Building heat across the West to challenge record highs this week
Above-average temperatures were generally limited to the Desert Southwest last week, but a shift in the jet stream pattern will bring expanding heat across much of the Intermountain West this week.
An upper-level dome of high pressure sat over the southern Plains last week, which resulted in an extended streak of triple-digit heat for many across Texas, Oklahoma and Kansas. This dome is forecast to shift west, along with the above-average temperatures.
Phoenix, Salt Lake City, Las Vegas and Reno, Nevada, are just some of the cities expected to challenge record-high temperatures through Wednesday.
Residents in Salt Lake City and Reno can expect highs in the middle to upper 90s on each afternoon through Friday, while the mercury soars into the upper 100s in Las Vegas and over 110 in Phoenix.

Along with an uptick in the temperatures, humidity levels will increase late this week as monsoon moisture streams into portions of the Desert Southwest. This will act to send Accuweather RealFeel® Temperatures about 5-10 degrees higher than what the thermometer registers, especially late in the week.
As dangerous heat builds, stay alert for the signs of heat-related illnesses.
Avoid strenuous outdoor activities during the hottest times of the day if at all possible. If you must be outdoors, remember to wear light-colored, loose-fitting clothing and take frequent breaks in the shade.
Double-check vehicles before walking away to ensure children or pets have not been left behind.
In what has been a lack-luster monsoon season so far for many this summer in the Southwest, the building heat will only act to increase wildfire concerns. Many cities have only picked up a fraction of their average rainfall over July and into the first half of August.
Across Arizona in particular, many of the larger cities recorded below-average rainfall in July. Tucson International Airport reported 1.07 inches of rainfall for the month (48% of average), Flagstaff’s Pulliam Airport observed 0.72 of an inch (28% of average), and Phoenix’s Sky Harbor International Airport only recorded a mere 0.17 of an inch of rainfall (16% of average).

While some monsoon moisture will return across the Desert Southwest and portions of the Intermountain West this week, many of the aforementioned cities will likely remain dry.
For individuals heading out into the mountains in search of cooler weather this week, be wary of thunderstorms erupting during the afternoon hours. Over the coming week, this threat will likely be confined primarily to the high terrain of New Mexico and Colorado.
The heat is expected to ease slightly late this week as additional moisture gets drawn northwestward, increasing humidity levels and dropping temperatures.
Download the free AccuWeather app to track the heat and possible thunderstorm activity. Keep checking back for updates on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.
