A series of storms will affect the entire length of California over this week, and should provide much needed rainfall almost everywhere in the state.
On Tuesday a much more potent—and warmer—storm will begin to affect the state. A low pressure area situated well off the coast is expected to draw high moisture content air from the tropics. This storm may have at least some characteristics of an “atmospheric river”. Atmospheric rivers are narrow bands of very moist air that provide as much as 90% of the poleward transport of water vapor in the atmosphere. Some atmospheric rivers may carry as much water (in vapor form) as the Amazon River.
Atmospheric river storms produce very high orographic rainfall when this moist air is forced up coastal mountain ranges. Because the air has its origin in the tropics, snow levels are usually quite high, and are expected to be over 7000’ for Tuesday’s storm.
Rainfall totals for the next five days are forecast to be greater than one inch at low elevation locations throughout the state, and five inches or more in some of the mountain locations.
James D. Means, Ph.D.
Atmospheric and Climate Scientist