Good evening from Southern Connecticut Weather!
Well, the **SCW 2025-26 Winter Forecast** was released yesterday, and we quickly turn the page to actual tracking and forecasting for the start of Meteorological Winter, which officially begins December 1.
We have increasing confidence that winter gets off to a fast start with a quick moving storm system expected to move into the region Tuesday. This is a quick look at what we're seeing so far, and where the current forecasting uncertainty is.
Expect our first call forecast and snow map to be issued tomorrow with a final call on Monday.
Well, the **SCW 2025-26 Winter Forecast** was released yesterday, and we quickly turn the page to actual tracking and forecasting for the start of Meteorological Winter, which officially begins December 1.
We have increasing confidence that winter gets off to a fast start with a quick moving storm system expected to move into the region Tuesday. This is a quick look at what we're seeing so far, and where the current forecasting uncertainty is.
Expect our first call forecast and snow map to be issued tomorrow with a final call on Monday.
Above: our new forecasting timeline graphic. This storm is currently at the edge of the medium range, which means that while there is increasing confidence that a storm is possible, there's still a lot of uncertainty.
Overall Setup
A coming cold front on Sunday is a big factor in what happens in Connecticut on Tuesday. Tomorrow we will start off with rain showers and perhaps some snow showers in colder spots in northern CT as a system that is moving well to our north drags in a reinforcing shot of cold. Tomorrow will be wet, particularly in the afternoon and evening, so expect some minor travel issues given how many are traveling tomorrow.
Overall Setup
A coming cold front on Sunday is a big factor in what happens in Connecticut on Tuesday. Tomorrow we will start off with rain showers and perhaps some snow showers in colder spots in northern CT as a system that is moving well to our north drags in a reinforcing shot of cold. Tomorrow will be wet, particularly in the afternoon and evening, so expect some minor travel issues given how many are traveling tomorrow.
Above: the 18z high resolution NAM depicting the rain showers that are likely to be around tomorrow. Although morning showers (and snow showers/mixed precipitation) is possible, the heaviest rain is likely in the afternoon before clearing tomorrow evening.
In the wake of the storm, a high pressure system will hold colder air in place on Monday, and the storm approaches Tuesday.
In the wake of the storm, a high pressure system will hold colder air in place on Monday, and the storm approaches Tuesday.
Above: the 18z Euro depicting the high pressure in New England. This will hold the cold in place, at least temporarily.
As you can see from the image above, by late Monday (00z Tuesday is 7pm Monday Eastern Time) our storm is starting to take shape, with two distinct pieces over the south and Great Lakes region respectively.
Here's where it gets complicated. Our high pressure will start retreating, which makes our hold to slip on the kind of cold necessary at the surface and aloft for an all snow event. This retreating high also helps open the door for the storm to more north, which could introduce more warmth depending on how strong it is.
As you can see from the image above, by late Monday (00z Tuesday is 7pm Monday Eastern Time) our storm is starting to take shape, with two distinct pieces over the south and Great Lakes region respectively.
Here's where it gets complicated. Our high pressure will start retreating, which makes our hold to slip on the kind of cold necessary at the surface and aloft for an all snow event. This retreating high also helps open the door for the storm to more north, which could introduce more warmth depending on how strong it is.
Above: the 18z Euro 500mb depiction of the system moving through the region late Monday through Wednesday morning. Below is the 18z GFS depiction in the same time period. The subtle differences in how they manage the development of the storm have a big impact on what the overall weather will be.
The Current Scenarios
Earlier I wrote about three scenarios, but I've refined them a little since then.
1. "North Track": 40% Chance
In this scenario, a strong low pressure amplifies further north, which would bring a snow to mix to rain event to most of the state. This would keep snow totals down for most of the state, with more rain for the coast and areas east of I-84. The GFS and long range NAM (which we do not find to be in its useful range yet) lead the way with this scenario.
Below is the 18z GFS depiction for Tuesday. The storm quickly moves through the region, and while we start off as snow, the surface low crosses SE Mass, bringing warmth to much of the state--enough for a flip to rain for many. Note the second graphic with temperatures at approximately 7pm Tuesday.
Earlier I wrote about three scenarios, but I've refined them a little since then.
1. "North Track": 40% Chance
In this scenario, a strong low pressure amplifies further north, which would bring a snow to mix to rain event to most of the state. This would keep snow totals down for most of the state, with more rain for the coast and areas east of I-84. The GFS and long range NAM (which we do not find to be in its useful range yet) lead the way with this scenario.
Below is the 18z GFS depiction for Tuesday. The storm quickly moves through the region, and while we start off as snow, the surface low crosses SE Mass, bringing warmth to much of the state--enough for a flip to rain for many. Note the second graphic with temperatures at approximately 7pm Tuesday.
2. "Thread the Needle": 50% Chance
In this scenario, our high pressure still retreats, but because the low pressure amplifies less and further south, the cold is locked in for longer, and most of the state stays snow or snow/sleet. This scenario provides the most frozen precipitation, though even at the coast there's likely going to be some rain. In early December it is simply climatologically favored (read: normal) for the shoreline to rain, especially in a retreating high scenario.
After leaning toward the third scenario for a while, the Euro has shifted toward this scenario, and is followed by some (but not all) of the second tier guidance. Note how temperatures are much colder for interior CT.
In this scenario, our high pressure still retreats, but because the low pressure amplifies less and further south, the cold is locked in for longer, and most of the state stays snow or snow/sleet. This scenario provides the most frozen precipitation, though even at the coast there's likely going to be some rain. In early December it is simply climatologically favored (read: normal) for the shoreline to rain, especially in a retreating high scenario.
After leaning toward the third scenario for a while, the Euro has shifted toward this scenario, and is followed by some (but not all) of the second tier guidance. Note how temperatures are much colder for interior CT.
3. Well South and Shredded: 10% Chance
This scenario has fallen out of favor a lot in the last day because of the guidance ticking more amplified, but if this were to occur, essentially our wave would end up much weaker and further off the coast. This would probably be the coldest solution, but it would also be the least impactful for the state.
At this time, only a few members of the ensembles show this potential. I do not think it is terribly viable at this time.
Ok, so how much snow?
Given how closely scenarios one and two are in likelihood, and how different our weather will be depending on which wins out, it's not the time for a snow map. That's coming tomorrow. What we can say however is that we currently expect a low to moderate impact event in CT on Tuesday with accumulating snow possible as early as Tuesday morning statewide. For inland CT, this looks like a plowable snowfall. Along the shoreline, there is much more uncertainty.
If I were making a map right now (and I am definitely not!) I would probably go with a coating to 2" along the coast and for much of New London County, with 2-5" elsewhere. But let's see how I feel tomorrow.
Stay tuned.
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
This scenario has fallen out of favor a lot in the last day because of the guidance ticking more amplified, but if this were to occur, essentially our wave would end up much weaker and further off the coast. This would probably be the coldest solution, but it would also be the least impactful for the state.
At this time, only a few members of the ensembles show this potential. I do not think it is terribly viable at this time.
Ok, so how much snow?
Given how closely scenarios one and two are in likelihood, and how different our weather will be depending on which wins out, it's not the time for a snow map. That's coming tomorrow. What we can say however is that we currently expect a low to moderate impact event in CT on Tuesday with accumulating snow possible as early as Tuesday morning statewide. For inland CT, this looks like a plowable snowfall. Along the shoreline, there is much more uncertainty.
If I were making a map right now (and I am definitely not!) I would probably go with a coating to 2" along the coast and for much of New London County, with 2-5" elsewhere. But let's see how I feel tomorrow.
Stay tuned.
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
