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Snowy Hibbo

Long Range Pattern Drivers & Evolution Thread

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This is a percent of average, first flake to last. For example, in Atlantic City the average is about 15 inches of snow per year, so the forecast for 125% of that would be a bit over 18 inches. There is an area of 150% from the Ohio Valley into the Great Lakes. Pittsburgh's average of 40 inches, so it says they should get about 60. You can see a large area of above normal, and it's tricky because if this works out to its full potential, there could be more over the East Coast. Also, the southern Rockies is a place where more may have to be forecasted, but for now I am relying on a drier idea to win out there.

The Verdict

The conditions in the oceans around the U.S. are ripe for major arctic outbreaks, but the early season, as has been the habit of late, is likely to start warm in the East. The worst-case scenario is a brutally cold old-fashioned winter. Precipitation should be plentiful again in the East given, the natural fight between the cold air to the west and the warm oceans to the east.

The West looks warm, though the Euro would argue that the Pioneer is onto something, sticking more cold into the southern Rockies. Buckle up, there is going to be plenty of cold around with January-March being colder against the normals in the East than December-February. If you start late with the winter, you are liable to end late.

Winter_2019_20_Snowfall.png

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11 hours ago, PB GFI said:

This is a percent of average, first flake to last. For example, in Atlantic City the average is about 15 inches of snow per year, so the forecast for 125% of that would be a bit over 18 inches. There is an area of 150% from the Ohio Valley into the Great Lakes. Pittsburgh's average of 40 inches, so it says they should get about 60. You can see a large area of above normal, and it's tricky because if this works out to its full potential, there could be more over the East Coast. Also, the southern Rockies is a place where more may have to be forecasted, but for now I am relying on a drier idea to win out there.

The Verdict

The conditions in the oceans around the U.S. are ripe for major arctic outbreaks, but the early season, as has been the habit of late, is likely to start warm in the East. The worst-case scenario is a brutally cold old-fashioned winter. Precipitation should be plentiful again in the East given, the natural fight between the cold air to the west and the warm oceans to the east.

The West looks warm, though the Euro would argue that the Pioneer is onto something, sticking more cold into the southern Rockies. Buckle up, there is going to be plenty of cold around with January-March being colder against the normals in the East than December-February. If you start late with the winter, you are liable to end late.

Winter_2019_20_Snowfall.png

So this relies on the warm seas around Alaska?

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15 minutes ago, PB GFI said:

 

I believe so man. 

I didn't see you post it explicitly, so just confirming this is Bastardi's early thoughts, right?

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12 minutes ago, 33andrain said:

I didn't see you post it explicitly, so just confirming this is Bastardi's early thoughts, right?

 

Yes sir. His, not mine. 

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10 minutes ago, Rtd208 said:

Just an FYI. DT (WxRisk) will have his early preliminary winter thoughts out this Sunday 9/8 for anyone who is interested.

Of course. Please post a link here when they're out.

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my early 2 cents worth of analogs if enso continues to cool are 1992-93, 1983-84 and 1966-67...a neg nao was lacking for the three years and the ao was mixed...even so NYC had two average winters and one great one...

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I know it's a bit soon, but the latest CANSIPS has below normal temps from October 2019 to March 2020 in the Eastern US. 

 

To add on, the Western US to Siberia is torched at the same time. 

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2 hours ago, Isotherm said:

The southern hemispheric stratospheric warming event, which @Snowy Hibbo has discussed heretofore, may have some non-specific implications globally. We are experiencing another episode of anomalous tropical stratospheric cooling, as a function of enhanced ozone transport [courtesy of the stronger BDC] which operates to decrease temperatures in the upper atmosphere tropically. The SSW occurred, but now the posthumous effects, pleiotropic in that it cools the SHEM sfc global temperatures, but contemporaneously increases tropical instability. The enhanced thermal stratification due to the diminution in upper atmospheric temperatures may result in a re-activation of the intraseasonal tropical signal, not too dissimilar from last winter. However, the z50 QBO reversal is a changed variable and could preclude a significant/anomalous reactivation. I will certainly continue to monitor these putative "posthumous" effects.

 

30mb2525.png

Thanks for the great information as always. I had some questions for you or anyone who feels comfortable answering them:

 Does the phase of the MJO during reactivation matter in terms of the mid/long term impacts (for example, a Phase 5 MJO activated by the decreased tropical strat temperatures vs a phase 8 MJO activated by decreased tropical strat temperatures)? If I remember right, that was one of the factors that influenced last winter, in that the SSW came at the wrong time and amped up the wrong phase of the MJO. If the activation is anomalous, it would be interesting to watch how that could impact ENSO going forward. 

 

I'm also wondering if the increased tropical instability applies to both hemispheres of the tropics, as when I googled the Brewer Dobson Circulation, it looks like there are two separate circulations for each hemisphere, so does a SSW in one hemisphere result in the North and South hemisphere circulations becoming stronger (resulting in increased tropical instability in both hemispheres) or does it primarily influence the winter hemisphere's tropical instability? In addition, how much of an impact might the increased tropical instability have on our 2019 hurricane season? Could it lead to faster development of tropical waves and depressions into tropical storms and hurricanes? Sorry for all the questions, it's just a really interesting topic that I'd like to know more about. I'm looking forward to your future updates, and thanks in advance to anyone who answers my questions. 

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2 hours ago, Isotherm said:

 

 

@Oglem. Good questions and I agree, it's a very interesting subject. Literature indicates that the MJO tends to amplify and slow-down significantly in octants 5-6-7 preceding/during a SSW, as wave driving is enhanced from trop-stat (last winter we also had some equatorial rossby wave interaction which slowed progression). A SSW occurring is an indicator that the BDC (Brewer Dobs. Circ) is more active than normal, and thus, the tropical stratosphere tends to cool. As the upper atmosphere increasingly cools, the vertical lapse rate increases. As you know, we often discuss the importance of lapse rates in the summer months re T-storm forecasting, because high lapse rates ---> more atmospheric instability via increased thermal stratification. The macro-scale effect is similar. 

 

It seems that once again, the MJO reactivation is / will occur in octants 5-6-7. Last winter, one of the issues was the SSW progression was painfully long [the whole month of January] , which kept the MJO more active, particularly in the unfavorable octants (5-6-7). 

 

And yes there are two circulations, the respective hemisphere's BDC active in the winter months. However, both circulations include the tropics, so the MJO/tropical activation would occur in either hemisphere's winter. The other point you broached is also true, which is the Atlantic hurricane season will probably experience a transient spike in activity later this month, courtesy of the SSW-->MJO-->Atlantic upward motion pathway. Not a given but I'd be willing to bet the tropics activate again in a couple of weeks.

 

With respect to winter effects, the upper atmosphere will warm well after the SSW effects diminish. Thus, this likely doesn't have significant relevance for the NHEM winter, although there may be pathways yet to be elucidated. The research is relatively nascent on this topic. Some question these hypothetical pathways [SSW/QBO/MJO], but the connections are fairly evident in the literature, and like everything in this field, it's a matter of piecing together exactly how and why these processes seem to occur. Nonetheless, correlational evidence is significant and offers strong clues that causation has a high likelihood of being present too.

 

As far as what I've read and discussed with colleagues, up until the 1990s or early 2000s. it was "common knowledge" that the Southern hemisphere had little to no affects on our weather up here.  

I always had a suspicion that this was incorrect, since the earth is a whole system.

Now research is finally being done in this area.

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What do we think of the latest CANSIPS? The August run seemed glitchy but was the first to show the switch to super Nina. There is SIGNIFICANT cooling that occurs within 30N and S through 8/2020. 

 

cansips_ssta_noice_global_12.png

 

The CANSIPS shows thoroughly below normal temps for most of the East Coast with a large cold pool developing off the coast in March and April in tandem with residual extreme warmth in much of the NPAC and NATL.

 

cansips_ssta_noice_global_7.png

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2 hours ago, dmillz25 said:

After the debacle of last winter I’ll be happy to get to avg

 

Last winter wasn't all that far from average really.

What made it feel worse, I think, were two things.

First, nearly all long range forecasters, myself included, thought it was going to be very snowy.

And secondly, most of our snow, fell outside of the heart of winter.

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3 minutes ago, Analog96 said:

 

Last winter wasn't all that far from average really.

What made it feel worse, I think, were two things.

First, nearly all long range forecasters, myself included, thought it was going to be very snowy.

And secondly, most of our snow, fell outside of the heart of winter.

Finished with 23.6 in dunellen about 4” short of average. And yes got 6.2” in November and 12.4” in March 

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1 minute ago, swamplover56 said:

Finished with 23.6 in dunellen about 4” short of average. And yes got 6.2” in November and 12.4” in March 

 

Hence my post.  In 2012, 2008, 2002, 1998, 1999, we would have happily signed up for last winter.

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