By Jennifer Moody
for the gazette-times | Posted: Saturday, September 29, 2007 12:00 am
No one officially recorded Lebanon's late-afternoon tornado Friday, but conditions were perfect for one to occur.
David Elson, a meteorologist with the Portland office of the National Weather Service, said radar data indicated thunderstorms, which means instability in the atmosphere, and a rotating storm pattern.
Funnel clouds are likely in the mid-valley during a "cold core low," an upper-atmosphere phenomenon in which a low-pressure storm moves over the area with very cold air near its center. The clouds become tornados if they touch the ground.
State Climatologist George Taylor said late Friday he hadn't heard about the one in Lebanon but wasn't surprised by it.
"With the cold low over us, we were speculating today there might be funnel clouds," he said.
Because a tornado rarely strikes a place where the wind can be measured directly, meteorologists calculate a tornado's wind speed from the damage it causes.
Elson said based on reports from the Lebanon incident, he guessed the wind gust was in the neighborhood of 75 miles per hour.
"That's a shot in the dark," he said.
Witnesses said Friday's tornado touched down for just a few seconds at about 5 p.m.
It ripped doors and pieces of roof from Bob Cate's equipment and seed storage buildings on Tennessee School Road. It took out four trees on his property, two at a neighbor's, and pieces of several others on its way to and from the area.
Elson said the thunderstorms in the mid-valley were expected to end Friday night and no hazardous weather - unless rain counts - is predicted for the next few days.
Temperatures are expected to be in the low- to mid-60s with showers likely most of the week.