The National Weather Service confirmed that an F-1 tornado touched down in the Islip area of Long Island Wednesday morning.

At the F-1 level, a tornado carries hurricane-force winds that can reach 110 mph. It can peel off roofs, push mobile homes off their foundations or blow vehicles off the road.

LIPA reports major power outages on Long Island. At its peak, some 51,000 customers were without power. Currently, 12,900 still have no electricity.

CBS 2's Lonnie Quinn says the severe weather is not over with yet. The tornado was caused by a low pressure system around Canada, near the Great Lakes, and will continue to push showers and storms throughout the Tri-State area until Friday, with some being severe.

Quinn said another tornado cannot be ruled out, but is less likely to happen in Manhattan, as opposed to the outer boroughs and suburbs. Tornadoes are caused by rotation in atmosphere from service winds flowing in opposite directions - where they meet and begin to spin.

The chances of tornado touching down in Manhattan is low because of concentration of high buildings which disrupt rotation. It isn't impossible, but it would be out of ordinary, Quinn said.

National Weather Service Meteorologist Brian Ciemnecki said the service received a number of reports of damage in the area after it issued a tornado warning between 9:19 a.m. and 9:45 a.m. on Wednesday. The NWS sent crew to examine the pattern of debris, and they determined that a tornado actually struck the area.

The weather service got its reports of trees down and other damage from members of the public and from emergency management staff, he said.

Implemented in place of the Fujita scale introduced in 1971, the enhanced Fujita scale began operational use on Feb. 1, 2007. The scale has the same basic design as the original Fujita scale, six categories from zero to five representing increasing degrees of damage. It was revised to reflect better examinations of tornado damage surveys, so as to align wind speeds more closely with associated storm damage.

On this new scale, Wednesday's tornado would be classified EF-1, according to CBS 2 meteorologist Jason Cali.

Suffolk County says there have been reports of what it's calling "tornado-like damage" in Islip Township at Iris Lane and the north service road of Sunrise Highway.

Suffolk firefighters are dealing with four house fires that were likely caused by lightning.

The United States averages about 1,200 tornadoes a year, but they are uncommon in the New York area. A tornado struck about 20 miles north of New York City last July, causing heavy damage to a Westchester County store.