Break from high wind events to begin in California -- but will rain come soon?
By
Alex Sosnowski, AccuWeather senior meteorologist
Published Nov 1, 2019 4:10 PM EDT
More than 400 firefighters worked around the clock, protecting homes from the fast-moving Maria Fire during the early morning of Nov. 1, in Santa Paula, California. Around 1,800 structures are threatened and around 7,500 people were ordered to evacuate.
After a break over the weekend, wildfire-ravaged California will continue to escape high wind events for early November, and there is the potential for some rain to start reaching portions of the state later this month.
California has been slammed with high wind events roughly every two to four days during the middle to the latter part of October, which is more frequent than normal for this time of year. The pattern has taken its toll with destructive wildfires that have had firefighters scrambling to protect neighborhoods.
The pattern into the middle of the month will feature weaker storms and a storm track farther to the east over the central United States. In turn, high pressure areas will be weaker that build in behind the storms and will be centered much farther inland over the West.
So, while there can be some minor wind events during the first half of November, they should pale in comparison to the strength and frequency of the windstorms from October.
The light winds should assist firefighters in gaining the upper hand on existing fires and limit the spread of any new fires that break out.
However, the brush will remain dry and the air will remain dry away from the immediate coast.
In terms of rainfall, there is some hope for a change in the jet stream pattern later during the second week of November that may hold for the rest of the month.
"The jet stream is forecast to take on a more west-to-east configuration from the Pacific Ocean to the interior western U.S. by the middle of November," Paul Pastelok, AccuWeather lead long-range meteorologist, said.
"This should promote more opportunities for storms to roll into the Northwest with some trailing cold fronts that can bring some rain to parts of Northern California," Pastelok said.
During this pattern, it is possible that a storm drops far enough south to bring a thorough soaking to portions of Northern California. Such a storm would greatly knock down the wildfire threat and perhaps mark its end for the rest of the year.
"In Southern California, the chance of rain moving in through mid-month is unlikely," Senior Long-Range Meteorologist Jack Boston said.
"But, if the pattern continues to evolve, then some rain may reach the Southland before month's end," Boston said.
California windstorms and fire season explained
There are two fire seasons in California in general, but they overlap during the early to middle part of the autumn, which creates prime fire weather.
Firefighters walk on a road leading to a residence as the Maria Fire burns on a hillside Thursday, Oct. 31, 2019, in Somis, Calif. (AP Photo/Marcio Jose Sanchez)
The two seasons are the summer brush fire season and the Santa Ana wind season. The Santa Ana season in Southern California tends to run from October through April.
The Santa Ana winds, and the Northern California counterpart Diablo winds, are caused as storms drop southeastward across the Rockies and high pressure areas build in their wake.
It is the rising atmospheric pressure that forces air to blast over the mountains and toward the coast, squeeze through the passes and funnel through the canyons. It's the same effect you may have noticed on a breezy day while walking in between tall buildings.
Typically, little to no rain falls from June through September over much of California, with the exception of occasional thunderstorms from the North American monsoon.
On average, rainfall begins to climb during the latter part of October through December. During October, rainfall in San Francisco is about 1 inch, while average rainfall in Los Angeles is about two-thirds of an inch. During November, average rainfall increases to about 2.40 inches in San Francisco and 1 inch in Los Angeles. During December, rainfall averages 4 inches in San Francisco and 2.33 inches in L.A.
The wettest part of the year in California tends to be from December to March. It is during these months that California receives the vast majority of its rainfall for the entire year.
Rain from the winter and early spring causes vegetation to flourish.
However, the heat and dryness during the summer then cause this brush to dry out and become fuel. Essentially, more growth from winter rain results in more brush to burn in the summer and fall.
Fires during the summer tend to be small due to light winds and tend to occur away from the coast, since the air near the coast is more moist.
A number of the summer brush fires are sparked by dry lightning strikes attributed to the North American monsoon.
By the early autumn, the brush is bone dry and the Santa Ana and Diablo events begin to kick in. These cause not only high winds, but also temperature surges along the coast and bring in very dry air from the interior.
In some years where and when seasonal rain comes early, the risk of large and numerous wildfires can be reduced and may remain relatively low as long as rains continue on a regular basis through the winter.
However, when rain fails to ramp up as it sometimes does later in the fall, ongoing high wind events can lead to wildfires or fast-moving firestorms that can periodically sweep across heavily populated areas during the winter and into the spring.
This year's peak fire season was delayed a bit since rain kept falling a bit later than average during the spring. It took a bit longer for the brush to reach critical dryness.
Nationally, the number of fires and acres burned is on a pace below that of 2018 and 2017, according to the National Interagency Fire Center.
Because of urban sprawl into rugged terrain of the canyons and longer running dry periods, the risk of damaging and dangerous wildfires through the year is increasing.
"AccuWeather's long-range team is anticipating average rain and mountain snow for this winter in California," Pastelok said.
While there should be enough rain on a regular basis this winter to lower the wildfire threat in general, there can be some episodes of dryness, when coupled with strong wind events, that could lead to fire flare-ups.
Download the free AccuWeather app to see the latest forecast for your region. Keep checking back for updates on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.
Report a Typo
News / Weather News
Break from high wind events to begin in California -- but will rain come soon?
By Alex Sosnowski, AccuWeather senior meteorologist
Published Nov 1, 2019 4:10 PM EDT
More than 400 firefighters worked around the clock, protecting homes from the fast-moving Maria Fire during the early morning of Nov. 1, in Santa Paula, California. Around 1,800 structures are threatened and around 7,500 people were ordered to evacuate.
After a break over the weekend, wildfire-ravaged California will continue to escape high wind events for early November, and there is the potential for some rain to start reaching portions of the state later this month.
California has been slammed with high wind events roughly every two to four days during the middle to the latter part of October, which is more frequent than normal for this time of year. The pattern has taken its toll with destructive wildfires that have had firefighters scrambling to protect neighborhoods.
The pattern into the middle of the month will feature weaker storms and a storm track farther to the east over the central United States. In turn, high pressure areas will be weaker that build in behind the storms and will be centered much farther inland over the West.
So, while there can be some minor wind events during the first half of November, they should pale in comparison to the strength and frequency of the windstorms from October.
The light winds should assist firefighters in gaining the upper hand on existing fires and limit the spread of any new fires that break out.
However, the brush will remain dry and the air will remain dry away from the immediate coast.
In terms of rainfall, there is some hope for a change in the jet stream pattern later during the second week of November that may hold for the rest of the month.
"The jet stream is forecast to take on a more west-to-east configuration from the Pacific Ocean to the interior western U.S. by the middle of November," Paul Pastelok, AccuWeather lead long-range meteorologist, said.
"This should promote more opportunities for storms to roll into the Northwest with some trailing cold fronts that can bring some rain to parts of Northern California," Pastelok said.
During this pattern, it is possible that a storm drops far enough south to bring a thorough soaking to portions of Northern California. Such a storm would greatly knock down the wildfire threat and perhaps mark its end for the rest of the year.
"In Southern California, the chance of rain moving in through mid-month is unlikely," Senior Long-Range Meteorologist Jack Boston said.
"But, if the pattern continues to evolve, then some rain may reach the Southland before month's end," Boston said.
Related:
California windstorms and fire season explained
There are two fire seasons in California in general, but they overlap during the early to middle part of the autumn, which creates prime fire weather.
Firefighters walk on a road leading to a residence as the Maria Fire burns on a hillside Thursday, Oct. 31, 2019, in Somis, Calif. (AP Photo/Marcio Jose Sanchez)
The two seasons are the summer brush fire season and the Santa Ana wind season. The Santa Ana season in Southern California tends to run from October through April.
The Santa Ana winds, and the Northern California counterpart Diablo winds, are caused as storms drop southeastward across the Rockies and high pressure areas build in their wake.
It is the rising atmospheric pressure that forces air to blast over the mountains and toward the coast, squeeze through the passes and funnel through the canyons. It's the same effect you may have noticed on a breezy day while walking in between tall buildings.
Typically, little to no rain falls from June through September over much of California, with the exception of occasional thunderstorms from the North American monsoon.
On average, rainfall begins to climb during the latter part of October through December. During October, rainfall in San Francisco is about 1 inch, while average rainfall in Los Angeles is about two-thirds of an inch. During November, average rainfall increases to about 2.40 inches in San Francisco and 1 inch in Los Angeles. During December, rainfall averages 4 inches in San Francisco and 2.33 inches in L.A.
The wettest part of the year in California tends to be from December to March. It is during these months that California receives the vast majority of its rainfall for the entire year.
Rain from the winter and early spring causes vegetation to flourish.
However, the heat and dryness during the summer then cause this brush to dry out and become fuel. Essentially, more growth from winter rain results in more brush to burn in the summer and fall.
Fires during the summer tend to be small due to light winds and tend to occur away from the coast, since the air near the coast is more moist.
A number of the summer brush fires are sparked by dry lightning strikes attributed to the North American monsoon.
By the early autumn, the brush is bone dry and the Santa Ana and Diablo events begin to kick in. These cause not only high winds, but also temperature surges along the coast and bring in very dry air from the interior.
In some years where and when seasonal rain comes early, the risk of large and numerous wildfires can be reduced and may remain relatively low as long as rains continue on a regular basis through the winter.
However, when rain fails to ramp up as it sometimes does later in the fall, ongoing high wind events can lead to wildfires or fast-moving firestorms that can periodically sweep across heavily populated areas during the winter and into the spring.
This year's peak fire season was delayed a bit since rain kept falling a bit later than average during the spring. It took a bit longer for the brush to reach critical dryness.
Nationally, the number of fires and acres burned is on a pace below that of 2018 and 2017, according to the National Interagency Fire Center.
Because of urban sprawl into rugged terrain of the canyons and longer running dry periods, the risk of damaging and dangerous wildfires through the year is increasing.
"AccuWeather's long-range team is anticipating average rain and mountain snow for this winter in California," Pastelok said.
While there should be enough rain on a regular basis this winter to lower the wildfire threat in general, there can be some episodes of dryness, when coupled with strong wind events, that could lead to fire flare-ups.
Download the free AccuWeather app to see the latest forecast for your region. Keep checking back for updates on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.
Report a Typo