Orographic Influences 5.
Severe storms affect many coastal regions during the winter and, to a lesser extent, in summer.
Regional differences exist, with oceanic extratropical cyclones affecting the coast of California to Alaska and continental extratropical cyclones moving from the interior of the continental United States to the east coast. Tropical cyclones, including hurricanes, may affect almost any part of the coast during summer and fall. Particularly important effects are caused by cold air outbreaks along the east coast and by rapidly intensifying storms over the Gulf Stream. Land-falling storms are directly modified in the coastal region where changes in the bottom boundary conditions are dramatic. Although hurricanes weaken over land because of the absence of latent heating at the surface, orographic barriers can affect the dynamics of the storm through blocking and actually enhance precipitation and winds in coastal areas.