December/January Medium/Long Range Discussion

[MountainGeek]

8 minutes ago, psuhoffman said:

If you want me to be critical one thing I don't like is how the PV is just sitting over the pole and seems stuck there off to day 15 on the euro guidance. Gefs breaks it down faster. That's really interfering in our ability to get blocking to lock in. Need that to move to get either cross polar flow and or permanent ridging up top to establish. 

Given the prevailing mood in here, the LAST thing we need is for you to be critical. 

I'm thinking after we get this current storm system out of the way we'll have better model clarity on our chances for next week -- wouldn't be surprised if something small/moderate sneaks up on us.

[Bob Chill]

30 minutes ago, psuhoffman said:

If you want me to be critical one thing I don't like is how the PV is just sitting over the pole and seems stuck there off to day 15 on the euro guidance. Gefs breaks it down faster. That's really interfering in our ability to get blocking to lock in. Need that to move to get either cross polar flow and or permanent ridging up top to establish. 

My gut instinct is telling me that it's wrong and even if it's right it's going to be transient. We'll know over time but my money is in not having a strong consolidated trop PV parked over the pole for any length of time if at all. 

[cbmclean]

1 hour ago, LP08 said:

For some good news..12z EPS looks much better than 0z through 222.  PV in NE Canada, -NAO, +PNA, -EPO with the Aleutian Trough.  I'd imagine the there will be some good looks in the individuals with that look.

 

240 below.

Would anyone be willing to explain how to visually evaluate the PNA and EPO state from an H5 map like the above?

[Maestrobjwa]

1 minute ago, cbmclean said:

Would anyone be willing to explain how to visually evaluate the PNA and EPO state from an H5 map like the above?

I have the same question!

[frd]

26 minutes ago, Bob Chill said:

My gut instinct is telling me that it's wrong and even if it's right it's going to be transient. We'll know over time but my money is in not having a strong consolidated trop PV parked over the pole for any length of time if at all. 

Agreed, will be interesting to see the weeklies this evening as the euro has been rather consistent on its evolution of the strat event, and maybe this carries over to the weeklies tonight.

I think the ongoing events with the SSWE is causing some issues.

Also, any changes in the mjo will effect other things as well,including the outcome and forecast of the strat event, blocking, etc. We have seen that happen already too. Certainly the high amp mjo lends itself as a big player. I also think the high amp MJO increases the risk later on in Jan of a very significant storm over the East.  

Maybe akin to a domino effect , one wrong fprecasted event triggers a ever increasing series of incorrect outcomes.  Therefore the long range guideance becomes very cloudy as someone here posted earlier today.  

disclaimer - maybe the weeklies step back as the data is from the zero run 

 

[frd]

MJO example, what a mess. 

from 

Severe Weather Blog

@blizzardof96

It looks like the statistical MJO models have all bases covered. Going to the GEFS or ECM won't provide much help at the moment either. It'll be a tough time for the long range models until they resolve this wave.

 

 

 

[LP08]

14 minutes ago, cbmclean said:

Would anyone be willing to explain how to visually evaluate the PNA and EPO state from an H5 map like the above?

+PNA is ridging over the west (ideally through the intermountain west) and -EPO is ridging that extends into Eastern Alaska.  We usually want a trough set up over the Aleutians.  The figure I posted was more of a neutral epo as that trough was a little to far east.  I am probably not the best person to be giving the explanation but on a broad sense, its what I grasp from the H5 plots.

[nj2va]

25 minutes ago, LP08 said:

+PNA is ridging over the west (ideally through the intermountain west) and -EPO is ridging that extends into Eastern Alaska.  We usually want a trough set up over the Aleutians.  The figure I posted was more of a neutral epo as that trough was a little to far east.  I am probably not the best person to be giving the explanation but on a broad sense, its what I grasp from the H5 plots.

That’s exactly my take as well.  Bump that trough west and it’d be a -EPO.  Currently its a neutral EPO.  

[nj2va]

Quite the powerful PACJET modeled on the GFS.  

[frd]

Quick look at Weeklies 

 

 

 

• NYMW - John Homenuk
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• Meteorologist
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• 2,452 posts
• Location: Scotch Plains, NJ

• Report post
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Posted 4 minutes ago

ECMWF WEEKLIES 12/27 REVIEW (NORTHEAST US) .....very impressed at first look

 

WEEK 1 | Hints of SE Ridging, Cold Air into Central US, -NAO

    Temps: Above Normal

    Precip: Above Normal

    Change: Slightly Warmer

 

WEEK 2 | Major W NHEM Ridging, Troughing into East

    Temps: Below Normal 

    Precip: Normal

    Change: Slightly Colder

 

WEEK 3 | -EPO and -AO Develops,  More Troughing in East

    Temps: Below Normal

    Precip: Normal

    Change: Much Colder

 

WEEK 4 | Poleward -EPO Continues, -NAO Develops

    Temps: Below Normal

    Precip: Above Normal

 

 

[Scraff]

Well the weeklies seem ok to me! Pretty much what most on here have been saying all along. Our chances are coming. Patience will be tested though. 

[nj2va]

Thanks @frd.  Haven’t looked yet but that’s definitely encouraging from HM.  Doesn’t seem delayed nor denied from his analysis. 

[osfan24]

Weeklies look great! Everything still going according to plan!

[clskinsfan]

3 hours ago, psuhoffman said:

Are we?  We had 3 straight years of above average snowfall from 2014 to 2016.  That is pretty rare actually.  Since then we had one really awful year, and one year that was actually only a little below a median winter even though people acted like it was god awful (probably because it was mediocre following a god awful winter and we got spoiled).  But where is the perception we are having bad luck?  Or did you just mean this winter so far?

In fairness. 2016 was one storm. The rest of the winter was abysmal. 

I really dont get the negativity in here though. We havent even hit our prime climo yet. The upcoming pattern looks serviceable at least. It is almost impossible for us not to luck into at least a couple of snows between mid Jan and mid Feb. with a decent pattern. Last winter the writing was on the wall early and I bailed early as a result. This winter still has a ton of promise.

[Isotherm]

My winter update analysis, for any interested:

[Bob Chill]

Imo- the primary reason this year is falling far short of other good years is the AO. We had a head fake in Nov that looked like we might have a nice -ao during Dec but that completely evaporated. It's remained pretty hostile honestly. If that doesn't change then the chances of a comeback will be muted.

The strat pv has been weak and displaced most of Dec but there was no response in the troposphere with any semblance of stable blocking. In a way it feels like a ripoff because we blamed the strong strat PV for our long run of strong +AO winters. This year got off on the right foot but it never materialized. Every time ens guidance has tried to build a neg AO it's faded.

Strong blocking events last 30-60 days. We're going to need one of those events to materialize before the end of Jan to put our area in an extended period of good chances. The sooner the better. Not a fan seeing the EPS showing a strongly positive AO D10-15. 

[Ralph Wiggum]

BIG exhale! Weeklies look steady as she goes....now to just get them to verify and we should all be smiling by this time next month at the latest. 

[nj2va]

2 minutes ago, Isotherm said:

My winter update analysis, for any interested:

Thanks for sharing...always enjoy reading your analysis.  You’re one of the best on the boards.  

[Isotherm]

Just now, nj2va said:

Thanks for sharing...always enjoy reading your analysis.  You’re one of the best on the boards.  

 

Thank you. One additional note is that - although in my opinion effective propagation is favored - the resolution of the stratospheric event isn't a prerequisite for the expected evolution of the winter. I created my winter outlook operating under the presumption of no technical SSW. There are other, significant indicators which favored a mean -NAO signal for this winter (weak-mod), and weak negative AO (I expected the center of the blocking more toward E Greenland rather than Arctic).

[Bob Chill]

Weeklies do look good but just checking week 3 from the 12/20 run against current week 2 progs doesn't give me much confidence. Basically, the very strong trop PV and low pressure over the pole was not picked up at all. If the current week 3 prog is going to verify then the thing to watch is the building of the EPO ridge displacing the strong trop pv from over the pole to Siberia. By week 3 the weeklies show higher heights and surface pressures building quickly in the arctic circle. By week 4 there is expansive high pressure in all the right places. 

 

[Maestrobjwa]

23 minutes ago, Bob Chill said:

Imo- the primary reason this year is falling far short of other good years is the AO. We had a head fake in Nov that looked like we might have a nice -ao during Dec but that completely evaporated. It's remained pretty hostile honestly. If that doesn't change then the chances of a comeback will be muted.

The strat pv has been weak and displaced most of Dec but there was no response in the troposphere with any semblance of stable blocking. In a way it feels like a ripoff because we blamed the strong strat PV for our long run of strong +AO winters. This year got off on the right foot but it never materialized. Every time ens guidance has tried to build a neg AO it's faded.

Strong blocking events last 30-60 days. We're going to need one of those events to materialize before the end of Jan to put our area in an extended period of good chances. The sooner the better. Not a fan seeing the EPS showing a strongly positive AO D10-15. 

Strongly positive? Yikes! Red flag or no? (I mean...it sunk the 1994-95 winter too, didn't it?)

[Ralph Wiggum]

2 minutes ago, Bob Chill said:

Weeklies do look good but just checking week 3 from the 12/20 run against current week 2 progs doesn't give me much confidence. Basically, the very strong trop PV and low pressure over the pole was not picked up at all. If the current week 3 prog is going to verify then the thing to watch is the building of the EPO ridge displacing the strong trop pv from over the pole to Siberia. By week 3 the weeklies show higher heights and surface pressures building quickly in the arctic circle. By week 4 there is expansive high pressure in all the right places. 

 

Isotherms update just covered this exact thing. Trop PV over NP *should* be a relatively short-lived feature irt geopotential heights in that region:

"Most of the high latitude blocking through the first 10 days of January will be over the NAO domain, as the z150 and tropospheric vortices will be displaced near the north pole, resulting in lower than normal geopotential heights there, at least initially."  - Isotherm

[BristowWx]

3 minutes ago, Bob Chill said:

Weeklies do look good but just checking week 3 from the 12/20 run against current week 2 progs doesn't give me much confidence. Basically, the very strong trop PV and low pressure over the pole was not picked up at all. If the current week 3 prog is going to verify then the thing to watch is the building of the EPO ridge displacing the strong trop pv from over the pole to Siberia. By week 3 the weeklies show higher heights and surface pressures building quickly in the arctic circle. By week 4 there is expansive high pressure in all the right places. 

 

Agree with you.  Week 4 is just about February.  Two months of met winter mostly snowless.  I would not have expected that this year.  Up in central Michigan for the holidays and tomorrow high of 55.  No snow anywhere.  Can’t win 

[Ralph Wiggum]

6 minutes ago, Maestrobjwa said:

Strongly positive? Yikes! Red flag or no? (I mean...it sunk the 1994-95 winter too, didn't it?)

I tend to put ALOT of stock in Isotherm's discussions and this doesnt concern me very much. He literally just touched on this subject 45 minutes ago and the propagation we should expect regarding the AO. Basically we flipped December and January due in part to the MJO coupled with the unforeseen strength of the current SSWE.

[nj2va]

1 minute ago, BristowWx said:

Agree with you.  Week 4 is just about February.  Two months of met winter mostly snowless.  I would not have expected that this year.  Up in central Michigan for the holidays and tomorrow high of 55.  No snow anywhere.  Can’t win 

 Where was the month of January written off?

[psuhoffman]

38 minutes ago, Isotherm said:

My winter update analysis, for any interested:

Many of us have been following your updates. Excellent read as always. Thanks!

[BristowWx]

8 minutes ago, nj2va said:

 Where was the month of January written off?

It wasn’t yet.  But I am skeptical of a turn around before the last week.  Love to be wrong on that.  Just takes so much time to turn the pattern around and then get a threat to materialize.  

[Bob Chill]

8 minutes ago, nj2va said:

 Where was the month of January written off?

Yea, I wasn't implying Jan was a bust. Only the next week looks particularly ugly. Beyond that looks fine. I was posting more big picture that if we don't get a stable favorable pattern in place before the end of Jan that it will be tough to have a big year. 

[psuhoffman]

21 minutes ago, Bob Chill said:

Weeklies do look good but just checking week 3 from the 12/20 run against current week 2 progs doesn't give me much confidence. Basically, the very strong trop PV and low pressure over the pole was not picked up at all. If the current week 3 prog is going to verify then the thing to watch is the building of the EPO ridge displacing the strong trop pv from over the pole to Siberia. By week 3 the weeklies show higher heights and surface pressures building quickly in the arctic circle. By week 4 there is expansive high pressure in all the right places. 

 

That bothered me some too. But I really suspect it's temporary. You can tell ridging is attempting to develop under the PV and is pressing and over time should dislodge that enough for what we need. That one stick is really all that's between the look we are getting and really good. 

Additionally I take some comfort that over the years when guidance is insistent in a specific look coming often it will be rushed and we have to wait longer but eventually it usually does materialize. The last couple years when the initial progred flip was a week of two into February that delay was a winter killer. The pattern did eventually get favorable but not until march and too late to save winter. If this pattern gets delayed from early January to late January that's not as problematic to our snow prospects. 

We should know in 2 weeks. 

[nj2va]

10 minutes ago, BristowWx said:

It wasn’t yet.  But I am skeptical of a turn around before the last week.  Love to be wrong on that.  Just takes so much time to turn the pattern around and then get a threat to materialize.  

I find it hard to believe we go January without seeing any snow.  We’ll know in 4 weeks.