Medium-long range thread

[am19psu]

in the long terms scheme of things how do they rank in terms of best to worse to forecasting the mjo? Or does each year dictate a new winner unlike every yr when the euro out performs the gfs.

This is relatively old information, since I learned at the 2010 AMS Tropical Conference, but the Euro was the only one with any skill past 7 days.

[phlwx]

till we get some sort of blocking imho, these cold shots are going to be transient...cold then a warm up with a storm then back to cold for a couple days etc... Only shots of snow would be for a storm that is timed perfectly with a trough or clipper systems

That's ok though...it beats having 70 in late November.

[HM]

in a backhanded sense the gfs might in the long run be better, that looks to be too much of an impulse to not get into the Pacific. The UK and EC may be worse just having it die in the circle of death before it can carry a change across. That's probably why those Euro weeklies are showing what they got.

The problem might be that the ENSO induced forcing this go around may be a tougher battle to deal with. I am not sure yet how fast we progress back to ph 7-8. Initially, I thought we would continue on a somewhat quicker pace but the -u winds at h85 are certainly stronger this time. There is going to be a tougher circulation across the Central Pacific to battle, so I could see a death in phase 5 occur.

Also, the Mid Latitudes and Subtropics are very stable currently and have been altered that way from the events that have occurred over the last 10 days. I'm not sure how much help these latitudes will be in supplying some sort of aid. The only thing I can think of to continue this MJO wave at the same rate would have to be its own momentum/strength combined with the peaking +QBO wave (an agent for quickness because of its tendency to weaken the wave at t=0 which may help to propagate things).

[mattinpa]

Ok, I'm out - winter can begin! LOL.

We haven't had many nice days this year, so I've enjoyed them, but it doesn't feel like this time of year. I have a feeling we get a well timed storm sometime in Dec, and that warmth will not be lasting.

[tombo82685]

fwiw, the euro has a storm sliding off the coast that develops an inverted trof where another storm forms...actually drops 2-4 3-6 on the region next tues into wednesday. I wouldn't hold your life onto it because its a pretty volitile setup....after that the pacific turns to crud with a flow right off the pacific. Only good thing may be the start of some blocking, though that ridge could be transient, not sure the 11-15 day ensembles would be the best guide to see if this occurs..

Note the huge push of positive anomalies pulsing up into where a west based nao would be. As i said up top the pacific looks dreadful with the return of the ak vortex...this would indicate a +epo, ao, near neutral nao and a -pna, not a good pattern. One encouraging sign is all the cold air is virtually located on our side of the pole...when the rubber band snaps, if it ever does, their is going to be some very cold air spilling south

[Grothar]

fwiw, the euro has a storm sliding off the coast that develops an inverted trof where another storm forms...actually drops 2-4 3-6 on the region next tues into wednesday. I wouldn't hold your life onto it because its a pretty volitile setup....after that the pacific turns to crud with a flow right off the pacific. Only good thing may be the start of some blocking, though that ridge could be transient, not sure the 11-15 day ensembles would be the best guide to see if this occurs..

Note the huge push of positive anomalies pulsing up into where a west based nao would be. As i said up top the pacific looks dreadful with the return of the ak vortex...this would indicate a +epo, ao, near neutral nao and a -pna, not a good pattern. One encouraging sign is all the cold air is virtually located on our side of the pole...when the rubber band snaps, if it ever does, their is going to be some very cold air spilling south

good synopsis and believable. That rubber band will snap because that is how fluid dynamics works. How cold is the question- enuf to be called the tundra with the little snow we get. White Christmas?

[am19psu]

You're not going to get a closed low over the Upper MS Valley AND a closed low near the benchmark. That Euro run is garbage beyond 192.

[Weathergun]

You're not going to get a closed low over the Upper MS Valley AND a closed low near the benchmark. That Euro run is garbage beyond 192.

Agreed. Euro seems to have a bias in cutting-off lows too far S&W, in the long range.

[tombo82685]

looks like a gradient like pattern setting up on the day 10 euro ens...with the emergence of the se ridge...

[tombo82685]

good synopsis and believable. That rubber band will snap because that is how fluid dynamics works. How cold is the question- enuf to be called the tundra with the little snow we get. White Christmas?

you need a mechanism to drive that south, like -nao or pos ao, which doesn't look to happen in the near furture,

[tombo82685]

whats interesting also, some of the gfs ensembles have a wave riding up the cold front next week. Some members have it into the cold air some into the warm air. All depends on the ridge axis out west as to how far east that front comes, because their should be some left over energy in the deep south. I would favor the lehigh valley and pocs for this moreso than the city on south.

[tombo82685]

This may be more of a wishcast, but i wonder if this is a way out of +nao and +ao in the long term. With all the cold air located around the pole and the warmth in the northeast and se canada. Hudson bay, has to be probably be above normal lake temperature wise. I think Tony mentioned this that the warm waters of the hudson bay can attract a pv and hold it their do to the temperature gradient. This is from the 6z gfs 500mb plots at hr 384. I drew a couple of arrows to show what possibly could happen if we slide the pv south away from the pole location, this should then trigger that ridge towards the greenland area, thus bringing the nao towards a neutral to negative state also aiding in the ao to come back towards neutral to negative. The way how to get a really cold pattern is to get a -epo and -nao with a -ao, this basically causing a wall of warm anomalies over the pole forcing all that cold south.

[am19psu]

I think Tony mentioned this that the warm waters of the hudson bay can attract a pv and hold it their do to the temperature gradient.

Colder SSTs attract the polar vortex from thermodynamic arguments

[tombo82685]

Colder SSTs attract the polar vortex from thermodynamic arguments

i deff quoted him wrong then, but i do remember him saying that once the pv gets towards the hudson bay its hard to dislodge.

edit: just saw his post on the first page saying since hudson bay isnt frozen yet, get the pv there in late winter it would be tough to dislodge.

[am19psu]

i deff quoted him wrong then, but i do remember him saying that once the pv gets towards the hudson bay its hard to dislodge.

edit: just saw his post on the first page saying since hudson bay isnt frozen yet, get the pv there in late winter it would be tough to dislodge.

Yeah, once Hudson Bay freezes over, it's a different story

[tombo82685]

starting to see a good push from the mjo...Would be nice to see the euro and ukmet having the right idea to bring this back towards phase 1, 2 is alright but thats corresponding to a trof pushing off the east coast and not great for coastal storms

ukmet heads it into the circle of death with some of its ens bringing it out towards phase 8 and 1

The euro enters the circle of death also with some of its ens members bringing it back towards phase 1-2 region

the gfs enters the circle of death around phase 5

[tombo82685]

curious to see what the 12z indiv ens show for the front passage next wednesday...the gfs is on the right idea but not their yet. Need the pieces of energy to have less interaction and not come out as one entity... separate the pieces of energy, allow the cold front to come through then get a wave up the front, which some of the 6z ens had...just throwing it out there for some discussion.

[mattinpa]

curious to see what the 12z indiv ens show for the front passage next wednesday...the gfs is on the right idea but not their yet. Need the pieces of energy to have less interaction and not come out as one entity... separate the pieces of energy, allow the cold front to come through then get a wave up the front, which some of the 6z ens had...just throwing it out there for some discussion.

Yeah, I thought the 6z OP was more towards the cold front then wave outcome, but the 12z GFS is still colder than before. Keep us posted.

[tombo82685]

a couple of hits on the ens a couple close calls, but no real overidding eveidence of a big threat

[tombo82685]

as figured, 12z euro lost the storm it had 0z run...at the end of the euro run hr 240 the whole pv drops right into south central canada, with sub 498 thicknesses in the midwest. The pattern at hr 240 looks pretty darn good. Would like to see the pna centered further east. The ridge axis on that scream whatever storm forms should cut, deff a north atlantic ridge to east based -nao, though it may be transient...this is all subject to change..probably won't even be there at 0z, but still wanted to point it out.

[Parsley]

Good stuff Tombo, thanks for keep us long range slackers in the loop.

[am19psu]

a couple of hits on the ens a couple close calls, but no real overidding eveidence of a big threat

I wouldn't be shocked to see a few backside flakes after the system next weekend, but I like the Lakes/Interior better.

[Rainshadow]

I wouldn't be shocked to see a few backside flakes after the system next weekend, but I like the Lakes/Interior better.

I'd almost say this would be one of our motor operandi for this upcoming winter. There have been a number of wavy fronts this fall.

Maybe you have more experience with this than I do, but the euro ensemble means are warmer (6-8C) than the op model with the one, two -epo blasts next week. This split seems to be holding. It will be interesting to see how this (these) verify.

[am19psu]

I'd almost say this would be one of our motor operandi for this upcoming winter. There have been a number of wavy fronts this fall.

Maybe you have more experience with this than I do, but the euro ensemble means are warmer (6-8C) than the op model with the one, two -epo blasts next week. This split seems to be holding. It will be interesting to see how this (these) verify.

Extremely unlikely

Part of the reason the ens means are so warm is there are two clusters of solutions. I don't know if you can check out the H5 spag charts, but maybe 1/3 of the members are showing a ridge over the EC D7-D9. For the cluster of members that show an EC trough, the op is actually in line with the mean of the cluster. I actually like the 12z op run.

[Rainshadow]

Extremely unlikely

Part of the reason the ens means are so warm is there are two clusters of solutions. I don't know if you can check out the H5 spag charts, but maybe 1/3 of the members are showing a ridge over the EC D7-D9. For the cluster of members that show an EC trough, the op is actually in line with the mean of the cluster. I actually like the 12z op run.

We don't see this even at work and being off today I'm stuck with just the e-wall and their freebie stuff. This now makes more sense. Thanks!

[tombo82685]

euro ens arent that bad looking, aiming the cold right towards the eastern us. They try and pop an east based -nao later in the period. Nice cross polar flow and a weak to neutral pna, which has flattned out a little, which would cause a little rebuttle from the se ridge...would love to see the ao head towards neutral or negative, but with how cold the stratosphere is right now, i dont see that happening as of yet.

[Harbourton]

Although the operational 12Z Euro from Allan's site may be an anomoly from the ensembles which aren't out yet, it is showing a -NAO coming.

Graph

[NaoPos]

Looking at allen's 500h height anomaly maps from the 12z euro, it does seem to like like a more "pure" -NAo. It's centered offshore eastern Greenland, but it looks to wanna stretch towards central greenland. I'll post the map once I get on my comp. I will say however, take it with a grain of salt. It's the 216-240hr time frame.

[tombo82685]

Although the operational 12Z Euro from Allan's site may be an anomoly from the ensembles which aren't out yet, it is showing a -NAO coming.Graph

only thing you have to watch out with those graphs is...yes its technically a -nao, and its ten times better than what we have now, but this -nao is east based which isnt that great, but still better than a pos nao. So its good that we are getting a -nao, but it still may not yield snow. I wih they had nao graphs that break it down towards east based or west based.

[tombo82685]

Looking at allen's 500h height anomaly maps from the 12z euro, it does seem to like like a more "pure" -NAo. It's centered offshore eastern Greenland, but it looks to wanna stretch towards central greenland. I'll post the map once I get on my comp. I will say however, take it with a grain of salt. It's the 216-240hr time frame.

for a good neg nao for us and especially south, you want that sucker to ridge back towards the davis straights and baffin island region, ala last year.