Prolonged Heat Wave to Remain Across the Western United States This Week

A prolonged heat wave has been forecasted to persist in the Western United States this week, causing above-normal temperatures. National Weather Service (NWS) meteorologists predict that over 100 degrees Fahrenheit are possible in some areas of the drought-stricken region from Wednesday, August 31. Weather forecasters reportedly fear it could reignite wildfires across the region once again.

The region took a heat break in recent days and weeks due to torrential rainfall provided by the North American monsoon. However, a resurgence of warm air will disrupt the break and could affect the states of California, Nevada, Washington, Utah, Colorado, Montana, Arizona, Idaho, and Oregon. Heat-related illnesses and deaths pose the greatest risk for the extreme weather event.

The renewed extreme heat occurs in the last days of the US summer season, which was marked by a combination of wet weather and dry conditions since June. From the West Coast to the East Coast, multiple states in recent months experienced a surge of extreme weather, breaking decades-old record of high temperatures, as well as heavy rainfall from the southwestern and southern US.

US meteorologists assess the looming threat could make the current season one of the hottest one in years. In California, forecasters say the incoming heat wave could be the most intense and longest this year alone. In 2021, a similar heat wave also struck the US Pacific Northwest, resulting in hundreds of confirmed deaths in Washington, Oregon, and the Canada's British Columbia province.

Prolonged Heatwave

A ridge of high pressure air will accumulate across the Western US this week. This will allow temperatures to steadily increase over time. The pattern will push the jet stream to the north and reduce the chance of widespread rainfall close to zero, according AccuWeather Meteorologist Andrew Kienzle.

The weather forecasting company says the NWS issued weather alerts for excessive heat in many areas of the region. 'Weather warnings' are in place for cities like Phoenix, Las Vegas, San Diego, Los Angeles, Bakersfield, Fresno, and 'excessive weather watches' for Sacramento. This means the chance of above-average temperatures is relatively high than weather without the influence of extreme heat.

NWS Forecast

The AccuWeather forecast is based on the NWS' Weather Prediction Center (WPC) short-range outlook on Tuesday, which states that the "prolonged and record heat wave" are building up over the West this week.

The WPC highlights a strong upper level ridging over the West is supporting widespread and unusually high temperatures; where daytime temperatures could soar into the 90s or lower 100s on Wednesday and especially on Thursday, September 1.

In its specific outlook, the US weather agency says temperatures could exceed 110 degrees Fahrenheit in some areas of the Southwest. Meanwhile, heat-related conditions are likely in much of the Northwest and Great Basin, the WPC adds.

According to NWS Meteorologist David Sweet, the incoming heat will likely lead to a "very high heat-illness risk," as cited by USA Today.