Derecho is a spanish word and basically means direct or straight. It can also mean right, as in right handed.
In regard to storms, a derecho is a straight line of severe windstorms. The derecho generally develops when long lived, fast paced, severe thunderstorms meet and form a squall line. A derecho is highly capable of exceeding hurricane force winds of over 100 miles per hour. Like hurricanes, derechos are common in the warm summer months of June and July, but can occur during cooler months.
|A shelf cloud along the leading edge of a derecho. Wikimedia|