at 5:17 PM by Pierce Larkin

Five Years Ago Today: Massachusetts Tornadoes

On this day five years ago, a severe weather event occurred in Massachusetts, and produced four tornadoes across a small area. These tornadoes occurred within a small proximity to Springfield, MA, with the strongest tornado taking a direct path across Springfield.

This is a map I made in ArcGIS showing the tracks of the tornadoes in MA on 06/01/2011. Data collected from the SPC
This is a map I made in ArcGIS showing the tracks of the tornadoes in MA on 06/01/2011. Data collected from the SPC.
One of the several tornado watches from 06/01/2011 in New England. h/t SPC
One of the several tornado watches from 06/01/2011 in New England. h/t SPC

Northeastern US severe weather events always fascinate me, but especially tornado events across that region. Storms usually move quickly to the east or southeast in relation to quick moving troughs. Wind shear typically isn’t super favorable for supercells and tornadoes; however, it was on this day. Additionally, tornadoes are not common at all across this portion of the world, and this creates a lot of intrigue in the systems that produce them.

This shows how rare of an event this was for New England. h/t NCDC NOAA
This shows how rare of an event this was for New England. h/t NCDC NOAA

On this day, the Massachusetts/Connecticut/Rhode Island region was downstream of a deep trough at all levels of the atmosphere over southeastern Canada. A strong jet streak on the order of about 80 knots at 500 mb was moving southeastward towards the region, and placed the region within the favorable exit region of the mid-level jet.

The 500 mb heights and winds on 6/1/2011. MA is located in the exit/divergent region of the jet stream. h/t SPC
The 500 mb heights and winds on 6/1/2011. MA is located in the exit/divergent region of the jet stream. h/t SPC

This created a favorable mid-level atmosphere for upward vertical motion across the region, which helped to enhance the severe thunderstorm threat. Additionally, the boundary layer (about the lowest 3 km of the atmosphere) was very moist, and thus unstable. This allowed for the storms to develop strong updrafts, which created mature storms.

CAPE of >2000 j/kg was present across the region that day, and this allowed for storms to become well established within the atmosphere. h/t SPC
CAPE of >2000 j/kg was present across the region that day, and this allowed for storms to become well established within the atmosphere. h/t SPC

Once the storms that developed just to the northeast of the region and moved into an environment that became increasingly well sheared in the lowest 3km of the atmosphere, this allowed for them to become supercellular in nature. If the 0-3km layer can be well sheared and have the directional component to it, this can enhance the updraft and create a mesoscyclone in the thunderstorm.

The effective shear values across the northeast for that day. Anything >40 knots is good for severe storms. This is the shear that helps to organize the thunderstorm, and keep the updraft and downdraft separate. h/t SPC
The effective shear values across the northeast for that day. Anything >40 knots is good for severe storms. This is the shear that helps to organize the thunderstorm, and keep the updraft and downdraft separate. h/t SPC
This gif shows the increasingly high 0-3km Storm Relative Helicity values. Helicity is just a measure of the potential for an updraft to act in a helical motion, which implies rotation. This is a good measurement for how strong the lowest level winds are, but also how well they are turning with height to create a rotating updraft. h/t SPC
This gif shows the increasingly high 0-3km Storm Relative Helicity values. Helicity is just a measure of the potential for an updraft to act in a helical motion, which implies rotation. This is a good measurement for how strong the lowest level winds are, but also how well they are turning with height to create a rotating updraft. h/t SPC
The chart at the top is called a hodograph, and it is a visual representation of what the atmosphere is doing in terms of wind direction and magnitude. The values within the black box indicate the shear numbers, which are more than enough for supercells and tornadoes. This sounding was release a little bit to the south of Springfield, MA on Long Island. h/t SPC
The chart at the top is called a hodograph, and it is a visual representation of what the atmosphere is doing in terms of wind direction and magnitude. The values within the black box indicate the shear numbers, which are more than enough for supercells and tornadoes. This sounding was release a little bit to the south of Springfield, MA on Long Island. h/t SPC

These storms moved into a highly sheared, unstable environment, and it allowed for strong supercells to develop and move across the region, dropping four tornadoes, including an EF-3 that hit Springfield, MA. Check out the evolution of the storms on radar, but also some videos of the storms themselves.

This is the base reflectivity loop of the supercells crossing central Massachusetts. h/t GRLevel2 and NCDC Radar Archive
This is the base velocity loop of the supercells crossing central Massachusetts. h/t GRLevel2 and NCDC Radar Archive

Unfortunately, there were 4 fatalities and 200 people injured with the storm that moved through Springfield, MA. Keep those folks in your thoughts and prayers, as I am sure this is a somber day for them.

This event fascinates me, as do move northeastern severe weather events. However, the combination of great directional and speed shear, and instability, allowed for a unique severe weather event to develop and move into the New England region five years ago today. For more info on these tornadoes, read through the report on their strength and damage the NWS in Boston did.