Good morning from Southern Connecticut Weather.
I'll get right to it. A significant winter storm is on the way. Winter storm warnings are up for all of the state for the first time this season. Let's dive in.
I'll get right to it. A significant winter storm is on the way. Winter storm warnings are up for all of the state for the first time this season. Let's dive in.
Above: the final call snow map, which was tweaked upward slightly.
Overall Setup
There aren't any substantive changes from what I said in the first call forecast about the overall setup. The cold is in place this morning with everyone in the teens and 20s currently. While temperatures will rise, we should have the cold held in place much better than the last mixed bag event. Our storm will quickly take shape later this evening as a low develops and slides off the coast and travels near the "Benchmark" which is a key zone for significant snows in New England. It's not quite a perfect system, however, as a warm nose could creep in aloft, leaving the chance of some mixing toward the end of the storm.
The NAM, which for a while was the least aggressive model, continues to show this risk in southern CT even as it comes in line with other guidance. Its depiction is below.
Overall Setup
There aren't any substantive changes from what I said in the first call forecast about the overall setup. The cold is in place this morning with everyone in the teens and 20s currently. While temperatures will rise, we should have the cold held in place much better than the last mixed bag event. Our storm will quickly take shape later this evening as a low develops and slides off the coast and travels near the "Benchmark" which is a key zone for significant snows in New England. It's not quite a perfect system, however, as a warm nose could creep in aloft, leaving the chance of some mixing toward the end of the storm.
The NAM, which for a while was the least aggressive model, continues to show this risk in southern CT even as it comes in line with other guidance. Its depiction is below.
The Forecast
Timing
To my surprise, this looks like the onset has slowed down some. That's a bit unusual given how quickly the flow has been. The overall thoughts are not that much different however in the whole scheme of things. It's still a fast mover, and today the overwhelming majority of activities are fine. Now it does look like snow starts between about 7-10pm. Snow should start from SW to NE, and the heavy snow will get going pretty quickly after onset, meaning you will probably want to be off the roads before if not shortly after the snow starts in your area. Travel late tonight into early Sunday will be tough.
The worst of the storm happens in the overnight hours, from about 10pm to 2am, with snow gradually diminishing in intensity after that. There is agreement that snow is done by late morning, so while the morning commute may be a little tricky, the afternoon should be fine and Super Bowl events should not be disrupted too much.
Snowfall Accumulation
Like the last few storms, I am tweaking the forecast just a bit to take the floor and ceiling up. I am now going with a statewide 5-10" zone as opposed to the original 4-8" forecast. This is primarily because high resolution guidance has gotten on board that the storm develops fast enough to bring a dynamic period of heavy snow to most of Connecticut as the storm passes to our south. With a developing storm however, there are some risks. With banding, there will be proverbial winners and losers, with some towns ending up with higher totals and the next town over maybe ending a little low because of subsidence (read: dry slotting).
The other risk that is on my mind is the prospect of mixing late in the storm as a warm nose tries to creep in aloft. This could mean a period of sleet or freezing drizzle in southern CT as precipitation slackens on the backside of the storm. That would actually make the storm a little more impactful, even if it cut down on totals some. My expectation is that ratios stay relatively close to 10:1, but for a time, particularly during the heaviest snow, there may be some very efficient snow growth. I think that introduces the risk that some spots end up with slightly over 8". For the coast, I think that the mix risk (which looks fairly likely at some point near the end of the storm) is not enough to preclude widespread 5" minimum totals. I'll be extremely annoyed if somehow we see widespread 4" amounts haha.
Here, I think the global models--the GFS and Euro are a good guide post. They bring in pretty significant precipitation overall with both showing a period of heavy snow. This is a better setup for significant snow than the mixed bag a few days ago, but folks need to keep expectations in check. I still think most places end up with between 5-8" of snow. Plenty significant considering that such a range represents half of what all of February usually produces. If the storm comes together a little faster or banding is oriented over CT better, there is a little upside. If it is slower to organize, the floor and ceiling are lowered. Simple as that.
Timing
To my surprise, this looks like the onset has slowed down some. That's a bit unusual given how quickly the flow has been. The overall thoughts are not that much different however in the whole scheme of things. It's still a fast mover, and today the overwhelming majority of activities are fine. Now it does look like snow starts between about 7-10pm. Snow should start from SW to NE, and the heavy snow will get going pretty quickly after onset, meaning you will probably want to be off the roads before if not shortly after the snow starts in your area. Travel late tonight into early Sunday will be tough.
The worst of the storm happens in the overnight hours, from about 10pm to 2am, with snow gradually diminishing in intensity after that. There is agreement that snow is done by late morning, so while the morning commute may be a little tricky, the afternoon should be fine and Super Bowl events should not be disrupted too much.
Snowfall Accumulation
Like the last few storms, I am tweaking the forecast just a bit to take the floor and ceiling up. I am now going with a statewide 5-10" zone as opposed to the original 4-8" forecast. This is primarily because high resolution guidance has gotten on board that the storm develops fast enough to bring a dynamic period of heavy snow to most of Connecticut as the storm passes to our south. With a developing storm however, there are some risks. With banding, there will be proverbial winners and losers, with some towns ending up with higher totals and the next town over maybe ending a little low because of subsidence (read: dry slotting).
The other risk that is on my mind is the prospect of mixing late in the storm as a warm nose tries to creep in aloft. This could mean a period of sleet or freezing drizzle in southern CT as precipitation slackens on the backside of the storm. That would actually make the storm a little more impactful, even if it cut down on totals some. My expectation is that ratios stay relatively close to 10:1, but for a time, particularly during the heaviest snow, there may be some very efficient snow growth. I think that introduces the risk that some spots end up with slightly over 8". For the coast, I think that the mix risk (which looks fairly likely at some point near the end of the storm) is not enough to preclude widespread 5" minimum totals. I'll be extremely annoyed if somehow we see widespread 4" amounts haha.
Here, I think the global models--the GFS and Euro are a good guide post. They bring in pretty significant precipitation overall with both showing a period of heavy snow. This is a better setup for significant snow than the mixed bag a few days ago, but folks need to keep expectations in check. I still think most places end up with between 5-8" of snow. Plenty significant considering that such a range represents half of what all of February usually produces. If the storm comes together a little faster or banding is oriented over CT better, there is a little upside. If it is slower to organize, the floor and ceiling are lowered. Simple as that.
Above: this morning's GFS depiction of our fast moving system. Even with the mix line close to the coast, there is a period of heavy snow overnight for most of CT that produces significant snowfall totals. The Euro effectively mirrors this.
Impact
This still looks like a moderate impact event, mostly because of the timing. Most of Saturday is fine, and the worst of the storm is Saturday night into Sunday morning. Super Bowl parties are still a go Sunday afternoon and evening when the storm is long gone. That said, tonight and Sunday morning will not be smooth sailing. Expect bad road conditions, delayed flights, and poor visibility during the worst of the storm. If there is some mixing, that could leave a heavier crust on top of what should be more powdery/fluffy snow and icy conditions, especially in southern CT. I don't think we have significant wind or power issues. Overall, it's a significant but fast moving winter storm that's hitting at a time of minimum impact.
After this one, we turn our attention to Tuesday, which is the next opportunity for snowfall. It has trended south and less impactful, for now.
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 still looks like a moderate impact event, mostly because of the timing. Most of Saturday is fine, and the worst of the storm is Saturday night into Sunday morning. Super Bowl parties are still a go Sunday afternoon and evening when the storm is long gone. That said, tonight and Sunday morning will not be smooth sailing. Expect bad road conditions, delayed flights, and poor visibility during the worst of the storm. If there is some mixing, that could leave a heavier crust on top of what should be more powdery/fluffy snow and icy conditions, especially in southern CT. I don't think we have significant wind or power issues. Overall, it's a significant but fast moving winter storm that's hitting at a time of minimum impact.
After this one, we turn our attention to Tuesday, which is the next opportunity for snowfall. It has trended south and less impactful, for now.
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
