Good evening from SCW.
Winter Storm Watches are up for all of Connecticut in anticipation of a winter storm that will impact the state Monday and Tuesday. In this first call, I am forecasting a moderate to high impact event, with highest impacts occurring Monday afternoon into Tuesday morning.
There's still a good amount of uncertainty so let's dive right in.
Winter Storm Watches are up for all of Connecticut in anticipation of a winter storm that will impact the state Monday and Tuesday. In this first call, I am forecasting a moderate to high impact event, with highest impacts occurring Monday afternoon into Tuesday morning.
There's still a good amount of uncertainty so let's dive right in.
Above: the SCW First Call Snow Map. For now, we want to hedge more broad and conservative with snowfall given the continued uncertainty and changes we've seen today on the guidance.
Overall Evolution
Things remain consistent with what I mentioned in prior updates. Our storm that came in on the California coast earlier in the week has reached the Midwest, with snow falling at this hour in Chicago. Tomorrow the storm will move into the Mid-Atlantic and begin redeveloping offshore, making it a Miller B type storm.
As it develops, it will be a strong low, but a bit more broad than usual. That means two things. First, there will be a very strong easterly flow that should throw heavy precipitation back into southern New England for a period. It also means that there's more of a chance of at least some dryslotting in the CT River Valley (Hartford and points north) as downsloping takes shape. Even so, right now I think whatever dryslotting that takes place is relatively minor, allowing for significant snow totals across the state.
As the low moves northeastward, there is a greater likelihood that mixing takes place along coastal CT, especially in SE CT. This is fairly typical in our noreasters, and has become a more prominent feature on the guidance today. That said, the antecedent cold looks pretty good, and most of what falls is likely to be snow even at the shore as the front end of the system comes in. Sleet would be the predominant mixing type.
Things remain consistent with what I mentioned in prior updates. Our storm that came in on the California coast earlier in the week has reached the Midwest, with snow falling at this hour in Chicago. Tomorrow the storm will move into the Mid-Atlantic and begin redeveloping offshore, making it a Miller B type storm.
As it develops, it will be a strong low, but a bit more broad than usual. That means two things. First, there will be a very strong easterly flow that should throw heavy precipitation back into southern New England for a period. It also means that there's more of a chance of at least some dryslotting in the CT River Valley (Hartford and points north) as downsloping takes shape. Even so, right now I think whatever dryslotting that takes place is relatively minor, allowing for significant snow totals across the state.
As the low moves northeastward, there is a greater likelihood that mixing takes place along coastal CT, especially in SE CT. This is fairly typical in our noreasters, and has become a more prominent feature on the guidance today. That said, the antecedent cold looks pretty good, and most of what falls is likely to be snow even at the shore as the front end of the system comes in. Sleet would be the predominant mixing type.
The 18z GFS depiction of the storm. Although it tries to bring rain into parts of the state, I think we keep things all snow inland with mixing possible at the shore, especially in SE CT. I am also posting the precipitation map from weathermodels.com. This is the 18z European forecast. That's a lot of precipitation. That leaves me thinking that there's more upside to this forecast for someone if banding breaks right.
Here are more details, and our grading criteria.
Here are more details, and our grading criteria.
Snow Accumulation
As you can see above, we are going with a general 6-12" for most of CT with a 4-8" zone for SE CT based on the increased likelihood of mixing. We wanted to go broad because there is significant uncertainty over where the best banding will line up--more than usual. This is also a more conservative call I believe, given the uncertainty regarding the placement of the banding and mixing potential at the shore. It's better to be prudent at this point in time.
There are two possible zones where higher totals have an elevated chance of happening.
The first is in NE CT--think the hill towns like Tolland and points east, where there's been a consistent signal of getting into the deformation banding zone. The second is SW CT--a place with a lot of downtrodden snow lovers, due to the proximity of another very strong banding signal that is just to the south of the region. No one in the SW zone should be doing cartwheels because I'm not saying there's a coming snow jackpot, but it's a place that's right on the cusp of higher totals should the precipitation distribution pan out.
For the rest of the state, 6-12" seems reasonable right now, with lower totals expected in the CT River Valley and higher totals possible in the (almost) always favorable snow spot of the NW hills. In this instance, I think a heavier and wetter snow is more likely in much of the state outside of the NW hills.
Timing
The overall timing has not shifted too much. We expect snow to break out from SW to NE on Monday morning, starting out fairly light. By afternoon, likely 1-4pm, we start to see some of the heavier snow work its way into the state. This is the beginning of the time period with the most impact, as I expect a very difficult Monday afternoon and evening commute.
Moderate to heavy snow is likely, with increasing wind especially in coastal areas. The transition to mixing would happen during the evening hours in coastal areas with moderate to heavy snow in the other parts of the state. Monday night does not look good for travel. This should continue into Tuesday morning, where things likely begin tapering before daybreak. That said, snow is still possible through the day on Tuesday, so expect a lot of delays and cancellations.
Road Conditions
Roads will be a mess, especially during that period between the afternoon and early morning when snow is likely to be heaviest. Expect a lot of early dismissals and afternoon/evening cancellations on Monday. The commute is likely to be a mess statewide during the late afternoon and evening so plan accordingly. Roads are likely to be slick into Tuesday, even as snow diminishes. The exception may be the coast, especially SE, where temperatures may rise above 32 during the mixing period or moments where there are lighter returns on radar.
Wind/Power Outages
I am a bit split on wind and outages in this first call. On one hand, I am not as impressed with the wind signal as I would be if this were a tighter low with more of a pressure gradient to work with. That said, it will be windy, with near blizzard conditions possible, especially at the shoreline. Right now, I think we're looking at maximum wind gusts between 35-50mph along the shore (highest in SE CT) with maximum wind gusts of 30-40mph inland. Essentially, the wind signal is fairly strong, but nothing particularly alarming to me at this time. However, the combination of strong wind and heavy wet snow is a concern, and I think we may see scattered outages, with the problems concentrated near the shore.
Overall Impact
This is likely to be our second high impact storm of the season. The combination of timing, heavy snowfall rates during the afternoon and evening, and wind should cause hazardous road conditions and a meaningful snowfall across the state. There are still significant points of uncertainty, such as the extent of mixing at the coast and wind potential, but overall, we have moderate confidence in a moderate to high impact event, with high impacts focused from Monday afternoon through early Tuesday morning. We will be refining this forecast tomorrow as we make our final call.
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.
-DB
As you can see above, we are going with a general 6-12" for most of CT with a 4-8" zone for SE CT based on the increased likelihood of mixing. We wanted to go broad because there is significant uncertainty over where the best banding will line up--more than usual. This is also a more conservative call I believe, given the uncertainty regarding the placement of the banding and mixing potential at the shore. It's better to be prudent at this point in time.
There are two possible zones where higher totals have an elevated chance of happening.
The first is in NE CT--think the hill towns like Tolland and points east, where there's been a consistent signal of getting into the deformation banding zone. The second is SW CT--a place with a lot of downtrodden snow lovers, due to the proximity of another very strong banding signal that is just to the south of the region. No one in the SW zone should be doing cartwheels because I'm not saying there's a coming snow jackpot, but it's a place that's right on the cusp of higher totals should the precipitation distribution pan out.
For the rest of the state, 6-12" seems reasonable right now, with lower totals expected in the CT River Valley and higher totals possible in the (almost) always favorable snow spot of the NW hills. In this instance, I think a heavier and wetter snow is more likely in much of the state outside of the NW hills.
Timing
The overall timing has not shifted too much. We expect snow to break out from SW to NE on Monday morning, starting out fairly light. By afternoon, likely 1-4pm, we start to see some of the heavier snow work its way into the state. This is the beginning of the time period with the most impact, as I expect a very difficult Monday afternoon and evening commute.
Moderate to heavy snow is likely, with increasing wind especially in coastal areas. The transition to mixing would happen during the evening hours in coastal areas with moderate to heavy snow in the other parts of the state. Monday night does not look good for travel. This should continue into Tuesday morning, where things likely begin tapering before daybreak. That said, snow is still possible through the day on Tuesday, so expect a lot of delays and cancellations.
Road Conditions
Roads will be a mess, especially during that period between the afternoon and early morning when snow is likely to be heaviest. Expect a lot of early dismissals and afternoon/evening cancellations on Monday. The commute is likely to be a mess statewide during the late afternoon and evening so plan accordingly. Roads are likely to be slick into Tuesday, even as snow diminishes. The exception may be the coast, especially SE, where temperatures may rise above 32 during the mixing period or moments where there are lighter returns on radar.
Wind/Power Outages
I am a bit split on wind and outages in this first call. On one hand, I am not as impressed with the wind signal as I would be if this were a tighter low with more of a pressure gradient to work with. That said, it will be windy, with near blizzard conditions possible, especially at the shoreline. Right now, I think we're looking at maximum wind gusts between 35-50mph along the shore (highest in SE CT) with maximum wind gusts of 30-40mph inland. Essentially, the wind signal is fairly strong, but nothing particularly alarming to me at this time. However, the combination of strong wind and heavy wet snow is a concern, and I think we may see scattered outages, with the problems concentrated near the shore.
Overall Impact
This is likely to be our second high impact storm of the season. The combination of timing, heavy snowfall rates during the afternoon and evening, and wind should cause hazardous road conditions and a meaningful snowfall across the state. There are still significant points of uncertainty, such as the extent of mixing at the coast and wind potential, but overall, we have moderate confidence in a moderate to high impact event, with high impacts focused from Monday afternoon through early Tuesday morning. We will be refining this forecast tomorrow as we make our final call.
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.
-DB
