Coming into Sunday, the potential for a significant severe weather event was on the table for New England. The region was put into a rather rare (for New England) "enhanced" risk for severe weather. This is level 3 of 5 on the severe storm outlook put out by the Storm Prediction Center.
On top of that, a large portion of New England was given a 10% chance for tornadoes. This was only the third time since 2010 that the Gray, Maine forecast area (which covers all of New Hampshire and the western half of Maine) has seen a tornado outlook that high.
Storm Prediction Center tornado outlook for Sunday:
As of 7pm, a total of six tornado warnings were issued across Vermont, New Hampshire and Connecticut. While none of these warnings had a confirmed tornado on the ground, rotation was seen both on radar and in videos from multiple storms around the region. This came as discrete supercell thunderstorms moved through the region. In addition to the tornado warnings, there were a handful of severe thunderstorm warnings tagged with "tornado possible" as the atmosphere was conducive for rotating supercells.
There was a large swath of storms over Vermont and New Hampshire with more isolated activity in Connecticut. A large gap between these two clusters kept Massachusetts largely out of the equation. At one point in the late afternoon hours, three tornado warnings were active across New England.
The first tornado warning of the day was issued for a portion of northwest Vermont, near Monkton. The cell traveled just to the north of Montpelier. A couple hours later, the same general area saw another potent storm move through. At one point, this cell had a tornado warning, severe thunderstorm warning and flash flood warning active at the same time as the cell moved to the north of Montpelier. Roads and a bridge were reported to be washed out in Worcester and Elmore, Vermont.
The most potent cell of the day may have been a cell that tore across southern New Hampshire. This cell sparked a tornado warning near the Vermont border around Brattleboro before speaking another one in the south-central part of the state in the greater Manchester area. A funnel cloud heading to the ground was confirmed, but whether or not it actually touched the ground creating a tornado will be determined by the National Weather Service at a later time.
At the same time this cell was over Manchester, another tornado warning was issued directly over the Hartford Metro area. New England had two tornado warnings active at the same time for two large population Centers.
On top of the rotating cell threat, there was also strong straight-line winds, which was the largest threat coming into the day. As of 7:15pm, around 25,000 customers were without power. Maine was leading the way with around 17,000 outages. Outages will likely continue to fluctuate through the evening. Numerous reports of trees and wires down have come in from across Vermont, New Hampshire and Connecticut.
While large hail was not a major concern coming into this event, there were isolated reports of significant hailstones. Hail over one inch in diameter fell across portions of southern Vermont and New Hampshire. The largest hail recorded came out of Raymond, New Hampshire, which saw stones up to 1.75 inches in diameter. Hail over an inch was seen in Swanzey and Chesterfield, New Hampshire.
The NASCAR race at the New Hampshire Motor Speedway saw a delayed start and was delayed again during the race due to the storms. The potent cell that prompted the tornado warnings over southern New Hampshire moved in the vicinity of Loudon, where the race track is located.