It’s not often that I feel the need to begin any conversation with the headline above, but in this instance, there is growing confidence that the state will experience a very significant winter weather event in less than 48 hours. Blizzard Watches remain up for the shoreline and southeastern counties, with winter storm warnings for the rest of the state. I would not be surprised to see blizzard headlines extended further inland at some point before or during this storm.
The afternoon guidance came in and had near unanimous agreement that a major winter storm is poised to hit the state. To be clear however, there are still details that, while small, are going to be critical in determining whether this is merely a major storm or a storm that reaches its atmospheric potential. There is a lot to discuss. Here’s what we know right now and here is our new map:
- It is increasingly likely that a major winter storm with widespread blizzard like conditions will impact the state on Tuesday.
- Right now, we expect snow to break out over the state early Tuesday morning before sunrise. The worst of the storm occurs between about 10am and 8pm, with conditions improving during the overnight hours.
- The combination of heavy snow and high winds will make many roads difficult if not nearly impossible to travel on safely.
- The high wind potential statewide has increased, and right now I expect scattered power outages for most of the state with possible widespread power outages in southeastern and coastal Connecticut.
- We see an upper end moderate coastal flooding potential, especially in the western portion of the Sound.
- We expect widespread cancellations and closings on Tuesday, with delays possible on Wednesday morning.
The Setup
The synoptic setup remains the same as we discussed in our last discussion. In the south, we will soon have an area of low pressure gathering strength and moving up the coast. As that happens, another low will be diving down from the Midwest. Monday and Tuesday these areas interact, with the Midwest low phasing with the Atlantic low.
The synoptic setup remains the same as we discussed in our last discussion. In the south, we will soon have an area of low pressure gathering strength and moving up the coast. As that happens, another low will be diving down from the Midwest. Monday and Tuesday these areas interact, with the Midwest low phasing with the Atlantic low.
Above you see the 12z CMC, which is on the western envelope of guidance but has the right general idea.
From there, it’s bombs away. The Atlantic low begins to rapidly deepen and move along the coast. As TW mentioned yesterday, one thing we are watching is the storm becoming too amplified too early, bringing the system further west, meaning more rain or mix for southeast Connecticut and the shoreline. Even in this case, warning level snows would most likely fall.
The other scenario we were watching, a south and east track, has become less of a concern today, with all the models save the GFS going with a further west and more amplified track. The GFS actually had this kind of scenario at the midday runs but we’re considering it less given the other consensus.
The other scenario we were watching, a south and east track, has become less of a concern today, with all the models save the GFS going with a further west and more amplified track. The GFS actually had this kind of scenario at the midday runs but we’re considering it less given the other consensus.
Impacts
Snowfall--right now, we’re taking a middle of the road approach when it comes to snowfall totals. We’re in line with many, but there are others who are going with higher totals. It is entirely possible that we increase these numbers tomorrow, but beware, there are still red flags that need to be resolved. We’re not just looking at the surface track, but also the trends in the mid to upper levels. In the upper levels, we’re watching how quickly things come together and how clean a phase we see. In the mid-levels, our best storms happen when we get a good 700mb low track. Usually, we’re in the best banding when that low is nearby. Take a look at this on the CMC. The surface and midlevel track will determine what kind of banding and dry slotting we see. This isn’t resolved yet, so stay tuned.
Snowfall--right now, we’re taking a middle of the road approach when it comes to snowfall totals. We’re in line with many, but there are others who are going with higher totals. It is entirely possible that we increase these numbers tomorrow, but beware, there are still red flags that need to be resolved. We’re not just looking at the surface track, but also the trends in the mid to upper levels. In the upper levels, we’re watching how quickly things come together and how clean a phase we see. In the mid-levels, our best storms happen when we get a good 700mb low track. Usually, we’re in the best banding when that low is nearby. Take a look at this on the CMC. The surface and midlevel track will determine what kind of banding and dry slotting we see. This isn’t resolved yet, so stay tuned.
Wind--wind has become a much greater threat in my opinion over the last 24 hours. The guidance has begun leaning toward much more wind during the height of the storm, with the Euro coming in with concerning depictions of peak wind gusts. We think that gusts between 40-60mph are possible statewide, with gusts that could be higher depending on the track of the low. People in areas that typically lose power should be preparing for outages, and others should closely watch the trends and be prepared as well. I don't think the euro winds verify, but if they did, it would be an extreme event across Connecticut.
12z GFS 10m wind gust potential. Image courtesy of Weatherbell Analytics.
Coastal Flooding--with the potential strength of the low, we are concerned about the potential of coastal flooding. If it happens, we think the most likely location is the western part of the Sound.
Duration/Timing--the guidance has slowed down the storm over the last few runs, but I still think that overall, this ends up being a shorter duration storm than some of our biggest events. This should cut down on snowfall accumulation potential. This should be a one day event, with the biggest impact happening during the day and into the early evening. In terms of timing, I think onset happens in the pre-dawn hours on Tuesday and effectively ends Tuesday night before midnight, though I can’t rule out continued light snow or snow showers into the early hours of Wednesday. I expect roads to be mostly cleared by the Wednesday morning commute, but delays are possible.
What to Watch For
As we continue tracking this over next 24-36 hours, there are things we won’t quite know until game time.
As we continue to track this, a little perspective. We’re not calling for historically high snowfall totals. This is likely to be a blizzard for many, and it’s important to remember that the combination of impacts makes this a potentially very high impact event. Take the storm seriously even if it isn't projected to be historic in the snowfall or duration department.
This forecast is highly volatile and dependent on many moving parts, so things can certainly change over the next 24-36 hours. Stay tuned for no hype updates. As always, thank you for continuing to make Southern Connecticut Weather your trusted source for all things Connecticut weather.
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!
-DB
Duration/Timing--the guidance has slowed down the storm over the last few runs, but I still think that overall, this ends up being a shorter duration storm than some of our biggest events. This should cut down on snowfall accumulation potential. This should be a one day event, with the biggest impact happening during the day and into the early evening. In terms of timing, I think onset happens in the pre-dawn hours on Tuesday and effectively ends Tuesday night before midnight, though I can’t rule out continued light snow or snow showers into the early hours of Wednesday. I expect roads to be mostly cleared by the Wednesday morning commute, but delays are possible.
What to Watch For
As we continue tracking this over next 24-36 hours, there are things we won’t quite know until game time.
- Exact track—It is important to know that the guidance is resolving issues on a global scale. 50-75 mile track shifts in our part of the globe happen. That’s why it’s important to have snowfall ranges here. Track matters and it impacts banding. We won’t know where it happens, we will, however, be able to predict the best spots by tomorrow.
- Dry slotting—as I mentioned earlier, where there is banding we have to watch for dryslotting nearby.
- Wind—wind speeds are often overmodeled during these events, I accounted for that in my forecast but if the track is close enough and the euro wind gusts come close to verifying watch out.
As we continue to track this, a little perspective. We’re not calling for historically high snowfall totals. This is likely to be a blizzard for many, and it’s important to remember that the combination of impacts makes this a potentially very high impact event. Take the storm seriously even if it isn't projected to be historic in the snowfall or duration department.
This forecast is highly volatile and dependent on many moving parts, so things can certainly change over the next 24-36 hours. Stay tuned for no hype updates. As always, thank you for continuing to make Southern Connecticut Weather your trusted source for all things Connecticut weather.
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!
-DB
