January 2020 Mid/Long Term Discussion

[showmethesnow]

43 minutes ago, Bob Chill said:

Ensembles have done an excellent job this year. There has only been one notable time where things made a big shift in the medium range and that was the brief -AO/NAO period we just had. That sorta popped up unexpectedly. Other than that d10-15 has done quite well. Especially since mid Dec. People who don't think models have any accuracy beyond 5-7 days are flat wrong this year. EPS has been killing it. 

After looking over the dismal overnight runs I decided to see if I could get any ammunition towards using the 'the models are probably wrong' excuse. So I looked into them somewhat this morning and I was honestly impressed with how the models have handled the longer ranges. Besides some occasional blips they were pretty much nailing the larger scale features and wavelengths. Can't recall them ever being this spot on before. 

[MJO812]

1 minute ago, Ji said:

wtf happened to next week. Euro has no snow and warm?

It was offshore  at 0z

Hopefully we all cash in but the timeframe is short.

[cbmclean]

12 minutes ago, psuhoffman said:

And even assuming the wave progresses thats still 2 weeks away from getting to cold phases at day 15 and the last attempt at that feat died.  

I can't wait for it to start doing curley-cues

[Ralph Wiggum]

Not surprised the Euro and GFS went cutter with the Jan 7ish window. CMC is still south but my guess is will trend cutter as well once lead time shrinks. PNA not timed right and se ridge flexes wrong time.

[cbmclean]

If you cycle through the GEFS to the very end, if you squint real hard you might be able to see it weakening and slowly migrating east.  TPV is absolutely nailed to Baffin Bay.

[Ralph Wiggum]

 

17 minutes ago, Ji said:

wtf happened to next week. Euro has no snow and warm?

Happy New Year @Ji

[BristowWx]

1 minute ago, cbmclean said:

If you cycle through the GEFS to the very end, if you squint real hard you might be able to see it weakening and slowly migrating east.  TPV is absolutely nailed to Baffin Bay.

now we are looking for any signs of life in the hinter lands of the ensembles.  But at least we are nearly at the top of the despair index so can only improve from here. 

[Ralph Wiggum]

Just now, BristowWx said:

now we are looking for any signs of life in the hinter lands of the ensembles.  But at least we are nearly at the top of the despair index so can only improve from here. 

I'm with PSU....give it till mid January before kicking to the curb. But the looks of things honestly, we are going to be hanging all hope on the final 1/3 of the season when things get convoluted. There is nothing wrong with that scenario either. Still feel a larger storm is in the cards. Might be 2016 redux one and done....who knows. 

[cbmclean]

6 minutes ago, cbmclean said:

If you cycle through the GEFS to the very end, if you squint real hard you might be able to see it weakening and slowly migrating east.  TPV is absolutely nailed to Baffin Bay.

Sorry, the "it" I was referring to was the Pacific Doom Blob.

[MountainGeek]

37 minutes ago, WinterWxLuvr said:

There was a period, and I forget when, when they showed a pattern that everyone was drooling over that didn’t materialize at all.

The warm period you highlighted verified very well but I’m gonna need to see verification over a long period before I’m gonna say any forecast at 15 days is reliable. 

For those who are interested, some good background from the ECMWF. Also notable is the fact that winter forecasts tend to be more reliable due to longer wavelengths. 

https://www.ecmwf.int/en/newsletter/153/meteorology/25-years-ensemble-forecasting-ecmwf

Evolution of ensemble forecast quality

Thanks to model upgrades, improvements in the data assimilation system, the use of more observations, and the ENS configuration changes discussed above, the ENS performance has increased substantially during the past 25 years.

Figure 7 Time evolution, from 1 January 1995 to today, of the Continuous Ranked Probability Skill Score (CRPSS) of ENS forecasts of 500 hPa geopotential height over the northern hemisphere, for lead times of 24 hours, 72 hours, 120 hours, 168 hours and 240 hours. Forecasts are verified against operational analyses. The more or less regular pattern of peaks and troughs in each line stems from differences in predictability related to the seasons: winter weather tends to be more predictable than summer weather.

[frd]

44 minutes ago, psuhoffman said:

Ummm.  Ironically the people wanting the IOD to release its grip on the mjo got their wish. And the minute it did the mjo rushed right to the warm phases just like last year.  Be careful what you wish for!   And even assuming the wave progresses thats still 2 weeks away from getting to cold phases at day 15 and the last attempt at that feat died.  

@bluewave mentioned this possibility a week ago. Today @donsutherland1posted  over at 33 that the IOD has indeed weakened even further . You can see here from the site  http://www.bom.gov.au/climate/enso/iod_1.txt

Would be great if Don could share his thoughts here. 

We are now below the threshold of a +IOD I believe.   

20191125,20191201,1.14
20191202,20191208,0.86
20191209,20191215,0.82
0191216,20191222,0.56
20191223,20191229,0.31

 

 

[psuhoffman]

30 minutes ago, Ji said:

wtf happened to next week. Euro has no snow and warm?

Climo beats op runs at range. The pattern never really supported a snowstorm.  Epo ridge is too far west without NAO support. Of the 88 snowstorms I looked at none were remotely like the pattern shown next week. And that was before it degraded further the last 24 hours. 

[frd]

38 minutes ago, Ji said:

wtf happened to next week. Euro has no snow and warm?

I prefer to simply use the AO as a guide to SECS events. Indices were not supportive. Of course, more to it than that, but a -AO is a money signal.  And we all know the current NAM state. 

[psuhoffman]

6 minutes ago, frd said:

@bluewave mentioned this possibility a week ago. Today @donsutherland1posted  over at 33 that the IOD has indeed weakened even further . You can see here from the site  http://www.bom.gov.au/climate/enso/iod_1.txt

Would be great if Don could share his thoughts here. 

We are now below the threshold of a +IOD I believe.   

20191125,20191201,1.14
20191202,20191208,0.86
20191209,20191215,0.82
0191216,20191222,0.56
20191223,20191229,0.31

 

 

The IOD was keeping the convection centered in phase 2. That’s not ideal but not that hostile either. Kind of a wash. I’m not an mjo expert so I didn’t add much but the whole last month while people were rooting on the IOD demise to release the mjo once the IO standing wave weakened I was thinking “but are we sure once released it’s not going to just rush back into warm phases like last year”. The sst profile in the mjo regions except for the IOD was a little too similar for my comfort level.  

[donsutherland1]

7 minutes ago, frd said:

I prefer to simply use the AO as a guide to SECS events. Indices were not supportive. Of course, more to it than that, but a -AO is a money signal.  And we all know the current NAM state. 

The AO is particularly important for the Middle Atlantic region and the NAO also carries weight. New England does much better thanks to its higher latitude and has had significant snowstorms even when the AO was in excess of +2.000 in January.

The following from my nearly daily discussion in the NYC forum holds true for the MD-DCA-VA areas:

Based on the forecast strongly positive AO to start January, the probability of a significant (6" or greater snowstorm) for the major cities of the Middle Atlantic region during the first week of January is low. Since 1950, the biggest snowfall for that region when the AO was +2.000 or above during the January 1-15 period occurred during January 14-15, 1954 when Philadelphia received 3.0" snow and New York City picked up 2.0". Boston has had numerous 6" or greater snowstorms during such cases, including one 10" or greater snowstorm. Therefore, the risk of significant snow would likely be greatest over New England assuming this relationship holds (no significant offsetting variables). 

Some of the newer AO forecasts keep the AO at +2.000 or above through January 10. If so, that development could adversely impact Mid-Atlantic significant snowfall prospects beyond the first week of January.

 

[Ralph Wiggum]

6 minutes ago, psuhoffman said:

Climo beats op runs at range. The pattern never really supported a snowstorm.  Epo ridge is too far west without NAO support. Of the 88 snowstorms I looked at none were remotely like the pattern shown next week. And that was before it degraded further the last 24 hours. 

If things degrade enough going forward they have to reach rock bottom at some point and start heading favorable.  It might be June but heck let's root for rock bottom sooner than later. Ens means toward the end say we are close.

[donsutherland1]

11 minutes ago, frd said:

@bluewave mentioned this possibility a week ago. Today @donsutherland1posted  over at 33 that the IOD has indeed weakened even further . You can see here from the site  http://www.bom.gov.au/climate/enso/iod_1.txt

Would be great if Don could share his thoughts here. 

We are now below the threshold of a +IOD I believe.   

20191125,20191201,1.14
20191202,20191208,0.86
20191209,20191215,0.82
0191216,20191222,0.56
20191223,20191229,0.31

 

 

The weakening IOD should reduce interference with the MJO. That should allow it to progress in more typical fashion. The forecast shift to the Maritime Continent (Phases 4-5) is real and the ridging forecast beyond 240 hours is increasingly likely to verify. Absent the MJO, that's still what one would expect given the forecast state of the teleconnections.

And if things aren't miserable enough, there's the risk that the EPS weeklies could deliver another serving of misery a little later today.

However, this does not mean that it is time to cancel winter. If things work out, the potential for a pattern change for colder and snowier weather could increase during late January. February might offer the best chance for meaningful snowfall in the Middle Atlantic region. 

We'll see, as a lot of variables are involved, but things should eventually get better all other things being considered.

[psuhoffman]

7 minutes ago, donsutherland1 said:

The weakening IOD should reduce interference with the MJO. That should allow it to progress in more typical fashion. The forecast shift to the Maritime Continent (Phases 4-5) is real and the ridging forecast beyond 240 hours is increasingly likely to verify. Absent the MJO, that's still what one would expect given the forecast state of the teleconnections.

And if things aren't miserable enough, there's the risk that the EPS weeklies could deliver another serving of misery a little later today.

However, this does not mean that it is time to cancel winter. If things work out, the potential for a pattern change for colder and snowier weather could increase during late January. February might offer the best chance for meaningful snowfall in the Middle Atlantic region. 

We'll see, as a lot of variables are involved, but things should eventually get better all other things being considered.

Thanks for your thoughts. Love when you pop in. 

[BristowWx]

9 minutes ago, donsutherland1 said:

The weakening IOD should reduce interference with the MJO. That should allow it to progress in more typical fashion. The forecast shift to the Maritime Continent (Phases 4-5) is real and the ridging forecast beyond 240 hours is increasingly likely to verify. Absent the MJO, that's still what one would expect given the forecast state of the teleconnections.

And if things aren't miserable enough, there's the risk that the EPS weeklies could deliver another serving of misery a little later today.

However, this does not mean that it is time to cancel winter. If things work out, the potential for a pattern change for colder and snowier weather could increase during late January. February might offer the best chance for meaningful snowfall in the Middle Atlantic region. 

We'll see, as a lot of variables are involved, but things should eventually get better all other things being considered.

Is that potential for pattern change to "colder and snowier in late Jan/Feb if things work out" because it can't get much worse than it is right now or something you are seeing that leads you to think that?  I mean we could trade one bad pattern for another giving us a different way to the same result. There was a lot of speculation in early Dec that things would turn around in late Dec/early Jan and well we know that is not happening.  Thanks in advance.  very much enjoy reading your posts.

[Maestrobjwa]

10 minutes ago, psuhoffman said:

The IOD was keeping the convection centered in phase 2. That’s not ideal but not that hostile either. Kind of a wash. I’m not an mjo expert so I didn’t add much but the whole last month while people were rooting on the IOD demise to release the mjo once the IO standing wave weakened I was thinking “but are we sure once released it’s not going to just rush back into warm phases like last year”. The sst profile in the mjo regions except for the IOD was a little too similar for my comfort level.  

Now, correct me if I'm overgenaralizing...and perhaps my worry isn't too rational...But I've always had a nagging fear of this being the new normal (that is, that we'll start seeing this every single year). I mean, I guess 2 years in a row doesn't mean much statistically, but...I'm just wondering (maybe this is more for the global warming thread...where I hesitate to traverse, lol)

[donsutherland1]

1 minute ago, BristowWx said:

Is that potential for pattern change to "colder and snowier in late Jan/Feb if things work out" because it can't get much worse than it is right now or something you are seeing that leads you to think that?  I mean we could trade one bad pattern for another giving us a different way to the same result. There was a lot of speculation in early Dec that things would turn around in late Dec/early Jan and well we know that is not happening.  Thanks in advance.  enjoy reading your posts.

It's due to two major assumptions:

1. The MJO's progression away from the Maritime Continent and through Phase 6 into Phase 7

2. A weakening of the strong polar vortex. There are a number of cases where a super strong polar vortex in early January weakened with sustained blocking occurring in late January and/or February

None of this is cast in stone, but there's enough reason to refrain from canceling winter (even if Ji has already done so).

[donsutherland1]

5 minutes ago, Maestrobjwa said:

Now, correct me if I'm overgenaralizing...and perhaps my worry isn't too rational...But I've always had a nagging fear of this being the new normal (that is, that we'll start seeing this every single year). I mean, I guess 2 years in a row doesn't mean much statistically, but...I'm just wondering (maybe this is more for the global warming thread...where I hesitate to traverse, lol)

There may be reason for concern. Some recent scientific literature:

https://www.nature.com/articles/s41586-019-1764-4

[frd]

1 minute ago, donsutherland1 said:

It's due to two major assumptions:

1. The MJO's progression away from the Maritime Continent and through Phase 6 into Phase 7

2. A weakening of the strong polar vortex. There are a number of cases where a super strong polar vortex in early January weakened with sustained blocking occurring in late January and/or February

None of this is cast in stone, but there's enough reason to refrain from canceling winter (even if Ji has already done so).

 

Thanks Don, great info as always !

As you and bluewave both mentioned it will be interesting to see whether the MJO has any effect down the road on the PV. 

 

  

[psuhoffman]

3 minutes ago, donsutherland1 said:

It's due to two major assumptions:

1. The MJO's progression away from the Maritime Continent and through Phase 6 into Phase 7

2. A weakening of the strong polar vortex. There are a number of cases where a super strong polar vortex in early January weakened with sustained blocking occurring in late January and/or February

None of this is cast in stone, but there's enough reason to refrain from canceling winter (even if Ji has already done so).

This is the key imo. Looking at all the analogs to a strong central pac ridge in January, most had that feature persist at least to some degree into Feb and March. The only years that went on to a snowier outcome had significant NAO help to mitigate its impact. Absent that...the comp years that the NAO remained positive were pretty awful here. Some had better outcomes NYC north.  Hopefully we see signs of a reversal of the NAM by mid January. 

[cbmclean]

5 minutes ago, psuhoffman said:

Looking at all the analogs to a strong central pac ridge in January, most had that feature persist at least to some degree into Feb and March.

I think you may have posted this before, but how many years were in your analog pool for Pacific Doom Blob?  Apparently there at least a few where the blob died earlier than others?  I know I'm reaching for straws here, but not much else to do.

[psuhoffman]

4 minutes ago, cbmclean said:

I think you may have posted this before, but how many years were in your analog pool for Pacific Doom Blob?  Apparently there at least a few where the blob died earlier than others?  I know I'm reaching for straws here, but not much else to do.

With a strong +NAM I didn’t see many that showed significant improvement. Part of that is because with a strong TPV over the pole it’s difficukt for that pac ridge to press into western north Am like we need. The strong NAM state naturally resists that. The years where that pac ridge migrated east also tended to have a - NAM along with it.  

Anything can happen but by far our best way out of this mess later in winter is through a flip in the NAM state. 

[Weather Will]

In a quick look, EPS still has weak support for a snow storm around next Thursday.  I know, grasping at straws.

[WinterWxLuvr]

2 hours ago, psuhoffman said:

Ummm.  Ironically the people wanting the IOD to release its grip on the mjo got their wish. And the minute it did the mjo rushed right to the warm phases just like last year.  Be careful what you wish for!   And even assuming the wave progresses thats still 2 weeks away from getting to cold phases at day 15 and the last attempt at that feat died.  

I guess you just have to laugh. This is like a horror show in every way right now. 

That phase diagram had it looping much sooner than that at this time about 8 days ago. My guess is that it will be back to 7 quickly.

[WinterWxLuvr]

CPC analogs to the current patterns include dates in Dec 95 and early Jan 87. Both of those years had major winter weather right at 21 days later.

[donsutherland1]

A quick note on teleconnections and Washington, DC's 6" or greater January snowstorms (1950-2019):

AO-/PNA+: 67%

AO+/PNA-: 0% (biggest: 3.9")

AO-: 80%

PNA+: 87%

NAO-: 67%

n=12

If one broadens the pool to include 4" or greater snowstorms (n=22), the numbers change very little for all but the NAO:

AO-/PNA+: 64%

AO+/PNA-: 0%

AO-: 77%

PNA+: 86%

NAO-: 55%

Note: All of the 10" or greater snowstorms occurred with an AO-/PNA+