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    Why Did So Many Tornadoes Hit Pennsylvania, New York in July?

    By , AccuWeather.com Senior Meteorologist
    July 22, 2014; 12:12 AM ET
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    During the first few of weeks of July, there have been at least eight confirmed tornadoes from northeastern Pennsylvania to central New York, which is well above average for the first half of the month.

    During July, over the 20-year period from 1991 to 2010, all of New York state averaged three tornadoes, while Pennsylvania averaged four tornadoes for the entire month.

    According to AccuWeather Senior Meteorologist Bernie Rayno, "The pulse of tornadoes this year can be attributed to an unusually far south dip in the jet stream over the Central and Eastern states."

    This graphic shows confirmed tornadoes in the NWS Binghamton, New York, area versus July and annual averages for tornadoes for New York and Pennsylvania. Confirmation of these tornadoes may have occurred days after the date of the incident. There were several other tornadoes outside of the Binghamton NWS office coverage area on these dates.

    The jet stream is a strong river of air high above the ground that not only moves weather systems along but also provides extra energy for storm systems and thunderstorms.

    "By July, typically the jet stream has retreated to along or a bit north of the United States, Canada border," Rayno stated.

    According to Eric Heden, meteorologist with the National Weather Service office in Binghamton, New York, "some lean years and active years for tornadoes are expected."

    The NWS in Binghamton attributes the increase in tornadoes partially due to improved equipment and reporting methods.

    AccuWeather.com Severe Weather Center
    Storm Prediction Center Reports
    Severe Weather Blog: Henry Margusity

    "We have advanced Doppler radar that can see the storms." Heden said. "More reports are coming in by way of cell phones and social media that were not present a couple of decades ago."

    Doppler radar can see through a storm and detect changes in wind direction and speed.

    However, Heden listed another active year for tornadoes in the region: 1998. During this year, more than five dozen tornadoes occurred in the area from Pennsylvania to New York, New Jersey and western New England.

    In the span of a few days from late May to early June 1998, two F3 tornadoes touched down in the zone from northeastern Pennsylvania to the southern tier or New York.

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