Extreme Heat Envelopes the Southwest and Threatens to Move Eastward

Posted: July 10, 2023 3:00 pm

Summer is in full swing across the Desert Southwest with the potential of record-breaking heat on the horizon this week. This heat will likely begin to spread to the Plains states by next week as the nation enters the dog days of summer. Here is a detailed look at this scorcher of a forecast.

Will Daily High Records Fall?

A building ridge of high pressure is anchored over the southwestern corner of the country, sending the temperatures soaring. The lack of moisture will also keep the mercury elevated in the coming days. In addition, a northward bulge in the jet stream in this part of the country will keep temperature readings high.

This bulge is forecast to move to the east by the following week, sending the extreme heat in the direction of the central U.S. and into the Southeast.

Numerous daily high records are in jeopardy of falling in the Southwest this week as the temperature remains on an upward trajectory. This includes the potential of record-breaking heat in the Phoenix area.

The worst of the heat is expected to peak by Thursday with the potential of a 120-degree day on the horizon. The city has only hit this milestone three times since historians began keeping these records. The all-time record high temperature for this part of Arizona is 122 degrees, set on June 26, 1990.

There is also the chance that Phoenix could notch readings over 110 degrees for at least 19 days in a row, breaking the previous record of 18 that has stood since 1974. The Valley of the Sun has recorded readings in this range every day since June 30.

The dome of high pressure positioned over the Four Corners region will trap the heat and keep moisture away. Unfortunately, nighttime lows will also remain high. This means it will be difficult to find any relief from the heat other than in air conditioned structures.

Local health experts are sounding the alarm about the potential of a rash of heat-related illnesses this week as the mercury refuses to budge. With overnight lows remaining in the low 90s in some parts of Phoenix, the rate of these illnesses will continue to rise.

The city and its environs will likely experience the urban heat island effect as the landscape of concrete and asphalt surfaces traps the heat and releases it continuously even after the sun goes down at night.

The National Weather Service (NWS) has issued an excessive heat warning in effect for the Phoenix area through at least July 16. In addition, there are multiple watches and advisories due to the heat in place for parts of southeastern California and into southwestern Arizona. These alerts extend in parts of southern New Mexico and the southwestern corner of Texas. You will want to stay abreast of any warnings and advisories in your community.

The lack of cooling in the overnight hours will undoubtedly put a strain on the area’s energy grids. Local officials are expecting extraordinarily high cooling demands this week as residents rely on air conditioning systems and fans to beat the heat.

Other Cities Expected to See Records Challenged

Although this part of the Southwest is certainly accustomed to triple digit readings in July, this week’s surge of heat will be significantly warmer than normal. For instance, the average daytime high in Las Vegas in mid-July lands around 105 degrees. The mercury may hit as high as 120 degrees in Sin City this week, translating to a reading well above normal even for the desert.

The dome of heat will build to the north, putting places such as Salt Lake City in the crosshairs. The capital city of Utah recorded a season-high temperature of 101 degrees on July 3. This reading may be challenged early this week with more heat in store. The city’s all-time record high is 107 degrees, coming just last summer.

Palm Springs, California will also come within striking distance of breaking 120 degrees. A forecast high of 119 degrees on Thursday will put this benchmark at risk of falling. The all-time record for the desert resort town is 125 degrees, dating back to July of 1995.

The heat will continue to expand to the east into Albuquerque, New Mexico. This populated city is forecast to reach the triple digits for several consecutive days. Albuquerque has yet to reach this threshold this year.

Limited Chances of Moisture Will Exacerbate the Heat

The heat will be exacerbated by the lack of moisture across the Four Corners and beyond. While there is the chance of isolated storm activity in the latter part of the week, these storm cells are not likely to deliver significant rain or cooling to the area.

The greatest chance of moisture will come from storms that are circulating to the north of this area over the Rocky Mountains and to the east into the Great Plains. The leftover and moisture associated with these systems could move into the Southwest this week, bringing some sparse shower activity to the dry region.

The true start of the North American Monsoon Season is not expected to kick off until late in July. Any moisture that sneaks into the Southwest this week could signal the start of higher humidity levels, triggering a cycle of more storms and slightly cooler temperature readings. However, any relief is likely to be brief and localized.

Heat-related illnesses are not the only concern as the temperature rises. The presence of storm activity could create dry lightning that ignites wildfires. An elevated risk of wildfires is to be expected in the coming days in the Southwest because of these conditions.

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