January 2023 Mid-Long Range Disco

[cbmclean]

27 minutes ago, CAPE said:

That's a PowerPoint presentation(in pdf) based on the paper referenced in my post. Good overview.

Thanks for the information, as always!

[cbmclean]

34 minutes ago, DarkSharkWX said:

Another presentation about the NPJ if anyone is interested in it:
https://www.weather.gov/media/sti/nggps/Presentations 2017/08 NGGPS17_PImeeting_Bosart.pdf

Thanks for the link, interesting stuff.

[WesternFringe]

7 hours ago, Bob Chill said:

This is an easy one... if it weren't for the -4 AO already, strat babble would be the talk of the town. Then when that fails, the MJO will be the new OG. However, in between all those emotional keystrokes, a couple of mid range jacked up and untracked events drop some snow anyway. But since it was 10'-12' short of expectations, it went unnoticed while hostile stats and climate posts keep the "hot tag" smokin' in the disco thread

Also this.

eta:  I had to take a break from this thread bc of all the vitriol and ad hominem attacks (always a good way to win an argument (eye roll)) like calling me childish.  

I had to laugh eventually.

Imagine the vitriol if I had said we will never snow here like we have snowed before!  Or if I said the data show we will never be snowy again!  I wonder whether some folks here would have just nodded along and said you are right.

i got attacked for saying the data don’t show a huge downturn and implying that we might get normal to above snowfall soon. And that it is location dependent and not an observable trend statistically. Lol 

i looked at the data set of annual snowfall with clear eyes.  I took Stats 1,2,3, and 4 at UVa when studying for my doctorate.  But suddenly I am trolling and childish when I say the data for DC statistically don’t show a cataclysmic drop in annual snowfall? 

Someone needs a reality and self over confidence/assurance check, but I don’t think it is me, since my self confidence was in the gutter following the hostile attacks last night.  

I stand by my data analysis, and don’t think the sky is falling and it is not is it ‘harder to snow around here’ anymore.  We are just in a bad stretch for some in some parts of the mid atlantic.

[cbmclean]

So here is the probabilistic forecast for the NPJ state from 

https://www.atmos.albany.edu/facstaff/awinters/realtime/Probabilistic_NPJPD.php

I'm trying to understand how to interpret thia graph So looks like we are going from a "poleward phase" to an "extended phase".  But the magnitude in the extended phase is not really all that high (I am assuming that magnitude equates to distance from the origin).

[CAPE]

1 hour ago, cbmclean said:

So here is the probabilistic forecast for the NPJ state from 

https://www.atmos.albany.edu/facstaff/awinters/realtime/Probabilistic_NPJPD.php

I'm trying to understand how to interpret thia graph So looks like we are going from a "poleward phase" to an "extended phase".  But the magnitude in the extended phase is not really all that high (I am assuming that magnitude equates to distance from the origin).

A little hard to read the dates but it initialized on the 0z run on 28th- at that point it is shifted poleward and also quite extended, and moving forward in time it retracts some(also less poleward), which makes sense if you look at the jet stream level winds over the N Pacific (and the 500 mb heights) for the 0z run.

eta- as for the magnitude of the jet extension and what constitutes 'too much' vs 'just enough' for our purposes, we have to consider other indices that interact. For example if there were a legitimate block downstream in the NAO space, that would slow/buckle the flow, and would have ramifications upstream as eastern ridging would be suppressed and replaced by the tendency for a trough- so for a given magnitude of Pac jet extension that was previously 'too much' with progressive flow, it may now not overwhelm and allow for a ridge in the PNA space or at least bring it to neutral.

[Weather Will]

Latest WB 18Z GEFS is better for the January 10th period potential….  12Z yesterday, the bad 12Z run today, and the latest.

[Weather Will]

WB extended GEFS.  4 days ago the 7 day snow period ending on the 19th compared to latest run for the same period.  Anomalies centered around the 10th for those that hate the snow maps….

[BristowWx]

8 minutes ago, Weather Will said:

WB extended GEFS.  4 days ago the 7 day snow period ending on the 19th compared to latest run for the same period.

Wow.  For peak climo that’s just……

[Weather Will]

1 minute ago, BristowWx said:

Wow.  For peak climo that’s just……

You take whatever crumbs we can get…this period is the only game in town the next couple of weeks.

[Eskimo Joe]

3 minutes ago, BristowWx said:

Wow.  For peak climo that’s just……

Yea, it's concerning.

[BristowWx]

1 minute ago, Eskimo Joe said:

Yea, it's concerning.

Maybe Feb?  Who knows 

[psuhoffman]

19 hours ago, WesternFringe said:

Well, folks are wrong then.  I ran the numbers and the slope of the line is virtually zero.  Yes, DC is getting .03” less per year on average over the 140 year period.  That is statistical noise.   DC is getting 0.17” more per year since 1960s.  That is also statistical noise.

The single digit snowfall years ‘trend’ is arbitrary, too.  Some years with 2 recordable events might yield 9.8” for the season and some years a 10.2” total could have come from 6 recordable storms.  We would need to look at snowfall per event by year to make any valid conclusions on snowstorms trending bigger or not.

i am not trolling.  I simply am saying the numbers in DC at least do not point to a cataclysmic drop in snowfall over the last century and a half.  They just don’t.

I will take you at your word that you are not trolling and engage one last time with what I take issue with in your statistical analysis.  But first I'll post some data that I will reference in my response below.  @Terpeast I have used only DCA data from 1942 onwards.  

DCA annual snowfall with a linear trendline and 30 year running mean imposed.  

18 year running probability of getting at least 10" of snow in any given season

18 yeas was not arbitrary but was chosen because in this discussion yesterday 18 years was agreed upon as a minimum data set to avoid overly skewed results to get a statistically significant result.  

Some additional facts. 

• The running 30 year mean snowfall at DCA has decreased from 17.8" to 13.9" over the period of record for the airport.  This trend is continuing and is getting even worse...the current 15 year mean is only 13.6"
• The median has decreased from 15.8" to 10.85".  This trend is also getting worse.  The current 15 year median is 7.8"
• The chances of getting at least 10" of snow in a given season have gone from 72% to 50% in a given season.  This trend also is getting worse...the current 15 year probability is 47%
• The chances of getting 15" in a season have gone from 53% to 27%.  
• The chances of DC getting 20" have gone from 40% to 17%

1) The words bolded above are all your opinion.  The slope is NOT 0, virtually is opinion...yes over any one year the change is insignificant but over a long period of time .03 adds up to 4" of snowfall we have lost annually over the period of record.  That is not insignificant when your average is only about 14".  That's more than 20% of our annual snowfall we have lost.  

2) Single digit snowfall years is not arbitrary, its a way of showing what chance there is of getting a significant amount of snow in any given year in DC.  We can use another number if you want...8", 12", 15", 18", 20"...they all show the exact same trend so it doesn't matter.  I didn't cherry pick 10 to skew the data, I picked 10 because its a nice simple even number to highlight the issue which is in any given year the odds of getting snow is going down.  That is true whether you use the threshold of any amount between about 7 and 20", outside that you get some crazy useless percentages because you're using a number outside a standard deviation.  

3)I've repeatedly said that using the probability of snowfall or the median is way more useful to a climate like DC and you repeatedly dismiss that which is your opinion and fine but I will explain what is wrong with a mean.  DC snow climo is inflated by anomalously snowy seasons like 1996, 2003, 2010 and 2014.  But the snow that happens in those winters doesn't make the years in between any less awful.   They do not affect what a typical winter is.  Getting a huge amount of snow every 7 years or so affects the mean a lot but isn't indicative of what any given winter is likely to be like...which is probabilistically much more likely to be one of those other 6 years.  Median filters out those big years better to give you a better indication of what any given specific season is likely to be like.  

 

4) You've said there is no evidence that the mean is being skewed but the evidence is right on the chart for everyone to see.  While the median and probabilities of snowfall are clearly decreasing the range of snowfall in any given year over a period of time is increasing.  The standard dev of snowfall is increasing.  Even though the baseline for snowfall is lower we have had several of the biggest snowfall seasons recently.  This is preventing the mean from dropping as quickly as the probabilities of snow in any given season are.  But for our purposes the probabilities are more important.  Who cares that it snows a crap ton once every blue moon when the truth is we spend 80% of the time in the total suckage periods in between that are getting worse!

 

5) You repeatedly try to manipulate the data by using an arbitrary date in the 1980's from which you can say "snowfall has increased since".  That is really bad statistically because snowfall does run in cycles.  We are no doubt in a down cycle right now.  I have never implied DC won't have better snowfall periods ahead.  But by cherry picking a date that is a minimum with which to compare the current point in time fails to acknowledge that over a longer period of time its evident that the "snowy" cycles are becoming less snowy and the "dreg" periods are becoming MORE dreg.  The current down cycle is no doubt a down cycle...but its worse than previous down cycles.  The recent snowy periods weren't as snowy as past snowy periods.  Over longer periods the downward trend is evident.  

 

[Terpeast]

8 minutes ago, BristowWx said:

Wow.  For peak climo that’s just……

Yeah its crap, at least how it’s modeled for now. 

It did tick up around an inch though. Best we can hope for in that period is a post frontal wave that pops up within 3-4 days. Otherwise we’re looking into the second half of the month. 

[psuhoffman]

2 minutes ago, Terpeast said:

Yeah its crap, at least how it’s modeled for now. 

It did tick up around an inch though. Best we can hope for in that period is a post frontal wave that pops up within 3-4 days. Otherwise we’re looking into the second half of the month. 

If I make it to January 10 without 1" of snow the numbers get even uglier.  It's a VERY small list...but most are years that ended with almost no snow at all around DC.  

[Maestrobjwa]

13 minutes ago, BristowWx said:

Wow.  For peak climo that’s just……

Well technically for OUR peak climo that's just at the start of it. I always view our peak window from mid-Jan through President's Day.

[Eskimo Joe]

12 minutes ago, BristowWx said:

Maybe Feb?  Who knows 

After Feb 14th, it's sun angle season. Our window is closing and quick. 

[BristowWx]

4 minutes ago, psuhoffman said:

If I make it to January 10 without 1" of snow the numbers get even uglier.  It's a VERY small list...but most are years that ended with almost no snow at all around DC.  

Well…I am thinking you won’t get 1 inch of snow before 10 Jan.  If it’s gonna get ugly at least we are going ugly early.  Learned that in the Navy.  

[Twilly05]

6 minutes ago, psuhoffman said:

I will take you at your word that you are not trolling and engage one last time with what I take issue with in your statistical analysis.  But first I'll post some data that I will reference in my response below.  @Terpeast I have used only DCA data from 1942 onwards.  

DCA annual snowfall with a linear trendline and 30 year running mean imposed.  

18 year running probability of getting at least 10" of snow in any given season

18 yeas was not arbitrary but was chosen because in this discussion yesterday 18 years was agreed upon as a minimum data set to avoid overly skewed results to get a statistically significant result.  

Some additional facts. 

The running 30 year mean snowfall at DCA has decreased from 17.8" to 13.9" over the period of record for the airport.  This trend is continuing and is getting even worse...the current 15 year mean is only 13.6"

The median has decreased from 15.8" to 10.85".  This trend is also getting worse.  The current 15 year median is 7.8"

The chances of getting at least 10" of snow in a given season have gone from 72% to 50% in a given season.  This trend also is getting worse...the current 15 year probability is 47%

The chances of getting 15" in a season have gone from 53% to 27%.  

The chances of DC getting 20" have gone from 40% to 17%

1) The words bolded above are all your opinion.  The slope is NOT 0, virtually is opinion...yes over any one year the change is insignificant but over a long period of time .03 adds up to 4" of snowfall we have lost annually over the period of record.  That is not insignificant when your average is only about 14".  That's more than 20% of our annual snowfall we have lost.  

2) Single digit snowfall years is not arbitrary, its a way of showing what chance there is of getting a significant amount of snow in any given year in DC.  We can use another number if you want...8", 12", 15", 18", 20"...they all show the exact same trend so it doesn't matter.  I didn't cherry pick 10 to skew the data, I picked 10 because its a nice simple even number to highlight the issue which is in any given year the odds of getting snow is going down.  That is true whether you use the threshold of any amount between about 7 and 20", outside that you get some crazy useless percentages because you're using a number outside a standard deviation.  

3)I've repeatedly said that using the probability of snowfall or the median is way more useful to a climate like DC and you repeatedly dismiss that which is your opinion and fine but I will explain what is wrong with a mean.  DC snow climo is inflated by anomalously snowy seasons like 1996, 2003, 2010 and 2014.  But the snow that happens in those winters doesn't make the years in between any less awful.   They do not affect what a typical winter is.  Getting a huge amount of snow every 7 years or so affects the mean a lot but isn't indicative of what any given winter is likely to be like...which is probabilistically much more likely to be one of those other 6 years.  Median filters out those big years better to give you a better indication of what any given specific season is likely to be like.  

 

4) You've said there is no evidence that the mean is being skewed but the evidence is right on the chart for everyone to see.  While the median and probabilities of snowfall are clearly decreasing the range of snowfall in any given year over a period of time is increasing.  The standard dev of snowfall is increasing.  Even though the baseline for snowfall is lower we have had several of the biggest snowfall seasons recently.  This is preventing the mean from dropping as quickly as the probabilities of snow in any given season are.  But for our purposes the probabilities are more important.  Who cares that it snows a crap ton once every blue moon when the truth is we spend 80% of the time in the total suckage periods in between that are getting worse!

 

5) You repeatedly try to manipulate the data by using an arbitrary date in the 1980's from which you can say "snowfall has increased since".  That is really bad statistically because snowfall does run in cycles.  We are no doubt in a down cycle right now.  I have never implied DC won't have better snowfall periods ahead.  But by cherry picking a date that is a minimum with which to compare the current point in time fails to acknowledge that over a longer period of time its evident that the "snowy" cycles are becoming less snowy and the "dreg" periods are becoming MORE dreg.  The current down cycle is no doubt a down cycle...but its worse than previous down cycles.  The recent snowy periods weren't as snowy as past snowy periods.  Over longer periods the downward trend is evident.  

 

Stats can be made to “prove” anything you want them to prove. Really comes down to 2 different opinions of what the “stats” say. Who cares? Everyone has an opinion. Sadly “science” has now been thrown into the political monkey grinder. Everyone has an agenda. Sad. 

[Eskimo Joe]

6 minutes ago, psuhoffman said:

If I make it to January 10 without 1" of snow the numbers get even uglier.  It's a VERY small list...but most are years that ended with almost no snow at all around DC.  

What years did that occur, and what were the final snow totals for DC?

[Terpeast]

9 minutes ago, psuhoffman said:

If I make it to January 10 without 1" of snow the numbers get even uglier.  It's a VERY small list...but most are years that ended with almost no snow at all around DC.  

Maybe this will be backloaded. Maybe we’ll get nothing. Nobody knows.

If we get a 3-4 incher at the end of February, I’ll take the W and then get ready for spring weather.

And if we really do get nothing… well… see you next year, I guess. 

[Maestrobjwa]

1 minute ago, psuhoffman said:

If I make it to January 10 without 1" of snow the numbers get even uglier.  It's a VERY small list...but most are years that ended with almost no snow at all around DC.  

And to think we just had a 1.8" winter 3 years ago...if that happens again do soon that would be so bad all you could do is laugh at it, lol

[psuhoffman]

19 minutes ago, BristowWx said:

Wow.  For peak climo that’s just……

this implies we have a peak climo anymore lol 

[cbmclean]

3 minutes ago, Eskimo Joe said:

After Feb 14th, it's sun angle season. Our window is closing and quick. 

Warning: adult language

 

[psuhoffman]

1 minute ago, Terpeast said:

Maybe this will be backloaded. Maybe we’ll get nothing. Nobody knows.

If we get a 3-4 incher at the end of February, I’ll take the W and then get ready for spring weather.

 

I will enjoy any snow we get.  If we don't get any I'll take my kids to Blackwater Falls in WV after they get an upslope event to play and go sledding.  I will see snow a few times when I go skiing in New England or Colorado.  It will be ok.  But we were all hopeful maybe this would be a "good for a nina" season...where we get close to median or maybe even closer to avg if we got lucky.  But it is becoming increasingly likely this is going to be one of the bad ones...like bad bad not just just kinda bad.  But likely doesn't mean definitely.  Even if every past comp was awful there aren't enough years to say its a statistical certainty.  But we all know this is how the really awful years start.  I still do have some hope...these statistics are just data.  Not a prediction.  But I will lay this out there...if the PV starts to couple with the TPV and we see the AO go extremely positive in January its game over.  

[psuhoffman]

9 minutes ago, Twilly05 said:

Stats can be made to “prove” anything you want them to prove. Really comes down to 2 different opinions of what the “stats” say. Who cares? Everyone has an opinion. Sadly “science” has now been thrown into the political monkey grinder. Everyone has an agenda. Sad. 

I didn't claim my stats proved anything...I simply laid out facts and explained why I disagreed with his analysis of the data.  Anyone is welcome to disagree with me.  I laid out the data, people can decide for themselves which interpretation they agree with.  

[Maestrobjwa]

7 minutes ago, psuhoffman said:

I will enjoy any snow we get.  If we don't get any I'll take my kids to Blackwater Falls in WV after they get an upslope event to play and go sledding.  I will see snow a few times when I go skiing in New England or Colorado.  It will be ok.  But we were all hopeful maybe this would be a "good for a nina" season...where we get close to median or maybe even closer to avg if we got lucky.  But it is becoming increasingly likely this is going to be one of the bad ones...like bad bad not just just kinda bad.  But likely doesn't mean definitely.  Even if every past comp was awful there aren't enough years to say its a statistical certainty.  But we all know this is how the really awful years start.  I still do have some hope...these statistics are just data.  Not a prediction.  But I will lay this out there...if the PV starts to couple with the TPV and we see the AO go extremely positive in January its game over.  

Now that too would be the second time in 3 years...have we ever seen 2 raging +AO seasons in such a short span?

[Maestrobjwa]

I'm telling ya there's a lot riding on that mod niño next year, lol

[psuhoffman]

1 minute ago, Maestrobjwa said:

Now that too would be the second time in 3 years...have we ever seen 2 raging AO seasons in such a short span?

We just had a raging -AO, about as negative an AO as we can ever get...we just didn't get any snow out of it lol.  

[psuhoffman]

1 minute ago, Maestrobjwa said:

I'm telling ya there's a lot riding on that mod niño next year, lol

I love snow...and I REALLY hope is snows 100" the next nino winter.  But the evil me kinda takes pleasure knowing at least if it is a total fail I get to see the total nuclear meltdown on here.  

[Maestrobjwa]

1 minute ago, psuhoffman said:

We just had a raging -AO, about as negative an AO as we can ever get...we just didn't get any snow out of it lol.  

Lol That would be tbe biggest joke ever if we go from raging negative to raging positive in the same dang season