WASHINGTON – Last Wednesday, two weak tornadoes skipped across Alexandria, Virginia, and Savage, Maryland, according to a post-storm survey conducted by the National Weather Service.
The local NWS office, located in Sterling, promptly issued tornado warnings for these storms.
Despite the official confirmation of a tornado, damage was minimal. A few trees were downed near Belle Haven Country Club. The tornado, veiled by curtains of heavy rain, lifted within minutes.
As the storms moved into Howard County, two minor injuries resulted from winds that peaked near 65 miles per hour. A tree crashed into an apartment building. A traffic sign was snapped. The spin-up whirled around on the ground for less than a minute.
Jim Lee, National Weather Service meteorologist in charge of the Baltimore/Washington office, tells WTOP that the agency is required to issue tornado warnings regardless of the expected magnitude of the threat.
“Our radar meteorologist did see the indication of a tornado on radar and so we went ahead and issued the tornado warning as we should have,” Lee says.
The system that produced the spin-ups was a linear band of thunderstorms. Meteorologists typically associate these types of storms with “low-end” tornadoes.
“When we see rotation on the radar (or) when we hear that there’s a funnel cloud from a reliable source, we want to go ahead and issue that tornado warning. We’d rather be safe than sorry.”
The Baltimore/Washington office issues weather warnings for a broad region from the Chesapeake Bay to the panhandle of West Virginia and from the Mason- Dixon Line to central Virginia.
“Last year our office put out sixteen tornado warnings. We had seven tornadoes actually occur. Similarly we had about 187 severe thunderstorm warnings. Looking at those stats, 80 percent of the time when we put out a warning we are going to get damage.”
Some have argued that communities in the path of weak tornadoes like those that touched down last week should be placed under severe thunderstorm warnings, which are typically issued when thunderstorm wind gusts greater than 59 miles per hour are imminent.
“When the radar meteorologist sees rotation, they’re going to go ahead and issue a tornado warning. That is our policy.” But Lee says that the agency is open to reassessing that policy with the goal of better serving the public.
“Last week in Fairfax, we got together with emergency managers and transportation planners… with the hope that we can create a dialogue and that we can go ahead and build upon that and maybe down the road at some point maybe modify the policy.”
Several years ago, various weather service offices would issue severe thunderstorm warnings for areas near storms that exhibited “weak” rotation.
“Spin-up tornadoes – they’re on the ground for one to four minutes and it’s a very transient type circulation. It spins down, does some damage, and then it lifts back up. It’s clear-cut in our policy that if we see rotation, we’re going to be issuing a tornado warning.”
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