Tornadoes and Flooding of April 27th and 28th, 2011
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Severe Weather of April 27th and 28th, 2011
Information Updated: 17 June 2011

OVERVIEW:

Unseasonably warm and moist air over the region on Wednesday April 27th fueled severe thunderstorms.

The thunderstorms occurred ahead of a cold front which would move through on Thursday morning. This was the same storm system responsible for the deadly outbreak of tornadoes across the Deep South that same evening and overnight. One tornado occurred in the evening of the 27th, and five more tornadoes occurred in Central PA after midnight in the early morning hours of April 28th, 2011. The strength of these tornadoes ranged from EF0 to EF2 on the Enhanced Fujita Scale.

The thunderstorms developed in an environment that was conducive to producing Supercell Thunderstorms. Supercells have the structure to produce the most-violent tornadoes.

Initially, on the afternoon of the 27th, thunderstorms did develop over Central Pennsylvania. The paths of the storms took them over the same places as heavy rain that occurred the past two days (Monday and Tuesday). This produced flooding in many locations, and some of those storms produced wind damage as well.

Most of the storms that produced tornadoes did not form until after midnight, that is, very early Thursday morning. One tornado did occur in the early evening, in Potter County, Northern PA.

Map of Tornadoes | Sounding | Surface Map Wed AM | Surface Map Thurs AM | IR Satellite Picture
Map of Central PA tornadoes on 4/28/2011

Map of Central PA Tornadoes on April 27th and 28th, 2011

High Resolution Image of the Map of Tornadoes

 

The Ayers Hill Tornado


Path Map and highlight summary of the Ayers Hill Tornado of April 27th, 2011

Path Map and highlight summary of the Ayers Hill Tornado of April 27th, 2011


 

Text Information of the Ayers Hill Tornado of April 27th, 2011

Text Information of the Ayers Hill Tornado of April 27th, 2011


 
 

The Broad Top City Tornado


Path Map and highlight summary of the Broad Top City Tornado of April 28th, 2011

Path Map and highlight summary of the Broad Top City Tornado of April 28th, 2011


 

Text Information of the Broad Top City Tornado of April 28th, 2011

Text Information of the Broad Top City Tornado of April 28th, 2011


 
 

The East Waterford Tornado


Path Map and highlight summary of the East Waterford Tornado of April 28th, 2011

Path Map and highlight summary of the East Waterford Tornado of April 28th, 2011


 

Text Information of the East Waterford Tornado of April 28th, 2011

Text Information of the East Waterford Tornado of April 28th, 2011


 
 

The Round Top Tornado


Path Map and highlight summary of the Round Top Tornado of April 28th, 2011

Path Map and highlight summary of the Round Top Tornado of April 28th, 2011


 

Text Information of the Round Top Tornado of April 28th, 2011

Text Information of the Round Top Tornado of April 28th, 2011


 
 

The Palmyra Tornado


Path Map and highlight summary of the Palmyra Tornado of April 28th, 2011

Path Map and highlight summary of the Palmyra Tornado of April 28th, 2011


 

Text Information of the Palmyra Tornado of April 28th, 2011

Text Information of the Palmyra Tornado of April 28th, 2011


 
 

The Ono Tornado


Path Map and highlight summary of the Ono Tornado of April 28th, 2011

Path Map and highlight summary of the Ono Tornado of April 28th, 2011


 

Text Information of the Ono Tornado of April 28th, 2011

Text Information of the Ono Tornado of April 28th, 2011


 
How common are Tornadoes in Pennsylvania?
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What is the EF Scale?
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Map of rainfall amounts for April 26th

Map of rainfall amounts for April 26th


Map of rainfall amounts for April 27th

Map of rainfall amounts for April 27th


Map of rainfall amounts for April 28th

Map of rainfall amounts for April 28th


 
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Page Last Modified: 17 June 2011 05:40:48 UTC
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