Good evening from Southern Connecticut Weather.
In the whole scheme of things, this isn't a big storm. However, we are already seeing impacts before the storm arrives as school districts across the state issue cancellations for tomorrow. More are on the way. A mixed bag storm will bring snow, sleet, freezing rain, and a little rain (southern CT) tomorrow. Let's get right to it.
In the whole scheme of things, this isn't a big storm. However, we are already seeing impacts before the storm arrives as school districts across the state issue cancellations for tomorrow. More are on the way. A mixed bag storm will bring snow, sleet, freezing rain, and a little rain (southern CT) tomorrow. Let's get right to it.
Above: the updated map for tomorrow, which includes snow and sleet. For interior CT, there is greater confidence now that we will have enough precipitation falling at below freezing temperatures to have a floor of 2", with some spots possibly ending up with 4" if things break right. For coastal CT, while there was some consideration of including the entire state in one 2-4" zone, I still want to respect the warm push that will be coming on the later side of the day. There will likely be some rain. For the entire state, some icing is possible with freezing rain/drizzle most likely inland but briefly possible at the shore. It's not a lot, but it's enough to make things very slick, particularly if it happens when surface temperatures are still below freezing.
Overall Setup
Not much more to add, other than winter weather advisories are now up for the entire state. We have cold that settled in today, and with clearing tonight temperatures will drop quite a bit tonight. The cold will be in place, and we will have a nice overrunning setup for snow that eventually changes to a mix as warmth erodes the cold, and for southern CT, rain eventually.
Overall Setup
Not much more to add, other than winter weather advisories are now up for the entire state. We have cold that settled in today, and with clearing tonight temperatures will drop quite a bit tonight. The cold will be in place, and we will have a nice overrunning setup for snow that eventually changes to a mix as warmth erodes the cold, and for southern CT, rain eventually.
Above: the latest high resolution NAM depiction of tomorrow. It won't play out exactly like this, but the evolution is correct. We will see an initial burst of snow statewide that could be moderate to heavy at times, then we will see mixing (sleet and then freezing rain) across the state as warm air erodes the cold aloft and works its way down. For places where the warmth reaches to the surface, we will see rain, but that's not likely until the storm is winding down.
Below: a diagram of how different types of precipitation fall!
Below: a diagram of how different types of precipitation fall!
The Forecast
Timing
Timing for the system has been a little more tricky than I thought, but overall I think we have a good sense of it. I still expect snow to overspread the state from SW to NE between about 4-8am. While it may not immediately come in as moderate/heavy, it is likely to do so quickly, with fairly good chances of snow falling from .5-1" an hour. The snow won't last terribly long, however, limiting snow accumulations. Things will change to sleet by as soon as mid-morning from south to north as the warmth aloft moves in, and then freezing rain will be possible late morning into the early afternoon. Precipitation will diminish in intensity in the early to mid-afternoon period, but interior areas especially will need to watch for the risk of freezing drizzle. The storm is gone by tomorrow night, but for inland areas it may not be until late at night that we rise above freezing. That is something I will be watching closely. This is another fast mover.
Snow Accumulation
With the guidance continuing to trend a bit colder, I thought it was prudent to once again raise the floor and ceiling slightly for interior CT. I don't expect widespread 4" amounts, and I think most end up with 2-3" of snow and sleet (note that sleet will compact the snow so if you are measuring you need to measure all of the snow that falls, clear your measuring area as soon as sleet starts, and measure the sleet), but there is enough of a risk that we continue to cool/the initial burst amps up a touch to introduce a 4" zone. I kept the 1-3" of snow and sleet for far southern CT as a conservative call, but there could once again be some spots especially inland that end up on the higher side. The snow/sleet doesn't tell the whole story however.
Like I said last night, there's not a lot of precipitation with this event, but it's the timing and type of precipitation that's the issue. Along the coast, I expect less snow, but the cold will be in place statewide. Adding a glaze of ice on top of snow will make things a mess. Even at the coast, most of the day could very well be near to below freezing, so freezing rain may be an issue for a time there too. Although the surface is looking a bit cooler, aloft we are still going to have enough warmth for mixing/ice.
Wind/Power Outages
Same as last night. Because this system isn't terribly powerful, I'm not expecting significant wind. In addition, the lack of additional precipitation also means that any icing will be light. Not enough for significant power issues. I think we see isolated to scattered outages at worst.
Impact
I still think that there are risks both ways for this to be a bit more or less impactful, but overall I think the forecast is in a good spot and the impacts are accounted for. There's not that much difference between 1-3 and 2-4" of snow/sleet. The icing potential is just enough for widespread cancellations and road impacts, especially given the timing of the system. Widespread cancellations is enough for us to call this high impact.
Timing
Timing for the system has been a little more tricky than I thought, but overall I think we have a good sense of it. I still expect snow to overspread the state from SW to NE between about 4-8am. While it may not immediately come in as moderate/heavy, it is likely to do so quickly, with fairly good chances of snow falling from .5-1" an hour. The snow won't last terribly long, however, limiting snow accumulations. Things will change to sleet by as soon as mid-morning from south to north as the warmth aloft moves in, and then freezing rain will be possible late morning into the early afternoon. Precipitation will diminish in intensity in the early to mid-afternoon period, but interior areas especially will need to watch for the risk of freezing drizzle. The storm is gone by tomorrow night, but for inland areas it may not be until late at night that we rise above freezing. That is something I will be watching closely. This is another fast mover.
Snow Accumulation
With the guidance continuing to trend a bit colder, I thought it was prudent to once again raise the floor and ceiling slightly for interior CT. I don't expect widespread 4" amounts, and I think most end up with 2-3" of snow and sleet (note that sleet will compact the snow so if you are measuring you need to measure all of the snow that falls, clear your measuring area as soon as sleet starts, and measure the sleet), but there is enough of a risk that we continue to cool/the initial burst amps up a touch to introduce a 4" zone. I kept the 1-3" of snow and sleet for far southern CT as a conservative call, but there could once again be some spots especially inland that end up on the higher side. The snow/sleet doesn't tell the whole story however.
Like I said last night, there's not a lot of precipitation with this event, but it's the timing and type of precipitation that's the issue. Along the coast, I expect less snow, but the cold will be in place statewide. Adding a glaze of ice on top of snow will make things a mess. Even at the coast, most of the day could very well be near to below freezing, so freezing rain may be an issue for a time there too. Although the surface is looking a bit cooler, aloft we are still going to have enough warmth for mixing/ice.
Wind/Power Outages
Same as last night. Because this system isn't terribly powerful, I'm not expecting significant wind. In addition, the lack of additional precipitation also means that any icing will be light. Not enough for significant power issues. I think we see isolated to scattered outages at worst.
Impact
I still think that there are risks both ways for this to be a bit more or less impactful, but overall I think the forecast is in a good spot and the impacts are accounted for. There's not that much difference between 1-3 and 2-4" of snow/sleet. The icing potential is just enough for widespread cancellations and road impacts, especially given the timing of the system. Widespread cancellations is enough for us to call this high impact.
Briefly looking ahead
I won't give much space to this yet, but the next winter storm is already on the heels of the coming one. There is cross guidance agreement that the weekend system is more likely to be a cold storm with greater intensity. As such, be prepared for a significant winter storm as soon as late Saturday into Sunday morning. Details TBD. Stay tuned for more by tomorrow night or early Friday.
Below are the Euro and GFS depictions of the storm as they peak on Sunday morning. There are timing differences and differences in temperature, but things are pointing toward a bigger event.
I won't give much space to this yet, but the next winter storm is already on the heels of the coming one. There is cross guidance agreement that the weekend system is more likely to be a cold storm with greater intensity. As such, be prepared for a significant winter storm as soon as late Saturday into Sunday morning. Details TBD. Stay tuned for more by tomorrow night or early Friday.
Below are the Euro and GFS depictions of the storm as they peak on Sunday morning. There are timing differences and differences in temperature, but things are pointing toward a bigger event.
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Thank you for reading SCW.
-DB
Thank you for reading SCW.
-DB
