Editor's note: This story was originally posted in May 2019 and was updated in Dec. 2019.

At least 34 tornadoes have hit Pennsylvania since the beginning of the year, according to the National Oceanic and Atmospheric Administration (NOAA).

Fifteen of those tornadoes occurred in May.

Thirteen of those occurred in one week.

According to the National Weather Service, the 34 tornadoes -- so far -- in 2019 makes it the third-highest number on record. 

1998 saw the most, with 61.

EF-2 tornado touched down in Caernarvon, near Morgantown, Berks County, NWS says [updates]

Tornadoes occur most frequently in April, May and June in Pennsylvania.

Pennsylvania typically averages 16 tornadoes for an entire year, according to research from NOAA.

"Of course, mid-Spring into mid-summer is our 'severe weather season,' so some T-storm threats is normal, but it’s been unusually active for sure this year," said Millersville meteorologist Eric Horst.

What's the difference between a tornado watch and a warning?

"The jet stream off the Pacific has been unusually strong the last few months due to enhancement by the El Nino ongoing in the Pacific—so this is a factor." said Horst. 

Horst also said that the pattern of severe weather will likely continue for a little while yet.

Severe Weather Pennsylvania

Damage is seen in a trailer park off Everett Street in Benton, Pa., Monday, April 15, 2019, caused by an EF1 tornado, according to the National Weather Service. (Jimmy May/Bloomsburg Press Enterprise via AP)

How are tornadoes measured?

Meteorologists use the Enhanced Fujita Scale to correspond winds with a score. Sometimes, winds can be hard to measure in the peak of a tornado, so sometimes the amount of damage caused by the tornado will act as an indicator of how fast the winds were.

EF-0: 65-85 miles per hour

EF-1: 86-110 miles per hour

EF-2: 111-135 miles per hour

EF-3: 136-165 miles per hour

EF-4: 166-200 miles per hour

EF-5: 200+ miles per hour

Severe Weather Pennsylvania

The remains of the Mill Race Golf Course clubhouse lie in the foreground, and trees are leveled in the background, Monday, April 15, 2019, in Benton, Pa., after being damaged by an EF1 tornado, according to the National Weather Service. (Jimmy May/Bloomsburg Press Enterprise via AP)

Where tornadoes touched down in Pennsylvania in 2019:

January 8:

NNE of New Lebanon, Mercer County, EF-1

April 14:

Springboro, Crawford County, EF-0

SE of Cooperstown, Venango County, EF-0

NE of Cherrytree, Venango County, EF-0

Starbrick to Scandia, Warren County, EF-2

April 15:

Buffalo Valley, Union County, EF-1

Benton, Columbia County, EF-2

Dushore, Sullivan County, EF-1

Scranton, Lackawanna County, EF-0

Harford Township, Susquehanna County, EF-1

April 19:

Knobsville, Fulton County, EF-1

St. Thomas, Franklin County, EF-2

Richvale, Huntingdon County, EF-1

Krause, Juniata County, EF-1

Lewistown, Mifflin County, EF-2

May 19: 

West Cocalico Township, Lancaster County, EF-1

Ottsville, Bucks County, EF-1

May 23:

Westmont, Cambria County, EF-0

May 25: 

Burrell Township, Indiana County, EF-1 

Homer City, Indiana County, EF-0

May 28: 

Caernarvon Township near Morgantown, Berks County, EF-2

Wysox Township, Bradford County, EF-1

Newton Township, Lackawanna County, EF-1

Penn Run, Indiana County, EF-0 

May 29: 

Losh Run, Perry County, EF-1

Border of Bucks, Lehigh counties, EF-0

Matamoras, Dauphin County, EF-1 

Falls Township, Wyoming County, EF-0

Dushore, Sullivan County, EF-0

Wells Tannery area, Fulton County, EF-1

June 16:

Sharon, Mercer County, EF-1

Parker, Butler and Armstrong Counties, EF-1

Commodore, Indiana County, EF-1

November 1:

Thurnbury Township, Delaware County, EF-2

Storm damage 052019

A roof was blown off of a house on Kline Road in West Cocalico Township Sunday, May 19, 2019. Neighbors said the roof had just been replaced. 

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