January Med/Long Range Disco Part 2

[Ji]

the EPS did kick us into the blue shade between Jan 27 and Jan 30. So that might be our next window to fail

 

[pasnownut]

18 minutes ago, usedtobe said:

I'm not very encouraged by the pattern and think our snow chances through the remainder of the month are below average.  That doesn't mean that there will be no chances but with all the system slated to start crashing into the west and a mean ridge in the east.  snow chances may be hard to find.  The ensembles from the Euro and from ERL PSD suggest that the EPO will be positive through the remainder of the month.  The pattern suggests the storm track will be to our north.  Yes, the NAO may go negative but not in a manner very favorable to us.  

Here are two discouraging teleconnnection forecasts.  The combination of a negative PNA and positive EPO pretty hard to overcome.  The PNa pattern may improve towards the end of the month but that's a long way off.  Have to hope thee ensembles are wrong. 

 

 

 

 

Thanks Wes (but after your read, i'm not going to say good to hear from you) ....lol

My question to you is that as the Euro has struggled this year, I'm wondering if your confidence in it has changed.

from CPC, it shows a slightly +PNA, coupled with a -AO towards EOM.  

Here is AO

As the GFS seems to be handling things somewhat better, wouldnt you add a little weight to it, as the above would argue for opportunities for cold to be available in the east.  If I've missed something, please let me know the errors of my ways.  Thanks in advance.

Nut

[Bob Chill]

29 minutes ago, usedtobe said:

I'm not very encouraged by the pattern and think our snow chances through the remainder of the month are below average.  That doesn't mean that there will be no chances but with all the system slated to start crashing into the west and a mean ridge in the east.  snow chances may be hard to find.  The ensembles from the Euro and from ERL PSD suggest that the EPO will be positive through the remainder of the month.  The pattern suggests the storm track will be to our north.  Yes, the NAO may go negative but not in a manner very favorable to us.  

Here are two discouraging teleconnnection forecasts.  The combination of a negative PNA and positive EPO pretty hard to overcome.  The PNa pattern may improve towards the end of the month but that's a long way off.  Have to hope thee ensembles are wrong. 

I'm not encouraged either, Wes. We're fighting the pac big time so getting a track underneath us will take an orchestrated pile of luck that we most likely don't have this year. D10-12 does show some interest with a good HP in a CAD spot. The ens members that do give us snow show some west track/cad mixed events. We really haven't had good hp placement all winter long so I'm skeptical but it's worth watching. 

 

[Bob Chill]

18 minutes ago, Ji said:

the EPS did kick us into the blue shade between Jan 27 and Jan 30. So that might be our next window to fail

 

That's because 1 of the EPS members gives the area 25-30". lol. Overall, less than a quarter have anything meaningful. Not a lot of support but better than a shutout. 

[Ji]

Just now, Bob Chill said:

That's because 1 of the EPS members gives the area 25-30". lol. Overall, less than a quarter have anything meaningful. Not a lot of support but better than a shutout. 

haha..those mean maps are the worst. Thats what i figured. Okay...see you February 10th

[Bob Chill]

2 minutes ago, Ji said:

haha..those mean maps are the worst. Thats what i figured. Okay...see you February 10th

At least the next 10-15 days will be easier to work with. Instead of worrying about what can go wrong (already taken care of with "everything" right now) we can just discuss what can go right and expect the worst. If we stick to talking about what can go right this thread will get about 10 posts per day. 

[Ji]

10 minutes ago, Bob Chill said:

At least the next 10-15 days will be easier to work with. Instead of worrying about what can go wrong (already taken care of with "everything" right now) we can just discuss what can go right and expect the worst. If we stick to talking about what can go right this thread will get about 10 posts per day. 

i think part of the problem...every snow event that we have tracked this year...have had great potential ratios and temps have always been a non issue....We need a traditional event where the snow is wet....I am at 32-33...its raining in OC...the carolinas are getting a rain storm....

[Bob Chill]

2 minutes ago, Ji said:

i think part of the problem...every snow event that we have tracked this year...have had great potential ratios and temps have always been a non issue....We need a traditional event where the snow is wet....I am at 32-33...its raining in OC...the carolinas are getting a rain storm....

IF (Jupiter sized IF) we do get something during the d10-15 range it's probably a western special changeover event. You are probably in one of the better spots for a very low odds, very low probability, west track CAD deal. 

[Bob Chill]

We all know the caveats of uber long range but it actually hasn't performed all that poorly this year. At least with pattern changes. They are happening the right way but the timing is always a little difficult to pin down. This flip to a dominant NPac/+EPO was very well modeled at 2 week leads. For the last week or so, long range guidance is really locked into some interesting changes starting right at the beginning of FEB. CFS weekly guidance has done as well as the euro weeklies this year and the accuracy has actually been fairly good at times. Right now the CFS weeklies and euro weeklies agree that the first week of Feb is a transition week. CFS actually looks pretty good for the first week. Not great but good..

 

 

From week 3 through week 6, the longwave pattern continuously morphs into a really good look. Euro weeklies look no different. Big -EPO ridge coming back (makes sense with the early winter base state we had)  and even some blocking. If this panel is right (over even the previous week or 2) we should have our shot at the real deal in Feb.

 

 

 

CFS monthy mean for Feb looks good too. Note the lower heights off the eastern tip of Canada....that's what you want to see for a good storm track here. 

[pasnownut]

Thanks Bob.  Maybe you can chime in on my response to Wes above?  CPC outlook through end of month didnt look dumpster fireish to me.  What am i missing?

[Bob Chill]

Just now, pasnownut said:

Thanks Bob.  Maybe you can chime in on my response to Wes above?  CPC outlook through end of month didnt look dumpster fireish to me.  What am i missing?

It's not the temps we're fighting. It's the storm track. It's going to be quite difficult to get any strong synoptic storm to not pass to our west....and drag a bunch of warm air with it...before the cold rushes in behind the rain...lol

[usedtobe]

52 minutes ago, pasnownut said:

Thanks Wes (but after your read, i'm not going to say good to hear from you) ....lol

My question to you is that as the Euro has struggled this year, I'm wondering if your confidence in it has changed.

from CPC, it shows a slightly +PNA, coupled with a -AO towards EOM.  

Here is AO

As the GFS seems to be handling things somewhat better, wouldnt you add a little weight to it, as the above would argue for opportunities for cold to be available in the east.  If I've missed something, please let me know the errors of my ways.  Thanks in advance.

Nut

Actually, the PSD graphicss I showed are from a low resolution version of the GEFS if I'm not mistaken.   I'm more concerned about the positive EPO than the PNA which on the PSD plot does got weakly positive by months end but is pretty negative for most of the month.   Isotherm also noted other reasons liek the MJO to be negative for most of the month.   Of course, the model forecasts could be wrong and the ridge could rebuild over AK faster than forecast as even ensemble means aren't much good beyond 10 days. 

 

[pasnownut]

Thanks to both responses,

While MJO is not favorable, I though a +PNA -AO albeit weak, would argue for opportunity.  I also have read that MJO influence is somewhat suspect in LR forecasting, especially when not a strong one.  They are closer to COD than a strong 4/5, which to me mutes the signal somewhat.  I always looked at AO/NAO as prerequisites for eastern opps.  This year has been a great lesson for me as to the EPO and its influence. While I know that the pac rules I guess I could argue that the AO might help to keep us from cutting.  

[usedtobe]

52 minutes ago, Bob Chill said:

It's not the temps we're fighting. It's the storm track. It's going to be quite difficult to get any strong synoptic storm to not pass to our west....and drag a bunch of warm air with it...before the cold rushes in behind the rain...lol

Our only hope I think is for a low to go to our north and set up a 50 50 low with weaker wave then digging just enough to pot of low before the next big storm takes a track to out north and west. 

 

[yoda]

Out on a limb here... but Day 9 and 10 on the 12z GGEM looks like it would be icy for a lil while and not rain as it depicts.  Large sprawling HP in Quebec in the 1045-1050mb range... though it is moving slowly eastward as the cutter progresses into MI

[frd]

Seems Ventrice's in-house MJO progression and the CFSv2 agree, along with the Euro weeklies, at least at this point in time.

 

 

 

[Ji]

Out on a limb here... but Day 9 and 10 on the 12z GGEM looks like it would be icy for a lil while and not rain as it depicts.  Large sprawling HP in Quebec in the 1045-1050mb range... though it is moving slowly eastward as the cutter progresses into MI

Not a chance

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[yoda]

3 minutes ago, Ji said:

Not a chance

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There would be CAD in that set up... not saying we would get all wintry -- there would def be a chance at some before the changeover to rain.  Besides, its the only real chance till at least the 27th

[Ji]

34 minutes ago, yoda said:

There would be CAD in that set up... not saying we would get all wintry -- there would def be a chance at some before the changeover to rain.  Besides, its the only real chance till at least the 27th

way too far N and E of us to give us CAD. Anyway..it dosent matter. The Jan 27-30 threat period is most likely over before it even really started

[pasnownut]

1 hour ago, yoda said:

There would be CAD in that set up... not saying we would get all wintry -- there would def be a chance at some before the changeover to rain.  Besides, its the only real chance till at least the 27th

verbatim on GFS

 

31 minutes ago, Ji said:

way too far N and E of us to give us CAD. Anyway..it dosent matter. The Jan 27-30 threat period is most likely over before it even really started

yeah, that HP is on the move and about 500 miles from where you'd want it.  Nothing upstream to hold it.  wash rinse repeat until tellies start realigning, and I'm hoping a week from now, we are tracking again.  

[psuhoffman]

The chances before feb have diminished somewhat from the look a few days ago. It was always going to be a long shot but there is more consensus that every wave will likely track north. That doesn't mean we don't get a well times surprise like Wes outlined but short that we probably are waiting until feb.  I would keep an eye on that discreet wave following the cutter next week. The vort has a decent pass and it's cold but right now dry. But there are a few runs in the ensembles that pop a weak to moderate event there. That's the kind of thing that could work. Weak system following a cutter that pulls a cold front down in front. 

My thoughts in February are still the same. Look I know it's long range. But like bob pointed out the guidance is actually doing well this year identifying the major pattern changes. Just because it didn't snow a lot doesn't mean they were wrong. Go back to early December and we were worried the pattern looked cold but dry. Then there was a 48-72 hour period where they trolled us with a false stj signal. That was a huge bust yes. But just one blip. Otherwise the guidance has nailed the general patterns well from range. Pattern and snow in my yard are 2 different things. 

Furthermore the fact is all of the objective evidence right now is good that things flip towards a better pattern sometime in early to mid February.  And it's not just model based.  There are some common sense projections regarding the typical timing of the mjo wave propagating through bad phases in the pacifIc.  Once that fades or moves into favorable regions again there is no reason to think the hostile pattern will continue. There is a good chance the previous base state reestablishes. So while it's way out and low confidence I see nothing that suggests we shouldn't be hopeful. 

Finally, a few years ago we had a thread with numbers regarding "evidence of a total fail year". It was true that going into February with a virtual shutout increases the chances of it being a crap year. However, even those analogs had a few notable late saves but 80% of the time if we enter feb with barely any snow were looking at an epic fail year.  Some of that is circular thinking since to get a total crap year we have to not have had snow before feb either but the numbers are what they are.

But the numbers in years where our snowfall is just mediocre going into feb isn't nearly as dire. A very high percentage of those years featured st least one good snowfall after feb 1. And a few had epic finishes. The last time this data was pulled out was 2015 and it served true. 

Expectations should be realistic. We're in a Nina. It's unlikely we go on some epic tear and finish with crazy snow totals. This very likely isn't one of those 2-3 years a decade that happens. But what I'm talking about is getting 2-4 more snowfalls and one of them a respectable event (say 4-8"). If we do that and can get the typical low spots like DCA out of single digits and get the better spots close to 20 that should be a win. I still think that is a possibility. 

[frd]

3 minutes ago, psuhoffman said:

The chances before feb have diminished somewhat from the look a few days ago. It was always going to be a long shot but there is more consensus that every wave will likely track north. That doesn't mean we don't get a well times surprise like Wes outlined but short that we probably are waiting until feb.  I would keep an eye on that discreet wave following the cutter next week. The vort has a decent pass and it's cold but right now dry. But there are a few runs in the ensembles that pop a weak to moderate event there. That's the kind of thing that could work. Weak system following a cutter that pulls a cold front down in front. 

My thoughts in February are still the same. Look I know it's long range. But like bob pointed out the guidance is actually doing well this year identifying the major pattern changes. Just because it didn't snow a lot doesn't mean they were wrong. Go back to early December and we were worried the pattern looked cold but dry. Then there was a 48-72 hour period where they trolled us with a false stj signal. That was a huge bust yes. But just one blip. Otherwise the guidance has nailed the general patterns well from range. Pattern and snow in my yard are 2 different things. 

Furthermore the fact is all of the objective evidence right now is good that things flip towards a better pattern sometime in early to mid February.  And it's not just model based.  There are some common sense projections regarding the typical timing of the mjo wave propagating through bad phases in the pacifIc.  Once that fades or moves into favorable regions again there is no reason to think the hostile pattern will continue. There is a good chance the previous base state reestablishes. So while it's way out and low confidence I see nothing that suggests we shouldn't be hopeful. 

Finally, a few years ago we had a thread with numbers regarding "evidence of a total fail year". It was true that going into February with a virtual shutout increases the chances of it being a crap year. However, even those analogs had a few notable late saves but 80% of the time if we enter feb with barely any snow were looking at an epic fail year.  Some of that is circular thinking since to get a total crap year we have to not have had snow before feb either but the numbers are what they are.

But the numbers in years where our snowfall is just mediocre going into feb isn't nearly as dire. A very high percentage of those years featured st least one good snowfall after feb 1. And a few had epic finishes. The last time this data was pulled out was 2015 and it served true. 

Expectations should be realistic. We're in a Nina. It's unlikely we go on some epic tear and finish with crazy snow totals. This very likely isn't one of those 2-3 years a decade that happens. But what I'm talking about is getting 2-4 more snowfalls and one of them a respectable event (say 4-8"). If we do that and can get the typical low spots like DCA out of single digits and get the better spots close to 20 that should be a win. I still think that is a possibility. 

Very true,  as what the GFS had as a late month cold / snow event has morphed into what makes more sense based on the the lack of the  negative EPO and PNA help.

   

 

 

[psuhoffman]

Since it's a slow period I wanted to talk about ensemble snow means. They aren't a good tool for diagnosing a pattern. But that doesn't mean they are totally useless. They are useless if you don't know how to look at them though. But do keep in mind glancing at snow plots on the ensembles is like watching the 5 min highlights. You aren't going to get the full picture unless you watch the coaches tape and that would be analyzing the h5 pattern and understanding what those anomalies, trends, and spread suggest. 

But I'll admit sometimes I have only a min and will glance at the snow mean just to get the highlight reel peek before doing real analysis when I have time. So if your going to look at those things how do you get something meaningful. 

First the mean isn't as important as how you get to it. A mean of 5" doesn't mean the GEFS thinks 5" is the most likely outcome. If the mean is 5" because of several crazy high 12"+ outliers but 60% of the members have 0-2" that means the most likely outcome is 0-2" but that the pattern holds the potential of a bigger hit if we get lucky. But honestly 90% of the time that's not going to happen. Seeing several big hits isn't meaningless, it does signify the potential exists within the pattern.  But the spread is just as important as the mean. 

You also have to know the bias of the data. The gefs on wxbell has a faulty algorithm that counts ice and marginal situations as snow. It's way too liberal. So a 4" mean on the gefs is roughly equivalent to a 2" mean on the EPS. And the gefs can have a false signal like mid dec last year when it was showing a drool worthy look but almost all the snow was really freezing rain. 

A lot of low probability threats over 15 days can also be a false signal. Just looking at the plots might show almost all of them with snow but if that's because of 3 threats where each only has a 1/3 hit rate the odds of actually getting a hit are way lower then just looking at the plots makes it appear. 

One last thing, a mean of about 1-3" is a generic base state for a blah pattern in winter. It means our chances are low but not totally impossible. A true shutout pattern like dec 2015 and 2016 will feature run after run of below 1" snow mean. But getting a 2" mean because a few outliers had fluke snow isn't an indication we're likely to get 2" in the next 2 weeks. It doesn't work that way. 

So those snow maps are still not even close to the best way to analyze long range patterns but if your going to look at them know what your really looking at and how probabilities and spread works and at least they can have some limited value. 

[Climate175]

[Scraff]

Hmmmmm...

[North Balti Zen]

34 minutes ago, psuhoffman said:

Since it's a slow period I wanted to talk about ensemble snow means. They aren't a good tool for diagnosing a pattern. But that doesn't mean they are totally useless. They are useless if you don't know how to look at them though. But do keep in mind glancing at snow plots on the ensembles is like watching the 5 min highlights. You aren't going to get the full picture unless you watch the coaches tape and that would be analyzing the h5 pattern and understanding what those anomalies, trends, and spread suggest. 

But I'll admit sometimes I have only a min and will glance at the snow mean just to get the highlight reel peek before doing real analysis when I have time. So if your going to look at those things how do you get something meaningful. 

First the mean isn't as important as how you get to it. A mean of 5" doesn't mean the GEFS thinks 5" is the most likely outcome. If the mean is 5" because of several crazy high 12"+ outliers but 60% of the members have 0-2" that means the most likely outcome is 0-2" but that the pattern holds the potential of a bigger hit if we get lucky. But honestly 90% of the time that's not going to happen. Seeing several big hits isn't meaningless, it does signify the potential exists within the pattern.  But the spread is just as important as the mean. 

You also have to know the bias of the data. The gefs on wxbell has a faulty algorithm that counts ice and marginal situations as snow. It's way too liberal. So a 4" mean on the gefs is roughly equivalent to a 2" mean on the EPS. And the gefs can have a false signal like mid dec last year when it was showing a drool worthy look but almost all the snow was really freezing rain. 

A lot of low probability threats over 15 days can also be a false signal. Just looking at the plots might show almost all of them with snow but if that's because of 3 threats where each only has a 1/3 hit rate the odds of actually getting a hit are way lower then just looking at the plots makes it appear. 

One last thing, a mean of about 1-3" is a generic base state for a blah pattern in winter. It means our chances are low but not totally impossible. A true shutout pattern like dec 2015 and 2016 will feature run after run of below 1" snow mean. But getting a 2" mean because a few outliers had fluke snow isn't an indication we're likely to get 2" in the next 2 weeks. It doesn't work that way. 

So those snow maps are still not even close to the best way to analyze long range patterns but if your going to look at them know what your really looking at and how probabilities and spread works and at least they can have some limited value. 

Certain posts I wish could be collected in a thread and pinned/saved for all time. This is one of them. Thanks for the overview, PSU.

[psuhoffman]

12 minutes ago, Scraff said:

Hmmmmm...

That's what I was referring to earlier. I'm not as sure as he seems to be but the general setup is there for it to become a threat. That's probably the only game in town the next 2 weeks. 

[Bob Chill]

26 minutes ago, psuhoffman said:

That's what I was referring to earlier. I'm not as sure as he seems to be but the general setup is there for it to become a threat. That's probably the only game in town the next 2 weeks. 

Euro has a shallow shortwave that pops a weak fish storm off the nc coast d9-10 after the rain storm. Ens don't like the idea at all though. I think we're pretty close to a shutout pattern until Feb. Not lights out but awful close for a while unless the trailer works out late next week. 

[BTRWx's Thanks Giving]

33 minutes ago, psuhoffman said:

That's what I was referring to earlier. I'm not as sure as he seems to be but the general setup is there for it to become a threat. That's probably the only game in town the next 2 weeks. 

Don't forget where he resides.

[Scraff]

21 minutes ago, Bob Chill said:

Euro has a shallow shortwave that pops a weak fish storm off the nc coast d9-10 after the rain storm. Ens don't like the idea at all though. I think we're pretty close to a shutout pattern until Feb. Not lights out but awful close for a while unless the trailer works out late next week. 

We have kind of done weird this winter, so nothing would surprise me if that trailer rolled through town bringing more treats for the kids.