A potentially deadly heat wave is expected to hit the West coast this week, marking the second consecutive week of such extreme weather conditions. The National Weather Service (NWS) has issued Excessive Heat Warnings and Heat Advisories across California’s Central Valley and the Desert Southwest, with the danger starting on Monday in Sacramento before expanding to Las Vegas and Phoenix on Tuesday and Wednesday, respectively, with temperatures remaining dangerous through Thursday.
The NWS warns that “dangerously hot conditions” are expected, with afternoon temperatures ranging from 105 to 112 degrees. Overexposure to heat can lead to heat cramps and exhaustion, which without intervention can escalate into heat stroke. The NWS issues Excessive Heat Watches when the heat index, or “feels-like” temperature, is forecast to reach dangerous levels within the next 24 to 72 hours. A watch then becomes a warning 12 hours before and during extremely dangerous heat conditions. In general, the NWS looks for the heat index to hit or exceed 105 degrees for at least two consecutive days with overnight air temperatures not expected to drop below 75 degrees.
This heat wave comes on the heels of last week’s record-breaking temperatures. On June 6, Las Vegas tied its all-time earliest record of 110 degrees, and the following morning, the city set a new record for warmest low temperature. Bishop, California, also shattered its previous record for the warmest low temperature by 7 degrees. Both Las Vegas and Phoenix are currently working to prevent a repeat of the exceptionally deadly summer of 2023, with heat-related deaths soaring in both cities.
California’s Central Valley is under Excessive Heat Warnings and Heat Advisories, with Sacramento experiencing temperatures significantly higher than its average high of 86 degrees. On Monday, the mercury will hit 96 degrees, and by Tuesday, it will top out at 103. Fresno and Bakersfield are expected to reach 105 degrees on Tuesday, while their average highs are 89 and 90, respectively.
Las Vegas, which averages a high of 98 degrees this time of year, will experience temperatures 10 degrees hotter than average on Wednesday, with outdoor activities sweltering in 109-degree heat. Although temperatures will cool slightly on Thursday, they are still expected to remain high, with FOX Weather forecasting a high of 106 degrees.
Both Sacramento and Las Vegas have been placed under a Level 3 out of 4 threat for heat-related impacts by the NWS. The NOAA recently introduced its nationwide index called HeatRisk, which states that “this level of heat affects anyone without effective cooling and/or adequate hydration” and can lead to health system strain, heat-sensitive industries, and infrastructure issues.
Arizona’s hottest temperatures are forecast for Wednesday and Thursday, with the NWS deeming this week’s temperatures “dangerously hot,” even for the usually warm Valley of the Sun. The average high for Phoenix is 103 degrees, but on Wednesday, it is expected to hit 111. Tucson, which typically experiences temperatures around 100 degrees at this time of year, is forecast to reach 109 degrees.
Excessive Heat Warnings and Heat Advisories should expire by Wednesday for California but continue through Thursday evening for parts of Arizona and Nevada. Phoenix, Tucson, Las Vegas, and Fresno will move from a major, or Level 3 out of 4, risk to a moderate, or Level 2 out of 4, HeatRisk.
