Posted: Jul 22, 2011 2:18 PM by Montana's News Station
The National Weather Service has issued a Tornado Watch until 9 pm on Friday for the following 11 counties in eastern Montana:
Daniels, Dawson, Garfield, McCone, Phillips, Prairie, Richland, Roosevelt, Sheridan, Valley, and Wibaux.
This includes the cities of Circle, Culbertson, Fairview, Fort Peck, Glasgow, Glendive, Jordan, Malta, Medicine Lake, Opheim, Plentywood, Poplar, Richey, Saco, Scobey, Sidney, Terry, Whitewater, Wibaux, Wolf Point, and Zortman.
A Tornado Watch should not be confused with a Tornado Warning; a Watch does NOT mean that a tornado has been spotted - it means only that conditions are favorable for the possible formation of a tornado.
Here's more on the difference from Storm Prediction Center:
2.1 What is a Severe Thunderstorm or Tornado Watch?
A Severe Thunderstorm Watch outlines an area where an organized episode of hail 1 inch diameter or larger and/or damaging thunderstorm winds are expected during a three to eight hour period. A Tornado Watch includes the large hail and damaging wind threats, as well as the possibility of multiple tornadoes. Typical watches cover about 25,000 square miles, or about half the size of Iowa.
2.4 What's the difference between a watch and a warning?
A watch means severe weather is possible during the next few hours, while a warning means that severe weather has been observed, or is expected soon.