Tornado warning
From Wikipedia, the free encyclopedia
A tornado warning is issued when:
- a tornado is reported on the ground or is indicated on doppler radar
- a waterspout is headed toward landfall
- a funnel cloud is reported in the sky
- a tropical cyclone is making landfall with winds greater than 115 mph (experimental for 2006, will be renamed "Extreme Wind Warning" if successful)
It is also issued when, depending on the circumstances:
- a thunderstorm with a threshold strong, tight rotation signature is indicated by doppler radar, or
- a rotating wall cloud is reported (in context of all other available information).
A tornado warning means there is immediate danger for the warned and immediately surrounding area -- if not from the relatively narrow tornado itself, from the severe thunderstorm producing (or likely to produce) it. All in the path of such a storm are urged to take cover immediately, as it is a life-threatening situation. A warning should not be confused with a tornado watch (issued by a national guidance center, the Storm Prediction Center) which only indicates that conditions are favorable for the formation of tornadoes.
In the United States, local offices of the National Weather Service issue warnings for tornadoes and severe thunderstorms on a per-county basis, narrowing down to parts of counties in many cases, and usually with a narrower pathcast of where the tornado(s) is expected to track within the area is mentioned in the warning message.
In Canada, similar criteria are used and warnings are issued by regional offices of the Meteorological Service of Canada of Environment Canada in Vancouver, Edmonton, Toronto, Montreal and Halifax.
Tornado warnings are generated via computer then disseminated through various communication routes accessed by the media and various agencies, on the internet, to NOAA satellites, and on NOAA Weather Radio.
The first tornado warning was issued by the meteorological staff of Tinker Air Force Base in 1947 and was also coincidentally the first successful tornado forecast.
Advances in technology, both in indentifying conditions and in distributing warnings effectively, have been credited with reducing the death toll from tornadoes. The average warning times have increased substantially to about 15 minutes; and in some cases to more than a one hour's warning of impending tornadoes. The U.S. tornado death rate has declined from 1.8 deaths per million people per year in 1925 to only 0.11 per million in 2000. Much of this change is credited to improvements in the tornado warning system.
[edit] Example of a tornado warning
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000 WFUS52 KMLB 020806 TORMLB FLC069-020900- /O.NEW.KMLB.TO.W.0003.070202T0804Z-070202T0900Z/ BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE MELBOURNE FL 304 AM EST FRI FEB 2 2007 THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A * TORNADO WARNING FOR... NORTHERN LAKE COUNTY IN EAST CENTRAL FLORIDA... THIS INCLUDES THE CITIES OF...PAISLEY...LISBON...LAKE GRIFFIN... LADY LAKE...THE VILLAGES...EMERALDA... * UNTIL 400 AM EST * AT 304 AM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 10 MILES WEST OF LADY LAKE. THIS STORM WAS MOVING EAST NORTHEAST AT 50 MPH. * THE TORNADO WILL BE NEAR... LADY LAKE AND THE VILLAGES BY 315 AM EST... PAISLEY BY 345 AM EST... THE SAFEST PLACE TO BE DURING A TORNADO IS IN A STRONG BUILDING ON THE LOWEST FLOOR...IN AN INTERIOR ROOM SUCH AS A BATHROOM OR CLOSET. KEEP AWAY FROM WINDOWS. GET UNDER A WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. USE BLANKETS OR PILLOWS TO COVER YOUR BODY. LAT...LON 2897 8216 2879 8209 2889 8136 2926 8165 $$
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