Meteorological Winter is on our doorstep and a divided state wonders...will we see a return to a "true" New England winter or another extended fall...
Above, the aftermath of a major winter storm in December 2020. This was the first of two widespread double digit snowfall events from that winter, which was the last time we saw a generally normal snowfall across Connecticut.
Below we have the opposite. Taken in March 2023, I think this image sums up the winter that wasn't in 2022-23, defined by patterns that looked favorable for winter, but on balance produced a the second warmest winter since the period of record began in 1896 for Connecticut and a historically snowless season.
Whether you love or hate winter, you can't help but laugh.
Below we have the opposite. Taken in March 2023, I think this image sums up the winter that wasn't in 2022-23, defined by patterns that looked favorable for winter, but on balance produced a the second warmest winter since the period of record began in 1896 for Connecticut and a historically snowless season.
Whether you love or hate winter, you can't help but laugh.
Introduction
This is our first winter forecast in a few years. We stopped because these have required an enormous amount of work and quite frankly we felt our lack of expertise in this kind of very long range forecasting only made it more difficult. Results even for the best of forecasters, meteorologists with decades of experience, can be mixed. It can only take one storm to completely trash a snow forecast, or an extended stretch of warmth to torch a strong temperature forecast.
That said, it's worth trying again. The hope is that this iteration of the winter forecast is more readable and engaging.
Meteorological Winter is a time scale that the meteorological community uses to cleanly cover the four seasons. Meteorological Winter begins on December 1 and ends the last day of February, hence the timing of our forecast. The snowfall forecast will also include March, because in recent years March has been a more wintry month than November, and at times, the most wintry month of astronomical winter (the real winter that runs from December 21 - March 19).
Our forecast is based on the major factors that influence the synoptic, or large scale, pattern that delivers the sensible weather we experience. Not all factors are equal, and that's where the seasonal analysis coalesces into a forecast.
There are a number of winter outlooks out there as you have likely already seen, and we're adding to that list. Each should be taken with a grain of salt. Seasonal forecasting is extremely difficult, and there are always parts that will be right, close to right, and just plain wrong. Let's hope we get the good stuff right.
Time to dive in.
This is our first winter forecast in a few years. We stopped because these have required an enormous amount of work and quite frankly we felt our lack of expertise in this kind of very long range forecasting only made it more difficult. Results even for the best of forecasters, meteorologists with decades of experience, can be mixed. It can only take one storm to completely trash a snow forecast, or an extended stretch of warmth to torch a strong temperature forecast.
That said, it's worth trying again. The hope is that this iteration of the winter forecast is more readable and engaging.
Meteorological Winter is a time scale that the meteorological community uses to cleanly cover the four seasons. Meteorological Winter begins on December 1 and ends the last day of February, hence the timing of our forecast. The snowfall forecast will also include March, because in recent years March has been a more wintry month than November, and at times, the most wintry month of astronomical winter (the real winter that runs from December 21 - March 19).
Our forecast is based on the major factors that influence the synoptic, or large scale, pattern that delivers the sensible weather we experience. Not all factors are equal, and that's where the seasonal analysis coalesces into a forecast.
There are a number of winter outlooks out there as you have likely already seen, and we're adding to that list. Each should be taken with a grain of salt. Seasonal forecasting is extremely difficult, and there are always parts that will be right, close to right, and just plain wrong. Let's hope we get the good stuff right.
Time to dive in.
Winter Forecast Methodology
Before we get to the part you care about, how much snow for your backyard, we should discuss the factors that we're looking at to make our forecast. This hasn't changed much from our last winter forecast, but this year there's less emphasis on ENSO and a little more on current conditions and teleconnections.
Here is how we weigh the various major factors.
Seasonal Models
Before we get to the part you care about, how much snow for your backyard, we should discuss the factors that we're looking at to make our forecast. This hasn't changed much from our last winter forecast, but this year there's less emphasis on ENSO and a little more on current conditions and teleconnections.
Here is how we weigh the various major factors.
- Seasonal Guidance (10%): These models are longer range versions of some of the global models we use for short and medium-range forecasting, as well as climate models. We look at the overall averages when looking at these, such as the average predicted temperature for January, rather than specific output such as total snowfall. They have some skill, but not enough for us to care strongly about. Remember, guidance is just that, guidance.
- Analogs (10%): We look at past years that have similarities to this year, whether it's conditions observed through the year, ENSO state, or teleconnections. Again, this brings some skill, but no two years are alike.
- ENSO (30%): This is what most of you are thinking about when asking how this winter will play out. This is a big factor in what our season will look like. ENSO stands for the El Nino Southern Oscillation, and it represents water temperatures--where anomalies determine whether an El Nino or La Nina is present--that influence global atmospheric conditions, hemispheric weather patterns, and our sensible weather. However, note that this is only 30% of our forecast. El Nino usually means some things for Connecticut, but it's more complicated by our shifting climate and the kind of El Nino we are likely to see this winter.
- Teleconnections (30%): There are many indices measuring current conditions in different parts of the world, from upper level features to regional ocean temperatures. While ENSO is global, teleconnections are regional. These are the conditions that drive the overall hemispheric pattern and are critical to how frequently we get cold, how often we get storms--rain or snow, and how much potential there is for snowfall. We will discuss the major drivers in the Atlantic and Pacific, and explain what the teleconnections forecast means for our weather.
- Current Conditions (15%): This is a little higher than normal, and with good reason. We've seen guidance shift just in the last few weeks with the progression for December, and with that much change it makes sense to do a little more "real-time" forecasting because the pattern in December is likely to influence the pattern beyond. Some parts of the upper level pattern have a strong correlation to what the default weather pattern is during the winter months.
- Gut Feeling (5%): This really just accounts for a general forecaster feeling given the totality of the evidence of how the season will proceed.
Seasonal Models
Let’s take a look at the seasonal models. For this forecast, we're looking at three of them, the Euro seasonal, the CanSIPS, and the CFS.
Essentially, these pieces of guidance attempt to model the upcoming months in much the same way that the medium range global models attempt to model the upcoming forecast period, that is, start with a set of initial observations and apply some physics package to those observations to make future forecasts for the next period on some interval. Then, that forecast is fed back into the model as the initial observations for the next period to be created off of, and so on.
Like the medium range guidance, small inaccuracies in initial data or projections grow exponentially as the recursive cycle continues. As a result, while seasonal models can give a window into a seasonal progression, they are notoriously unstable. That's why they have low weight in our forecast.
Not many images on this section, but we included the hot off the presses Canadian CANSIPS temperature anomaly for December. Warmer than normal, but not by much. The Euro has an older run that has a warmer December, and the CFS is also warmer. That creates a little confidence that we have a warmer than normal winter--in line with ENSO climatology for El Nino, but it's not a blowtorch like last year or recent years. The seasonal models diverge for the following months, but all agree on a wetter than normal March. Looking at them, not much stock is put in, especially this year.
Essentially, these pieces of guidance attempt to model the upcoming months in much the same way that the medium range global models attempt to model the upcoming forecast period, that is, start with a set of initial observations and apply some physics package to those observations to make future forecasts for the next period on some interval. Then, that forecast is fed back into the model as the initial observations for the next period to be created off of, and so on.
Like the medium range guidance, small inaccuracies in initial data or projections grow exponentially as the recursive cycle continues. As a result, while seasonal models can give a window into a seasonal progression, they are notoriously unstable. That's why they have low weight in our forecast.
Not many images on this section, but we included the hot off the presses Canadian CANSIPS temperature anomaly for December. Warmer than normal, but not by much. The Euro has an older run that has a warmer December, and the CFS is also warmer. That creates a little confidence that we have a warmer than normal winter--in line with ENSO climatology for El Nino, but it's not a blowtorch like last year or recent years. The seasonal models diverge for the following months, but all agree on a wetter than normal March. Looking at them, not much stock is put in, especially this year.
Analogs
The Climate Prediction Center produces a list of analogs that match the upper air patterns over the United States. Analogs are helpful in quickly identifying similar patterns and seasons that correlate to what we're seeing currently. For our resident meteorologist GP, he has identified 2009-10 and 2002-03 as analogs. Not quite what many would expect for an El Nino year. What happened in those years?
In 2009-10, we saw a winter that brought temperatures near normal (-0.8) overall in DJF (December, January, February) but brought below normal snowfall inland and above normal snowfall in southern CT. If you recall, this was the historic year that brought snow to the Mid-Atlantic. This was because of a very strong negative North Atlantic Oscillation (NAO) that suppressed storms south. We don't see that strong of a -NAO, but having any hint of a weaker -NAO could open us up to a colder and more snowy winter.
Note how precipitation was near normal and just above in southern CT and how cold temperatures were across the US. We're not expecting continental US cold to be anything to the same extent this year.
The Climate Prediction Center produces a list of analogs that match the upper air patterns over the United States. Analogs are helpful in quickly identifying similar patterns and seasons that correlate to what we're seeing currently. For our resident meteorologist GP, he has identified 2009-10 and 2002-03 as analogs. Not quite what many would expect for an El Nino year. What happened in those years?
In 2009-10, we saw a winter that brought temperatures near normal (-0.8) overall in DJF (December, January, February) but brought below normal snowfall inland and above normal snowfall in southern CT. If you recall, this was the historic year that brought snow to the Mid-Atlantic. This was because of a very strong negative North Atlantic Oscillation (NAO) that suppressed storms south. We don't see that strong of a -NAO, but having any hint of a weaker -NAO could open us up to a colder and more snowy winter.
Note how precipitation was near normal and just above in southern CT and how cold temperatures were across the US. We're not expecting continental US cold to be anything to the same extent this year.
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What happened in 2002-03? Well, if you like winter, that was a classic one. We had cold anomalies centered over the east coast with a classic western ridge, and precipitation near normal. Snowfall? Well above normal across Connecticut and a snowstorm on Christmas Day.
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ENSO
Now let's talk about the big dog factor, ENSO. Whether we are in an El Nino or La Nina is the big driver of global weather patterns. The prior three years saw us in a La Nina, before recently, and rapidly, seeing a reversal into the upward bound of a moderate El Nino. It's likely we see a strong Nino, but fall short of a super nino.
As of the November 27 ENSO update by the Climate Prediction Center, El Nino conditions are present and have a 62% chance of continuing through June 2024.
Now let's talk about the big dog factor, ENSO. Whether we are in an El Nino or La Nina is the big driver of global weather patterns. The prior three years saw us in a La Nina, before recently, and rapidly, seeing a reversal into the upward bound of a moderate El Nino. It's likely we see a strong Nino, but fall short of a super nino.
As of the November 27 ENSO update by the Climate Prediction Center, El Nino conditions are present and have a 62% chance of continuing through June 2024.
Latest model predictions, and the forecast from the CPC, keeps our El Nino in the moderate-strong range, peaking in January. This is critical, as the orientation of the El Nino likely keeps this from being so strong (read: super Nino) that we're overwhelmed by warmth.
Generally, a Nina shifts storm tracks further to the north and west, meaning that we are flooded with warm air as a storm approaches, and flooded with warmer air in general as the jet stream stays to the north more often. This can also happen in a strong to super Nino. A weak to moderate one however, can do the opposite. This year is complicated.
On one hand, the onset of a strong Nino implies that we see significant warmth, however that warmth is usually peaking in December. This year it looks like the orientation and speed at which the Nino has developed puts December in the "non-torch" category with an atmospheric lag, meaning a winter that may resemble a less traditional Nino.
Generally, a Nina shifts storm tracks further to the north and west, meaning that we are flooded with warm air as a storm approaches, and flooded with warmer air in general as the jet stream stays to the north more often. This can also happen in a strong to super Nino. A weak to moderate one however, can do the opposite. This year is complicated.
On one hand, the onset of a strong Nino implies that we see significant warmth, however that warmth is usually peaking in December. This year it looks like the orientation and speed at which the Nino has developed puts December in the "non-torch" category with an atmospheric lag, meaning a winter that may resemble a less traditional Nino.
Teleconnections
Much of this overview is taken from past winter forecasts, because the fundamentals never change.
The thing you will hear most about during the winter season will be teleconnections. If you’re looking for a short to medium range signal to what the winter potential is, this is it, as teleconnections are essentially the elements of the upper level pattern that determine the orientation of the Jet Stream, location of coldest temperatures, and the activity level (storminess) in the flow.
These indices measure current conditions at certain placements in the atmosphere, most commonly, the presence of a ridge or a trough. In New England, we place heavy attention to four major teleconnectors--the AO and NAO in the Atlantic, and the PNA and EPO in the Pacific.
Arctic Oscillation (AO)
First, the Arctic Oscillation, or AO. This is an index measuring pressure anomalies in the Arctic, and is strongly correlated with temperatures in our area for the winter months. A positive phase of the AO consists of below average geopotential heights. A negative phase consists of the opposite. In a negative phase of the AO, the polar vortex over the Arctic is weaker, resulting in weaker upper level winds that make it easier for Arctic air to penetrate further south. Another result is a further south storm track. With a positive AO, the opposite is true. Stronger upper level winds keep the polar vortex in check, making it less likely for deep cold air intrusions and ideal storm tracks.
This year, which gives us greater confidence that December is not the blowtorch we have unfortunately become accustomed to in recent years, is that the upper level winds are forecast to weaken the Polar Vortex (PV). This is a higher than normal confidence idea, since it is medium range. This likely means that it will be easier to see intrusions of cold, much like November, in the latter third of December and into 2024.
Below is an image showing what a strong AO looks like. The image is merely illustrative, but note how the heights are well below average in the polar region. That’s a warm period.
Much of this overview is taken from past winter forecasts, because the fundamentals never change.
The thing you will hear most about during the winter season will be teleconnections. If you’re looking for a short to medium range signal to what the winter potential is, this is it, as teleconnections are essentially the elements of the upper level pattern that determine the orientation of the Jet Stream, location of coldest temperatures, and the activity level (storminess) in the flow.
These indices measure current conditions at certain placements in the atmosphere, most commonly, the presence of a ridge or a trough. In New England, we place heavy attention to four major teleconnectors--the AO and NAO in the Atlantic, and the PNA and EPO in the Pacific.
Arctic Oscillation (AO)
First, the Arctic Oscillation, or AO. This is an index measuring pressure anomalies in the Arctic, and is strongly correlated with temperatures in our area for the winter months. A positive phase of the AO consists of below average geopotential heights. A negative phase consists of the opposite. In a negative phase of the AO, the polar vortex over the Arctic is weaker, resulting in weaker upper level winds that make it easier for Arctic air to penetrate further south. Another result is a further south storm track. With a positive AO, the opposite is true. Stronger upper level winds keep the polar vortex in check, making it less likely for deep cold air intrusions and ideal storm tracks.
This year, which gives us greater confidence that December is not the blowtorch we have unfortunately become accustomed to in recent years, is that the upper level winds are forecast to weaken the Polar Vortex (PV). This is a higher than normal confidence idea, since it is medium range. This likely means that it will be easier to see intrusions of cold, much like November, in the latter third of December and into 2024.
Below is an image showing what a strong AO looks like. The image is merely illustrative, but note how the heights are well below average in the polar region. That’s a warm period.
North Atlantic Oscillation (NAO)
The NAO is the North Atlantic Oscillation, and is a close relative of the AO. Here, forecasters look at two pressure centers in the Atlantic--an area of low pressure near Greenland, and a high pressure system near the Azores. Generally, during the winter we’re paying close attention to heights around Greenland. The strength and exact placement of these features tend to have a significant impact on the placement of the jet stream--absolutely critical for cold air placement and storm track in tandem. During a negative phase, we see higher heights over the Greenland area, and below average heights over the western Atlantic and (usually) the eastern US. The opposite generally occurs with a +NAO, which means more progressive tracks and more warmer storm tracks.
While a persistently negative NAO is not necessary for a cold and snowy winter, having a -NAO, even if transient, can be a major factor in producing some of our biggest winter weather events, as a -NAO usually implies more blocking is available, while a +NAO represents a faster pattern with less room for storms to amplify. Further complicating matters is the position of the heights. A west based -NAO is more likely to produce a cold and stormy period than an east based -NAO.
A persistent -NAO is less likely this year, so very different than 2009-10. However, the presence of a -NAO in December is strongly correlated to frequent blocking during the winter season. That is forecast to occur this December, counter to what we'd usually see if one just looked at ENSO. Even if the -NAO is transient this season, avoiding a long term and persistent +NAO is a big deal.
Here's the latest European Ensemble forecast in 500mb view and the graph of models all showing a -NAO to persist through the first third of December.
The NAO is the North Atlantic Oscillation, and is a close relative of the AO. Here, forecasters look at two pressure centers in the Atlantic--an area of low pressure near Greenland, and a high pressure system near the Azores. Generally, during the winter we’re paying close attention to heights around Greenland. The strength and exact placement of these features tend to have a significant impact on the placement of the jet stream--absolutely critical for cold air placement and storm track in tandem. During a negative phase, we see higher heights over the Greenland area, and below average heights over the western Atlantic and (usually) the eastern US. The opposite generally occurs with a +NAO, which means more progressive tracks and more warmer storm tracks.
While a persistently negative NAO is not necessary for a cold and snowy winter, having a -NAO, even if transient, can be a major factor in producing some of our biggest winter weather events, as a -NAO usually implies more blocking is available, while a +NAO represents a faster pattern with less room for storms to amplify. Further complicating matters is the position of the heights. A west based -NAO is more likely to produce a cold and stormy period than an east based -NAO.
A persistent -NAO is less likely this year, so very different than 2009-10. However, the presence of a -NAO in December is strongly correlated to frequent blocking during the winter season. That is forecast to occur this December, counter to what we'd usually see if one just looked at ENSO. Even if the -NAO is transient this season, avoiding a long term and persistent +NAO is a big deal.
Here's the latest European Ensemble forecast in 500mb view and the graph of models all showing a -NAO to persist through the first third of December.
Pacific/North American Pattern (PNA)
Having favorable Atlantic teleconnections is important, but as we learned last year, New England needs the Pacific to cooperate for a normal winter. The Pacific is vital to determining the course of a Connecticut winter. The PNA is one of the most important teleconnectors, with a significant influence over North America. A positive PNA phase occurs when there are higher heights over the Pacific and western US. This correlates to ridging over the western US and a trough (transporting colder air) over the eastern US. In a negative phase, the opposite occurs.
The position of the western ridge matters quite a bit. Too far west and storms can cut to our west, bringing rainy systems or nothing at all. Too far east and storm tracks could develop too far offshore to bring significant precipitation events. While we are more likely to see a favorable Atlantic pattern, there are some mixed signals on what happens in the Pacific, especially early. We think that there will be a window for a more favorable winter pattern that is driven by the Pacific, most likely later in the season.
Having favorable Atlantic teleconnections is important, but as we learned last year, New England needs the Pacific to cooperate for a normal winter. The Pacific is vital to determining the course of a Connecticut winter. The PNA is one of the most important teleconnectors, with a significant influence over North America. A positive PNA phase occurs when there are higher heights over the Pacific and western US. This correlates to ridging over the western US and a trough (transporting colder air) over the eastern US. In a negative phase, the opposite occurs.
The position of the western ridge matters quite a bit. Too far west and storms can cut to our west, bringing rainy systems or nothing at all. Too far east and storm tracks could develop too far offshore to bring significant precipitation events. While we are more likely to see a favorable Atlantic pattern, there are some mixed signals on what happens in the Pacific, especially early. We think that there will be a window for a more favorable winter pattern that is driven by the Pacific, most likely later in the season.
East Pacific Oscillation (EPO)
Finally, we have the East Pacific Oscillation, or EPO. The EPO is a major driver in allowing Canada to develop cold air that feeds into the US, or shutting off any mechanism to deliver cold to much of Canada or the US. Here, we’re looking at heights over the northeast Pacific and Alaska. Higher heights over this region brings warmer than normal weather over that region, but it serves up an almost ideal mechanism for cold air delivery in the continental US, as a resulting Arctic high in northwest Canada and trough over the US work in tandem to funnel cold into the region. At times, we can see as sprawling enough -EPO to develop what is called “cross-polar flow”. This is the extreme cold that comes straight from the polar region without much moderation. That's part of how we got the brief Arctic plunge in early February 2023, a historic cold shot in the second warmest winter on record.
With a positive EPO phase, we potentially see extended fall. In a +EPO, we get a persistent low (vortex) in the northeast Pacific and Alaska, which creates favorable conditions for the dreaded PAC jet to inundate Canada and much of the continental US with warm Pacific air. If you have this kind of pattern persist, you can almost guarantee little cold and snow.
Here's a look at the positive and negative phases of the EPO and their effects on our sensible weather.
Finally, we have the East Pacific Oscillation, or EPO. The EPO is a major driver in allowing Canada to develop cold air that feeds into the US, or shutting off any mechanism to deliver cold to much of Canada or the US. Here, we’re looking at heights over the northeast Pacific and Alaska. Higher heights over this region brings warmer than normal weather over that region, but it serves up an almost ideal mechanism for cold air delivery in the continental US, as a resulting Arctic high in northwest Canada and trough over the US work in tandem to funnel cold into the region. At times, we can see as sprawling enough -EPO to develop what is called “cross-polar flow”. This is the extreme cold that comes straight from the polar region without much moderation. That's part of how we got the brief Arctic plunge in early February 2023, a historic cold shot in the second warmest winter on record.
With a positive EPO phase, we potentially see extended fall. In a +EPO, we get a persistent low (vortex) in the northeast Pacific and Alaska, which creates favorable conditions for the dreaded PAC jet to inundate Canada and much of the continental US with warm Pacific air. If you have this kind of pattern persist, you can almost guarantee little cold and snow.
Here's a look at the positive and negative phases of the EPO and their effects on our sensible weather.
Overall, it looks like the teleconnections favor a closer to normal winter, despite the moderate-strong El Nino ENSO state, both in temperature, precipitation, and snowfall. The most favorable teleconnections however look to occur after January 15, which is in line with ENSO climatology for a Nino of this strength.
Current Conditions & Gut Feeling
Entering December, current conditions matter a little more than in the past given the release date and more mixed signal from ENSO. We are heading into December after our first below normal temperature November since 2019. November temperatures actually don't mean much for winter in Connecticut, but the upper level pattern does.
Rather than entering December staring down a blowtorch, which tends to be the case with El Nino years, especially recently, we have a -NAO unfolding and a continued teleconnection pattern that favors normal to below normal temperatures in early December.
Current Conditions & Gut Feeling
Entering December, current conditions matter a little more than in the past given the release date and more mixed signal from ENSO. We are heading into December after our first below normal temperature November since 2019. November temperatures actually don't mean much for winter in Connecticut, but the upper level pattern does.
Rather than entering December staring down a blowtorch, which tends to be the case with El Nino years, especially recently, we have a -NAO unfolding and a continued teleconnection pattern that favors normal to below normal temperatures in early December.
Before getting too excited, there is almost certainly going to be a mild period in December and probably all of our months even going into March. It looks like December will start out relatively below normal in temperatures. Climatology is still hostile for snow for most, so we're not expecting a particularly snowy period. We should mild up around the middle of the month, and then forecasts start to diverge with the European weekly guidance bringing in colder conditions again for the last 10 days or so of the month.
That's a departure from just a few weeks ago, which had December decidedly warmer than normal. Given current conditions, and the projected conditions in the first third of December, we think despite above normal temperatures on balance, the general pattern will be closer to what is necessary for a near normal winter. This ties into our gut feeling, that while a lot of focus will be on the fact that it's an El Nino, December being more normal seasonally as ENSO peaks in January means that another blowtorch over the winter and virtual snowless season is unlikely.
That's a departure from just a few weeks ago, which had December decidedly warmer than normal. Given current conditions, and the projected conditions in the first third of December, we think despite above normal temperatures on balance, the general pattern will be closer to what is necessary for a near normal winter. This ties into our gut feeling, that while a lot of focus will be on the fact that it's an El Nino, December being more normal seasonally as ENSO peaks in January means that another blowtorch over the winter and virtual snowless season is unlikely.
The Forecast
Now for the moment you've all been waiting for. How much snow in my backyard? Before going there, let's talk about what a normal season is.
Now for the moment you've all been waiting for. How much snow in my backyard? Before going there, let's talk about what a normal season is.
Above: the latest climatology for annual snowfall from the Northeast Regional Climate Center. Unfortunately, more detailed maps for CT are hard to come by.
Just using rough numbers:
For the southern Connecticut, snow tends to average between approximately 25-35", with the lowest in SE Connecticut due to marine influence of Long Island Sound and highest just a few miles inland. The official reporting station at Bridgeport averages 31.7" through the end of March annually.
For lower elevation in central northern CT, such as Hartford, Snowfall tends to average between 40-50". In Hartford it is probably around 45" a year, and at the official inland reporting station in Windsor Locks, an annual snowfall of 48.5" is the average.
In elevated hill towns in western and eastern CT, such as a Tolland or Torrington, you probably average between 50-60". The highest elevations in NW CT will average over 60".
Every year has warm and cold periods, as well as snowy/dry/wet periods. That's normal. It's the persistence of one or the other that will define the winter.
Just using rough numbers:
For the southern Connecticut, snow tends to average between approximately 25-35", with the lowest in SE Connecticut due to marine influence of Long Island Sound and highest just a few miles inland. The official reporting station at Bridgeport averages 31.7" through the end of March annually.
For lower elevation in central northern CT, such as Hartford, Snowfall tends to average between 40-50". In Hartford it is probably around 45" a year, and at the official inland reporting station in Windsor Locks, an annual snowfall of 48.5" is the average.
In elevated hill towns in western and eastern CT, such as a Tolland or Torrington, you probably average between 50-60". The highest elevations in NW CT will average over 60".
Every year has warm and cold periods, as well as snowy/dry/wet periods. That's normal. It's the persistence of one or the other that will define the winter.
Temperatures
This will answer a lot of the questions from our Facebook page. While there is the general feeling out there that the potentially strong El Nino will mean another blowtorch (over 3 degrees above normal), the current upper level pattern and long range teleconnection signal suggests that while it will be warmer than normal, it won't be overwhelmingly so. December has the strongest chance to finish above normal, and if January and February are a degree or two normal that doesn't necessarily preclude cold periods and a virtual snowless month.
This doesn't look like last year.
Temperature Forecast
December: 1 to 2 degrees above normal
January: 1 to 2 degrees above normal
February: -.5 degree below normal to 1 degree above normal
Winter Composite: 1-2 degrees above normal
Precipitation
With regard to precipitation, it looks like we will be returning to our wetter than normal pattern, though we do not expect nearly the amount of precipitation that we saw this summer and fall. That's easy to say, as summer holds more moisture in the air, but even relative to winters past, we don't see a high end high precipitation winter. Things look near to slightly above normal. The southern stream of the Jet Stream should be active, leading to storms that will balance out between snow, mixed, and rain events.
Precipitation Forecast
December: 100% to 120% of normal
January: 90% to 110% of normal
February: 90% to 110% of normal
Winter Composite: 90% to 110% of normal
Snowfall
It's all about snow. Some of you may have skipped the entire forecast to read this section. Snowfall dominates our perception of winter. Last year we actually started off ok with a minor early December event, but then the wheels fell off in epic fashion.
It's important to remember El Nino climatology. A Nino in itself isn't bad for a normal winter. Normally you have a warmer and less wintry December, followed by a transition to colder and more wintry conditions in the second half of January and through February and sometimes even early March. This is what we call a "backloaded winter" and that's the expectation here.
This year, we think the El Nino is balanced out by a favorable December teleconnection pattern. Even if December ends up less snowy than normal, the expectation is that after January 15, we see a return of favorable conditions for colder and snowy periods. There is a huge difference between this pattern on December 10 and January 10.
The thing to watch is not snow in December, but rather 1) whether the mild period materializes in mid-December/how strong it is, and 2) what the end of December upper level pattern becomes. If it is a transition earlier to more wintry conditions, that is a likely signal of an active and wintry 2024.
There hasn't been much winter the last half decade, and we are not calling for above normal snowfall, but normal seems like the most likely bet at this time, and that will feel like a strong winter given the lack of it we've seen the last few years.
With a more active southern stream we are likely to see storm tracks that are to our south and come close enough for additional all snow events. There will be more storms that cut to our west in December as the Pacific pattern sorts itself out. That should change in mid-late January through February, which is right where we normally see our main snow events. Using the rough averages posted above, this is what we see.
Remember, each month has its own snowfall average. You are least likely on average to see significant snow in December, with more in January, a peak in February, and some snow during the first 20 days of March.
Snowfall Forecast
December: 50% to 70% of normal
January: 80% to 100% of normal
February: 100% to 120% of normal
March: 80% to 100% of normal
Winter Snowfall: 80%-100% of normal across Connecticut
Overall, a pretty normal winter.
Finally, let us reiterate one more thing: normal is good. Sure, we have fun with the fact that there are winter lovers and winter haters, but I think what gets lost in our own individual concerns or rooting interests with weather is that each season serves an essential function for our environment. In spring, we need normal cloudy and rainy days to allow for the growing season to begin strong. In summer, we need drier periods to allow for growing but also humid days to prevent the kind of fire risk we see in the much drier west. In the fall, we need warm days and cool nights that allow for the growing season to end gradually and migration/hibernation patterns to remain consistent for native and visiting species alike. Extreme weather and harmful consequences fill the void when normal patterns and conditions are absent.
Having a winter with normal cold and normal snow/precipitation can slow or halt the creep of invasive species that thrive in warmer weather and severely impact our environment. Tick populations, that have a very real impact on people, can be culled somewhat with longer periods of cold weather that have become harder to achieve in recent years.
While it may be inconvenient, a normal winter would be welcome.
As always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.
Thank you for reading SCW.
-SCW Team (Written by DB)
This will answer a lot of the questions from our Facebook page. While there is the general feeling out there that the potentially strong El Nino will mean another blowtorch (over 3 degrees above normal), the current upper level pattern and long range teleconnection signal suggests that while it will be warmer than normal, it won't be overwhelmingly so. December has the strongest chance to finish above normal, and if January and February are a degree or two normal that doesn't necessarily preclude cold periods and a virtual snowless month.
This doesn't look like last year.
Temperature Forecast
December: 1 to 2 degrees above normal
January: 1 to 2 degrees above normal
February: -.5 degree below normal to 1 degree above normal
Winter Composite: 1-2 degrees above normal
Precipitation
With regard to precipitation, it looks like we will be returning to our wetter than normal pattern, though we do not expect nearly the amount of precipitation that we saw this summer and fall. That's easy to say, as summer holds more moisture in the air, but even relative to winters past, we don't see a high end high precipitation winter. Things look near to slightly above normal. The southern stream of the Jet Stream should be active, leading to storms that will balance out between snow, mixed, and rain events.
Precipitation Forecast
December: 100% to 120% of normal
January: 90% to 110% of normal
February: 90% to 110% of normal
Winter Composite: 90% to 110% of normal
Snowfall
It's all about snow. Some of you may have skipped the entire forecast to read this section. Snowfall dominates our perception of winter. Last year we actually started off ok with a minor early December event, but then the wheels fell off in epic fashion.
It's important to remember El Nino climatology. A Nino in itself isn't bad for a normal winter. Normally you have a warmer and less wintry December, followed by a transition to colder and more wintry conditions in the second half of January and through February and sometimes even early March. This is what we call a "backloaded winter" and that's the expectation here.
This year, we think the El Nino is balanced out by a favorable December teleconnection pattern. Even if December ends up less snowy than normal, the expectation is that after January 15, we see a return of favorable conditions for colder and snowy periods. There is a huge difference between this pattern on December 10 and January 10.
The thing to watch is not snow in December, but rather 1) whether the mild period materializes in mid-December/how strong it is, and 2) what the end of December upper level pattern becomes. If it is a transition earlier to more wintry conditions, that is a likely signal of an active and wintry 2024.
There hasn't been much winter the last half decade, and we are not calling for above normal snowfall, but normal seems like the most likely bet at this time, and that will feel like a strong winter given the lack of it we've seen the last few years.
With a more active southern stream we are likely to see storm tracks that are to our south and come close enough for additional all snow events. There will be more storms that cut to our west in December as the Pacific pattern sorts itself out. That should change in mid-late January through February, which is right where we normally see our main snow events. Using the rough averages posted above, this is what we see.
Remember, each month has its own snowfall average. You are least likely on average to see significant snow in December, with more in January, a peak in February, and some snow during the first 20 days of March.
Snowfall Forecast
December: 50% to 70% of normal
January: 80% to 100% of normal
February: 100% to 120% of normal
March: 80% to 100% of normal
Winter Snowfall: 80%-100% of normal across Connecticut
Overall, a pretty normal winter.
Finally, let us reiterate one more thing: normal is good. Sure, we have fun with the fact that there are winter lovers and winter haters, but I think what gets lost in our own individual concerns or rooting interests with weather is that each season serves an essential function for our environment. In spring, we need normal cloudy and rainy days to allow for the growing season to begin strong. In summer, we need drier periods to allow for growing but also humid days to prevent the kind of fire risk we see in the much drier west. In the fall, we need warm days and cool nights that allow for the growing season to end gradually and migration/hibernation patterns to remain consistent for native and visiting species alike. Extreme weather and harmful consequences fill the void when normal patterns and conditions are absent.
Having a winter with normal cold and normal snow/precipitation can slow or halt the creep of invasive species that thrive in warmer weather and severely impact our environment. Tick populations, that have a very real impact on people, can be culled somewhat with longer periods of cold weather that have become harder to achieve in recent years.
While it may be inconvenient, a normal winter would be welcome.
As always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.
Thank you for reading SCW.
-SCW Team (Written by DB)
