Dangerous, Extreme Heat Envelops Much Of The West; Heat Slides East This Week

Tom Moore
Published: June 6,2016
Portions of the West will continue to swelter early this week in a late-spring heat wave that is one of the sharpest so early in the year for some locations.
The high temperature of 115 degrees at Phoenix, Arizona, on Saturday was their earliest 115 degree temperature on record. Through Monday, Phoenix set four straight daily record highs.
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 slowly slides east. Later this week, this will allow above-average temperatures to move into the Plains, Midwest and portions of the South.

Early Week Western Heat

Current Temperatures

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.
Much of the West will continue to experience above-average temperatures, with highs up to 25 degrees warmer than average through Tuesday.

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

High temperatures reached 115 degrees in Phoenix Saturday and 113 degrees Sunday, while Death Valley, California, topped out at 119 degrees both Saturday and Sunday. Death Valley only dropped to 94 degrees for a low Sunday morning, which was a record warm low for June 5.
Excessive heat warnings remain in place for portions of southeastern California and southern Nevada through Wednesday.

Current Heat Alerts

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.
Numerous daily record highs remain in jeopardy through early this week.

City	Record High Tuesday	Record High Wednesday
Phoenix	115˚	115˚
Las Vegas	109˚	112˚
Yakima, Washington	101˚	105˚
Portland, Oregon	93˚	94˚

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 the 90s are expected in the Portland area through Tuesday.
Highs in Seattle topped the 90-degree mark Sunday for the first time this year, with an official high of 93 degrees at Seattle-Tacoma International Airport. 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. Temperatures will remain warm through Tuesday with highs climbing into the 80s.

Forecast Highs

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

Heat Slowly Slides East

The upper-level ridge of high pressure will slowly slide eastward this week, allowing the hot conditions to expand into the Plains, Midwest and eventually portions of the South. Much of the northern and central Plains will see highs 10 to 25 degrees warmer than average by Thursday.
The Midwest will begin to see much warmer temperatures Friday and Saturday. Highs in the low to mid 90s are likey for much of the region by Saturday. Chicago may see their first 90-degree day on Saturday. Lows will be above average as well, with temperatures not expected to fall below 70 degrees this weekend for much of the Midwest and South.

Forecast Highs

Portions of the Ohio Valley and Tennessee Valley will also see the heat build by the weekend. Temperatures are expected to climb into the mid 90s for many areas, including Nashville and Atlanta.
(FORECAST: Fargo, North Dakota | St. Louis | Louisville, Kentucky)

Records Set 

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.
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)

Saturday, more records continue to pour in, including:

• Needles, California : 118 degrees
• Phoenix : 115 degrees 
• Las Vegas : 109 degrees (tied)
• Medford, Oregon: 100 degrees
• Portland, Oregon : 98 degrees

Numerous records were set on Sunday, including:

• Boise, Idaho: 97 degrees
• Phoenix: 113 degrees
• Tucson, Arizona: 110 degrees
• Las Vegas: 109 degrees
• Yakima, Washington: 101 degrees
• Portland, Oregon: 100 degrees
• Spokane, Washington: 95 degrees
• Grand Canyon Airport: 95 degrees
• Eugene, Oregon: 94 degrees
• Seattle: 93 degrees

(MAP: Actual Highs)

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