Chautauqua County Tornado November 14th, 2011

CHAUTAUQUA COUNTY TORNADO - NOVEMBER 14, 2011

During the late afternoon of Monday November 14th a line of severe thunderstorms developed to the west of Buffalo and raced across the Western Southern Tier of New York. A surface cold front provided the lift necessary to develop the line of severe weather and a very strong wind field aloft provided a favorable environment for rotating supercell thunderstorms. The storms rapidly intensified as they crossed lake Erie with individual cells moving at an astounding rate of 60 to 70 mph. As the storms raced ashore in Chautauqua County, they produced significant damage.

A damage survey conducted by the National Weather Service in coordination with Emergency Management office from Chautauqua county confirmed that two EF-2 tornadoes touched down and were responsible for the bulk of the damage in the villages of Fredonia and Westfield. As the storms continued east across Cattaraugus and Allegany counties they produced additional straight line wind damage. This web page provides a brief review of the meteorological factors that contributed to the severe weather that afternoon. The photographs of damage at the bottom of this report were taken by the WFO Buffalo Storm Survey Team.

The weather pattern on Monday afternoon November 14th featured a cold front that extended from a Low east of Hudson Bay Canada to another Low over western Lake Erie (Fig 1). NOAA's Storm Prediction Center outlined an area just to the south and west of New York State with a Slight Risk Area for severe weather that afternoon and evening.

Figure 1: NCEP Surface Analysis Monday November 14th at 21z.

Figure 2: WSR-88D reflectivity image taken at 2124z (4:21PM EST), about 1/2 hour before the first report of damage Fredonia, NY.

As Figure 2 shows, by 424PM a line of thunderstorms had rapidly developed over Lake Erie and took on a very ominous appearance with no less then a half dozen discreet thunderstorms cells that showed severe weather characteristics. It was the two lead cells that produced the tornadoes as they came onshore within the next hour or so.

Figure 3 shows radar reflectivity (left) and radial velocity (right) images off the WSR-88D at 4:45PM, about 10 minutes before the damage in Fredonia. Note the outbound radial velocity (dashed arrow) of 30 kts. in close proximity to the inbound velocity (dashed arrow) of 90 kts. The storm was moving toward the east at nearly 70mph and the 90 kt (~104 mph) wind was heading right for Fredonia.

Figure 3: WSR-88D 0.5 degree reflectivity (left) and
velocity (right) at 2145z Monday November 14, 2011.

Figure 4 shows radar reflectivity (left) and radial velocity (right) images off the WSR-88D at 5:08PM, as the damage was occurring in Westfield. Note the inbound radial velocity (dashed arrow) of 95 kts. (~109mph) just south of the village.

Figure 4: WSR-88D 0.5 degree reflectivity (left) and
velocity (right) at 2208z Monday November 14, 2011.

Figure 5 and 6 show the damage paths that resulted from the EF-2 tornadoes on the Enhanced Fujita Scale . A Survey Team from the National Weather Service met with the Emergency Manager from Chautauqua county who escorted them to sites where damage was reported. Based on examination of the evidence and comparison with the WSR-88D radar data, the Team determined that a EF-2 Tornadoes with wind speeds of approximately 105-115mph cut a swath of 100 to 125 yds. along paths of 3 to 5 miles. Each of the points along the damage path in the figure represent locations where damage was examined.

Disclaimer

Figure 5 and 6: Damage paths determined from the
survey conducted by NWS and Emergency
Management officials.

Damage Photos Taken by NWS Survey Team

Figure 7

Figure 8

Figures 7 and 8 show the before and after images of a pole barn and 3-story barn located on County Touring Rte 21 in Westfield, NY.

Figure 9a-9b show damage to outbuildings on South Gate St in Westfield. Two people rode out the storm in the brown van next to the damage. Figure 9c-9d show damage to a barn and home on Martin Wright Rd in Westfield.

10a

10b

10c

Figure 10a shows a destroyed garage on the corner of University Park and Risley St. in Fredonia. Figure 10b shows a large tree "topped" on Chestnut St. and Figure 10c is an image of a barn that was destroyed on Van Buren Rd. in Fredonia.

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