85th AMS Annual Meeting

Tuesday, 11 January 2005: 3:30 PM
2004: A record year for tornadoes
Joseph T. Schaefer, NOAA/NWS/NCEP/SPC, Norman, OK; and D. W. McCarthy and G. W. Carbin
The 2004 tornado year began slowly, just as the previous year had. However, it will likely go into the record books as the year with the most reported tornadoes since record keeping began in 1950. Preliminary numbers indicate that nearly 1, 600 tornadoes occurred during 2004 eclipsing the previous record 1,424 tornadoes in 1998. Since 2003 is listed second in the books with 1,376 tornadoes, there were two back-to-back years that rank near the top for tornado activity.

The first quarter of 2004 was marked with significantly below normal tornado activity. This was a result of an upper air pattern that was generally characterized by a large upper level low over the Great Lakes that kept northwesterly flow aloft from the Northern Plains into the Southeastern U.S. This in turn retarded the normal springtime return of Gulf of Mexico moisture northward into the Lower Mississippi Valley and Gulf Coast states.

The first killer tornadoes of the year occurred on April 20th as a flurry of tornadic storms developed along and just north of a warm front across central Illinois. A tornado moved through Peru, IL, some 70 miles southwest of Chicago, killing eight people who had taken shelter in the town tavern. A month later, the quasi-stationary upper air pattern broke allowing a more zonal pattern across the central U.S. which then developed into southwest flow as the Bermuda High set up off the eastern FL coast. This started a week of tornadic storms between May 21st and 30th that produced 445 individual tornado reports.

The year was also marked by a record number of tornadoes in both August and September. The vast majority of these tornadoes were associated with Tropical Storm Bonnie, Hurricane Charley, Hurricane Frances, Hurricane Ivan and Hurricane Jeanne. Nearly 300 tornado reports were filed with these tropical systems, the most of its kind on record. Preliminary data indicate that Hurricane Frances produced 117 tornadoes. If they all verify, this would eclipse the record number of 115 tornadoes associated with a tropical system set by Hurricane Beulah in 1967. The meteorology of these hurricane related tornadoes will be discussed in a separate paper Bill McCaul in this session.

This presentation will review the meteorology of the 2004 tornadoes and specifically note several events that were especially noteworthy because of their impact

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