Red Flag Warning to be followed by snow in Owens Valley

It will also be very windy in Northern California

Red Flag Warning Sierras
Red Flag Warning issued at 1:57 a.m. PST Nov. 25, 2019. NWS.

8:24 a.m. PST November 25, 2019

Strong north winds gusting up to 50 mph in the Southern Sierras on Monday with humidity in the low teens has generated a Red Flag Warning for Owens Valley. The wind behind a cold front is expected to reach Bishop, California around 10 a.m. and then spread down to the rest of the valley by noon, continuing into the early evening before gusts decrease to less than 35 mph.

It will also be very windy in Northern California on Monday but no Red Flag Warnings have been issued for that part of the state as of 8:15 a.m. Monday.

strong wind forecast northern california

The enhanced wildfire danger will be followed by a winter storm warning from late Tuesday afternoon through Friday morning. Significant snow accumulations are predicted for much of Inyo County, the southern Great Basin, and higher elevations of the Mojave Desert. Forecasters expect total snow accumulations of five to 10 inches in the Owens Valley and 12 to 36 inches in the mountains, with winds gusting up to 45 mph.

(Red Flag Warnings can be modified throughout the day as NWS offices around the country update and revise their weather forecasts.)

Extreme fire weather results in more potential power shutoffs in California

Electricity could be shut off for millions of people

Red Flag Warnings October 29, 2019
Red Flag Warnings for extreme fire danger October 29, 2019. NWS.

Red Flag Warnings in northern and southern California include forecasts for very strong winds and single digit humidity that will make wildfires difficult or impossible to suppress until, 1) the weather changes, or 2) the fire runs out of fuel.

Conditions in the southern part of the state will be critical, especially in the greater Los Angeles area which should expect 30 to 55 mph winds gusting at 75 to 85 with humidity of 3 to 8 percent.

Below is the National Weather Service forecast for Santa Clarita, near last week’s Tick Fire north of Los Angeles: Tuesday night, winds 41 to 46 mph gusting out of the northeast at 61 to 68. The relative humidity will drop to the single digits by noon on Wednesday.

NWS forecast wind Santa Clarita, CA
NWS forecast for the Santa Clarita, CA area, beginning October 29, 2019. The wind barbs point to the direction the wind will be FROM.

Below is information about this weather event from Jim Cantore of The Weather Channel Tuesday morning:

red flag conditions southern california wind humidity
Jim Cantore, The Weather Channel.

The three large utility companies could potentially shut off the power to millions of people in California beginning Tuesday. The maps below were collected from the web sites of the power companies at 8:30 a.m. PDT October 29 and show areas that could potentially be affected by power shutoffs. The information could change.

areas risk power shutoffs SDG&E
San Diego Gas & Electric’s communities at risk of power shutoffs October 29, 2019. SDG&E.
areas risk power shutoffs SCE
Southern California Edison’s areas at risk of power shutoffs October 29, 2019. SCE.
Pacific Gas & Electric's areas risk power shutoffs
Pacific Gas & Electric’s areas at risk of power shutoffs October 29, 2019. PG&E.

(Red Flag Warnings can be modified throughout the day as NWS offices around the country update and revise their weather forecasts.)

Critical to extremely critical fire weather predicted for southern California

The fire weather in southern California for Tuesday night through Thursday, October 29-31, is predicted to be the most severe so far this year. Wind gusts of 50 to 70 mph are possible in the mountains and foothills and relative humidity could drop into the single digits.

In areas of northern California a Red Flag Warning will be in effect from 8 a.m.  PDT Tuesday until 4 p.m. PDT Wednesday. The wind is expected to be out of the north or northeast at 15 to 35 mph with gusts of 35 to 60 mph, locally higher in canyons and exposed ridges.

(Red Flag Warnings can be modified throughout the day as NWS offices around the country update and revise their weather forecasts.)

Smoke forecast and Red Flag Warnings for Sunday Oct. 27

Smoke will affect areas in Arizona, New Mexico, and southern California

smoke forecast October 27, 2019
Forecast for vertically integrated (high level) smoke at 5 p.m. PDT October 27, 2019.

On Sunday October 27 smoke from wildfires in northwest Mexico will affect areas in southern California, Arizona, and New Mexico.

smoke forecast October 27, 2019
Forecast for near surface (low level) smoke at 5 p.m. PDT October 27, 2019.
Red Flag Warnings
Red Flag Warnings as of 7 p.m. PDT October 26, 2019. Times are CDT.

The smoke in Mexico has been coming from the fires shown on the map below.

fires wildfires northwest Mexico
Map showing heat detected on wildfires in northwest Mexico as last as 1:36 p.m. PDT October 26, 2019.

Smoke predicted to affect San Francisco Bay area

Possibly the strongest wind event of the fall season will occur in northern California Saturday morning into Monday

forecast 4 a.m. PDT October 26 fire wildfire smoke
Forecast for the distribution of near surface smoke at 4 a.m. PDT October 26, in the San Francisco area and south as far as Santa Barbara. Click to enlarge.

UPDATED at 6:09 p.m. PDT October 25, 2019

The map above is the forecast for the distribution of near surface smoke at 4 a.m. PDT October 26, in the San Francisco area and south as far as Santa Barbara.


7:56 a.m. PDT October 25, 2019

northern california San Francisco Forecast near surface smoke western united states
Forecast for near surface smoke in the western U.S. at 5 p.m. PDT Oct. 25, 2019

Forecasters predict that smoke from the Kincade and Tick Fires will heavily affect some locations in northern and southern California Friday. Especially affected will be the San Francisco Bay Area, from San Jose north to Santa Rosa, including the city of San Francisco.

Smoke from prescribed burning will be noticed by residents in Oregon, Idaho, and Montana.

northern california San Francisco Forecast near surface smoke northern California
Forecast for near surface smoke in northern California at 5 p.m. PDT Oct. 25, 2019

Red  Flag Warnings will continue in Southern California until Friday night.

Red Flag Warnings Fire Weather Watches
Red Flag Warnings and Fire Weather Watches, at 7 a.m. PDT Oct. 25, 2019. Times are CDT.

Very strong, dry winds are in the forecast for northern California beginning Saturday morning. This wind event which will continue into Monday is being described as “likely the strongest wind storm of the fall season” with northeast to east winds of 30 to 40 mph gusting at 45 to 70. The Watch areas in the map above will probably be upgraded to Red Flag Warnings by late Friday or Saturday morning.

(Red Flag Warnings can be modified throughout the day as NWS offices around the country update and revise their weather forecasts.)

Santa Ana Wildfire Threat Index in SoCal this week, “Moderate”

Santa Ana Threat Index
The fire threat for four areas in southern California on October 24 and 25 is described as “Moderate”. This example is for the Los Angeles and Ventura areas, showing Threat Level, Wind Strength, and Fuel Moisture on Thursday October 24.

A wildland fire danger forecasting tool called the Santa Ana Wildfire Threat Index (SAWTI) is categorizing the fire threat from the strong winds predicted for Thursday and Friday of this week in southern California as “Moderate”. This includes Los Angeles, Ventura, Orange County, Inland Empire, and San Diego. The Santa Barbara area is shown as “no rating” for this week. Most other tools for predicting fire danger would use a stronger adjective for the predicted conditions.

The SAWTI uses a predictive model that includes wind strength, dead fuel moisture, live fuel moisture, atmospheric moisture, and the greenness of annual grasses to create a daily threat assessment of the fuel conditions across Southern California. The output is then compared to climatological data and historical fire occurrence to establish the index rating. It does not assess conditions in the central or northern part of the state.

The SAWTI is a product of the US Forest Service and Predictive Services, according to the website dedicated to the tool. The site does not specify which of the numerous Predictive Services  and Forest Service offices are involved.

Red Flag Warnings
Red Flag Warnings, produced at 6:30 a.m. PDT October 23, 2019. Times are CDT.

For northern California the forecast on Thursday and Friday is for north to northeast winds of 15 to 30 mph gusting at 35 to 45 with humidity in the teens. For southern California: northeast winds of 20 to 40 gusting up to 65 with humidity in the single digits. These predicted numbers vary depending on the exact location.

(Red Flag Warnings can be modified throughout the day as NWS offices around the country update and revise their weather forecasts.)