National Weather Service United States Department of Commerce

Atmospheric River Bringing Heavy Rain to Southern California and Heavy Snow to the Sierra Nevadas

A strong atmospheric river will continue heavy rain over southern California through Friday. The heaviest rainfall is ongoing today in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall has begun over the Sierra Nevada Mountains and will continue through Friday. Travel will become increasingly difficult over the passes due to snow and strong winds. Read More >

 

 

 

Weather Risk Outlook

The Weather Risk Outlook colors are determined after NWS Pendleton meteorologists examine both the impact level of potential weather scenarios AND the associated probability of those scenarios. The resulting outlook displays the highest risk for each day.

NWS Pendleton meteorologists first use the impact table to determine the level of impact expected with a forecast weather event.

NWS Pendleton meteorologists then determine the color by determining the probability of occurrence using all the available information and then reference the matrix to determine the risk level associated with the forecast weather event.