2022 2023 winter outlook for the Northeast part two

 

Welcome to part two of my 2022-2023 winter outlook. Part, one went into this seasons triple dip La Nina, a few teleconnections, and the Hunga Tonga Volcanic eruption. Part one, showed how both of those are arguing for a colder than average winter for a large part of the Northeast.  Part two will go into the Pacific Decadal Oscillation, the Eastern Pacific Oscillation, the Quasi Biennial Oscillation, and the Pacific North American Pattern, and how they detract or enhance the atmospheric effect of the La Nina and Volcanic eruption. Part two will go into possible storm tracks we should see this winter. As well as some thoughts on the Polar Vortex. I will also go more into analogue winters and make some adjustment from part one.

 2022-2023 winter outlook part one

Teleconnections:

 

Pacific Decadal Oscillation (PDO):

The PDO is a change in the Sea Surface Temperatures pattern in the North Pacific Ocean above 20-degree north latitude. Like all teleconnections the PDO has a positive (warm) phase and a negative (cool) phase. Generally during the positive phase, warmer SST exist along the Northwest Coast and West Coast of Canada. During the positive phase the wintertime temperatures tend to be warmer across the western CONUS and cooler in the eastern CONUS, during the negative phase the opposite is generally true. The Phases of the PDO can enhance or diminish the effects caused by the ENSO. So, when we have a negative PDO during a La Nina, it can increase the impacts on temperature and precipitation patterns typical of La Nina. The last two winters involved negative PDO’s.

When we look at the SST in the northern Pacific, we can see those warm SST off the West Coast south of Alaska. It seems the PDO is starting to turn positive.

 

The La Nina, PDO and the Hunga Tonga Hunga eruption will make this winter very distinctive:

As I said in part one, this winter is going to feature a triple dip weak to moderate East Based La Nina. The fact that we look to see a positive PDO during this coming winter, is a big deal. Every other triple dip La Nina had a negative PDO. So, therefor they enhanced the La Nina in those winters. So clearly as rare as these triple dip La Nina’s are, this one is going to be one of kind. Looking back at La Nina winters that had a positive PDO, we come up with 1908-1909, 1938-1939, 1984-1985, 1995-1996 and 2005-2006.

Only 95-96 featured a weak polar vortex and a strong very persistent negative phase of the AO and NAO. That winter was an extremely snowy winter. Due to how the pattern for the entire winter was perfect for winter storms. So that doesn’t mean this winter would end up the same. But, each one of these winters featured average to above average snowfall across our region.

Hunga Tonga Hunga volcano:

In part one I went into some detail on the Hunga Tonga Hunga eruption. But that volcanic eruption is so unique, that it forces me to talk more about it and the impacts it could bring for this winter.

Here are a couple of images that show the amount of Water Vapor from the eruption and its distribution across the globe. We can see that the amount of water vapor released is astonishing. We can also see that the vast majority of the stratospheric water vapor is confined to the Southern Hemisphere.  The amount and distribution are going to have a big say in this winter’s temperature and precipitation pattern. In fact, the eruption aftereffects are the main reason this hurricane season has acted the way it has.

 

It all comes down to balance, or in this case the lack of balance.

In part one I showed the stratospheric cooling at occurred in the Southern Hemisphere. When we go to see the stratospheric data from the CPC and look at the 30hPa layer of the Southern Stratosphere we can see that the current temperature (shown by the red line, is at a historically low level. It is well below the base line. The 50hPa layer shows the same kind of well below average cooling. All of this rapid cooling was a result of all that water vapor being sent into the Southern Hemisphere stratosphere causing the upper atmosphere to contract.  As a result of the upper atmospheric cooling the troposphere ended up warming due to the expansion of the lower atmosphere

But when we look at the stratospheric data for the Northern Hemisphere, we see the exact opposite, those 30hPa and 50hPa layer temperatures are above average.

The Subtropical Jet has been very active this year; which is very atypical for a La Nina year. This is one of the main reasons this year’s hurricane season turned out the way it did. The Northern Hemisphere atmospheric profile was a blend of La Nina and El Nino; which led to all that extra windshear over the tropical Atlantic due to the active subtropical jet. So that well above average hurricane season forecast, never had a chance to get going. This was all a result of the global atmospheric circulation trying to find balance. This is already affecting the polar vortex over the Arctic. In these images we can see while the Polar Vortex over the Antarctic is very strong and well defined. The Polar Vortex over the Arctic is very weak and very elongated.

North 

 

South

Source Earth Null School

As this pattern continues, the Subtropical jet is going to be much more active for the 2022-2023 winter than is typical of a La Nina winter.  With the Polar Jet being active and also having an active Subtropical Jet; there is going to be increased chances for phasing involving the Northern and Southern Jets. How this phasing comes about will be determined by these winters storm tracks.

 

Other important Teleconnections:

The Quasi Biennial Oscillation (QBO):

The QBO deals with the variation in wind flow in the lower stratosphere at the 30hPA layer above the equator. The QBO can influence weather patterns across the globe. This alternating belt of strong stratospheric wind completely changes direction right around every 14 months. So, the full cycle is roughly 28 months. When the winds are westerly (WQBO) the QBO is in its positive phase. So, when they blow in the easterly (EQBO) direction the QBO is in its negative phase.  The QBO has in influence on the strength of the jet stream, polar vortex and the likelihood of high latitude blocking.

During the positive phase winter temperatures across northern New York State into Northern New England are more likely to be colder than average, with the Mid Atlantic and New England likely to be drier than average. During the negative phase the cold shifts south a bit; so Central and Southern New York State, Southern New England, Pennsylvania, and the Middle Atlantic to be cooler than average. During the negative phase the entire Northeast and Northern Middle Atlantic tend to be drier than average.

Here is a look at the QBO composites

 

Source…Philly Weather Authority

Dec – Feb Temperature and Precipitation anomaly probability maps.

Westerly QBO

 

 

Source World Climate Service

Eastern QBO

 

 

Source World Climate Service

Last winter the QBO was negative; currently the QBO is in a positive phase. As of September, the index was at +9.80.

This year has seen the upper atmospheric winds fairly weak. Could this have something to do with the volcanic eruption back in January? Maybe. With this, it should lend some support for high latitude blocking and a decent chance for some stratospheric warming here in the Northern Hemisphere.

 

 

The Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO):

The AO is a northern hemisphere circulation pattern that influences the position of the northern jet stream. It also has some influence on the strength of the polar jet as well as the strength of the Polar Vortex.

During the positive phase the Northeast and Northern Mid Atlantic Region generally see warmer and more moderate winters. During a positive phase of the AO, the Polar Vortex is generally strong.

During the negative phase the Northeast and Northern Mid-Atlantic Region generally see more in the way of cold and stormy winters. During a negative phase of the AO, the Polar Vortex is generally weaker.

The NAO deals with the air pressure pattern between Greenland and the Azores. During the positive phase, the CONUS generally sees a Zonal west-east flow, which typically keeps the cold air bottled up in Canada; this is generally because we see little high latitude blocking during the positive phase of the NAO. 

During the negative phase, we generally see a lot of high latitude blocking over Greenland. The blocking forces the Jet stream to buckle, bringing cold air outbreaks into the Great Lakes and Northeast.

 

 

When we see an east based La Nina, typically we see a predominate negative AO and NAO.

 

 Pacific North American Pattern (PNA):

When the PNA is positive generally in Western Canada and the Western CONUS. it is warmer than average and the Eastern CONUS. is colder than average, there is also a tendency for the eastern CONUS to see below average precipitation as well. When it’s negative, we see the opposite occur more times than not. Currently the PNA is in a positive phase.

 

 

Courtesy of the NWS Climate Prediction Center

Given the overall setup, I favor the idea of the PNA being primarily positive this winter.  

 

Eastern Pacific Oscillation (EPO):

The EPO deals with the atmospheric flow pattern across the Eastern Pacific including Alaska. In other words, the EPO is about the placement of the trough around the Aleutians into the Gulf of Alaska. During a positive EPO the trough is located in the Central and Eastern Gulf of Alaska. As a result, we see strong Pacific jet pushing in a mild north Pacific air flow pattern into the Western CONUS, as this air flows over and down the Eastern slopes of the Rocky Mountains, it warms up and dries out. This typically results in warmer than average temperatures across the Central and Eastern CONUS. During a negative EPO the trough is centered in the Aleutians into the Western Gulf of Alaska. This results in a ridge over the Eastern Pacific off the West Coast. Because of the ridge, the western flow of that mild Pacific air is diverted up toward Alaska.  As Alaska warms, we see the cold Arctic air displaced and forced to move down the western ridge into the Central CONUS. Because of this the Plains and Great Lakes tend to be very cold, some of this cold migrates East into the Northeast and Northern Middle Atlantic.  So typically, our region tends to see colder overall temperatures during a negative EPO.

 

This winter the EPO is going to be the composer, controlling how all these factors mesh. Because the EPO has a major influence on storm tracks across North America.

 

Storm Tracks:

This winter’s storm tracks will be based on the idea of moderate East Based La Nina that will weaken as we get into Midwinter, this along with the pattern setup caused by a positive PDO that interacts with a primarily negative AO and negative NAO and the phase orientation of the EPO during the winter of 2022-2023. This will be enhanced by the results of the Hunga Tonga Volcanic eruption making for a very active subtropical jet, and the increased chances for higher latitude blocking over Greenland due to the QBO. The type of storm and precipitation type will be mainly determined by the phase of the EPO and NAO; these are variable and so we will see a range in outcomes.  

 

When the EPO is positive, the pattern would favor a general storm track into the Great Lakes.  A positive NAO would mean a lot of snow into the Western Great Lakes. We would expect mixing over the interior parts of the Northeast into the Eastern Great Lakes, with a quick change over to rain along the coast. If the NAO is negative, The Northeast would expect to see a substantial mixed precipitation type storm.

When the EPO is negative, the pattern would favor a general snowstorm in the Northeast and Middle Atlantic.  A positive NAO would mean a less chance for phasing between the northern and southern jets, with a general track farther from the coast, this would favor snow for interior New York State and Pennsylvania, leaving the Middle Atlantic and New England more likely a missing out on heavy snow. If the NAO is negative, The Northeast and Middle Atlantic would expect to see a substantial winter storm, due to the high likelihood of both jet streams phasing, with even the potential for a triple phase event. A triple phase storm is when we see the subtropical Jet, the Pacific Jet and the Polar Jet all phase. A true triple phase snowstorm is rare but when they occur, they end up as monster snowstorms.  The pattern this year is going to favor the chance for Miller A and Miller B nor’easters.

Types of winter storms link

Polar Vortex:

As I showed earlier the Polar Vortex has been very disrupted and fairly weak. Now while the Polar Vortex is strengthening as it should be at this time of year. But given the factors I went over; I don’t see the Polar Vortex becoming strong this winter. So it will be easier for the vortex to elongate and split.

 

Analogues:

1908-1909, 1938-1939, 1984-1985, 1990-1991, 1995-1996, 2005-2006, 2010-2011, 2013-2014.

These analogues are based on winters that had a positive PDO with an East based La Nina, had similar SST pattern, and a cool southern hemisphere.

Conclusion:

In part one I discussed how December and January look to be active and wintery. I still believe this to be the case. It is unclear how the end of February into March will act due to the weakening La Nina.

I believe the polar vortex will be weak and will have the potential to be disrupted several times.

The subtropical jet is going to stay active right through the winter, which is something we don’t typically see during a La Nina winter.  

 

Based on the analysis so far, I think this winter will end up colder overall than I indicated it would be in part one. The pattern is looking to be very active with the chance for several cold outbreaks. The pattern should produce several opportunities storm tracks near and offshore, with the idea of prevalent blocking over Greenland due to a general negative NAO, the chance for these storms phasing will be rather high. As for the Lower Great Lakes, this looks to be an active lake effect snow winter.  

Eastern Long Island along the Connecticut Coast into Rhode Island, look to see near average temperatures, and average snowfall.

For Maryland, the major Cities along the I-95 Corridor, Eastern Long Island, Southeastern Massachusetts including Boston will see average to slightly above average snowfall with overall temperatures ending up around average.

For much of the rest of the interior Pennsylvania, New York State and New England, generally below average overall temperatures with snowfall ending up above average.  This is looking to be a good Lake effect snow winter.  

 

Well, that’s it. I will be releasing part three end of November into the first week of December. Part three will cover the overall trend that has been occurring since part two was released, and will attempt to narrow things down a bit more.

 

 

 

 

 

The 2022 2023 Winter Outlook for the Northeast Part one.

 

Part one of the winter outlook will be largely based on analysis of Sea Surface Temperatures (particularly those in the equatorial Pacific), looking at possible analog years, snow extent across Siberia, and the possibility for high latitude blocking events and how that ties in with the Southern Hemisphere volcanic eruption in January of this year.

What is a seasonal outlook?

A seasonal outlook isn’t like short range and medium range forecast, trying to accurately forecast something like an entire winter season is a complicated process. At the start it looks at how temperature and precipitation are trending, using tools like satellites, radar, and automated surface observations. Then comparing a variety of atmospheric and oceanic factors as well as things like are snow cover and soil wetness; these are teleconnections and other indicators. Using these can give some insight into possible weather patterns that those factors could lead to. Then looking at computer output and looking at past years that had a similar look are taken into consideration. The closer the analogue pattern is to the current pattern, the more weight it is given. Then this information is compiled, then apply their experience and applying climatology for a given area and local geography, to try to come up with a general long-term weather average, of what is likely to occur over the next three to four months.

 

This is only October based on early analysis, there is time for things to change. So I expect to see some changes in the pattern, that could alter things enough to make me adjust what I’m seeing right now.

 

Okay let’s start the discussion, on what I think is going to happen.

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The El Nino and Southern Oscillation (ENSO):

The ENSO involves Sea Surface Temperature (SST) anomalies across the equatorial Pacific.  ENSO consist of a warm phase, a neutral phase, and a cool phase. La Nina is the colder phase, these various phases typically cycle every three to seven years. These changes disrupt wind, cloud, and pressure patterns over the Pacific, triggering temperature and precipitation changes across the planet.  

It’s important to remember that La Nina’s are not all the same. The region can see different outcomes depending on the placement of the La Nina, as well as if it is considered weak, moderate, or strong. Also, La Nina isn’t the only factor when it comes to the wintertime pattern.

La Nina is still here. So, we can expect it to be a major driver in this upcoming winter’s temperature and precipitation pattern. La Nina’s on average tend to be snowier than average across northern New York State and northern New England. Weak to moderate La Nina’s tend to be snowier over a large part of the Northeast. While strong La Nina’s tend to be much less snowy over southern New England into the Middle Atlantic. The La Nina should stay weak to moderate for this winter.

 

Looking at SST anomalies, we can see the La Nina stands out clearly in the equatorial eastern and central Pacific.  Chart of the ocean analysis shows those cold ocean anomalies in the tropical Pacific spans almost the entire length of the tropical Pacific. Looking more closely at the latest analysis of the ENSO regions below, you can see the strongest cold anomalies returning in the eastern region. Overall, La Nina looks in a healthy state.  The SST chart also shows the warm anomalies in the northern Pacific and northern Atlantic.

This seasons La Nina will be the triple dip La Nina.  This is only the fourth time we’ve seen a triple La Nina since records have been kept, the other winters that were the third in a row was 1955 – 1956, the next one was 1975 -1976, the other was 2000 -2001. Here is a timeline of La Nina events from 1900 to 2022.

Last winter there were several winter storms during January and February. There were also a couple of big coastal snowstorms. Those of Y’all who were in the right place , got a lot of snow out of these coastal storms, while others didn’t see much if anything at all. But the result was that many cities in the I-95 corridor ended up with average to above average snowfall.

 

IRI ENSO model predictions of ENSO, show that this seasons La Nina should extend at least through the heart of winter 2022 – 2023.

 

A large majority of the models in the plume predict SSTs to remain below-normal at the level of a La Nina until at least Dec-Feb 2023.

 

The latest equatorial T Penatd anomaly

Shows subsurface water temperatures in the Pacific are quite cold. This lends a lot of support to the staying power of our current La Nina conditions.

  

On the latest SOI analysis below, we can see persistent positive values with a strong recent burst. Such data further supports stronger trade winds and ocean cooling in the ENSO regions, sustaining and further cooling the La Nina towards Winter 2022/2023.

 

 

As is usually the case in a La Nina, the Southern Ridge will be an influence this winter. For now, I don’t think the southeast ridge will be as influential as it was last winter.

 

Analogue winters:

1955 -1956, 1975-1976, 2000-2001

This shows that 3rd year La Nina’s tend to be colder than average across the Northeast and Middle Atlantic, with northern New York State and northern New England being 2°F to 3°F below average.  As far as the precipitation anomalies Maryland, Delaware, southwestern Pennsylvania, and southern New Jersey tend to see slightly below average  wintertime precipitation, with the rest of the region seeing average to slightly above average wintertime precipitation.

Looking at the analogs for the individual months, third year La Ninas, tend to see winter start early, with both December and January quite cold, then for February and March temperatures warm a bit, so winter 2022 -2023 could end up front loaded.

When we look at years that saw similar Sea Surface Temperature patterns, we’re left with 2005,2013, 2014, 2020, and 2021.

Here are comparisons of our current SST anomalies to those five years.

 

For now, the analogue winters I will use are

1975 -1976, 1985-1986, 2000-2001, 2005,2013, 2014, 2020, and 2021

 

There is a correlation between warm Octobers and October tropical activity and colder winters here in the Northeast and northern Middle Atlantic. It remains to be seen if October ends up overall warmer than average; or if we a couple of tropical cyclones come close or make landfall on the U.S. But if we do, it will increase the odds of a cold winter here in the Northeast.

 

 

Siberian snow cover:

Now that we’re in Mid-October, we can try to get a feel for what’s going in with Siberian snow cover. A few weeks ago, snow cover in Siberia was quickly expanding. In fact, it was the fastest advance in over 12 years. But since then, snow cover advance as slowed down a lot.  So currently Siberian snow cover is at a moderate level when compared to other years. The pattern over that part of the world is such, that I don’t expect to see any big changes in snow extent over the 7-10 days. After that conditions should become more conductive for more in the way of snow, so we should see snow cover expand.

I expect by the end of October snow extent will be above average. The question is will it be slightly above average or well above average. Given the current pause in snowfall over Siberia, it will be an uphill climb to reach well above average. But the pattern that looks to setup says it could be possible. We will see.

 

 

A few teleconnection thoughts:

 

The Madden Julian Oscillation (MJO):

The MJO is currently in phase six. Phase six on average tends to favor ridging over western North America and troughing over eastern North America. This could keep October on the coolish side. A cooler overall October would mean a cold winter would be less likely, but that would only be one factor.

The Atlantic Oscillation (AO):

Right now, the AO is positive. Then it looks to become more neutral for much of the rest of October. I think the AO will become overall negative during the first week of November

The North Atlantic Oscillation (NAO):

While the AO is going to be neutral for a week or two. The NAO looks to be negative during the same time. The NAO will likely stay slightly negative for at least the first part of November.

 

The Hunga Tonga Volcanic eruption:

The eruption in the southern Pacific, Introduced a lot of water vapor and debris into the stratosphere in the Southern Hemisphere. The eruption resulted in a large stratospheric cooling event in the Southern Hemisphere. There is a correlation between what happened in the Southern Hemisphere earlier this year, and high latitude blocking over Greenland and a predominantly negative NAO pattern for this winter.

Years that had similar Southern Hemisphere cooling were 1988,1990,2002,2004, 2009, 2010,2016, 2019,2022  

 

Looking at the 500mb geopotential height composite anomaly those analogue years, based on  1991 2020 climatology  for the winter months of December through February. It clearly shows that idea of an overall negative NAO with higher latitude blocking over Greenland, is a good bet for this winter. 

 

High latitude blocking does tend to increase the odds of cold air outbreak in the Central and Eastern U.S.

 

As far as the Polar Vortex, I don’t think it will be super weak like we’ve seen in winters like 2020-2021. But we still should end up with a few times the polar Vortex breaks down enough to allow some of that arctic air to move into the Northeast.

 

Great Lakes water temperature:

 

Temperatures over the last few weeks have been generally below average. As a result, the water temperatures across the Great Lakes are slightly cooler than average for this time of year. The Lakes will cool down slowly as we head into mid-November. Lake effect snow should be average to above average this winter.

 

 

Images from the PRISM Climate Group at Oregon State University

 

Bottom line, and putting it all together:

On average for the Northeast and northern Middle Atlantic region, La Nina winters tend to be rather chilly, with snow typically ending up a story of the haves and have nots.

This winter looks Likely to have an active northern jet stream and a persistent ridge in the Southeast US. I

 

Because of all the stratospheric cooling earlier this from the Hunga Tonga volcanic eruption , I think there should be a more predominate tendency for the NAO to stay generally negative during winter 2022-2023. Which will lead to a greater chance for blocking over Greenland and increasing the odds for at least some cold air outbreaks. That along with the tendency for triple dip La Nina to be colder than average. I think this winter will be at least somewhat overall colder than the last couple of winters.  

 

Temperatures:

Based on the analogue package I’m currently using, winter 2022-2023 will likely start early. The pattern I see developing will likely be somewhat bookend like, with a lot of cold on the front end, then February could be warmish, before we see a cool down before April.

December into Mid-January is likely to be cold.

The end of January and into Mid-February could be inundated with some milder temperatures. So, there is a chance during that time temperatures will be overall above average for that time of year.

Then March will likely turn chilly again.

Snowfall:

Based on the pattern that looks to setup, interior parts of the region look to be more in the way of snowy, while parts of the Middle Atlantic and southern New England will see less in the way of snow. But all in all I see winter 2022-2023 being more in the way of what some expect winter to look like in our region.

Western and Central Pennsylvania, western into central New York State and into the Adirondacks should end up with snowfall that is  120%  to 130 % of the seasonal average.

 Northern into Central New England  slightly above average with total amounts of 105% to 115% of average.  

For eastern New York State and the Hudson Valley, southern New England, New Jersey, eastern Maryland, Delaware, and New Jersey.   85% to 100%

As for the major coastal cities,  New York City and Boston snowfall looks to be right around average. For cities like Washington D.C., Philadelphia, Baltimore snowfall will most likely be slightly below average to below average.

Snowfall in New England into Maryland, Delaware, and New Jersey, especially for the I-95 Corridor, a lot will depend on the storm track evolving from any Coastal storms that do develop.

 

Well, that’s it for Part one, as we get closer to the official start of winter. I will have a better handle on how things look to trend, as I release part 2 and maybe part three these will try to narrow things down more and provide more detail.

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