Dangerous, Extreme Heat Envelops Much Of The West Through the Weekend

Tom Moore
Published: June 4,2016
Parts of the West will continue to swelter in a late-spring heat wave into the new week ahead that is one of the sharpest so early in the calendar in some locations.
Friday, almost two dozen cities tied or set daily record highs, including...

• Phoenix: 113 degrees
• Las Vegas: 107 degrees (tied)
• Reno, Nevada: 96 degrees
• San Francsico (SFO Int'l Airport): 87 degrees (tied)

Thursday, Death Valley National Park recorded a high of 120 degrees, topping the daily record, there. This was the nation's first 120-degree high of 2016.
Saturday, more records continue to pour in, including

• Needles, California : 118 degrees
• Phoenix : 115 degrees 
• Las Vegas : 109 degrees (tied)
• Portland, Oregon : 97 degrees

(MAP: Actual Highs)
The high temperature of 115 degrees at Phoenix, Arizona, on Saturday was their earliest 115 degree temperature on record.
The heat will sear not just the typically scorching Desert Southwest, but it has expanded into the Pacific Northwest, Great Basin and Rockies, as an impressive high-pressure ridge aloft expands.
When this pattern occurs, the air sinks and warms, and the result is very few clouds and extremely high temperatures. The highest temperatures of the season will be felt across a large area.

Dangerous western heat is expected as a massive ridge aloft expands this week.

The National Weather Service (NWS) has issued excessive heat warnings for portions of southeastern California, southern Nevada, western and southern Arizona, western Oregon and far southwest Washington. This includes the cities of Las Vegas, Phoenix, Tucson and Portland, Oregon. Heat advisories have been issued for Seattle and Tacoma, Washington.

Current Heat Alerts

High temperatures are likely to reach 115 degrees in Phoenix, while Death Valley, California, could see temperatures approach or exceed 120 degrees again on Sunday
Phoenix usually sees their first 110 degree day in mid-June, as the weeks before the wet phase of the North American monsoon are typically the hottest in the Desert Southwest.

Take Extra Precautions With Temperatures Reaching The Danger Zone

For residents and visitors to Las Vegas, daytime highs could approach 110 degrees this weekend. The record earliest 110-degree plus high in Las Vegas is June 6, 2010, so this could be an all-time early record-breaker in Sin City.
Numerous daily record highs are in jeopardy this weekend, lingering into early next week.

City	Record High Sunday	Record High Monday	Record High Tuesday
Phoenix	112˚	110˚	115˚
Las Vegas	108˚	110˚	109˚
Reno, Nevada	99	97˚	100˚
Portland, Oregon	96˚	98˚	93˚

In addition to the daily records that are possible, the NWS Office in Portland said on Thursday that, "this is one of the earliest heat waves of this magnitude. This could be the earliest reaching 100 degrees at some locations."
Highs in Seattle could top the 90-degree mark Sunday for the first time this year. Seattle averages only three days of 90-degree-plus heat each year. Last summer, the Emerald City sweltered through a record 12 days of 90s.

Forecast Highs

(MAPS: 10-day High/Low Temperature Maps)

Potential Impacts

This type of heat can be life-threatening for some, especially if you aren't adequately prepared. Remember: heat-related illnesses, such as heat exhaustion and heat stroke, are possible under these extreme conditions. If you are traveling with young children or pets, please do not leave them unattended in a hot vehicle.
The NWS office in Phoenix has issued some great heat safety tips.

• Drink before you are thirsty.
• Reduce time in the sun.
• Avoid strenuous activity; postpone outdoor activities.
• Seek air-conditioned buildings.
• Help the elderly, kids and pets stay cool.
• Keep window blinds closed.

February Record Heat

It was back in February when early-season heat first made an appearance across parts of the Southwest. Dozens of record highs were toppled across the Golden State, Desert Southwest and other parts of the West as many locations rose into the 80s and 90s.
The warmth was a staggering 15 to 25 degrees above average, even warmer than typical highs during the hottest months of the summer.
Phoenix recorded its earliest 90-degree day on record on Feb. 10, more than a full week ahead of the previous earliest occurrence on Feb. 24, 1986 and 1904, according to the NWS.
Death Valley reached the 90-degree mark for the first time this year on Feb. 15, topping a daily record and missing the earliest such "first 90s" of the year by just five days (Feb. 10, 2006). Incidentally, America's hottest location sees more days with highs in the 90s or above each year (193 days) than days below 90 degrees (172).
MORE: Southwest Heat Wave, July 2, 2013