Good afternoon from Southern Connecticut Weather!
Today was a bit of a break from winter, as temperatures surged into the 40s across the state and some light rain showers fell in southern areas. However, this winter isn’t going out without a fight, and it’ll continue that fight tonight as a wave of anafrontal snows move into the region.
Setup/Models/Trends
A cold front swings in from the NW later tonight, bringing temperatures back below the freezing mark statewide from NW to SE. At the same time, precipitation moves in from the SW as light rain. The first question of the night is how long does it take for temperatures to drop below freezing? As of now, it seems that temperatures are on track to drop to a level supporting snow relatively soon after the precipitation starts, meaning that most of the QPF will fall as snow and not rain or sleet, but a delay in that changeover would result in lower accumulations due to a higher proportion of QPF being wasted on sleet/rain. Something to keep in mind.
The far more important question however, is how far north the two waves of precipitation make it this evening into tomorrow. Modeling is in good agreement in bringing most of the precipitation in two distinct waves along the front, but how far north the precipitation is able to make it is the question. Most guidance today ticked north a bit with the positioning of the bands of precipitation and as a result brings the entire state into steady snows, but only just. A slight shift south and the northern tier of the state would be taken out of steady snow, while another bump north brings the higher accumulations currently reserved for southern areas into more of the state. The sphere of model guidance encompasses both of these edge cases and several scenarios in between as well. Here’s a look at the NAM and UKMET models, showing the southern and northern edges of the guidance. Most of the other models are somewhere in the middle.
Today was a bit of a break from winter, as temperatures surged into the 40s across the state and some light rain showers fell in southern areas. However, this winter isn’t going out without a fight, and it’ll continue that fight tonight as a wave of anafrontal snows move into the region.
Setup/Models/Trends
A cold front swings in from the NW later tonight, bringing temperatures back below the freezing mark statewide from NW to SE. At the same time, precipitation moves in from the SW as light rain. The first question of the night is how long does it take for temperatures to drop below freezing? As of now, it seems that temperatures are on track to drop to a level supporting snow relatively soon after the precipitation starts, meaning that most of the QPF will fall as snow and not rain or sleet, but a delay in that changeover would result in lower accumulations due to a higher proportion of QPF being wasted on sleet/rain. Something to keep in mind.
The far more important question however, is how far north the two waves of precipitation make it this evening into tomorrow. Modeling is in good agreement in bringing most of the precipitation in two distinct waves along the front, but how far north the precipitation is able to make it is the question. Most guidance today ticked north a bit with the positioning of the bands of precipitation and as a result brings the entire state into steady snows, but only just. A slight shift south and the northern tier of the state would be taken out of steady snow, while another bump north brings the higher accumulations currently reserved for southern areas into more of the state. The sphere of model guidance encompasses both of these edge cases and several scenarios in between as well. Here’s a look at the NAM and UKMET models, showing the southern and northern edges of the guidance. Most of the other models are somewhere in the middle.
As far as a forecast goes, we leaned towards a GFS/GGEM/Euro consensus as this best represents the “middle ground” between the extreme NAM and UKMET scenarios. A quick peek at the new NAM shows that it trended closer to the consensus and as a result we may be a bit less bullish than the new consensus on this map, but considering a marginal temp profile at first and the potential for dry air on the northern fringe, I’m OK with being a bit conservative relative to guidance.
Forecast/Timing
Here’s a look at our forecast snowmap for this event.
Forecast/Timing
Here’s a look at our forecast snowmap for this event.
As far as timing goes, precipitation looks to move in from SW to NE after the evening rush comes to a close around 8 PM. Initially, most precipitation should start as light rain, but as the colder air comes in behind the front from the NW, precipitation will quickly flip to snow, with perhaps a period of sleet as an interlude. By midnight or shortly after, we expect most of the state to be seeing snow, with generally light rates prevailing. As the wave of precipitation pushes north, moderate snow will begin to push north onto the south coast and will continue north overnight. By shortly before daybreak, we expect the southern half of the state to be seeing moderate snow, with northern portions of the state seeing lighter snow. Here’s a snapshot from the short range HRRR model showing this.
If the more northerly solutions verify, we’ll see this area of moderate snow expand to the northern border by the morning rush, but regardless, the commute looks to be a slow and snowy one. The snow should reach it’s northern extent around the peak of the rush hour, and then slowly slink south over the course of the morning, with snow exiting the state by mid-afternoon.
As of now, the consensus on guidance keeps the second wave of precipitation south of our area tomorrow afternoon, but if it verifies on the northern edge of expectations, we’ll see some more snow make it’s way into the southern portion of the state, and we may have to up accumulations if that did impact us. As of now we have not factored any additional substantial accumulations from this second wave into the forecast, but we are keeping an eye on it nonetheless and will update if needed.
We do expect some closings and delays tomorrow morning as a result of this snowfall, and travel will likely be tricky, especially on lightly trafficked secondary roads. If you’re heading out tomorrow, please take it slow, be safe, and leave plenty of time to get to your destination.
We’ll be updating throughout the event as needed, but until then, thank you in advance for sharing this discussion with your friends and for reading Southern Connecticut Weather!
-SA
As of now, the consensus on guidance keeps the second wave of precipitation south of our area tomorrow afternoon, but if it verifies on the northern edge of expectations, we’ll see some more snow make it’s way into the southern portion of the state, and we may have to up accumulations if that did impact us. As of now we have not factored any additional substantial accumulations from this second wave into the forecast, but we are keeping an eye on it nonetheless and will update if needed.
We do expect some closings and delays tomorrow morning as a result of this snowfall, and travel will likely be tricky, especially on lightly trafficked secondary roads. If you’re heading out tomorrow, please take it slow, be safe, and leave plenty of time to get to your destination.
We’ll be updating throughout the event as needed, but until then, thank you in advance for sharing this discussion with your friends and for reading Southern Connecticut Weather!
-SA
