The 2024 and 2025 Northeast Winter Outlook Part One

 

Meteorological winter is just around the corner, officially beginning Sunday, December 1st. So, it’s time to start talking about what may be. The season will have ups and downs, alternating between warm and cold. At times we could see a few bouts of bitterly cold air. There will be a chance for a few significant snow events as well.

What is a seasonal outlook?

A seasonal outlook is different from short and medium range forecast. Instead, it tries to predict the overall pattern when it comes to temperature and precipitation pattern that could occur during the entire season. It attempts to place some light on the three possible outcomes, above average, average, and below average.  A seasonal outlook deals with the overall global climate pattern that looks to be prevalent.  It is more of an overall snapshot of what to expect, instead of the a more accurate shorter-term forecast.

The 2024-2025 winter outlook will be divided into two parts. Part one will be based on early analysis. If I see more interest or the pattern looks to make a big change, I would issue a part three.

 

Okay, let’s take a look at how things might unfold.

 

Sea Surface Temperatures:

 

Last October

 

This October.

 

Comparing last October to this October we can see some difference and a lot of things that look similar.

In the Pacific we can see warm SST in the northwestern Pacific, with more cooling in the northeast Pacific.  The SST in the equatorial Pacific look much different than last year. Last October we had an El Nino that was transitioning to ENSO neutral. This year we’re transitioning from ENSO neutral to what looks like a La Nina. The current SST anomalies in the western Atlantic are even warmer than last Octobers’.

 

 Teleconnections:

 

The Atlantic Oscillation (AO)…

The AO deals with the strength of the Polar Vortex (PV) and determines whether or not there will be a supply of Arctic air available to fuel winter weather. I will explain more about the PV when I discuss the current snow cover. A positive AO indicates that the PV will be strong and Arctic air will have a greater chance of cold arctic air staying locked up near the pole while a negative AO indicates the potential for a weaker PV leading to a greater chance for arctic air to escape southward. The AO can flip phases on a weekly basis.

The North Atlantic Oscillation (NAO)…

The NAO, in its negative state, indicates high-latitude blocking over Greenland. This lingering area of high pressure causes the flow to stagnate. The storm track is often underneath it and can result in persistent storminess for the Eastern US. On the contrary, a positive NAO has no such block and the storm track moves quickly across the CONUS and out into the Atlantic. Like the AO, the NAO can switch Phases often.

Can the eastern US still get winter weather with a positive NAO? Yes, but they’re often quick-hitters and rarely significant events.

 

The Pacific Decadal Oscillation (PDO)…

 The PDO deals with sea surface temperature anomalies over the Northern Pacific (north of 20° north latitude), as with all teleconnections it has a positive and negative phase. These phases typically last for decades. The PDO represents the oceans response to the atmosphere.  In this way it is a prime driver for low pressure systems in the north Pacific, for example the Aleutian low-pressure system in the Gulf of Alaska. Depending on how strong this low is, it will have a different impact on wind flow, and the pressure gradient. If the Aleutian Low is very strong, we tend to see a stronger southernly flow along the immediate West Coast.

The positive phase is characterized by cool SSTs north of Hawaii and warmer than average SSTs in the Gulf of Alaska and along the West Coast of North America. The negative phase we see the opposite, warmer than average SSTs north of Hawaii and cooler than average SSTs in the Gulf of Alaska and along the West Coast of North America.

During the positive phase the Mid-Atlantic and Northeast is more likely to experience overall below average temperatures for December, January and February. During the negative phase the opposite is true, with the Mid-Atlantic and Northeast likely to experience overall above average temperatures for December, January and February.

 

Pacific North American Pattern (PNA)…

The PNA involves the flow pattern over the Northeast Pacific. As a result, it is a major player in the weather pattern over North America. The PNA is very variable, changing between positive and negative every few weeks.

 

The PDO and the PNA are closely linked to each other…

 

There is a direct correlation link between the PDO and the PNA. During the winter the correlation is greater than 0.80.

 

The PNA is closely related to the strength of the Aleutian Low and the strength of the PDO

 

The PNA for our purposes here, is the PNA is the main driver of the trough ridge pattern over North America

 

During a negative PNA there typically is more overall upper level troughing over the western U.S leading to cooler and wetter conditions, while the eastern U.S. is more likely to see overall ridging leading to drier and warmer conditions. During a positive PNA the eastern U.S. sees more in the way of troughing while the western U.S. sees more in the way of ridging.  

 

Quasi-Biennial Oscillation (QBO)…

The QBO is another prime teleconnection driver of climate. The QBO deals with stratospheric winds. The negative phase leads to the winds blowing in an easterly direction, with the positive phase having winds in the westerly direction. The QBO is a major driver of the strength of the Polar Vortex. When the QBO is positive the polar vortex tends to be stronger overall. A negative QBO tends to see a higher likelihood of a weaker polar vortex.

  

EL Nino Southern Oscillation (ENSO)...

The ENSO involves Sea Surface Temperature anomalies across the equatorial Pacific. It has a warm phase called El Nino, a cool phase called La Nina, when neither is in place, the ENSO is considered neutral.

Like I said above last winter was an El Nino, typically that means cooler temperature anomalies for southern half of the U.S. with a warmer temperature anomaly over the northern tier. Precipitation during a El Nino typically sees the northern tier anomalies drier in the northern tier, and wetter in the southern tier.  During La Nina we see the opposite occur with temperature and precipitation anomalies.

The temperature and precipitation correlation anomalies during La Nina can be seen in these two graphics.

 

 

 

Physical Sciences Laboratory

 

 

Physical Sciences Laboratory

 

We’re in the process of transitioning from El Nino to La Nina

 

La Nina:

 

A La Nina would affect the weather this winter in the US, he said. The north may experience colder-than-average conditions while it would be warmer to the south.

This La Nina should be weak to moderate, but a weak one is much more likely.

 

Weak La-Nina’s tend to be fickle with a lot of variability. So, teleconnections like the MJO, PNA, NAO and AO will play a huge role in how things play out week to week as we go through the winter season.

 

The call for a colder wetter winter is based on a La Nina forming out West and impacting the jet stream

I expect the northern polar jet will be very variable, with the southern subtropical jet being weaker.  This would generally correlate to seeing wetter anomalies in the north and drier anomalies in the south.

 

Models:

 

National Multi Model Ensemble (NMME)

Precipitation

 

November – January

 

 

January - March

 

 

Temperature

 

Nov to Jan

 

Some possible analogue winters:

Weak La Nina years

1950-1951, 1954-1955, 1964-1965, 1967-1968, 1971-1972, 1974-1975, 2000-2001, 2005-2006, 2008-2009, 2016,2017, 20017-2018, 2022-2023

 

Closest match for Weak La Nina years

2016-2017

 

ENSO Neutral Winters

2017-2018

2022-2023

 

Primary storm track:

Storm tracks will be a result of a weak La Nina and strong influence from the NAO and AO.  The pattern setting up supports the idea of

Clippers

Lake Cutters

Appalachian runners

Inland runners (Miller B nor’easters) that transfer to the coast.

The classic Miller A nor’easter will be very hard to come by.

 

Putting it all together:

Based on the current look of the teleconnection and the analogue package I’m using for now.

With the Idea of the polar jet stream being amplified and the subtropical jet being weaker; we will have a pattern that could support a strong ridge in the west that would increase the odds of polar air masses into the eastern U.S.

Much of the winter will be driven by the slowly developing weak La Nina and a positive QBO. This would mean they will fight each other at times during the upcoming winter.

A positive QBO will tend to decrease the odds for high latitude blocking, which means we will see stretches of zonal (west to east) flow. This combination would lead to a higher likelihood of less cold air outbreaks during the winter. So, while polar air entering the pattern is there, arctic outbreaks might be more difficult to happen.

Based on this we could see winter start out a little more hard-hitting during the 2nd half of November. With the heart of winter being variable. Then Spring arriving a bit sooner than we’ve seen the last few years.   

 

I’m going to break the region into zones. I think this will make it easier to understand what I’m generally expecting. This will be biased on the 30-year average.

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Zone one…

Those of y’all in zone one, will see overall slightly below average temperatures during December to end of February. As far as general precipitation it should end up being wetter than average. With the cooler temperatures snowfall should end up slightly above average to above average as well. I expect those near the Great Lakes will experience several lake effect snow events. So, the typical snowbelts should end up with overall above average to well above average snowfall for the season.

This doesn’t mean there won’t be warm periods. As I said above, La Nina tends to bring highly variable conditions so every storm will depend on how the pendulum is sitting.   

Winter while not the old fashion winters from decades pass, it shouldn’t be all that bad.

Zone two…

This zone looks to see overall near average temperatures, along with average general precipitation. There will be an issue with mix events during the winter. As far as snowfall that looks to be overall average to slightly above average.

Winter will end up being a bit of a roller coaster, but there should be some snow events.

 

Zone three…

This zone looks to see overall average temperatures to slightly above average, along with average general precipitation. There will be an issue with mix events during the winter. So, expect to see many events start out as a mix then switch over to snow, or starting out as snow and changing to a mix. But there will be a chance for pure snow events.  As far as snowfall that looks to be overall average to slightly below average.

Winter will end up being very hit and miss.

 

Zone four…

This zone looks to see overall Temperatures above average with precipitation near average.  Snowfall accumulations will be below to well below average, when everything is said and done. Unless a storm tracks just right, I don’t except to see much in the way of snow. some of your storms will be a mix. But generally, many of them could be all-rain events. It is possible some places in zone four, won’t see any snow this winter.

Winter will end up being lack-luster

 

That very warm Atlantic..

Above I mentioned the super warm SST in the North Atlantic. As I’ve said before, there is no doubt that the oceans and atmosphere are becoming warmer. This is impacting weather patterns and storm tracks.  The warm water temperatures mean more water is evaporating, while the warmer air temperatures mean the atmosphere can hold more water vapor.  

I have to try and factor this idea into my outlook. As the ocean/atmosphere dynamics will lead to a greater chance for above average amounts of heat. This won’t only effect storm tracks it could also impact storm intensity.

Over the summer, the entire Northeast saw the effects of this idea; there were several very significant rain events, that lead to major flooding. This idea will likely impact winter storms, with more available moisture for storms to drop snow on parts of the region.

Coastal storms like nor’easters strengthen over warm ocean waters. The interaction of the warm water and colder polar/arctic air can create monster storms. A La Nina pattern impacts the jet stream, which reduces the odds for coastal nor’easters. But depending on what the other teleconnections are doing at the time. Those warm waters could produce a massive storm.

So northern parts of the region should see some cold and snow, while the Middle Atlantic and I-95 could see a warmer winter and maybe little in the way of snow. It will depend on how the AO and NAO behave. The last few winters have had many setups that resulted in close calls with snowstorms, but one thing or another didn’t line up, leading to storms being suppressed to the south and east, resulting in a lack of real winter weather.  

Well, that’s it for part one.

 

I hope you found this interesting and educational. As always, I can’t answer questions about the outlooks from other outlets. But I will always answer all y’all’s questions in regards to my outlooks and forecast.

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