Good evening from Southern Connecticut Weather!
For most of the last decade, winter was hard to find. From blowtorches to poorly positioned patterns to just plain bad luck, winter had trouble sticking around.
Not so much this year.
A cool end of summer and fall has led to our coldest winter in 15 years. As I type, we're in the midst of a higher end cold snap, frequently sourced directly from the Arctic. Meteorological Winter, which lasts December-February is now 2/3 of the way done, and normally during a La Nina winter we can expect that spring would be around the corner about now. While we are gaining over two minutes of sunlight each day now, there is no such luck that it coincides with an early spring this year.
In this special discussion I want to take a look at the winter so far, where it stacks up against others, and provide a bit of an outlook for what's ahead.
For most of the last decade, winter was hard to find. From blowtorches to poorly positioned patterns to just plain bad luck, winter had trouble sticking around.
Not so much this year.
A cool end of summer and fall has led to our coldest winter in 15 years. As I type, we're in the midst of a higher end cold snap, frequently sourced directly from the Arctic. Meteorological Winter, which lasts December-February is now 2/3 of the way done, and normally during a La Nina winter we can expect that spring would be around the corner about now. While we are gaining over two minutes of sunlight each day now, there is no such luck that it coincides with an early spring this year.
In this special discussion I want to take a look at the winter so far, where it stacks up against others, and provide a bit of an outlook for what's ahead.
Above: a visible satellite image of the east coast and the big winter storm that produced more than a foot of snow in the Carolinas, and triggered snow as far south as Naples, FL. Snow cover extends from Canada to Georgia in this image.
Temperature
You don't really need me to tell you that it's been cold, but just how cold has it been?
There are a few ways to look at this. Let's start in the most recent Arctic outbreak.
In the last 7 days (ending yesterday), the average temperature at Hartford (BDL) was a frigid 10.8 degrees. Where does that stack up?
The last four times that we've had a week with the average temperature this cold was 2018, 2015, 2005, and 2000. For the same period at Bridgeport (BDR) the average temperature was 17.1, driven higher in large part due to warmer low temperatures. For this station, 2018, 2015, 2005, and 2004 were the last time a week had been so cold.
In a streak that was broken today, BDL recorded 9 consecutive days with high temperatures at or below 25, tied with the historic cold outbreak in 2018. The streak was one day short of making this the coldest stretch by this metric since 1979.
Temperature
You don't really need me to tell you that it's been cold, but just how cold has it been?
There are a few ways to look at this. Let's start in the most recent Arctic outbreak.
In the last 7 days (ending yesterday), the average temperature at Hartford (BDL) was a frigid 10.8 degrees. Where does that stack up?
The last four times that we've had a week with the average temperature this cold was 2018, 2015, 2005, and 2000. For the same period at Bridgeport (BDR) the average temperature was 17.1, driven higher in large part due to warmer low temperatures. For this station, 2018, 2015, 2005, and 2004 were the last time a week had been so cold.
In a streak that was broken today, BDL recorded 9 consecutive days with high temperatures at or below 25, tied with the historic cold outbreak in 2018. The streak was one day short of making this the coldest stretch by this metric since 1979.
Bridgeport hasn't had cold that deep, but it has been in a deep freeze. The BDR streak also ended today.
Now let's zoom out a little and look at the season so far.
Both Hartford and Bridgeport finished December and January below normal, with December colder relative to normal than January, which had the mini thaw early.
For Bridgeport, this is the 23rd coldest winter as of January 31. The four most recent that were as cold are 2011, 2009, 2004, and 2003.
For Hartford (BDL), this is the 19th coldest winter as of January 31. The four most recent that were as cold are 2011, 2004, 2003, and 2001.
This is particularly impressive to me given that three of the top five warmest starts to winter have happened in the last ten years.
What do the numbers so far tell us? It tells us that while we've been cold for sure, this season really settles into more classic New England winter territory rather than all-time cold. We've been spoiled with warm winters. This year so far has returned to what many used to know.
This comes with a caveat. Most agree that the teleconnection pattern, specifically the -WPO, has allowed for persistent cold loading in Canada with shots of Arctic cold flowing into the east. This happens as the WPO along with a more favorable (for winter weather lovers) EPO and AO in the Atlantic force ridging into the Arctic and displace the cold further southeast.
That has not been the case everywhere. As cold as it has been here, it has been an absolute blowtorch on average in the rest of the country since November, especially in the Rockies.
Both Hartford and Bridgeport finished December and January below normal, with December colder relative to normal than January, which had the mini thaw early.
For Bridgeport, this is the 23rd coldest winter as of January 31. The four most recent that were as cold are 2011, 2009, 2004, and 2003.
For Hartford (BDL), this is the 19th coldest winter as of January 31. The four most recent that were as cold are 2011, 2004, 2003, and 2001.
This is particularly impressive to me given that three of the top five warmest starts to winter have happened in the last ten years.
What do the numbers so far tell us? It tells us that while we've been cold for sure, this season really settles into more classic New England winter territory rather than all-time cold. We've been spoiled with warm winters. This year so far has returned to what many used to know.
This comes with a caveat. Most agree that the teleconnection pattern, specifically the -WPO, has allowed for persistent cold loading in Canada with shots of Arctic cold flowing into the east. This happens as the WPO along with a more favorable (for winter weather lovers) EPO and AO in the Atlantic force ridging into the Arctic and displace the cold further southeast.
That has not been the case everywhere. As cold as it has been here, it has been an absolute blowtorch on average in the rest of the country since November, especially in the Rockies.
Above: an analysis of the overall temperature from November 1-January 31. While it's been cold here, it's been very warm for the rest of the country.
Snowfall
Snowfall
Above: today's snowfall analysis around the continental U.S., showing approximately 41% of the country under some level of snow cover. Every state east of the Rockies has seen snow this winter.
December started out cold and not particularly snowy, but the period leading up to the holidays got active, followed by a mini thaw in January and then our blockbuster winter storm. There's always the question of whether a cold pattern will lead to snow, and overall, that has been the case so far.
December started out cold and not particularly snowy, but the period leading up to the holidays got active, followed by a mini thaw in January and then our blockbuster winter storm. There's always the question of whether a cold pattern will lead to snow, and overall, that has been the case so far.
Above is the snowfall accumulation graph for Hartford (BDL) from the start of Meteorological Winter on December 1 through today. The blue line is our record season to date and the red line is our record lowest season to date. The brown line is normal and the green is this season. As you can see, for much of January BDL was actually below normal snowfall overall, until the blockbuster storm put us well above normal, for now.
Bridgeport is even more impressive. If you like winter in southern CT you love this graph. Since about mid-December Bridgeport and much of coastal CT have been above normal in snowfall, and the big storm put us well above normal here. It would take a significant reversal of the pattern at this point for southern CT to end the season below normal. That said, there's still plenty of time...
Once again, what we see from the data is that we're back in classic New England winter territory. For CT, this winter has been good to great so far if you like snowfall. The data also show how important it is for both smaller events (the small jumps in accumulation) and larger ones to hit in order to reach our normal snowfall.
All that said, we are still not getting enough precipitation. Remember that the snow we watch accumulate is mostly air, and without moisture laden systems we can still have an active winter and come out of it drier than normal. We're on track for that with a dry spell that goes back to fall.
Once again, what we see from the data is that we're back in classic New England winter territory. For CT, this winter has been good to great so far if you like snowfall. The data also show how important it is for both smaller events (the small jumps in accumulation) and larger ones to hit in order to reach our normal snowfall.
All that said, we are still not getting enough precipitation. Remember that the snow we watch accumulate is mostly air, and without moisture laden systems we can still have an active winter and come out of it drier than normal. We're on track for that with a dry spell that goes back to fall.
Although it's not too bad right now, we could use a more active period of storms.
Above: the Drought Monitor showing most of CT back in abnormally dry conditions.
What's to Come
What's to Come
Above: the Climate Prediction Center (CPC) forecast for February temperatures. The CPC lists the state as having a 50-60% chance of finishing February below normal temperature. We concur.
In the temperature category, as a reminder in our winter forecast we discussed how the transition away from La Nina could mean that we don't have a typical early spring that you get in a textbook Nina. That seems to be the case, with the La Nina still hanging on but barely.
Looking at our teleconnection forecast, we so far have accurately predicted that the PNA would be less hostile. This teleconnection is essential to cold loading in the east. However, we were way off on the WPO, which is a new one we featured this year. It has been strongly negative, which has overwhelmed the periods where other teleconnection states would have otherwise suggested periods of warmth in the east.
In the temperature category, as a reminder in our winter forecast we discussed how the transition away from La Nina could mean that we don't have a typical early spring that you get in a textbook Nina. That seems to be the case, with the La Nina still hanging on but barely.
Looking at our teleconnection forecast, we so far have accurately predicted that the PNA would be less hostile. This teleconnection is essential to cold loading in the east. However, we were way off on the WPO, which is a new one we featured this year. It has been strongly negative, which has overwhelmed the periods where other teleconnection states would have otherwise suggested periods of warmth in the east.
Note how low the WPO was before the start of February, and note where it is going. This sharp rise to positive strongly suggests that our cold source may get cut off after this week. Note how it starts a sharp decline afterward on the guidance. Our next thaw is unlikely to herald an early spring. Other models also strongly suggest that the Arctic spigot gets cut off after another big shot at the end of the week.
Despite the break of the freezing streak in Connecticut today, there is another perhaps bigger shot of Arctic air that is increasingly likely this weekend. After that, we should break the pattern of Arctic cold, at least through mid-February. However, as we get to the end of the month and head into March, we should start seeing a colder pattern, but less extreme than the one we're in now, taking shape again. At that point in the season, as climatology starts to move toward spring, the exceptional Arctic outbreaks seem less likely.
However, as that temperature contrast (baroclinic zone) shifts, that may be when our storm pattern becomes more active for all types of wintry storms and even a few storms that cut to our west. If there is a Sudden Stratospheric Warming Event, this month, as some guidance continues to suggest, that heightens the odds that March starts out cold and potentially stormy.
Folks, we are not marching toward spring yet...
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.
-DB
Despite the break of the freezing streak in Connecticut today, there is another perhaps bigger shot of Arctic air that is increasingly likely this weekend. After that, we should break the pattern of Arctic cold, at least through mid-February. However, as we get to the end of the month and head into March, we should start seeing a colder pattern, but less extreme than the one we're in now, taking shape again. At that point in the season, as climatology starts to move toward spring, the exceptional Arctic outbreaks seem less likely.
However, as that temperature contrast (baroclinic zone) shifts, that may be when our storm pattern becomes more active for all types of wintry storms and even a few storms that cut to our west. If there is a Sudden Stratospheric Warming Event, this month, as some guidance continues to suggest, that heightens the odds that March starts out cold and potentially stormy.
- The bottom line as we look ahead is that the odds of big Arctic outbreaks look to be over after the latest and possibly strongest one coming this weekend.
- In the wake of this outbreak, a mid-month thaw is increasingly likely.
- A colder than normal pattern is still likely to return by the latter part of February.
- We have likely not seen our last snowfall, as a potentially stormy pattern guides us into at least mid-March.
Folks, we are not marching toward spring yet...
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.
-DB
