Triple-digit temperatures to hinder firefighting, challenge records in Southwest
By
Ryan Adamson, AccuWeather meteorologist
Updated Sep 5, 2021 12:18 AM EDT
Video taken by Cal Fire shows a "jaw-dropping" slow-motion view of the Chaparral Fire, burning in California's Riverside and San Diego counties.
A surge of warmth is forecast in the Southwest that will challenge not only weary firefighters battling numerous wildfires but also record highs in several cities.
Temperatures are expected to be 10-15 degrees Fahrenheit above normal early this week, landing in the upper 90s to 110 degrees in several locations.
"As a dome of high pressure builds over the Southwestern states Sunday into the early week, temperatures will begin to soar," said AccuWeather Meteorologist Renee Duff.
Even though most places are expected to fall short of records, especially when taking into account the nearby wildfire smoke, a few locations could come close. According to Duff, records may be in jeopardy in Las Vegas and Reno, Nevada, and Fresno, California. High temperatures are forecast to be near the record high of 106 degrees Fahrenheit on Monday in Fresno and approach the record of 108 degrees in Las Vegas on Tuesday.
High temperatures will also hover around 100 F or higher in Phoenix through much of this week. The city is forecast to reach 105 F on Labor Day, but that temperature is well short of the daily record for Sept. 6 of 113 from 2020.
Parts of the Southwest have received beneficial rain thanks to the monsoon in recent weeks, while others have missed out on the needed moisture. However, AccuWeather forecasters say that moisture will begin to decrease and temperatures will be on the rise in the coming days.
"Monsoonal moisture will largely be held in check as high pressure migrates west over the next couple of days," said AccuWeather Senior Meteorologist Tyler Roys.
High pressure causes sinking air. With sinking air in place, thunderstorms are unlikely to develop since rising air is needed for thunderstorm formation. Sinking air also promotes warming, which will allow temperatures to increase.
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Besides the effect that the above-normal temperatures will have on increasing cooling demands, this will also make conditions more difficult for those fighting the numerous wildfires. In addition, the high pressure could cause another problem.
"Air quality could grow even worse due to the air underneath the high-pressure system becoming rather stagnant outside of localized breezes," stated Duff.
Although the hot weather will make it difficult for firefighters and air quality will not be good, the lighter winds will create the benefit of making it unlikely for fires to spread quickly. That said, the conditions are very dry. This is especially true in Northern California where rain has not fallen in quite some time.
Several fires are burning in the region. One of the most notable is the Dixie Fire, which has burned over 865,000 acres and is the second-largest fire in California history.
Meanwhile, the Caldor Fire has scorched more than 210,000 acres and is now the 15th largest fire in California history. The Caldor Fire also forced evacuations of the 22,000 residents of South Lake Tahoe, California. The lighter winds allowed some people to return to their homes on Thursday, according to The Associated Press.
Above-normal temperatures are likely to persist through at least Tuesday in much of the region before a slight cooldown occurs by Wednesday. Although temperatures will decline only slightly, parts of Northern California could have locally gusty winds as a ripple in the atmosphere moves through Washington and Oregon. The prospect of gusty winds and no rain will again raise the fire danger.
It is possible that some monsoon moisture may return by the end of the week. However, some of the thunderstorms that develop may contain more lightning and gusty winds than rain, further increasing the risk of current fires spreading and new fires being ignited.
For the latest weather news check back on AccuWeather.com Watch AccuWeather Network on DIRECTV, Frontier, Spectrum, AT&T TV NOW, fuboTV, Philo, and Verizon Fios. AccuWeatherNOW is streaming on Roku and XUMO.
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News / Weather Forecasts
Triple-digit temperatures to hinder firefighting, challenge records in Southwest
By Ryan Adamson, AccuWeather meteorologist
Updated Sep 5, 2021 12:18 AM EDT
Video taken by Cal Fire shows a "jaw-dropping" slow-motion view of the Chaparral Fire, burning in California's Riverside and San Diego counties.
A surge of warmth is forecast in the Southwest that will challenge not only weary firefighters battling numerous wildfires but also record highs in several cities.
Temperatures are expected to be 10-15 degrees Fahrenheit above normal early this week, landing in the upper 90s to 110 degrees in several locations.
"As a dome of high pressure builds over the Southwestern states Sunday into the early week, temperatures will begin to soar," said AccuWeather Meteorologist Renee Duff.
Even though most places are expected to fall short of records, especially when taking into account the nearby wildfire smoke, a few locations could come close. According to Duff, records may be in jeopardy in Las Vegas and Reno, Nevada, and Fresno, California. High temperatures are forecast to be near the record high of 106 degrees Fahrenheit on Monday in Fresno and approach the record of 108 degrees in Las Vegas on Tuesday.
High temperatures will also hover around 100 F or higher in Phoenix through much of this week. The city is forecast to reach 105 F on Labor Day, but that temperature is well short of the daily record for Sept. 6 of 113 from 2020.
Parts of the Southwest have received beneficial rain thanks to the monsoon in recent weeks, while others have missed out on the needed moisture. However, AccuWeather forecasters say that moisture will begin to decrease and temperatures will be on the rise in the coming days.
"Monsoonal moisture will largely be held in check as high pressure migrates west over the next couple of days," said AccuWeather Senior Meteorologist Tyler Roys.
High pressure causes sinking air. With sinking air in place, thunderstorms are unlikely to develop since rising air is needed for thunderstorm formation. Sinking air also promotes warming, which will allow temperatures to increase.
CLICK HERE FOR THE FREE ACCUWEATHER APP
Besides the effect that the above-normal temperatures will have on increasing cooling demands, this will also make conditions more difficult for those fighting the numerous wildfires. In addition, the high pressure could cause another problem.
"Air quality could grow even worse due to the air underneath the high-pressure system becoming rather stagnant outside of localized breezes," stated Duff.
Although the hot weather will make it difficult for firefighters and air quality will not be good, the lighter winds will create the benefit of making it unlikely for fires to spread quickly. That said, the conditions are very dry. This is especially true in Northern California where rain has not fallen in quite some time.
Several fires are burning in the region. One of the most notable is the Dixie Fire, which has burned over 865,000 acres and is the second-largest fire in California history.
Meanwhile, the Caldor Fire has scorched more than 210,000 acres and is now the 15th largest fire in California history. The Caldor Fire also forced evacuations of the 22,000 residents of South Lake Tahoe, California. The lighter winds allowed some people to return to their homes on Thursday, according to The Associated Press.
Above-normal temperatures are likely to persist through at least Tuesday in much of the region before a slight cooldown occurs by Wednesday. Although temperatures will decline only slightly, parts of Northern California could have locally gusty winds as a ripple in the atmosphere moves through Washington and Oregon. The prospect of gusty winds and no rain will again raise the fire danger.
It is possible that some monsoon moisture may return by the end of the week. However, some of the thunderstorms that develop may contain more lightning and gusty winds than rain, further increasing the risk of current fires spreading and new fires being ignited.
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For the latest weather news check back on AccuWeather.com Watch AccuWeather Network on DIRECTV, Frontier, Spectrum, AT&T TV NOW, fuboTV, Philo, and Verizon Fios. AccuWeatherNOW is streaming on Roku and XUMO.
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