Nice Early Spring Thundery Light Show In New England Last Night

Those of you New Englanders who like warm season thunderstorms got a treat last evening, even if it wasn't particularly warm.

As I'm sure many of you saw and heard, a number of thunderstorms rolled through New York and New England on Sunday, thanks to a strong storm system.

It's the same system that brought tornadoes to the Midwest on Saturday. Luckily for us, no tornadoes.  

There were actually severe thunderstorm warnings in parts of southern New England and northwestern New York during this episode.

A few of those warnings verified in terms of hail size.  Golf ball sized hail came down in Worcester, Massachusetts and there were several reports of quarter sized hail in Massachusetts and Rhode Island.

Here in Vermont, several areas reported smaller hail in the storms, mostly pea sized or just marginally bigger. But still, that's impressive for a March thunderstorm.

True to form for New England, not every part of the region had thunderstorms.  Western and northern Maine was enduring a winter storm of wet snow and sleet.

Screen grab of lots of lightning activity in
New England Sunday evening. Image from
lightningmaps.org

The thunderstorms erupted because the strong storm system that was over the Great Lakes Sunday  created strong instability.  That means temperatures dropped quickly as you went up in elevation, so that allowed air currents to rise into towering clouds that produced thunderstorms.

Additionally, the storm was causing a general lift in the atmosphere anyway, so with all that upward motion in the air, thunderstorms were able to blossom.  One key ingredient for thunderstorms is strongly rising air, so there you go.

These were known as elevated storms. There was a thin layer of cool air near the Earth's surface. That's why it was only in the 30s and 40s when the storm rolled through.

But there was a warmer layer above. That warm layer was essentially the base of the storms. Then the air cooled dramatically from that warm layer on upward.  That was the instability that helped trigger the thunderstorms.

These storms contrasted with the kinds of thunderstorms we usually get in the summertime, which are commony surface-based, not elevated. Surface based means that the sun has warmed the lowest levels of the atmosphere, where we live. From there rising air currents create thunderstorms without any low level layer of chillier air.

That parent storm system that caused the thunderstorms is still pestering New England today. Here in Vermont, I doubt there will be any thunderstorms, but it will be showery and cool, although this morning will be on the dry side.  There migtht be some snow or mixed precipitation way up in the mountains.

NOAA's Storm Prediction Center has southern New England in a marginal risk zone for severe storms, though. The threat would be isolated reports of large hail again.

It's been an interesting winter and early spring for New England and New York thunderstorms. Just before New Year, there was a bizarre storm that created both freezing rain and thunderstorms with large hail in central and southern New England, as far north as southern Vermont.

On March 20, strong storms caused straight line wind damage in northern New York and far northwestern Vermont, which is awfully early in the season for that to be happening.