"Derecho" (deh-ray'-cho) is not a common word among Wisconsin weather watchers - but it could be before the week is out. A derecho is a strong weather pattern that occurs every 1-to-2 years across the central and northeastern U.S., normally in a band from Texas to New England. The Upper Midwest shows signs of such a pattern brewing - and metro areas from Milwaukee to Pittsburgh could see a line of heavy thunderstorms, golf-ball-sized hail, tornadoes, straight-line winds of 70-miles-an-hour, and the damage that goes with all that.

A derecho is normally strong enough to tip over semi-trucks and tear off roof shingles. The storm activity is expected to begin today in Montana and Wyoming. Heavy thunderstorms are being predicted for parts of Wisconsin tomorrow, and the derecho is due in the Badger State on Thursday.