Winter 2017-18 Disco

[Bob Chill]

I'm not really that big on analogs anymore to be honest. I think enso climo in general will tell us most of what we need to know. As we move forward in time, analogs from the 50s-70s become less useful because average heights have trended higher around the entire planet during the last 30 years. Because of this, even the same general height patterns in the 50s-70s are less likely to produce the same results if they happen today. Not implying that the same pattern will be wildly different wx wise or anything. Just that the climate isn't static and we have gone through some fairly rapid changes around the globe the last 30 years compared to the last hundred years before that. This is probably more apparent in the SE and MA and not as much the further you go north. "Slightly warmer versions" of identical patterns can substantially affect what is most important to us....snowfall. The SE probably agrees with my thoughts as well. 

Another thing that makes analogs tricky is the short window. We spend a lot of time discussing and analyzing a short 12-14 week window. Analogs are good for generalizations but chaos and timing differences embedded in similar patterns often don't produce similar results. For example, if 2 winters have the same general pattern progressions but the timing is different by as little as 2-3 weeks, it can make a big difference. So much so that even if the patterns evolved in similar fashions, the personality (or memory) of the 2 winters could be very different. In our area a cold and wet last 2 weeks of Nov is usually very different than cold and wet first 2 weeks of Dec. Same thing happens at the end of met winter as we move through the end of Feb into early March. 

Most seasonal forecasts use probabilistic forecasting for a good reason. Now that enso has come into focus and long range models actually have decent skill, it's kinda easy to make a general probabilistic outlook right now. Chances of below normal snowfall is higher than above normal. Temps are probably equal chances with hedge towards above normal. Of all the factors (temps, snow, precip) I think precip has the highest chance at being below normal compared to the other factors.  I probably won't change my mind on this until if/when something makes me do it in Dec. 

 

[BTRWx]

27 minutes ago, Bob Chill said:

I'm not really that big on analogs anymore to be honest. I think enso climo in general will tell us most of what we need to know. As we move forward in time, analogs from the 50s-70s become less useful because average heights have trended higher around the entire planet during the last 30 years. Because of this, even the same general height patterns in the 50s-70s are less likely to produce the same results if they happen today. Not implying that the same pattern will be wildly different wx wise or anything. Just that the climate isn't static and we have gone through some fairly rapid changes around the globe the last 30 years compared to the last hundred years before that. This is probably more apparent in the SE and MA and not as much the further you go north. "Slightly warmer versions" of identical patterns can substantially affect what is most important to us....snowfall. The SE probably agrees with my thoughts as well. 

Another thing that makes analogs tricky is the short window. We spend a lot of time discussing and analyzing a short 12-14 week window. Analogs are good for generalizations but chaos and timing differences embedded in similar patterns often don't produce similar results. For example, if 2 winters have the same general pattern progressions but the timing is different by as little as 2-3 weeks, it can make a big difference. So much so that even if the patterns evolved in similar fashions, the personality (or memory) of the 2 winters could be very different. In our area a cold and wet last 2 weeks of Nov is usually very different than cold and wet first 2 weeks of Dec. Same thing happens at the end of met winter as we move through the end of Feb into early March. 

Most seasonal forecasts use probabilistic forecasting for a good reason. Now that enso has come into focus and long range models actually have decent skill, it's kinda easy to make a general probabilistic outlook right now. Chances of below normal snowfall is higher than above normal. Temps are probably equal chances with hedge towards above normal. Of all the factors (temps, snow, precip) I think precip has the highest chance at being below normal compared to the other factors.  I probably won't change my mind on this until if/when something makes me do it in Dec. 

 

It doesn't mean those of us who want to use analogs shouldn't.

[showmethesnow]

25 minutes ago, Bob Chill said:

I'm not really that big on analogs anymore to be honest. I think enso climo in general will tell us most of what we need to know. As we move forward in time, analogs from the 50s-70s become less useful because average heights have trended higher around the entire planet during the last 30 years. Because of this, even the same general height patterns in the 50s-70s are less likely to produce the same results if they happen today. Not implying that the same pattern will be wildly different wx wise or anything. Just that the climate isn't static and we have gone through some fairly rapid changes around the globe the last 30 years compared to the last hundred years before that. This is probably more apparent in the SE and MA and not as much the further you go north. "Slightly warmer versions" of identical patterns can substantially affect what is most important to us....snowfall. The SE probably agrees with my thoughts as well. 

Another thing that makes analogs tricky is the short window. We spend a lot of time discussing and analyzing a short 12-14 week window. Analogs are good for generalizations but chaos and timing differences embedded in similar patterns often don't produce similar results. For example, if 2 winters have the same general pattern progressions but the timing is different by as little as 2-3 weeks, it can make a big difference. So much so that even if the patterns evolved in similar fashions, the personality (or memory) of the 2 winters could be very different. In our area a cold and wet last 2 weeks of Nov is usually very different than cold and wet first 2 weeks of Dec. Same thing happens at the end of met winter as we move through the end of Feb into early March. 

Most seasonal forecasts use probabilistic forecasting for a good reason. Now that enso has come into focus and long range models actually have decent skill, it's kinda easy to make a general probabilistic outlook right now. Chances of below normal snowfall is higher than above normal. Temps are probably equal chances with hedge towards above normal. Of all the factors (temps, snow, precip) I think precip has the highest chance at being below normal compared to the other factors.  I probably won't change my mind on this until if/when something makes me do it in Dec. 

 

Considering our region is almost always on the fine line between no snow, little snow and lots of snow also factors in. So though two years may match up exceptionally well and the pattern evolves similarly, just a 50 mile difference can mean a world of difference. That's why I take historical snowfall totals within our region with a grain of salt. I would much rather see a map of the east coast snowfall for the year to get an idea if we were at least in the game or whether we were sucking wind.

[mitchnick]

Let me wrap up any sane winter forecast for this area this year as follows: If we fail to get sufficient blocking, we're screwed....period. If we get sufficient blocking to get us in the game, we're gunna still need a lot of luck, and we won't know how or what kind of luck until each event shows itself.

Everyone back to work now.

 

p.s. that forecast probably applies to any seasonal winter forecast around here, but NINA's all the time

[BTRWx]

4 minutes ago, mitchnick said:

Let me wrap up any sane winter forecast for this area this year as follows: If we fail to get sufficient blocking, we're screwed....period. If we get sufficient blocking to get us in the game, we're gunna still need a lot of luck, and we won't know how or what kind of luck until each event shows itself.

Everyone back to work now.

 

p.s. that forecast probably applies to any seasonal winter forecast around here, but NINA's all the time

That's where analog years can come in handy imo.  Forecasting the exact timing of blocking to develop is nearly impossible, but analogs can give hints at whether we should anticipate blocking to develop in the longer range.

[showmethesnow]

7 minutes ago, mitchnick said:

Let me wrap up any sane winter forecast for this area this year as follows: If we fail to get sufficient blocking, we're screwed....period. If we get sufficient blocking to get us in the game, we're gunna still need a lot of luck, and we won't know how or what kind of luck until each event shows itself.

Everyone back to work now.

 

p.s. that forecast probably applies to any seasonal winter forecast around here, but NINA's all the time

Want to add one thing here about the blocking. Many years we can still score with an east based -NAO but I don't believe that will be the case here. IMO we will need to see a west based -NAO as well as possibly blocking over top to have a chance. Otherwise the cold shots coming into the west/plains will pull back into Canada before they reach the east coast. We need that blocking mechanism to keep that cold trapped underneath as it progresses eastward.

[Bob Chill]

^95-96 was Pac driven. Give me a massive aleutian low/trough and +PNA and I won't worry nearly as much about blocking. 

[mitchnick]

57 minutes ago, Bob Chill said:

^95-96 was Pac driven. Give me a massive aleutian low/trough and +PNA and I won't worry nearly as much about blocking. 

I'll have to disagree with you there Bob. NAO was negative most of the winter, working in tandem with the Pacific. The 2 together were a perfect match for us.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/month_nao_index.shtml

[mitchnick]

Personally,  I think I prefer a decent -AO to a -NAO given the choice, but will obviously take what I can get. Most of oir historic storms came with a strong - AO if memory serves me. 

[ORH_wxman]

2 hours ago, Bob Chill said:

I'm not really that big on analogs anymore to be honest. I think enso climo in general will tell us most of what we need to know. As we move forward in time, analogs from the 50s-70s become less useful because average heights have trended higher around the entire planet during the last 30 years. Because of this, even the same general height patterns in the 50s-70s are less likely to produce the same results if they happen today. Not implying that the same pattern will be wildly different wx wise or anything. Just that the climate isn't static and we have gone through some fairly rapid changes around the globe the last 30 years compared to the last hundred years before that. This is probably more apparent in the SE and MA and not as much the further you go north. "Slightly warmer versions" of identical patterns can substantially affect what is most important to us....snowfall. The SE probably agrees with my thoughts as well. 

Another thing that makes analogs tricky is the short window. We spend a lot of time discussing and analyzing a short 12-14 week window. Analogs are good for generalizations but chaos and timing differences embedded in similar patterns often don't produce similar results. For example, if 2 winters have the same general pattern progressions but the timing is different by as little as 2-3 weeks, it can make a big difference. So much so that even if the patterns evolved in similar fashions, the personality (or memory) of the 2 winters could be very different. In our area a cold and wet last 2 weeks of Nov is usually very different than cold and wet first 2 weeks of Dec. Same thing happens at the end of met winter as we move through the end of Feb into early March. 

Most seasonal forecasts use probabilistic forecasting for a good reason. Now that enso has come into focus and long range models actually have decent skill, it's kinda easy to make a general probabilistic outlook right now. Chances of below normal snowfall is higher than above normal. Temps are probably equal chances with hedge towards above normal. Of all the factors (temps, snow, precip) I think precip has the highest chance at being below normal compared to the other factors.  I probably won't change my mind on this until if/when something makes me do it in Dec. 

 

You definitely have to be careful looking at the just the heights nowadays....you can have a lot of above normal heights in the arctic but it doesn't necessarily mean blocking...it just means the arctic is warm. Often that means there's blocking, but there's plenty of instances (esp in the post-2005 world) where the high heights up there are just a result of warm temps up through the column...a similar pattern in the 1970s would produce no "blocking".

[Bob Chill]

35 minutes ago, ORH_wxman said:

You definitely have to be careful looking at the just the heights nowadays....you can have a lot of above normal heights in the arctic but it doesn't necessarily mean blocking...it just means the arctic is warm. Often that means there's blocking, but there's plenty of instances (esp in the post-2005 world) where the high heights up there are just a result of warm temps up through the column...a similar pattern in the 1970s would produce no "blocking".

Thanks for this. After seeing countless h5 plots from old years and experiencing different results it started making sense. I think it was either you or coastal who has posted this stuff in more detail over the years. One of mistakes weenies (like myself) make is just looking at height panels and skipping MSLP panels. IIRC, numerical AO/NAO calculations are at the 1000mb level right? So surface panels are a better representation although h5 panels can be much easier to identify HL blocking with. I look at both now and it makes a difference. 

[CAPE]

Since it is Friday happy hour, the latest offering of the ever changing CFSv2 looks pretty decent for Dec and Jan.

[BTRWx]

1 hour ago, ORH_wxman said:

You definitely have to be careful looking at the just the heights nowadays....you can have a lot of above normal heights in the arctic but it doesn't necessarily mean blocking...it just means the arctic is warm. Often that means there's blocking, but there's plenty of instances (esp in the post-2005 world) where the high heights up there are just a result of warm temps up through the column...a similar pattern in the 1970s would produce no "blocking".

I definitely would like to see an example please.

[uncle W]

1 hour ago, mitchnick said:

Personally,  I think I prefer a decent -AO to a -NAO given the choice, but will obviously take what I can get. Most of oir historic storms came with a strong - AO if memory serves me. 

the ao was very negative in December 1995...

[showmethesnow]

1 hour ago, BTRWx said:

I think we want to see the opposite.

eta: As a general rule, what showmethesnow said is true.  But the data I keep seeing for nina years looks different.  1962-1963 with the East-based -NAO was a weak nina year.  1965-1966 with the west-based -NAO was a strong nino year.  Amazingly, both years were good winters for us, but the nina snow was mostly in December and the nino snow was mostly in January. wow!

 

1962-63 was actually a cold neutral not a Nina and it also featured a +PNA for the winter (D-J). With a +PNA in place you will see ridging in the west and troughing in the east thus you have a mechanism already in place to get cold into the east. La Nina's typically feature a -PNA which features troughing in the west and ridging in the east. This setup typically sends the cold into the west and then withdraws it back into Canada before it can get into the east unless there is some sort of blocking in place. 

Looking over the other years most of the better snow years actually featured a cold neutral (-.5 value or less) not a La Nina so would not be surprised if they also featured a +PNA as well.

1967-68 is actually a good example of what I am referring to and it also featured one of the better snowfall tallies for a -enso/-pdo combo with 25 inches. Though we have a -PNA we also see blocking that extends over top of us and to the west. And the temps respond accordingly.

So even though there are always exceptions to the rule I still believe that our chances with an east based -NAO are much slimmer then a typical year unless there is other blocking working in tandem with it to the west to drive the cold into our region. We might still get the noreaster's with an E based Nao but without the cold we are talking galoshes instead of snow boots.

 

 

 

 

[BristowWx]

14 minutes ago, showmethesnow said:

1962-63 was actually a cold neutral not a Nina and it also featured a +PNA for the winter (D-J). With a +PNA in place you will see ridging in the west and troughing in the east thus you have a mechanism already in place to get cold into the east. La Nina's typically feature a -PNA which features troughing in the west and ridging in the east. This setup typically sends the cold into the west and then withdraws it back into Canada before it can get into the east unless there is some sort of blocking in place. 

Looking over the other years most of the better snow years actually featured a cold neutral (-.5 value or less) not a La Nina so would not be surprised if they also featured a +PNA as well.

1967-68 is actually a good example of what I am referring to and it also featured one of the better snowfall tallies for a -enso/-pdo combo with 25 inches. Though we have a -PNA we also see blocking that extends over top of us and to the west. And the temps respond accordingly.

So even though there are always exceptions to the rule I still believe that our chances with an east based -NAO are much slimmer then a typical year unless there is other blocking working in tandem with it to the west to drive the cold into our region. We might still get the noreaster's with an E based Nao but without the cold we are talking galoshes instead of snow boots.

 

 

 

 

And we haven't even talked about the pig SER yet...another dominant player in our weather it seems in winter..actually always.  There are so many ways you cannot have snow here.  I believe that was an ever present feature last year.  

[showmethesnow]

32 minutes ago, BristowWx said:

And we haven't even talked about the pig SER yet...another dominant player in our weather it seems in winter..actually always.  There are so many ways you cannot have snow here.  I believe that was an ever present feature last year.  

With what looks to be a Nina incoming I am sure we will have plenty of time to talk about the SER (SE Ridging) this winter. 

Lets just cross our fingers that we get the blocking to help beat that down.

[WinterWxLuvr]

If we can top these (as sh*t winters) I'll be amazed. Put me in the camp of there's no way in hell.

First up, 15-16.  Not even a single event until Jan 22, and a whopping 4.25" for the remainder of the winter after the one hit wonder.

Then we have 16-17. A wonderful 1/2" in December, a remarkably heavy (in context of the past 2 winters) 2 5/8" in January, a wonderful 0" in Feb leading up to a who gives a sh*t March storm.

I'll take my chances without worrying about any of the indices or past analogs.

[showmethesnow]

20 hours ago, ORH_wxman said:

I would weight them less. I wouldn't say ignore them completely though. Especially during periods when we are locked into a strong -PDO. They are def decent analogs for a -PDO/-NAO winter...kind of like what we saw in 2010-2011 or to a lesser extent 2008-2009. The Agung eruption really influenced the 1963-1965 period though IMHO so i think t is good to keep that in mind. Prob similar to being careful with 1992-1994 after pinatubo. 

 

20 hours ago, WVclimo said:

Mt Agung is poised to possibly erupt again:

http://www.abc.net.au/news/2017-09-22/mt-agung-bali-volcanoo-hundreds-evacuated-amid-eruption-fears/8976224

Warning level has been raised to level 4 'Eruption imminent'. Officials feel that an eruption could occur as soon as Sunday as smoke was seen rising off the volcano Friday night. 

http://www.smh.com.au/world/bali-volcano-australians-warned-to-check-travel-plans-as-240000-residents-evacuate-20170922-gynb00.html

[ORH_wxman]

14 hours ago, showmethesnow said:

 

Warning level has been raised to level 4 'Eruption imminent'. Officials feel that an eruption could occur as soon as Sunday as smoke was seen rising off the volcano Friday night. 

http://www.smh.com.au/world/bali-volcano-australians-warned-to-check-travel-plans-as-240000-residents-evacuate-20170922-gynb00.html

If it is as strong (or stronger) as the 1963 eruption, that would be a huge deal. It would affect the climate for at least a year or two.

[BTRWx]

39 minutes ago, ORH_wxman said:

If it is as strong (or stronger) as the 1963 eruption, that would be a huge deal. It would affect the climate for at least a year or two.

Know of any open access journal reports from the 1963 eruption?

[Maestrobjwa]

53 minutes ago, ORH_wxman said:

If it is as strong (or stronger) as the 1963 eruption, that would be a huge deal. It would affect the climate for at least a year or two.

I just kinda poked my head in here and was perplexed to see talk about eruptions, lol So what's this about that eruption influencing climate??

[showmethesnow]

5 hours ago, Maestrobjwa said:

I just kinda poked my head in here and was perplexed to see talk about eruptions, lol So what's this about that eruption influencing climate??

Wouldn't that be something? Here we are worrying about La Nina and how it will affect the winter and lo and behold we get a volcanic eruption that turns everything on its head. Guess we wait and watch to see how strong and what type of an eruption we do get. 

[ORH_wxman]

8 hours ago, Maestrobjwa said:

I just kinda poked my head in here and was perplexed to see talk about eruptions, lol So what's this about that eruption influencing climate??

Agung is a tropical volcano which last erupted in 1963. That eruption was a VEI 5...so not as strong as Pinatubo but still strong enough to have a noticeable impact on the climate. The tropical volcanoes have a disproportionate influence as their stratospheric aerosols spread more efficiently. 

If it erupts again but is something weaker than a VEI 5, then the impact would likely be fairly minimal. But it bears close watching because Agung has a history of explosive eruptions...it is believed to have last erupted in the 1820s quite explosively before the 1963 event occurred. 

[Isotherm]

2 hours ago, ORH_wxman said:

Agung is a tropical volcano which last erupted in 1963. That eruption was a VEI 5...so not as strong as Pinatubo but still strong enough to have a noticeable impact on the climate. The tropical volcanoes have a disproportionate influence as their stratospheric aerosols spread more efficiently. 

If it erupts again but is something weaker than a VEI 5, then the impact would likely be fairly minimal. But it bears close watching because Agung has a history of explosive eruptions...it is believed to have last erupted in the 1820s quite explosively before the 1963 event occurred. 

 

For reference:

[Maestrobjwa]

8 hours ago, ORH_wxman said:

Agung is a tropical volcano which last erupted in 1963. That eruption was a VEI 5...so not as strong as Pinatubo but still strong enough to have a noticeable impact on the climate. The tropical volcanoes have a disproportionate influence as their stratospheric aerosols spread more efficiently. 

If it erupts again but is something weaker than a VEI 5, then the impact would likely be fairly minimal. But it bears close watching because Agung has a history of explosive eruptions...it is believed to have last erupted in the 1820s quite explosively before the 1963 event occurred. 

Interesting...So, could you explain a little more about how exactly that affects the climate?

[snowman19]

12 hours ago, showmethesnow said:

Wouldn't that be something? Here we are worrying about La Nina and how it will affect the winter and lo and behold we get a volcanic eruption that turns everything on its head. Guess we wait and watch to see how strong and what type of an eruption we do get. 

Apparently the latest is that the experts are now saying this eruption is unlikely to reach or exceed the 1963 eruption 

[WVclimo]

The 1963 event was in the top 10% of all volcanic eruptions in the past 10,000 years.  Probably not likely to match that.

[Isotherm]

48 minutes ago, snowman19 said:

Apparently the latest is that the experts are now saying this eruption is unlikely to reach or exceed the 1963 eruption 

 

Can you post your source? I performed a cursory internet search and couldn't find that anywhere. Not sure if accurate predictions are truly possible either.

[showmethesnow]

42 minutes ago, Isotherm said:

 

Can you post your source? I performed a cursory internet search and couldn't find that anywhere. Not sure if accurate predictions are truly possible either.

I couldn't find anything either so it isn't just you.