Forecasting derecho intensity using model instability parameters

Abstract

Upon reaching the American Midwest on their migration westward, the early European settlers encountered ferocious windstorms more intense and frequent than experienced in their homeland. One type of intense convective storm with damaging straight-line winds was termed the "derecho" by Gustavus Hinrichs, a forecaster with the Iowa Weather Bureau, in the late 1800's (Hinrichs, 1888). In Spanish, derecho means 'straight'; a correlation to tornado, which is a variation on the Spanish word for thunderstorm, tronada. Derechos are linear in nature and often contain severe weather producing features such as the bow echo and line echo wave pattern, or LEWP. These mesoscale storm complexes are responsible for much of the damage associated with severe thunderstorms in the United States.