This data comes from the Online Tornado Project....Database is dated for 1950-2012.As far as I know these numbers are correct .
Mercer County on MAY 31, 1985.
Pennsylvania:Allegheny County June 3, 1980.
Clearfield County May 31, 1985.
Erie County May 31, 1985 (at 15:25).
Erie County May 31, 1985 (at 15:01).
Mercer County May 31, 1985.
Somerset County June 2, 1998.
Venango County May 31, 1985.
Warren County May 31, 1985.
New York State:Columbia County on Aug 28, 1973
Chautauqua County on May 31, 1985
Montgomery County on July 10, 1989.
Hartford County Oct 3, 1979.
New Haven County July 10, 1989.
Massachusetts:Berkshire County on Aug 28, 1973.
The great Worcester County tornado, on Jun 9, 1953. I will come back to this tornado in a bit.
Maryland:Charles County Apr 28, 2002.
Garrett County Jun 2, 1998.
Could there have been others ? I know there have been other F4 and F5 tornadoes, beyond a shadow of a doubt. Decent record keeping on tornadoes only goes back more or less to 1950. Before that Tornadoes were mentioned sometimes, but many weren't. But even after 1950 the records can be sketchy. The F-scale was introduced in 1971. Tornadoes that have F-scale rating before that time, are estimates based on secondhand evidence.
One Such tornado was the 1878 Wallingford Connecticut tornado. Estimated to have been an F4. This is the deadliest tornado in Connecticut history.
The violent 1953 Worcester tornado, which killed 94 and left at least 288 injured, was rated an F4 . Several people myself included believe it was probably an F5. The tornado was rated F5 by Thomas P. Grazulis in Significant Tornadoes 1680-1991: A Chronology and Analysis of Events.
Grazulis is an author, producer, meteorologist, and storm chaser. Grazulis amassed one of three authoritative tornado databases, those being the National Tornado Database assembled and maintained by NOAA agencies, the University of Chicago DAPPL database founded by Fujita which ended at his retirement in 1992, and the Grazulis Tornado Project database.
The list of F1/EF1 - F3/EF3 is much longer, than the above list.
A partial list of outbreaks that have stuck the Northeast.
Four-State Tornado Swarm August 15, 1787. This has the distinction of being the first known U.S tornado outbreak.
September 9, 1821. New England tornado outbreak .
September 20, 1845 New York outbreak.
May 1896 tornado outbreak sequence.
1926 La Plata, Maryland tornado outbreak.
June 22–23, 1944 Appalachians tornado outbreak, deadly tornadoes were observed in Pennsylvania and Maryland.
May 2, 1983 New York State
May 31, 1985 United States–Canada tornado outbreak.
July 10, 1989 Northeastern United States tornado outbreak.
May 31 1998 Pennsylvania, New York, New Hampshire, and Connecticut outbreak.
So you can see that New York and the rest of the Northeast is no stranger to violent tornadoes. Governor Andrew Cuomo said "New York State doesn't get tornadoes". However, when you crunch the numbers of total tornadoes by state, from 1950-2012, New York State ranks 30th among all states in total tornadoes. On average New York State sees 10 tornadoes a year, Pennsylvania sees 16 on average, For the entire Northeast, the number of yearly tornadoes is 46.I've been asked by several people, are there more tornadoes now than there was 15-30 years ago? I've seen the same question inferred on my Facebook weather page. It's a fact, the number of reported tornadoes across the northeast is rising slightly when compared to the 1950-2012 tornado data bases, especially over the last 12-14 years.
So based on those statistics, the number of annual tornadoes is increasing. But there are a couple of other facts we have to take into consideration, People are interconnected now more than any other time in human history. We have social media, we have portable tablets, and smart phones, and many other little gadgets. Most of these gadgets have cameras on them. Most people always have a camera of some kind with them most of the time. So it is very easy to take pictures of severe weather events, like tornadoes. With social media sites like Facebook, Twitter, YouTube, and many others, it is very easy to show the world what you saw.
For example, take the EF1 tornado that touched down in Deerfield, NY, Tuesday evening. That was caught on video. Without that video evidence, the NWS most likely wouldn't have done a storm survey at all. Without a survey, there wouldn't have been a record of a tornado in Deerfield on that date. The actual number of tornadoes that occur in the Northeast (and the U.S.) every year, is very likely much higher than what is reported. There are many tornadoes that are not seen by human eyes. So like the proverbial Bear in the Woods......if no one saw the tornado...was there a tornado?
Also, the NWS has better equipment than they did just 10 years ago. Things like Dual-Polarization Radar (Dual-Pol) that lets us see into severe thunderstorm like never before.So is the number of tornadoes increasing? Maybe. But I think it is far more likely that the improved detection and reporting systems we have at our disposal, is the reason for the increased reported tornado activity.
The tornado that took the lives of four people in Smithfield, NY, on Tuesday evening, is not the first deadly tornado in the Northeast, and sadly it won't be the last. The only good thing that could possibly come from the tragedy in Smithfield, is that people take severe weather seriously, that they become weather-aware.