Western States Brace For Record Heat Wave This Weekend

We outlined Tuesday that multiple heat waves would plague the Western half of the US. The first round struck early in the week and lasted through mid-week, and the second is just beginning. 

The worst of the second wave is expected to affect upwards of 28 million people from California to Washington State. 

Excessive heat warnings have already been posted for California, Nevada, western Arizona, and western Utah. Watches have also been posted for interior portions of Oregon and southern Idaho.

Large swaths of the West could experience temperatures 20 or more degrees above average. Below is a temperature anomalies forecast showing the heat dome could last through mid-next week

“Extreme heat will significantly increase the potential for heat related illnesses,” the National Weather Service in Hanford, Califonia, warned. “Confidence is very high for a dangerous heat wave to persist through Monday and maybe into Tuesday.”

The sweltering heat could reach double digits in some areas. 

In Hanford itself, temperatures could hit 110 degrees Friday, Saturday, Sunday and Monday. Records in Hanford date to 1899, and show that highs of 110 degrees or greater have occurred on four or more consecutive days on only five occasions. That makes the duration and magnitude of the episode a once in roughly 20-year event.

Sacramento is looking at a five-day stretch with highs in the triple digits, including a forecast 110 degrees Saturday. Redding is likely to hit 113 degrees Friday, 115 on Saturday and 113 on Sunday. Highs Monday may be a slightly less inhospitable 110 degrees. The city has never recorded more than three consecutive days at 113 degrees or greater.

Modesto, Calif., will see highs around 108 degrees both weekend days.

Potentially more concerning will be the overnight lows, which won’t be very low at all — temperatures may dip only into the upper 70s or lower 80s in some spots. On Saturday night, Modesto is projected to fall only to 80 degrees before temperatures skyrocket again in the morning. In fact, most of the Central Valley will not fall beneath 80 degrees during the overnight period on Saturday.

Central Valley locations “will be extremely warm overnight, where high minimum temp records may be achieved as well,” wrote the Weather Service in Sacramento. Warm overnight lows are especially dangerous for anyone without air conditioning because they make it difficult for the body to enter its natural cooling phase.

It’s not just central California that will be experiencing saunalike warmth. Salt Lake City could be near 100 degrees each day through Monday. Las Vegas will be scorched by heat that’s extreme even for the Nevada desert, with highs in the 110s likely through Tuesday. Both weekend days could peak near 117 degrees. In Las Vegas, a hint of monsoonal moisture sneaking in from the southwest could help hold overnight lows in the 90s. 

A few other long-standing records could topple, like in the Yosemite Valley of California, which is forecast to hit 110 degrees both weekend days. It’s been 106 years since that last occurred.

Saturday’s predicted high of 130 degrees would match the Earth’s highest reliably measured temperature since at least 1931. (Death Valley also reached 130 last August.) On Sunday and Monday, it’s forecast to hit 129 and 127. – The Washington Post

The good news is that positive temperature anomalies should decrease across the Western half of the US by the middle of next week and hopefully return the region to average temperatures. 

Meanwhile, heat wave after heat wave in the West is causing concern about a ferocious wildfire season, power prices spiking, rolling blackouts, crop losses, water shortages, grasshopper plague, among other things.