Smoke Plume Weather

Intense heat, low humidity and extremely dry fuel moisture of the vegetation near Mt. Diablo led to explosive development of the Morgan Fire at times on Sunday afternoon. A towering ‘column plume’ fire took shape, an indication of heat driving upward motion like strong updrafts in a thunderstorm with the smoke fanning outward near the top into the slightly offshore winds above moving in the opposite direction of the late day sea breeze below. As rapidly growing fires develop, rising air will cause air to move inward to replace it, causing wind shifts that can lead to challenging fire weather behavior. Winds are expected to increase slightly into Monday with onshore winds leading to cooling temperatures and slightly higher humidity levels by Tuesday. Rob Mayeda