My official 2018 2019 winter outlook.

I started talking about this coming winter even before the summer.  I've directly and indirectly said I believe this winter will be quite cold and chilly. I said months ago that this winter most likely would be coming early and staying late. The success I had forecasting during this year's Atlantic hurricane season is the same pattern going forward. The Pacific and Atlantic tropical seasons will have an impact on winter 2018-2019. I've been trying to keep all y'all informed; I started posting my preliminary  thoughts on this winter back on August 7th. But even way before that I've posted about the evolving pattern and how that pattern related to this upcoming winter.   If you haven't read my preliminary winter thoughts, I encourage you to do so. Here are the links.

Part 1

Part 2

part 3

Those three part installments laid the ground work for this post.  We are now in the last part of October. So far everything I've been talking about  on my weather pages and in several blog post has come to past.  we are now quickly changing over the winter pattern; the cold has indeed arrived early.  Before I get started, first of all let me say for the umpteenth time , I think it will be a cold and snowy winter for much of the eastern half of the U.S.

But remember  I'm talking overall colder than average temperatures and above average snowfall for most of the Northeast and the Mid Atlantic. It won't be subzero all the time; as we see every winter there will be warm ups from time to time. Also remember wintertime precipitation is  sleet, freezing rain, snow, and sometimes even rain.  The pattern going forward will support all of these at some points over winter 2018-2019.

Last winter we saw a lot of variable conditions.  It started out cold, then got very cold from around Christmas into the first week of January.  Mid January into much of February we warmed to well above average. Then cooled back off for March into Much of April.  We also had five major nor'easters. One In January and four back to back in March. 

OK what about this winter:

The Northeast and Middle-Atlantic have turned very cold  by October standards.  As we get  into November the trough will adjust west and sit over the Plains.  Then it should adjust back east as we get into winter.

The models are moving toward the thoughts I've been laying out.  Even the CFSv2  (which normally has a hard time finding cold in any pattern) is coming around to the idea that the Northeast and Mid-Atlantic will be quite cold this winter.  The JMA and Euro are also adjusting to a very cold look for December through February.  The Euro weekly is showing a lot of cold for 2/3 of the CONUS over the next 46 days, the core of the cold looks to be over the Great Lakes, Midwest, and the Northeast.  This would absolutely play into the pattern I've been talking about for months.

Here is how the CFSv2 has been progressing.

The Euro 46 day overall temperature anomaly.

 Analog Years:

1958-1959 1968-1969, 1972-1973 1976-1977,1977-1978, 1986-1987, 1994-1995, 2002-2003, 2006-2007, 2009-2010, 2014-2015. 2002-03 is leading the pack at least for now.  If you remember back to 2002-03 that October acted very much like this one. Other years that are in the running are 1968-69, 1986-87, 1994-95, and 2009-10, 2014-2015.  When doing analogs we blend the years that had similar patterns; this is what the temperature outlook maps are based on. The maps show an overall blend of those analog years.  So during the winter, different aspects of those analog years will manifest themselves.   

Looking at the Sea Surface Temperature (SST) anomalies:

The Pacific:

     The El Nino Southern Oscillation (ENSO):

Winters  tend to be colder than average in the Central and Eastern US during El Nino Modoki, as opposed to an Eastern based normal El NIno which tends to be warmer in the Central and Eastern U.S.

The ENSO  region in the Pacific is heading toward a  weak to moderate  Modoki  (centrally based) El Nino in the tropical Pacific. The El Nino conditions are becoming more and more apparent.   Looking at the global SST pattern, the tropical Pacific has a very distinct El Nino look.  We can also see the colder SST near South America. Over the next several weeks we will see the ENSO evolve toward a Modoki even more.  The subsurface water temperatures  already show the El Nino Modoki footprint. The reason a Modoki leads to East Coast troughing has to do with how energy release forces a trough north of the center of the warm SST. If the heat is in the central Pacific then there will be a trough in the north central Pacific south of the Aleutians. This would cause a ridge east of the trough. This ridge would be over the West Coast. This in turn means a overall trough would be over the East Coast.  If the warm SST were in the eastern Pacific, the process would cause a trough over the West Coast and a Ridge over the East Coast. We saw this occur back in 2015.  

     The Eastern Pacific Oscillation:

When we have a Modoki El Nino, it improves the odds for a negative EPO. A negative EPO would allow the eastern Pacific to warm up, bringing some of this warmth to the west coast of North America.

     The Blob:

Warmer than normal water in the northern Pacific. The blob is looking quite extraordinary. The last time it looked similar to this was the winter of 2014-2015. A strong blob Is a good indication of West Coast Ridging setting up during winter 2018-2019.

      The Quasi-Biennial Oscillation (QBO):

The QBO has a direct correlation to winter weather patterns.

The QBO is east based but is trending west. But I think we will see the east based QBO hang around into February. This is important, when the QBO is in the eastern phase we tend to see more stratospheric warming events, especially when combined with low solar activity.   

      PDO:

The Pacific Decadal Oscillation (PDO), like all teleconnections it has a warm and cool phase. The PDO has a big impact on the strength of the ENSO. The PDO can intensify or diminish the impacts of the ENSO. A warm phase PDO will work hand in hand with an El Nino. A cold phase in the PDO will amplify the effects of La Nina. Conversely, if the PDO and ENSO are in opposite phases they act as a counter balance to each other.  Last fall we had a positive PDO that was trending negative.  Winter 2017-2018 featured a neutral trending  to a negative PDO.  The result was we had  a trough in the west and a stronger than average southeast ridge what causes all kinds of havoc with our winter temperatures.   

 The PDO is positive (This is the so called "warm blob" That sits just south of Alaska)  and that looks to continue into at least Spring of 2019. This would help promote the western ridge and an east trough. This would help ensure  below average temperatures in the Southeast, Mid Atlantic into the Northeast. This would also favor above average winter precipitation too.    

The Atlantic:

We have above average SST along the East Coast and Gulf of Mexico.  Those warm SST will help to lend support to any coastal storms that do develop.  With general  eastern troughing expected,  we should see chances for digging troughs to amplify and phase with the cold arctic air.  So there will be a chance for at least a few bigger Nor'easters.

Colder than average temperatures near Greenland.  The winter of 2014-2015 saw this area of the North Atlantic even colder than it is now.  Those on the global warming side of the isle say this cold blob is because the current and circulation patterns in the Atlantic are slowing.  But I think it is just because of climate variability.   

The Atlantic Oscillation (AO) and North Atlantic Oscillation (NAO) have been strongly positive for a long time.  But Hurricane Michael has forced a pattern change. Part of the change was warming in the stratosphere. As a result of that the AO and NAO have both tanked.  With the negative AO and NAO we now have blocking setting up. The blocking is leading to all that cold Canadian air to pour south into the U.S.  This kind of blocking pattern is exactly what one would expect from a east based QBO.  Those cold SST around Greenland is a good signal for a colder Northeast.

The  Indian Ocean:

The east  Indian Ocean is cooler than the west Indian Ocean and northeast of Australia.  This is important,  when we have that setup in the Indian Ocean and a El Nino we tend to see the MJO try to stay neutral or stay in the colder phases for the East Coast.  Phases 8,1, and 2.

The Madden-Julian Oscillation (MJO):

The factors above have an influence on the MJO.  The MJO will be what decides where the strongest convection will set up.  This in turn will affect how the Pacific jet behaves.  Last winter the MJO moved into warm phases 4,5, and 6. This caused the warmth we experienced for the end of January and February.  When we have a Modoki El Nino the MJO is typically able to push farther eastward do to the effect on air motion in the Central Pacific.  This leads to plenty of moisture for MJO caused convection.   A Modoki El Nino sees warm SST in the central Pacific with cooler SST east and west of there. Typically when we see colder SST in Indonesia we tend to see the MJO stay mostly or completely in the colder phases 8,1, and 2. This is another key showing we should have a colder winter.

Solar Cycle:

Low solar activity is a sign for cooler as opposed to warmer winter temperatures.  There is a weak correlation between solar activity and temperature.  The reason for this is most likely because when the Sun is quiet we have last solar radiation impacting the atmosphere. It has been noticed that when we have less solar radiation impacting the Earth, we have increased ozone levels in the Stratosphere. A warmer Stratosphere over the Arctic means the polar vortex is weaker, which makes it easier for pieces of the cold arctic air can break off and migrate south into the CONUS. It was Drew Shindell who first noticed the connection between ozone level and temperature. 

This season we have a very quiet Sun. So this supports my thoughts on a colder than average winter here in the Northeast.  

Snowpack and High Latitude Blocking:

Northern Hemisphere snowpack is valuable tool in trying to figure out if we will see high latitude blocking during the upcoming winter. This can help us gauge if the winter will be more inclined for cold shots.   Siberian snow cover is behind from where it was last year at this time. could this throw a monkey wrench into my outlook...maybe.  But on the other hand,  the area where the snow is located is more important than the extent of coverage.  When looking at Eurasia we're concerned if there is snow below 60⁰ N;  There has been  expanding  snow in that part of Siberia.  So based on Eurasia snow cover, there is weak signal for high latitude blocking.   The Canadian and Greenland Snowpack are well above average for this time of year.  There has also been snow in the Rockies, this is ahead of last year.  Snowpack is a very important factor; the more snow the more modification the air masses will experience over the winter  as they drop south.

There is a correlation between years that have low solar activity and blocking near Greenland.  All of this is a good indicator that we should see above average chances for blocking this winter.

There is a correlation between tropical activity and East Coast winter temperatures.  Strong October Gulf Hurricanes tend to precede cold East Coast winters.  Another interesting tidbit, is years that saw a Pacific tropical cyclone impact the desert Southwest also lead to cold East Coast winters.  This year we saw two do this.

The bottom line:

Summer into Fall 2018 has been acting very El Nino Modoki like.

Temperature:

I have strong confidence that I'm right on the developing pattern.  All of the factors I went over work to influence the Idea of an East Coast Trough, with the higher probability for Greenland Blocking, I think this will be a fairly cold winter. Here is a look at both my thoughts on winter temperatures across the CONUS and for the Northeast and Middle-Atlantic.

We have to expect the trough over the east right now, will relax and pull west for part of  December, maybe even into the start of January. But any warmth for December/January shouldn't be a blowtorch. The warming could last two to four weeks. During this time, we would see more in the way of  temperatures  slightly above average to above average. November will still most likely end up being overall below average. The cold that is available could overwhelm the pattern, making for some periods of near record to record breaking cold.  December most likely will be warm. But the seasonal temperatures should come back around Christmas.  The first week or two of January could be warmer than average. Then the bottom could fall out, with things becoming very cold. The analog years I've latched onto would support that Idea. But I think ,  the rest of January, February , and into March look pretty overall cold based on the analogs and the pattern that has been with us all year.  The Models are trending colder, this is a good sign that I'm on the right track for this upcoming December through February timeframe.  

Winter Precipitation:

Winters that feature an El Nino Modoki tend to see more of an active southern jet stream.  An active southern branch increases the likelihood of East Coast winter storms. ... more snow storms....more snow.  This is why I have the Middle-Atlantic into the Southeast with well above average snowfall for this winter.  There is also the risk for a few ice storms this winter. The Ice storm risk will be greatest in the Southeast; but, I can't rule out the possibility of an ice storm in the Northeast.  I'm thinking this winter will see slightly below average to average lake effect snow in the snow belts . But lake snow is volatile so trying to forecast the entire Lake Effect season is almost impossible.  But based on the analogs, I think my Lake effect idea has merit.   

  

If something happens that changes my mind on some of this; I will post an update on the temperature and precipitation pattern for this winter around mid November.

Images courtesy of WeatherBell Analytics, Tropical Tidbits, National Oceanic and Atmospheric Administration, National Solar Observatory.