Wow, what a busy early morning across the area as a line of tropical downpours and thunderstorms moved on through. The most concerning thunderstorm was on the back side of the line of storms that prompted two separate tornado warning to be issued by the National Weather Service between 3:00-4:00am. The rotation was strong from Marlborough to Concord, both towns reporting numerous trees down and power issue. The graphics below are radar images from that storm that moved in. You’ll note a bit of a hook/tail on the radar images that also correlated with the areas of rotation (brighter reds next to greens on velocity scan).
While we often get most of our severe weather during the afternoon, when the daytime heating is at it’s max, it’s possible to get isolated severe storms at night if the set-up is right. With a high humidity, tropical airmass in place and very strong wind shear (change in wind direction and speed from the surface, up), we had ingredients come together overnight to produce isolated severe storms. With strong wind shear, the strongest storm was able to rotate and exhibit strong rotation, possibly producing a tornado. We’ll await official word from the National Weather Service later today as they’ll sent out their survey team to determine weather it was straightline (damage pushes in the same direction) wind damage or tornadic (damage pattern shows turning). NWS mentioned earlier this morning gate to gate shear (velocity total of winds in opposite direction) of 70kts…. which is strong enough to produce a tornado, so that’s quite a possible outcome.
Regardless, there’s clean-up to be had and power to restore. While we don’t want to see severe weather, we do want to see the rain. With the tropical air in place, many towns picked up between 0.50-1.00″ of water. The rain ends early this morning as sunshine, low humidity and an active breeze returns.
Even a taste of Fall shows up tonight.
The weather’s on easy street through much of the week aside from an isolated storm Friday.
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