There have been a few big April snowstorms in Connecticut.
- March 31-April 1, 1997 storm dropped 10″-25″ of snow across the state.
- April 6, 1982 storm crushed most of interior Connecticut with 10″-20″ of snow.
- April 3-4, 1915 dropped 8″-16″ across Connecticut.
- April 9-10, 1996 dropped around 6″ in western Connecticut and 10″-15″ in eastern Connecticut (including the shoreline).
Big storms aren’t common in April but they’re certainly not unheard of. In almost all cases tightly wound 500mb and 850mb lows pass underneath or east of Connecticut producing strong upward vertical motion and dynamic cooling. The 1982 case, however, was a bit different with a near record cold airmass in place.
To get big snows in April, especially in the Valley or on the coast, you need a near perfect track. A 700/850mb low between Block Island and Groton is imperative. Additionally a bombing surface low south of Connecticut is important in order for the northerly ageostrophic wind to maintain cold temperatures in the boundary layer. Additionally the peak of the storm can’t be centered around midday because it is tough to get significant accumulation with the sun angle so high.
The 12z GFS (along with other models in the last 24 hours) have shown the close-to-perfect track and intensity for an April snowstorm. It’s too early to say with much certainty what’s going to happen here but this is something to watch closely.
There’s very little wiggle room for an April snowstorm. Everything has to be perfect.