We have fully transitioned to spring in Connecticut. In fact, meteorological summer is just a month away! Much like with our significant winter storm forecasts, it's time to analyze our winter forecast for the 2023-24 season.
Our trend of extremely warm and underwhelming true winters continued with an important caveat--a higher end snowstorm in February that accounted for a substantial portion of our winter snowfall. We thought it'd be closer to a normal winter, and it wasn't even close. Let's look at the results.
Temperatures
We were far too conservative, and honestly, I wonder if the train is running away with regard to our winter temperature climate. We highlighted that the potentially strong El Nino could mean another blowtorch (over 3 degrees above normal), and while the upper level pattern didn't necessarily flood us with the kind of warmth we've seen in recent record warm winters, it was right up there with the warmest of them. We had warmth and very few extended cold periods. Once again, nighttime lows being well above normal really pushed temperature averages higher. We didn't have a true Arctic outbreak either. This kind of multi-year anomalous warmth has me concerned for the environmental changes that are taking root, but setting that aside, our temperature forecast was horrendous.
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
Temperature Actuals
December: +6.5 at Hartford/+3.9 at Bridgeport
January: +4.3 at Hartford/+3.1 at Bridgeport
February: +4.9 at Hartford/+3.6 at Bridgeport
Winter Composite: +5.3 at Hartford/+3.5 at Bridgeport
Grade: F
What's the Long Term Trend?
While it's easy enough to look at what happened and call it a day, I think it's also important to look at the long term trend we're seeing. Below is the average temperature at the official reporting stations of Hartford (BDL) and Bridgeport (BDR) for the last 30 years.
The green line is the average over the time period. The first thing you'll notice is that temperatures of course have a cyclical element to them. The late 90s had warm winters, followed by a series of colder than normal winters (actually some very cold winters) in the early 2000s.
What has me concerned about this most recent period is the duration of the warmth and scale of it. Some of our warmest winters on record have dominated the last decade. Worse, the most recent below normal winters have been warmer than preceding below normal winters. In the past, we had very few consecutive winters that were warmer than normal. At Hartford there are 3 years in the late 90s (1997-99), 2 years in the 2000s (2006-07), and 2 twice in 2012-2013 and again in 2016-2017. The years 2020-24 have all been above normal, and it has been nine years since our last truly cold winter.
This is exceptional warmth and the consecutive warm winters are already having an impact on our climate with things like the exploding tick population and rise of invasive species that are able to survive milder winters.
Indications already are that the next winter will be warm...
The precipitation grade won't be good either. We thought correctly that we'd be in a wetter than normal pattern, but quite frankly, we could not have guessed that we'd see a historically summer and fall continue through the winter. That's exactly what happened, as we saw a barrage of high precipitation winter storms.
Hartford had 7 days in the December-February period with 1" of precipitation or more. The average is 2.5 days. It also saw 14 days with .50" of precipitation. The average is 7. While it wasn't part of the forecast period, March was excessively wet as well. We said we didn't see a high end high precipitation winter and were dead wrong. Ugh.
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
Precipitation Forecast
December: 203% at Hartford/191% at Bridgeport
January: 164% at Hartford/210% at Bridgeport
February: 60% at Hartford/60% at Bridgeport
Winter Composite: 174% at Hartford (Record)/158% at Bridgeport
Grade: D-
What's the Long Term Trend?
I'm glad I looked at the longer term trend for precipitation, because this helped move the grade from F to D-. It's almost a pity move. This past winter was historically wet. Although we're looking at the 30 year period below at Hartford and Bridgeport I looked at the entire period of record at both locations, which goes back to 1905 at Hartford and 1948 at Bridgeport. This past winter was off the charts wet for Hartford--the wettest on record. The entire record. For Bridgeport it was the wettest in 30 years and second wettest on record. That's not something easily predicted.
With a changing climate you can see that we're seeing more precipitation laden winters as well. Keep in mind that we're looking at the winter season here, not the entire year, but we've seen consistently wetter than normal winters since about 2007, and very few consecutive drier than normal winters in the same period. As winters likely continue to warm, I don't think this general trend will stop, though we will certainly have below normal precipitation winters.
The historically wet winter merely adds insult to injury for snow lovers. Like we said in our forecast, it's all about snow. We expected a backloaded winter, and to the extent that there was a winter, it was backloaded. That doesn't help much, as both December and March were snowless despite plenty of precipitation. While we did see the upper level pattern materialize as we expected in January, it was just tough sledding to get any good cold into the region in time for our frequent storms. The one time it did, it was an exceptionally difficult and nearly miraculous winter storm that accounted for much of the snowfall in the state in February. Ironically, that storm was supposed to herald a very strong winter pattern, but that ended up being a dud.
Truly bad, and just a step above disastrous--both in the snowfall and forecast.
Unlike temperatures, I don't think that snowfall is settling into a new and far less wintry normal. We've seen plenty of storms in the 2010s, and I think we're just in a very poor period for snowfall.
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
Snowfall Forecast
December: 0% at Hartford/0% at Bridgeport
January: 109% at Hartford/65% at Bridgeport
February: 57% at Hartford/94% at Bridgeport
March: 0% at Hartford/0% at Bridgeport
Winter Composite: 48% at Hartford/46% at Bridgeport
Grade: F
What's the Long Term Trend?
I mean it sincerely when I write that I'm not sure if there is a discernible long term trend with snowfall. For the charts above, I used 30 years of records because you really want to see a multi-decadal period of record to have a real understanding of significant trends. Snowfall is highly variable. Some years are warm and snowy. Some years are cold and dry. Some years are normal, and other years have a big storm or two that skew numbers.
Let's look first at the length of the season. Here, this data uses Connecticut as a whole for first and last 1" snowfalls. These numbers vary widely between different snowfall amounts. What bolsters the overall data on the shortening of the winter season is the steep increase in the number of days in the growing season--weeks overall--in the last 30 years.
It's indisputable that the last half decade has been well below normal in snowfall. Rather than snow totals, let's look at a good proxy for the severity of storms--the amount of winter warnings issued. Here we're again looking statewide at winter storm warnings and blizzard warnings. You can tell that we're in lean years given the lack of warnings lately.
It was a bad winter and bad forecast. We thought it'd be warm, and it was a blowtorch. We thought it would be wet and it was a downright deluge. We thought snowfall would be near to below normal, and it was less than half of normal. In this multi-year period, we've learned how much the Pacific pattern is dominant. The combination of a strong El Nino and poor Pacific pattern overwhelmed any solid Atlantic pattern we had, and made even great track coastal storms way too warm for snow, especially at the coast. Winter lovers can take solace in one big winter storm for the year, but there is no joy to be found among the SCW team as we give this winter forecast our worst grade since publishing these. We hold ourselves accountable regardless.
Final Grade: F
Better luck next year.
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Thank you for reading SCW.
-DB