Temperatures in the scorching hot Southwest are expected to climb higher in the coming days. Locations including Phoenix and Las Vegas could flirt with all-time record highs.
Published Jul 12, 2023 3:26 PM EDT | Updated Jul 14, 2023 12:09 PM EDT
The already scorching hot Southwest is expected to get hotter later this week, AccuWeather meteorologists say. The dangerously hot weather will raise the risk of wildfires and potentially challenge all-time record highs in some cities.
"A number of locations over the Southwest will challenge daily record highs this weekend," AccuWeather Meteorologist Haley Taylor said.
Due to the long-duration heat wave, excessive heat warnings were in effect across the Desert Southwest, including in cities such as Phoenix, Las Vegas and Palm Springs, California.
A jet arrives at sunset at Sky Harbor International Airport, Monday, July 10, 2023, in Phoenix. Phoenix is the epicenter of what may turn out to be an unprecedented extreme heat wave around the Southwest. (AP Photo/Matt York)
A strong area of high pressure, known as a heat dome, and a shift in the position of the jet stream are two key factors that have led to the brutal heat.
From late this week to early next week that northward bulge of the jet stream will be as extreme as it can be over the interior Southwest. Since this region is typically the hottest zone in the United States during the summer, it can get dangerously hot in the coming days.
The extreme heat and blazing sunshine can cause most individuals to become rapidly dehydrated, experts warn. People are urged to avoid strenuous activity during the daylight hours, to increase their intake of fluids and seek an air-conditioned environment when possible to avoid the potential of heat exhaustion and heatstroke. AccuWeather RealFeel® Temperatures can be more than a dozen degrees above the actual temperature in some locations.
On Friday, projected high temperatures will come within a few degrees of daily records for July 14 in many cities in Arizona, southern Nevada and interior Southern California.
"Fresno, California, could challenge its record high for any date on Sunday," AccuWeather Meteorologist Alex DaSilva said. That all-time record of 115 degrees Fahrenheit was set way back in 1905.
AccuWeather meteorologists expect Fresno to have highs of 105 or greater each day from Friday through the middle of next week, which is the local threshold for what defines a heat wave. With the magnitude of the extreme temperatures in the forecast, the heat wave will be close to some of the worst in recent years, based on the AccuWeather HeatWave Severity Index™.
In downtown Los Angeles, temperatures are forecast to peak near 90 F this weekend and could extend into next week as well. In the City of Angels, a heat wave is three or more days in a row with high temperatures of 90 or greater. Temperatures hit 90 in the downtown area on Thursday for the first time this year.
Some 250 miles to the northeast of Los Angeles, at one of the hottest places on Earth, temperatures are forecast to climb into the upper 120s and could hit 130 degrees in Death Valley, California. The world record air temperature of 134 F was officially set in Death Valley on July 10, 1913, at the Furnace Creek observation site. The valley floor sits nearly 300 feet below sea level.
That record has been disputed by some meteorologists. The highest temperature at Death Valley since 1913 that has been approved by the World Meteorological Organization is 129, set on June 30, 2013. The station also preliminarily reached 130 degrees on Aug. 16, 2020, and July 9, 2021.
Meanwhile, Phoenix, which is aptly known as the Valley of the Sun, has been experiencing a lengthy stretch of days with high temperatures of at least 110 degrees. As of Thursday, July 13, Phoenix has experienced 14 days in a row with high temperatures ranging from 110 to 116. The city is currently experiencing its third longest streak of days with temperatures at or above 110 F on record.
As the heat builds into this weekend and persists into early next week, there is the potential for Phoenix to reach the 120-degree mark. Temperatures have only reached or exceeded this threshold three times there since record-keeping began in 1896. The three 120-degree readings all occurred in the 1990s. The city's all-time high of 122 was recorded on June 26, 1990.
Another record that could be set in Phoenix has to do with the level of warmth at night. Thus far in the heat wave, the city has not dipped below the 90-degree mark each night since July 10. Should the string of oppressively warm nights continue for eight days, it would break the record set in July and August of 2020 and in August of 2012.
Las Vegas is another desert metro area that has an excellent chance of approaching its all-time record high. That 117-degree mark has been reached five times, most recently on July 10, 2021. Temperatures are projected to come within a couple of degrees of that mark from Saturday to Monday with daily records being challenged or broken each day.
Several hundred miles to the northeast of Las Vegas, Salt Lake City will have highs within a couple of degrees of 100 each day through Wednesday of next week. As of Wednesday, Utah’s capital has hit 100 two times in July compared to a historical average high in the low to mid-90s.
Extra caution is needed with campfires, grills and power equipment
Despite wet conditions this past winter in many areas and excessive snowfall in the mountains, which continues to melt this summer, vegetation at intermediate and low elevations will continue to dry out considerably in the hot conditions and intense sunshine. The extra moisture has led to an increase in the growth of sagebrush and grasses in the region. This vegetation then becomes fuel for wildfires to develop during much of the balance of the summer and into the fall.
There is an elevated wildfire risk for Thursday in parts of Utah and Arizona.
Where is the monsoon?
The annual event that sparks thunderstorms over the southwest, known as the North American monsoon will continue to be suppressed over the next week or two at least. This change in wind direction that allows moisture to creep northward from the tropical Pacific, Mexico and the Gulf of Mexico has been delayed.
However, some uptick in moisture in recent days may allow very spotty thunderstorm activity in parts of eastern Arizona, New Mexico and southern Colorado. Where the storms manage to bring a downpour, they may cool the local environment for a day or two. But, many of the storms may bring little or no rain and could kick up dust or trigger lightning-induced wildfires.
People are urged to use caution when hiking in the mountains due to the lightning strike risk from sudden storms that may develop during the midday and afternoon hours.
There are some dangers when taking a dip in area mountain streams as well. The waters flowing out of the mountains from melting snow are ice-cold and could lead to a dangerous shock for many individuals, AccuWeather Western Weather Expert Ken Clark warned.
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