Much-needed precipitation to eye parched California
By
Alex Sosnowski, AccuWeather senior meteorologist
Updated Apr 21, 2021 2:35 PM EST
Experts at San José State University's Fire Weather Research Laboratory say they are concerned about dry vegetation and the growing risk of wildfires.
California is in desperate need of moisture in the form of rain and mountain snow. Since the water year began on Oct. 1, 2020, most areas are within the 25th to 50th percentile of average.
Even though the tail end of the rainy season is at hand in California, there is some hope for late-season rain and mountain snow in the coming days and weeks as AccuWeather meteorologists say storms from the Pacific are about to take a jog much farther south.
For example, downtown Los Angeles has only received 5.80 inches of rain since Oct. 1, compared to an average of 14.06 inches. Farther north, in Sacramento, only 6.54 inches of rain has been recorded compared to a normal amount of 16.95 inches.
At the start of 2020, much of California was in good shape due to ample rain and mountain snow over the prior year, according to the United States Drought Monitor. However, as storms became more scarce during 2020, abnormally dry conditions expanded and evolved progressively into more serious phases of drought. As of Thursday, April 15, 2021, 99% of the state was considered to be in abnormally dry conditions or worse. Nearly 40% of California was considered to be under extreme drought conditions -- the second-highest level of drought just under exceptional drought.
The dry conditions have already been contributing to sporadic wildfires along the Pacific coast. A small fire prompted the evacuation of nearly two dozen homes in Guvilan Hills, Riverside County, California, on Monday, according to ABC7.
But AccuWeather forecasters say there is some good news, at least on the weather maps. A series of storms appears to be lining up over the Pacific Ocean with the potential for some aid from the weather.
A large Pacific storm was visible off the West Coast of the U.S. on Tuesday, April 19, 2021. (NOAA / GOES-WEST)
Rain and mountain snow are expected to begin in the western portions of Washington and Oregon Saturday before wet weather expands southward into Northern California Sunday and Monday, AccuWeather Long-Range Meteorologist Brandon Buckingham said.
"This could prove to be very beneficial for the northern and central portions of the Sierra Nevada, Coast Ranges and valleys, although it could come at the risk of flash flooding in some spots," Buckingham stated.
As of April 20, the amount of water locked up in the snowpack over the Sierra Nevada ranged between 40 and 60% of average, according to the Natural Resources Conservation Service. The lean snowpack means less snow will be available to melt during the spring and summer, which will translate to less runoff to fill streams and reservoirs in the region. Above-average temperatures in recent weeks have expedited the runoff. The faster the snow melts in the spring, the less snow is likely to be available to melt during the summer.
The upcoming pattern from this weekend to early next week is not likely to bring a blockbuster amount of snow, but it has the potential to unload several inches over the high country of the central and northern Sierra Nevada.
At this time it appears that much of Southern California will be south of where significant rainfall is likely to target.
"It is possible that even the Los Angeles Basin receives some rain showers from this system early next week," Buckingham said.
There is the chance for another storm or two to bring wet weather to California.
The weather pattern may remain active along the Pacific coast into the first week or two of May, AccuWeather Lead Long-Range Meteorologist Paul Pastelok said.
CLICK HERE FOR THE FREE ACCUWEATHER APP
"We are seeing signs that southward undulations in the jet stream will continue to develop over the Pacific Ocean and pivot toward the West Coast," Pastelok explained. "This setup should continue to pump some moisture in from the Pacific and into the western U.S. into the first part of May."
Pastelok stated that even though it is possible for a couple of rounds of showers to reach Southern California and even southern Nevada and Arizona during the first week or two of May, the pattern is not consistent enough to make a definitive call either way.
Very little rain tends to occur in California during May, even in northern areas. On average, Los Angeles and San Diego normally pick up 0.12 of an inch of rain with 0.47 of an inch in San Francisco and 0.68 of an inch in Sacramento. The central and northern Sierra Nevada tend to squeeze out some moisture in May with an average of 1.07 inches at Lake Tahoe, California.
By June, average rainfall is negligible across the state, except for several tenths of an inch over the Sierra Nevada.
Most of the state has not seen a drop of rain during the first 20 days of April. Usually, there is generally 1 inch to 1.50 inches of rain during April in Northern California and 0.50 of an inch to 1 inch of rain in the south, away from the deserts.
Mariella Velazquez with her daughter Elisa Medina, 11, who has autism, jump under the rain in El Monte, Calif., Saturday, Jan. 23, 2021. Rain and snow fell in a series of storms that moved through California during the winter. The storms over the winter have done little to ease the drought. (AP Photo/Damian Dovarganes)
Late-season rain and snow may seem like too little too late, but even light to moderate amounts of rain and mountain snow in the spring can shorten or delay the heat and fire season just a bit. Eventually, though, all the spring growth that resulted from moisture over the winter will dry and become potential fuels for the upcoming fire season. This is why experts advise homeowners to keep brush to a minimum around their homes.
The upcoming weather pattern will also knock temperatures down by several degrees as a flow of air from the cool waters of the Pacific Ocean will increase. The biggest surge of cooler air will occur over interior areas of Central and Northern California, where temperatures are likely to be slashed by 10-25 degrees Fahrenheit in general compared to the middle and latter part of this week.
For example, in Sacramento, following highs in the lower to middle 80s Wednesday and Thursday, highs are projected to be in the middle 60s Sunday. The temperature in Palm Springs, California, is expected to trend upward into the middle 90s Saturday before the surge of cooler air slashes temperatures. The highs Monday will only climb into the mid-70s.
Temperatures are likely to fluctuate through the first half of May in California as storms cycle in from the Pacific.
As spring transitions into the summer months, interior Southern Californians may face similar high energy demands to that of last year.
"Temperatures in Southern California took off in late May 2020 and that actually may occur again this year as we expect a northward bulge in the jet stream to set up over the southwestern U.S. this summer," Pastelok said.
During the summer of 2020, temperatures averaged 2 to 5 degrees above average over the interior Southwest in Palm Springs, Las Vegas and Phoenix.
"But, closer to the coast, especially in areas farther to the north, we expect a big difference compared to last summer with lower temperatures due to more of a marine layer or persistent breeze from the Pacific."
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
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News / Winter Weather
Much-needed precipitation to eye parched California
By Alex Sosnowski, AccuWeather senior meteorologist
Updated Apr 21, 2021 2:35 PM EST
Experts at San José State University's Fire Weather Research Laboratory say they are concerned about dry vegetation and the growing risk of wildfires.
California is in desperate need of moisture in the form of rain and mountain snow. Since the water year began on Oct. 1, 2020, most areas are within the 25th to 50th percentile of average.
Even though the tail end of the rainy season is at hand in California, there is some hope for late-season rain and mountain snow in the coming days and weeks as AccuWeather meteorologists say storms from the Pacific are about to take a jog much farther south.
For example, downtown Los Angeles has only received 5.80 inches of rain since Oct. 1, compared to an average of 14.06 inches. Farther north, in Sacramento, only 6.54 inches of rain has been recorded compared to a normal amount of 16.95 inches.
At the start of 2020, much of California was in good shape due to ample rain and mountain snow over the prior year, according to the United States Drought Monitor. However, as storms became more scarce during 2020, abnormally dry conditions expanded and evolved progressively into more serious phases of drought. As of Thursday, April 15, 2021, 99% of the state was considered to be in abnormally dry conditions or worse. Nearly 40% of California was considered to be under extreme drought conditions -- the second-highest level of drought just under exceptional drought.
The dry conditions have already been contributing to sporadic wildfires along the Pacific coast. A small fire prompted the evacuation of nearly two dozen homes in Guvilan Hills, Riverside County, California, on Monday, according to ABC7.
But AccuWeather forecasters say there is some good news, at least on the weather maps. A series of storms appears to be lining up over the Pacific Ocean with the potential for some aid from the weather.
A large Pacific storm was visible off the West Coast of the U.S. on Tuesday, April 19, 2021. (NOAA / GOES-WEST)
Rain and mountain snow are expected to begin in the western portions of Washington and Oregon Saturday before wet weather expands southward into Northern California Sunday and Monday, AccuWeather Long-Range Meteorologist Brandon Buckingham said.
"This could prove to be very beneficial for the northern and central portions of the Sierra Nevada, Coast Ranges and valleys, although it could come at the risk of flash flooding in some spots," Buckingham stated.
As of April 20, the amount of water locked up in the snowpack over the Sierra Nevada ranged between 40 and 60% of average, according to the Natural Resources Conservation Service. The lean snowpack means less snow will be available to melt during the spring and summer, which will translate to less runoff to fill streams and reservoirs in the region. Above-average temperatures in recent weeks have expedited the runoff. The faster the snow melts in the spring, the less snow is likely to be available to melt during the summer.
The upcoming pattern from this weekend to early next week is not likely to bring a blockbuster amount of snow, but it has the potential to unload several inches over the high country of the central and northern Sierra Nevada.
At this time it appears that much of Southern California will be south of where significant rainfall is likely to target.
"It is possible that even the Los Angeles Basin receives some rain showers from this system early next week," Buckingham said.
There is the chance for another storm or two to bring wet weather to California.
The weather pattern may remain active along the Pacific coast into the first week or two of May, AccuWeather Lead Long-Range Meteorologist Paul Pastelok said.
CLICK HERE FOR THE FREE ACCUWEATHER APP
"We are seeing signs that southward undulations in the jet stream will continue to develop over the Pacific Ocean and pivot toward the West Coast," Pastelok explained. "This setup should continue to pump some moisture in from the Pacific and into the western U.S. into the first part of May."
Pastelok stated that even though it is possible for a couple of rounds of showers to reach Southern California and even southern Nevada and Arizona during the first week or two of May, the pattern is not consistent enough to make a definitive call either way.
Very little rain tends to occur in California during May, even in northern areas. On average, Los Angeles and San Diego normally pick up 0.12 of an inch of rain with 0.47 of an inch in San Francisco and 0.68 of an inch in Sacramento. The central and northern Sierra Nevada tend to squeeze out some moisture in May with an average of 1.07 inches at Lake Tahoe, California.
By June, average rainfall is negligible across the state, except for several tenths of an inch over the Sierra Nevada.
Most of the state has not seen a drop of rain during the first 20 days of April. Usually, there is generally 1 inch to 1.50 inches of rain during April in Northern California and 0.50 of an inch to 1 inch of rain in the south, away from the deserts.
Mariella Velazquez with her daughter Elisa Medina, 11, who has autism, jump under the rain in El Monte, Calif., Saturday, Jan. 23, 2021. Rain and snow fell in a series of storms that moved through California during the winter. The storms over the winter have done little to ease the drought. (AP Photo/Damian Dovarganes)
Late-season rain and snow may seem like too little too late, but even light to moderate amounts of rain and mountain snow in the spring can shorten or delay the heat and fire season just a bit. Eventually, though, all the spring growth that resulted from moisture over the winter will dry and become potential fuels for the upcoming fire season. This is why experts advise homeowners to keep brush to a minimum around their homes.
The upcoming weather pattern will also knock temperatures down by several degrees as a flow of air from the cool waters of the Pacific Ocean will increase. The biggest surge of cooler air will occur over interior areas of Central and Northern California, where temperatures are likely to be slashed by 10-25 degrees Fahrenheit in general compared to the middle and latter part of this week.
For example, in Sacramento, following highs in the lower to middle 80s Wednesday and Thursday, highs are projected to be in the middle 60s Sunday. The temperature in Palm Springs, California, is expected to trend upward into the middle 90s Saturday before the surge of cooler air slashes temperatures. The highs Monday will only climb into the mid-70s.
Related:
Temperatures are likely to fluctuate through the first half of May in California as storms cycle in from the Pacific.
As spring transitions into the summer months, interior Southern Californians may face similar high energy demands to that of last year.
"Temperatures in Southern California took off in late May 2020 and that actually may occur again this year as we expect a northward bulge in the jet stream to set up over the southwestern U.S. this summer," Pastelok said.
During the summer of 2020, temperatures averaged 2 to 5 degrees above average over the interior Southwest in Palm Springs, Las Vegas and Phoenix.
"But, closer to the coast, especially in areas farther to the north, we expect a big difference compared to last summer with lower temperatures due to more of a marine layer or persistent breeze from the Pacific."
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
Report a Typo