Thunderstorms in Southwest could be double-edged sword
Moisture from the tropical Pacific will help fuel drenching thunderstorms in parts of the Southwest, but all of the storms may not prove to be beneficial.
By
Ryan Adamson, AccuWeather meteorologist
Updated Sep 24, 2021 11:13 AM EDT
Shower and thunderstorm activity is forecast to increase in the drought-plagued Southwest into this weekend, but AccuWeather forecasters say that may not necessarily be all good news.
"There is a risk that thunderstorms with little rain develop in parts of the Southwest and on the edge of a ripple in the jet stream," said AccuWeather Senior Meteorologist Alex Sosnowski.
As the jet stream dips southward into Nevada, Arizona and Utah into Friday evening, thunderstorms are likely to develop. AccuWeather forecasters say the chance of thunderstorms will remain in place into the weekend as a disturbance in the jet stream drops farther south off the California coast by Saturday. However, widespread drenching rain is not expected in California or Nevada, where it is needed the most.
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"With little moisture involved, dry lightning could occur, especially across Southern California," said AccuWeather Meteorologist Jessica Storm, who noted that dry lightning is a phenomenon that forms during a thunderstorm when limited or no rainfall occurs.
This may lead to the development of new wildfires. The thunderstorm risk can extend as far north as the Sierra Nevada in California, where the enormous Caldor Fire is still burning.
While some of the thunderstorms will be dry, that is not expected to be the case with each and every storm.
A renewed monsoon effect will generate enough moisture over the Southwest that could result in a beneficial showers, especially in portions of Arizona and New Mexico this weekend. Any rainfall that does not trigger flash flooding will be greatly welcomed, according to Sosnowski.
"However, not enough rain is expected to fall on a broad enough scale to bring a noticeable change to extremely low water levels in reservoirs," Sosnowski added.
Too much rain could still become a concern in remote areas, forecasters say.
A few of the stronger storms could contain heavy rain that could result in localized flash flooding, with the highest risk of flooding expected in the mountains and in any burn scar locations where fires have charred the landscape.
An active summer monsoon has helped alleviate the drought in some areas, but parts of the Southwest are still in an extreme or exceptional drought, according to the United States Drought Monitor.
Even though the highest likelihood of thunderstorms will be across the higher elevations of central and Southern California and Arizona, much more of the region will have increased moisture in the air.
"Higher humidity levels and lower temperatures will be beneficial, especially in any location where showers occur," said Sosnowski.
With some areas dealing with drought for time periods ranging from several months to several years, any reduction in the wildfire threat will be brief. Multiple storms with much more widespread and soaking rain are what it will take to alleviate the long-term drought, forecasters say.
For the latest weather news check back on AccuWeather.com. Watch AccuWeather Network on DIRECTV, DIRECTVstream, Frontier, Spectrum, fuboTV, Philo, and Verizon Fios. AccuWeatherNOW is streaming on Roku and XUMO.
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News / Weather Forecasts
Thunderstorms in Southwest could be double-edged sword
Moisture from the tropical Pacific will help fuel drenching thunderstorms in parts of the Southwest, but all of the storms may not prove to be beneficial.
By Ryan Adamson, AccuWeather meteorologist
Updated Sep 24, 2021 11:13 AM EDT
Shower and thunderstorm activity is forecast to increase in the drought-plagued Southwest into this weekend, but AccuWeather forecasters say that may not necessarily be all good news.
"There is a risk that thunderstorms with little rain develop in parts of the Southwest and on the edge of a ripple in the jet stream," said AccuWeather Senior Meteorologist Alex Sosnowski.
As the jet stream dips southward into Nevada, Arizona and Utah into Friday evening, thunderstorms are likely to develop. AccuWeather forecasters say the chance of thunderstorms will remain in place into the weekend as a disturbance in the jet stream drops farther south off the California coast by Saturday. However, widespread drenching rain is not expected in California or Nevada, where it is needed the most.
CLICK HERE FOR THE FREE ACCUWEATHER APP
"With little moisture involved, dry lightning could occur, especially across Southern California," said AccuWeather Meteorologist Jessica Storm, who noted that dry lightning is a phenomenon that forms during a thunderstorm when limited or no rainfall occurs.
This may lead to the development of new wildfires. The thunderstorm risk can extend as far north as the Sierra Nevada in California, where the enormous Caldor Fire is still burning.
While some of the thunderstorms will be dry, that is not expected to be the case with each and every storm.
A renewed monsoon effect will generate enough moisture over the Southwest that could result in a beneficial showers, especially in portions of Arizona and New Mexico this weekend. Any rainfall that does not trigger flash flooding will be greatly welcomed, according to Sosnowski.
"However, not enough rain is expected to fall on a broad enough scale to bring a noticeable change to extremely low water levels in reservoirs," Sosnowski added.
Too much rain could still become a concern in remote areas, forecasters say.
A few of the stronger storms could contain heavy rain that could result in localized flash flooding, with the highest risk of flooding expected in the mountains and in any burn scar locations where fires have charred the landscape.
An active summer monsoon has helped alleviate the drought in some areas, but parts of the Southwest are still in an extreme or exceptional drought, according to the United States Drought Monitor.
Even though the highest likelihood of thunderstorms will be across the higher elevations of central and Southern California and Arizona, much more of the region will have increased moisture in the air.
"Higher humidity levels and lower temperatures will be beneficial, especially in any location where showers occur," said Sosnowski.
With some areas dealing with drought for time periods ranging from several months to several years, any reduction in the wildfire threat will be brief. Multiple storms with much more widespread and soaking rain are what it will take to alleviate the long-term drought, forecasters say.
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For the latest weather news check back on AccuWeather.com. Watch AccuWeather Network on DIRECTV, DIRECTVstream, Frontier, Spectrum, fuboTV, Philo, and Verizon Fios. AccuWeatherNOW is streaming on Roku and XUMO.
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