Around 8:00 yesterday Twitter came alive with pictures from viewers in Newtown and Southbury with incredible images of an isolated thunderstorm that was moving out of the Litchfield Hills into the Housatonic River Valley.
The top of this storm only reached ~30,000 ft but it was a beautiful looking storm in person. It was totally isolated with the anvil being blown off to the southeast resulting in a crystal clear view from the southwest of it looking northeast at the low level mesocyclone.
Radar shows there was a mesocyclone, albeit weak, with a rotational velocity of approximately 20 knots. The unusually clear view, plus the setting sun, lead to a really cool view of this thing that is pretty unusual for New England. In Southbury you can see a beaver tail with scud/inflow reaching up to the rugged wall cloud at the base of the mesocyclone.
And on the other side of the storm in Southington you can see the cumulonimbus tower with the relatively low looking anvil and mammatus cloud spreading out the south and east of the storm.
The storm has the classic supercell “mothership” structure with the rain free base and wall cloud under the updraft.
There were other isolated showers and thunderstorms that died out in the state and produced some really cool looking anvils and structures. There was one I saw around 8:00 to the southwest of Hartford from a dying shower (nothing on radar… just a leftover cloud) and there was another really neat one to the northwest of Connecticut from a dying shower over the Berkshires.
A quick look at some of the evening weather balloon launches shows an environment that wasn’t terribly impressive but sufficient for some scattered convection.
There is veering with height on the lowest 3 km of the atmosphere on the Albany sounding (0-3km storm relative helicity around 145m2/s2) with just over 1200 j/kg of CAPE. This was sufficient for a small supercell and the updraft was strong enough to result in hail. Radar showed a three body scatter spike over several elevation slices in Woodbury before the storm moved into Southbury and Newtown.