Strong and damaging winds are expected to start in parts of northern and central California as early as Sunday night and last until Wednesday.
Strong wind alerts are in effect for more than 30 million people, from central northern California to southern California.
A strong area of high pressure will build up in the northwest on Sunday night and on Monday, this area of high pressure will move to the Great Basin on Tuesday. As this high pressure area increases, a low pressure area will develop on the southern California coast.
The proximity and strength of the two systems are important. This is known as a pressure gradient, which is expected to be quite strong and will cause these intense winds to develop earlier this week.
Winds flow from high pressure areas to low pressure areas, so in this case, the winds for this event are expected to be offshore winds, when the wind moves from land to sea. Locally, in different areas of California, these wind events are often called “Diablo winds”, “Mono winds” or “Santa Ana winds”.
Timing
Northern and central California areas are expected to experience these strong winds first, arriving late on Sunday and lasting until Tuesday.
The strongest winds in northern and central California are expected to develop Monday night through Tuesday morning.
The strongest winds in southern California are expected on Tuesday.
Such strong winds can lead to the fall of trees and power lines, power outages and potentially widespread critical climatic conditions in much of the state.
Fire climate
Typical fire conditions in southern California are fueled by a combination of above average temperatures, low humidity, dry vegetation and strong winds. The development of low pressure on the southern California coast may limit some of these factors, bringing with it colder temperatures and higher humidity values. Because of this, the climatic conditions of the fire may be somewhat limited earlier this week.
However, many locations in Southern California, including Los Angeles, have not seen measurable rain since late December, meaning the region’s vegetation took more than two weeks to dry.
Southern California has also experienced record heat in recent days, in addition to the region’s growing drought.
When you take dry vegetation, drought conditions and strong winds into account, all it takes is a spark for the fire to start and spread quickly. The Storm Prediction Center did not rule out the chance of critical fire conditions, especially on Monday.
The SPC also said that these humidity values may drop below in some locations due to downward winds – dry winds that flow from east to west through mountain passes in California – which can lead to a few hours of critical fire conditions on Monday afternoon.
This low pressure area, however, will bring some much-needed rain and snow to parts of the southwest in the coming days, which will help to reduce widespread drought conditions across the region.