March 22, 2007 Meeting

The meeting was held at the National Weather Service Office in Jackson. Our guest speaker was Kevin Pence, Science and Operations Officer from the National Weather Service Forecast Office in Birmingham, AL.

Meeting Minutes

The second meeting of Jackson Chapter’s NWA/AMS in 2007 was held on Thursday, March 22, 2007, at 7:00 pm, at the National Weather Service Forecast Office in Jackson, MS. The meeting was opened by chapter President Eric Carpenter, with 13 people in attendance.

Discussion was initiated by Eric Carpenter in the opening session, concerning the chapter’s orders of business:

  • Eric Carpenter is currently holding on to the money for the chapter’s treasury, which currently amounts to $185.00.
  • Carolyn Bryant, Chapter Webmaster, has been able to get the web page established. Several improvements have been made since the last meeting.
  • Eric Carpenter suggested that the chapter needs to be more formal with membership dues and documentation. The chapter will begin to keep record of membership and dues beginning in January.
  • Dr. Loren White has agreed to update the officers with the American Meteorological Society.

Following the opening session, Eric Carpenter introduced the guest speaker for the evening, Kevin Pence, Science and Operations Officer from the National Weather Service Forecast Office in Birmingham, AL. Mr. Pence worked at the NWS office in Jackson, MS, beginning in 1981. He then took the SOO position at the NWS office in Birmingham in 1993, and he has held this position since.

Mr. Pence’s topic of discussion was on the April 8, 1998, tornado outbreak. Specifically, he focused on a supercell that produced F3, F5, and F2 tornadoes in the Birmingham County Warning Area.

The first tornado touched down at 7:01 pm in east Pickens County, and lasted until 7:29 pm when it ended in Tuscaloosa County. This first tornado was rated an F2 on the Fujita scale, and resulted in zero fatalities and two injuries.

The second tornado was at least a half mile wide and had a track over 30 miles long as it tracked through Jefferson County. This tornado was initially weak, with a rating of around F0 to F1. The storm intersected with a gravity wave, which approached from the south. Around the time this occurred, the tornado intensified, becoming an F5 tornado. This tornado resulted in 32 fatalities and 250 injuries. This tornado dissipated before reaching the Interstate 65 corridor.

The third tornado developed after the supercell took on a bow characteristic. This tornado touched down in St. Clair County, and was given an F2 rating. Another 2 fatalities were added to this supercell’s death toll with this tornado.

This supercell took on a “classic” characteristic as it developed and moved through Jefferson County, with features such as a hook, V-notch, and forward flank. The rotational velocity was maxed out. Once this supercell moved out of Jefferson County, it took on more of a bow characteristic. This supercell continued into Georgia, producing 3 more tornadoes, and overall resulting in 35 fatalities and 286 injuries between Alabama and Georgia, with the majority occurring with the F5 that moved through Jefferson County.

With the event, there were also several other storms across north Alabama. One supercell produced hail that busted through windshields. A storm survey was conducted with this storm, but no confirmed tornado was found.

Overall, the Birmingham Weather Forecast Office issued 109 warnings between 12z on April 8th, through 10Z on the 9th. Of these warnings, 88 occurred between 22Z and 05Z. This made for an average of 12.5 warnings per hour, or 1 warning every 4 minutes and 48 seconds for 7 hours. Needless to say, the tornado outbreak of April 8, 1998, was a significant event in Mr. Pence’s career.

Following Mr. Pence’s presentation, Chad Entremont invited everyone to look at the archived radar data from the April 8, 1998, event on GR2Analyst.

The meeting was adjourned by Eric Carpenter.

Advertisements