Already today, I have seen one comment that the Massachusetts tornado was “unpredictable.” While this has been a horrible tornado season (worst in more than a half century), the tornadoes have been extremely well predicted.
That said, I have also received a number of questions about how the long-track Massachusetts tornado was forecast and tracked and I’m happy to answer them. The graphic below was posted on this blog the evening before the tornado. Western Massachusetts is in the 30% relative probability area for tornadoes and severe thunderstorms which is a high number for the day before an event.
The graphic below was posted on my AccuWeather Pro blog (where I go into the deeper meteorology than I do in this public blog) about three hours before the tornado formed. I call the probability of tornadoes “very high.” The oval was where I was forecasting the high tornado risk. A tornado watch was issued for the public about twenty minutes later.
The tornado’s formation, from a “supercell” thunderstorm, evolved as it would in a Kansas tornado. Here is the radar at the touchdown point of West Springfield complete with “debris ball” (circled) which is a signature of a tornado on the ground.
The radar’s Doppler wind display was very helpful throughout the afternoon showing the tremendous value the public has received from the National Weather Service’s investment in Doppler radar in the 1990′s.
The last well-defined debris ball was east of Fiskdale at 5:18pm EDT.
AccuWeather’s SkyGuard® meteorologists were tracking the tornado and informing clients throughout the afternoon. The National Weather Service issued warnings for the public, a number of which were the topic of special reports at AccuWeather.com and on this blog.
Not only did we use “Kansas” techniques on this tornado, a friend of mine from Wichita was vacationing with his family in Boston while this was going on. He wrote,
Thanks, Mike. As luck would have it, we passed on a side trip to Sturbridge and are somewhat north of the primary storm. Glad I looked in on your blog and moved my family out of harm’s way…
In June, 1953, before a tornado warning program existed in the U.S., a tornado struck Worcester, MA killing 94. It is likely that yesterday’s forecasts and warnings kept the death toll (tragically, four) lower than it otherwise would have been.