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January Medium/Long Range Discussion

nj2va

By nj2va,
in Mid Atlantic

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psuhoffman

psuhoffman

Posted
Posted
10 minutes ago, showmethesnow said:

Not going to go back and read your comments but my impression was that you wanted nothing to do with a pv on this side of the globe well placed or not because you felt it was too risky as to cause interference with the general flow through the CONUS.

I want no part of a severely displaced PV into the Conus.  For everytime that lead to a big snow blitz there are two examples where we got some crazy 1-2 week cold and dry and that's it. The most common outcomes seem to be "some snow" but nothing epic. Our real extreme snow periods are 90% from a combo of stj activity timed up with a favorable blocking/high pressure alignment up top, usually with a tpv in the 50/50 space or sometimes to our west in Canada but usually nowhere near us.  I obviously wasn't clear and there are variables. If the epo is positive then we might need a further displaced PV to help offset. But i was kind of running off the assumption we develop a -epo -nao regime and in that case if I had to choose I would rather have no PV and roll the dice during mid winter than contend with a poorly placed one that runs interference more often then if aids in some crazy event. Now if I wanted straight cold PV is the way to go. 

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showmethesnow

showmethesnow

Posted
Posted
1 minute ago, psuhoffman said:

I want no part of a severely displaced PV into the Conus.  For everytime that lead to a big snow blitz there are two examples where we got some crazy 1-2 week cold and dry and that's it. The most common outcomes seem to be "some snow" but nothing epic. Our real extreme snow periods are 90% from a combo of stj activity timed up with a favorable blocking/high pressure alignment up top, usually with a tpv in the 50/50 space or sometimes to our west in Canada but usually nowhere near us.  I obviously wasn't clear and there are variables. If the epo is positive then we might need a further displaced PV to help offset. But i was kind of running off the assumption we develop a -epo -nao regime and in that case if I had to choose I would rather have no PV and roll the dice during mid winter than contend with a poorly placed one that runs interference more often then if aids in some crazy event. Now if I wanted straight cold PV is the way to go. 

Now though I feel we will end up with a pv displaced far to the south I never mentioned it running into the CONUS itself though it wouldn't surprise me if we might in fact see brief incursions. Think the strong southern jet/southeast ridging that has been prevalent this winter will help to deter from that. In fact the thoughts of an active SS jet and SE ridging pushing back against any pv seen in southern Canada actually excites me to the possibilities along the battle lines between those features. Battle lines that would more then likely set up somewhere through the mid-Atlantic.

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psuhoffman

psuhoffman

Posted
Posted
24 minutes ago, C.A.P.E. said:

Many times when we have our 'epic' HL patterns, the 50-50 low can result from smaller vortices being shed off of a parent TPV (sitting in the vicinity of Hudson Bay), rotating down and getting 'trapped' underneath the NA block.

Yea those weak vortices that get stuck under the blocking are ideal. I meant a true PV blue ball of death getting displaced into southern Canada or the US. In our best snow analogs you see high heights all across Canada except the 50/50 space. That's where we want and major vortices to get stuck. But if you look at daily plots you see weak vortices in the flow but given they are barely below avg heights up there they get smoothed out in a multi day composite. I treat a day 15 ens like a composite because timing and placement permutations at that range will also smooth out details. So I don't want to see some big blue ball on a day 15 ens. 

There are exceptions. This was all off the assumption we get a -epo nao longwave pattern. Of we are working with a less ideal pattern then sometimes a deal with the devil is necessary and late 2015 a displaced PV worked out and suppressed some waves down into us that likely would have gone north otherwise. But if I have the ideal longwave pattern a strong PV displacement into our region offers more risk than reward imo. 

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psuhoffman

psuhoffman

Posted
Posted
11 minutes ago, showmethesnow said:

Now though I feel we will end up with a pv displaced far to the south I never mentioned it running into the CONUS itself though it wouldn't surprise me if we might in fact see brief incursions. Think the strong southern jet/southeast ridging that has been prevalent this winter will help to deter from that. In fact the thoughts of an active SS jet and SE ridging pushing back against any pv seen in southern Canada actually excites me to the possibilities along the battle lines between those features. Battle lines that would more then likely set up somewhere through the mid-Atlantic.

See my post to cape. Ideally when we have nao and epo blocking we just want higher heights all over Canada and a tpv stuck under the block around the 50/50 region. That doesn't mean there can't be weak vortices that are barely or not even below normal heights up there but seeing a lot of blue over southern Canada during a -nao regime isn't a snow look for us. If a PV there is too strong it can be suppressive or it can also promote NS vorts to track through the lakes around that PV in Canada also running interference.  When we see snow events that had a PV there it's usually when we had a less ideal longwave pattern and that PV altered it into a workable one like 2015 or 2014. If (big if) we get a great nao and epo look going i would rather just see red all across Canada on the h5 plots. 

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CAPE

CAPE

Posted
Posted
2 minutes ago, psuhoffman said:

See my post to cape. Ideally when we have nao and epo blocking we just want higher heights all over Canada and a tpv stuck under the block around the 50/50 region. That doesn't mean there can't be weak vortices that are barely or not even below normal heights up there but seeing a lot of blue over southern Canada during a -nao regime isn't a snow look for us. If a PV there is too strong it can be suppressive or it can also promote NS vorts to track through the lakes around that PV in Canada also running interference.  When we see snow events that had a PV there it's usually when we had a less ideal longwave pattern and that PV altered it into a workable one like 2015 or 2014. If (big if) we get a great nao and epo look going i would rather just see red all across Canada on the h5 plots. 

I will go along with this.

Of course, this may very well be a meteorological impossibility. :whistle:

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psuhoffman

psuhoffman

Posted
Posted
2 minutes ago, C.A.P.E. said:

I will go along with this.

Of course, this may very well be a meteorological impossibility. :whistle:

That guy. 

I made a New Years resolution to not waste time arguing with people who claim things that actually have happened can't happen or are impossible.  This doesn't pertain just to weather. 

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CAPE

CAPE

Posted
Posted
2 minutes ago, psuhoffman said:

6z gefs starts to lower heights near 50/50 towards the end. First sign of that. Very good look at the end. 

Yes it does and it is a good look.

Go look at the op run at the very end and notice how those lower heights get into the 50-50 position. ;)

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WxUSAF

WxUSAF

Posted
Posted
6 minutes ago, psuhoffman said:

6z gefs starts to lower heights near 50/50 towards the end. First sign of that. Very good look at the end. 

0z looked much better in that regard actually. But way out there. Want to get the Pac sorted first.

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pasnownut

pasnownut

Posted
Posted
2 hours ago, losetoa6 said:

Late Weekend coastal threat is still there and actually looks a little better  on this mornings Gefs as far as low strength and rough placement.  Eps stepped back some but still a signal . Roughly 8 days out so oodles of time left to adjust 

Gefs 

gfs-ens_mslpa_us_36.png

Eps 

ecmwf-ens_mslpa_us_10.png

Gefs 500s....nothing super exciting but only minor to doable adjustments on most needed and at day 8 leads...not too much  to ask to get some action .

f192.gif

Yoda cancelled that one last night. 

Move on....:P

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pasnownut

pasnownut

Posted
Posted
10 minutes ago, psuhoffman said:

6z gefs starts to lower heights near 50/50 towards the end. First sign of that. Very good look at the end. 

Yeah, looking at overnights was encouraging to say the least.  Nice to see the PAC starting to pop some ridging. 

Still way way out there, but as long as we have some continuity in the coming days, it'll be nice to back off on the blood pressure pills for a while.

 

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pasnownut

pasnownut

Posted
Posted
2 minutes ago, poolz1 said:

New MJO plots look pretty good.  GEFS and Euro agree on a strong push into 8 and then a move into the COD.

Here's the euro...getting closer to a decent move into phase 1

2Gas6sG.gif

Its been discussed but worth mentioning again, that as long as its coming out of the right phases (8/1), a move to the COD isnt quite as concerning.  Just something to watch.

 

Edit..looks like CAPE beat me to the same point  

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poolz1

poolz1

Posted
Posted
4 minutes ago, C.A.P.E. said:

Hopefully we have a legit weak Nino now and the atmosphere is beginning to respond. Let it drive from here on out.

Interesting that things are starting to line up with the BOMM forecast from 12/30.  This progression would be perfect....

Vm7KHWl.gif

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nj2va

nj2va

Posted
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Posted
Just now, poolz1 said:

Interesting that things are starting to line up with the BOMM forecast from 12/30.  This progression would be perfect....

 

I read somewhere (can’t remember where) that the BOMM has actually been doing well with the MJO forecast, which this supports.  Agree with the last few posts that the ongoing decline/persistent negative SOI coupled with the MJO push into 7/8/COD would be great for us.  The atmosphere can do its thing.

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MillvilleWx

MillvilleWx

Posted
Posted
Just now, poolz1 said:

Interesting that things are starting to line up with the BOMM forecast from 12/30.  This progression would be perfect....

Vm7KHWl.gif

This is what you want to see for the east coast. A slightly greater amplitude into 8 and 1 before a crash is preferred, but you have to take what you get at this point. There are some positive signs in the long term starting to show their hands. Of course, still a few weeks away (Isn't it always?), but the trends recently are becoming more favorable. SOI tanking is my favorite. That, I believe, has been a major bugaboo in what has transpired. The PAC drivers had to shift or else this winter was doomed and there was no two way around it. The fact we are seeing incremental change is a step in the right direction. We need Canada and areas to our north to gain a snow pack, or lay down some fresh snow so we can mitigate any moderation as cold traverses into the lower latitudes. Boundary line into southern VA would be most preferred. I think that's what the LR progs are indicating.

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snowmagnet

snowmagnet

Posted
Posted
3 hours ago, showmethesnow said:

I know PSU isn't really a big fan of seeing the PV anywhere on this side of the globe because he doesn't want anything to interrupt the general mid-latitude flow and feels that climo at this time will take care of the cold. I myself say, bring it on. Love seeing the pv rotating around as it provides better cold as well as the potential of better dynamics and extremes with any systems. Now I would take the pv planted around the Hudson Bay region any day of the week because that is probably the most favorable for our location. But I think we are going to see the pv much farther south then that. So though we may risk bouts of suppression we are also looking at increased odds of big and/or extreme events. 

I believe it was ‘14-‘15 that we couldn’t buy a -NAO but the PV displacement acted as a substitute and helped us have a busy second half of winter. 

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