The National Weather Service has issued a severe thunderstorm watch for Ann Arbor, Michigan until 5:00 PM this afternoon. The graphic is from the Weather Underground site, and shows the Detroit area at about 2:15 PM today. (Ann Arbor is marked with the target symbol)
Here’s a helpful “Public Information Statement” about what it means when the NWS issues “watches” and “warnings”:
“A Severe Thunderstorm Watch has been issued by the National Weather Service in Michigan. In the interest of public safety the following safety rules are provided. Public and commercial broadcast stations serving the affected area are asked to frequently broadcast these messages while the watch is in effect.
A quick reminder… the term watch means conditions are favorable for development of severe weather in the designated area. During a watch… there is no cause for immediate concern. You should go about your normal business but keep abreast of weather developments. Public safety officials should… however… activate prearranged plans.
A warning… on the other hand… means a severe thunderstorm or tornado has been observed or indicated by radar. People in the path of the storm should take immediate precautions as outlined here…
Severe thunderstorms produce strong damaging winds of 58 mph or greater… large hail three quarters of an inch in diameter or greater… heavy rain and deadly lightning. Winds in excess of 58 mph can push over shallow rooted trees… break off tree limbs about the size of your wrist… and damage chimneys and TV antennas. In rare occasions severe thunderstorms can produce winds in excess of 80 mph which could break windows… Peel surfaces off of roofs… snap large trees and move trailer homes and automobiles. Hail three quarters of an inch in diameter or larger can damage windows… vehicles… and exterior finishes of buildings… especially if accompanied by severe winds.
Persons should stay indoors and away from areas with loose items that could become flying debris. Severe thunderstorms can and occasionally do produce tornadoes so be prepared to move to an appropriate shelter should it become necessary. Lightning is one of
the worst killers… so stay indoors and avoid using electrical appliances. You should get out of open fields and off of farm or other types of heavy equipment. Avoid towers or tall trees. If on a boat or swimming… get out of the water and to shore as quickly as
possible. Also avoid areas subject to flash flooding.”