After we mucked up the morning commute last week we’ll do the same for the evening commute tomorrow. A rather complex and ugly looking low pressure system is advancing toward Connecticut and will bring snow across the state between 12 p.m. and 2 p.m. with a couple inches by commute time.
The 12z NAM shows a relatively impressive burst of snow between 4 p.m. and 7 p.m. but (as usual) this seems a bit overdone. Many of our other models are more modest including the GFS and European.
Even with a good burst of precipitation the atmosphere may struggle to produce rapidly accumulating snow. The reason why is that most of the strongest lift will be in a part of the atmosphere that is not cold enough to produce dendrites. Here’s a useful (and funky) way of looking at it.
The yellow area is the part of the atmosphere between -12c and -18c. This is the area that produces snowflakes the most efficiently and the dendrites produced accumulate the most readily. It’s a win-win for big snowfall accumulation. The red lines show the amount of lift in the atmosphere and notice the strongest lift is well underneath the best snow growth.
The NAM is not the only model that shows this less than ideal snow growth. Another negative for this “storm” is that on the shoreline winds will have a tough time veering to the north which will keep some of the mild maritime air near the shoreline for most of the storm’s beginning.
I do think a period of sleet and freezing rain is likely inland after the snow ends which will make travel slippery for sure.
So how much snow? On average most of us will see 2″-4″ followed by some ice. Less than an inch is likely on the shoreline and areas north of Hartford may see an inch or two more.