East Coast A Hot Spot For Severe Storms This Year; Vermont, Not So Much

A strong thunderstorm over Georgia, Vermont on August
11 that would go on to earn a severe thunderstorm warning
in eastern Franklin County.  It was one of a below 
average 45 severe thunderstorm warnings issued so far
this year from the Burlington, VT NWS office. 

You'd expect the place that has had the most severe thunderstorm warnings this year would be some place like tornado alley in Oklahoma or Texas, or maybe the Deep South, or the lightning capital of the nation, Florida.  

Nope. The 2021 hot spot for severe, damaging storms is in the Baltimore-Washington DC area, according to the Washington Post Capital Weather Gang. 

That wouldn't seem like the most likely place.  Sure, there is plenty hot, humid spring and summer air in that neck of the woods to fuel big storms.  But you wouldn't expect that area to be the king of severe.  

Maybe Ma Nature is fed up with the kookiness of Washington and is trying to send a message?  

A severe thunderstorm is defined as one with winds of at least 58 mph and/or hail the diameter of quarters or bigger.  A severe thunderstorm warning means a storm that likely contains those conditions was detected.  It usually, but not always means there really is a severe thunderstorm. Every once in awhile, no damage is reported with a storm that had been deemed severe.

In those cases, the storm really wasn't severe or it hit an area where nobody was around to report or even see damage.  Basically, though, if you receive a severe thunderstorm warning, you should expect such a storm and take shelter right away. A severe thunderstorm warning means trouble looms.

In the Mid-Atlantic, trouble loomed a LOT this  year.

The Washington Post says:

This map shows the number of severe thunderstorm warnings
issued by each National Weather Service local office in the 
nation. Click on the map to make it bigger and easier
to see. Image is from the Washington Post. 

"The National Weather Service office serving the Washington-Baltimore region has issued a whopping 528 severe thunderstorm warnings for its zone of responsibility from eastern West Virginia to the Chesapeake Bay.  That number even surpasses the warning count for the area around storm-prone Norman, Oklahoma, which has received a second-most 489 warnings."

The number of storm warnings in the Washington-Baltimore area is about 223 more than normal.

National Weather Service offices surrounding the Washington-Baltimore NWS district also had much more storm warnings that average.

In our neck of the woods in northern New England and northern New York, though, we've had a light storm season.  

 The National Weather Service Burlington office forecast area covers all of Vermont except our southernmost two counties and northern New York from about Whitehall on the Rutland County, Vermont border to northeast of Watertown, New York along the St. Lawrence River valley.

In this zone, there have been 45 severe thunderstorm warnings so far this year, which is 16 fewer than normal.  

Again, click on map to make it bigger and easier to see.
The departure above or below normal of severe thunderstorm
warnings issued so far this year. Image from the 
Washington Post. 

The rest of northern New England, covered by NWS offices headquartered in Gray, and Caribou, Maine have had a similarly light year.  A vast area of the Great Plains and Mid-South of the United States also had a very light severe storm year so far, relative to average, anyway. 

Up here in northern New England, severe thunderstorm warnings are usually few and far between from now until next spring, so I don't expect the number of severe storm warnings to go up much.  In general, the further south you go, the more likely there will be more severe thunderstorms before the close of 2021.  

Generally speaking, a persistent dip in the jet stream centered over the Great Lakes created this pattern.  The weather pattern favored dry, stable west to northwest winds over the Midwest that helped squelch storms.

This same pattern kept bringing storm systems, cold fronts and lots of humid air to the eastern United States, which encouraged storms. 

In northern New England, persistent ridges of high pressure over southeastern Canada often suppressed the rough weather to our south.  While this Canadian ridge mostly kept us warmer than average, it also kept those storm systems in the East from working their way far enough north to influence much. 

The cold fronts also ran into dry air associated with the southeastern Canadian high pressure, and that helped keep storms to a minimum.