. A good start is to see if it materializes as advertised. Most likely we see a -NAO for the end of the month period. How negative it gets and how long it lasts is TBD. EPS is not as robust as the GEFS with the NA blocky look, and has been trending both the AO and NAO to neutral as we move into December. As always, we shall see.

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1 hour ago, C.A.P.E. said:

I don't think too much blocking is even remotely a concern at this point. A good start is to see if it materializes as advertised. Most likely we see a -NAO for the end of the month period. How negative it gets and how long it lasts is TBD. EPS is not as robust as the GEFS with the NA blocky look, and has been trending both the AO and NAO to neutral as we move into December. As always, we shall see.

Agreed.  In the last few years I've become a fan of -AO for winter opps here in the east, but will GLADLY put an N in front of it.  

 

I'd think we'd all take our chances just to see a modeled -NAO come to light.  Strength/duration are secondary concerns to me as that domain has been a wrench in our spokes for a long long time.  Cautiously optimistic that we are heading towards a nice start early in the season. 

Nice to see the ducks coming back to the pond.  

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1 hour ago, C.A.P.E. said:

I don't think too much blocking is even remotely a concern at this point. A good start is to see if it materializes as advertised. Most likely we see a -NAO for the end of the month period. How negative it gets and how long it lasts is TBD. EPS is not as robust as the GEFS with the NA blocky look, and has been trending both the AO and NAO to neutral as we move into December. As always, we shall see.

According to the the Euro, as you know,  most of the true arctic air shifts over to Siberia by day 10.  Wonder again about the progression of things at the very end of November and early December. Really have two schools of thought on the matter. 

I believe it was two or three winters ago when a similar occurrence happened and eventually that arctic air mass sloshed back to our side of the pole and eventually  made it to the lower latitudes.  Over time the air mass over Siberia is really going to get even colder. Some 1065 mb Highs over there. Maybe the seeds planted for the next time we tap into cross polar flow. 

No extreme cold in sight after day 10 though. 

  .         

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10 minutes ago, frd said:

Have to see how this plays out in December.  This is the latest update. So you have the Euro versus the UKMO

 

GFS has the strong vortex and shows alignment between trop and strat fwiw. Not the biggest fan of seeing the cold air locked up in Siberia but I'll roll the dice with marginal/borderline temps if it means storm chances vs arctic cold and dry as a bone. I know there can be an argument made for good storms on the backside of a retreating PV but not much we can do if it sets shop over on the other side of the N Hemi in early winter. Still TBD tho obviously. Split camps as you noted.

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19 minutes ago, frd said:

According to the the Euro, as you know,  most of the true arctic air shifts over to Siberia by day 10.  Wonder again about the progression of things at the very end of November and early December. Really have two schools of thought on the matter. 

I believe it was two or three winters ago when a similar occurrence happened and eventually that arctic air mass sloshed back to our side of the pole and eventually  made it to the lower latitudes.  Over time the air mass over Siberia is really going to get even colder. Some 1065 mb Highs over there. Maybe the seeds planted for the next time we tap into cross polar flow. 

No extreme cold in sight after day 10 though. 

  .         

Not too concerned with seeing "extreme" cold here in the near term. It rarely does us any good before mid Dec. There are some hints on the ens guidance of ridging trying to reestablish in the EPO domain, so there is that. We are all just trying to get a feel for the potential background state at this juncture, and seeing persistent troughing near the Aleutians and the lack of a SE ridge are good signs. We will see how things evolve in the HL/NA. Not seeing any indications yet of a raging +AO/NAO developing going forward.(other than most climate/ seasonal models suggesting it lol)

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1 minute ago, Ralph Wiggum said:

GFS has the strong vortex and shows alignment between trop and strat fwiw. Not the biggest fan of seeing the cold air locked up in Siberia but I'll roll the dice with marginal/borderline temps if it means storm chances vs arctic cold and dry as a bone. I know there can be an argument made for good storms on the backside of a retreating PV but not much we can do if it sets shop over on the other side of the N Hemi in early winter. Still TBD tho obviously. Split camps as you noted.

still beats the heck outta discussing warm n endless PIG ridge.  Being early like it is, I'm fine w/ either camp to be honest, but understand your concerns.  

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

Not too concerned with seeing "extreme" cold here in the near term. It rarely does us any good before mid Dec. There are some hints on the ens guidance of ridging trying to reestablish in the EPO domain, so there is that. We are all just trying to get a feel for the potential background state at this juncture, and seeing persistent troughing near the Aleutians and the lack of a SE ridge are good signs. We will see how things evolve in the HL/NA. Not seeing any indications yet of a raging +AO/NAO developing going forward.(other than most climate/ seasonal models suggesting it lol)

Yes, the signs so far are positive. I was looking this morning at the other side of the pole and there are forecasts going out in time for some crazy low latitude snowfall in that region.

Speculation increasing that if we do re-establish the previous cross-polar flow in late December or Jan., it could be very brutal. Some mets who engage in seasonal forecasting have  mentioned this potential for the first half of winter.   My request is some moisture to go with that cold please. 

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26 minutes ago, frd said:

Yes, the signs so far are positive. I was looking this morning at the other side of the pole and there are forecasts going out in time for some crazy low latitude snowfall in that region.

Speculation increasing that if we do re-establish the previous cross-polar flow in late December or Jan., it could be very brutal. Some mets who engage in seasonal forecasting have  mentioned this potential for the first half of winter.   My request is some moisture to go with that cold please. 

If the latest GEFS have generally the right idea (yuge IF) we get cross polar flow to open up Dec.  Its all speculation of course but jumping on what Ralph said....it does seem that we may settle back into Aleutian trough, -EPO and scan ridging toward the first of Dec. A lot of things to be cautiously positive about.  

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14 minutes ago, poolz1 said:

If the latest GEFS have generally the right idea (yuge IF) we get cross polar flow to open up Dec.  Its all speculation of course but jumping on what Ralph said....it does seem that we may settle back into Aleutian trough, -EPO and scan ridging toward the first of Dec. A lot of things to be cautiously positive about.  

 

Do you have any research or memory to support how well the GEFS , the Euro and the regular GFS does with strat forecasts ?  ( or how well against each other ) I recall at times the GEFS does very well. I also read that the GloSea model ( from Euro I think ) has had a coup from time to time.    

I ask because I came across this morning two interesting posts. Goes along with my post above. 

You may even be aware of this already. 

 

 

 

 

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12 minutes ago, poolz1 said:

@frd  I really dont have any idea....It would be interesting to see some verifications. I have only been following the strat for a few years and realize its pretty complex.  Complexity means slow learning due to a current hectic life! lol

Personally, I could strictly look at 500mb and below all winter every winter and do totally fine figuring out how things are going without knowing a thing about the strat. 

We can have plenty of trop blocking without any type of warming event or disruption and vice versa. The only thing we really care about as snow weenies is to not have a combination of a strong/cold strat pv AND a strong +AO. Outside of that (IMO) us weenies are all better off not worrying about it. 

 

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1 hour ago, Bob Chill said:

Personally, I could strictly look at 500mb and below all winter every winter and do totally fine figuring out how things are going without knowing a thing about the strat. 

We can have plenty of trop blocking without any type of warming event or disruption and vice versa. The only thing we really care about as snow weenies is to not have a combination of a strong/cold strat pv AND a strong +AO. Outside of that (IMO) us weenies are all better off not worrying about it. 

 

I agree with you...If you are looking at the strat for a strictly mby sport then, you are probably doing it wrong.  I find it interesting though....

I do agree with some others here that I would prefer just a consistent weakening, stretching and knocking around.  Other drivers, right now at least, look to generally be in our favor this season and we dont need a big split for this winter to be decent or even possibly screw up a decent pattern.

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HM reinforcing what many of us here know already,  times are a changing in terms of using historical analogs to help with seasonal forecasting.

You really need to be creative and do your homework.  Recent years only prove this more and more in my opinion. 

    

 

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12 minutes ago, WxUSAF said:

Yup, GEFS mean definitely has had a cross polar flow look at the very end of the last few runs, with 12z being the clearest example. Got to keep the STJ going in tandem.

GEPS jumping on board too and throws a -NAO in just for fun. GEPS has a really nice mean pattern. Cold supply, -EPO/NAO combo, split flow/bagginess in the SW undercutting the PNA ridge, and a 50/50... I mean what's not to like on this panel other than the fact it's the GEPS? lol

gem-ens_z500a_nhem_65.png

 

I had a hunch the EPO would play nice at times this winter. Not claiming I thought it would happen out of the gate but nice to see the general idea may show up pretty quick. \

I'm waiting for the CFS weekly to start to cave on week 3 but it's steadfast showing a dog doo pattern in early Dec. I put a lot more credence in the global ens than seasonal stuff but considering we're still talking 2 weeks out it's hard to hug any outcome yet. 

cfs-avg_z500aMean_nhem_3.png

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I wish there was an option to remove the color scheme sometimes....Though not a great looking pattern on that 7 day mean just looking at the height lines looks like a +PNA that reaches all the way north of AK.  Washed out of course but the anomalies make it a little deceiving imo.   

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1 minute ago, frd said:

This was touched on yesterday a bit, but the thing is the Euro is not backing down on the +NAO call at all. And, yes, it could be correct .

And then again, persistence does not mean it is correct either. 

 

 

 

Always skeptical of mean patterns. You don’t know how it arrived there. I think people take the word “average” and think consistency. That mean could easily come from a slightly negative NAO for 24 of those days and 6 days of a huge positive NAO. 
 

If course I have no way of knowing as I don’t really have any idea of how that mean is determined.

And I would assume that’s an ensemble forecast?  If so, that makes it even foggier.

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2 minutes ago, WinterWxLuvr said:

f course I have no way of knowing as I don’t really have any idea of how that mean is determined.

And I would assume that’s an ensemble forecast?  If so, that makes it even foggier.

In that same post they mentioned this :

 

 

 

 

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