Dueling heat waves continued to roast the Lower 48 as more than 100 million people remained under heat alerts on Friday.
The heat waves follow several others this summer, including an unprecedented late-June event that delivered numerous all-time highs to the Pacific Northwest. Both corners of the contiguous United States have endured abnormally hot weather this summer. Climate change is boosting the intensity and frequency of such events.
Pacific Northwest heat
The heat event is peaking in Washington, Oregon, Northern California and western Idaho. Excessive-heat warnings for these areas are in place for Friday and Saturday.
Record highs are anticipated Friday in Seattle and Portland. Other locations in Washington state expecting record highs include Olympia and Yakima.
Temperatures in Portland are slated to top 100 degrees for a second day in a row. With five days at or above 100 this year, the city is tied with 1941 and 1977 for the most 100-degree days in a summer. One more 100-degree day, perhaps Friday, would mean 2021 stands alone on top of the list.
On Thursday, Bellingham, Wash., hit 100 for the first time on record. This is quite remarkable for a location 80 miles north of Seattle, on the water. It topped the old all-time maximum of 99 set during the June heat wave, among numerous other all-time records set across the region this year.
Hot and smoky conditions expected today. Here is the latest smoke forecast. Smoke will start to gradually clear from west to east tonight with air quality improving as onshore flow returns. Expect smoke to linger through Saturday. #wawx pic.twitter.com/RwOsm5IrZl
— NWS Seattle (@NWSSeattle) August 13, 2021
A sample of record highs on Thursday:
- Eugene, Ore. — 104 degrees
- Redmond, Ore. — 101 degrees
- Vancouver, Wash. — 103 degrees
- Portland — 102 degrees (tie)
- Bellingham — 100 degrees (all-time)
- Olympia — 96 degrees (tie)
- South Lake Tahoe, Calif. — 90 degrees
Severe heat has also been occurring north of the international border. Several all-time monthly highs for August were set Thursday in British Columbia, including at Port Alberni and Abbotsford.
In addition to the extreme heat, places like Seattle will be dealing with smoky skies thanks to numerous wildfires in the region, coupled with the hot land-to-sea flow. Smoke has been an issue across the country, but particularly in the Pacific Northwest, in recent weeks. The combination of excessive heat and extreme drought have intensified conditions ripe for fires across much of the West.
The local Weather Service expects sky conditions to improve in and around Seattle this weekend as the wind direction shifts.
The core of the heat wave will drop south this weekend. Excessive-heat watches are up for portions of Southern California and neighboring Nevada from Saturday through Monday.
Temperatures are forecast to rise into the 100-to-110-degree range for much of Southern California and the Central Valley to the north this weekend into early next week. The hottest day across this area appears likely to be Sunday.
Very Hot conditions expected for interior sections this weekend, with highs up to 107 deg, and lows in the mid to upper 70s. Take precautions to stay cool, and check on others. Stay alert for signs of heat related illness! #SoCal #CAwx #CAheat pic.twitter.com/9bNnWvJY0c
— NWS Los Angeles (@NWSLosAngeles) August 12, 2021
Heading into next week, temperatures in California and neighboring areas will dip back to the 90s to around 100, except in typically hotter locations of the desert.
Northeast U.S. heat
Excessive-heat warnings are up for Friday in southeastern Pennsylvania and much of New Jersey, including the Philadelphia metro area. Heat advisories run from North Carolina up the coast to Maine.
Friday is the final day of significant heat on the East Coast in this episode. When a cold front sweeps through on Saturday, many spots will have seen a week straight of hot conditions. Even Saturday will be cooler, if not truly cool, thanks to the front bringing more clouds, with some storms, and eventually displacing the hot air.
A number of record highs are anticipated in the Mid-Atlantic and Northeast on Friday, in places such as Bridgeport, Conn., and Annapolis and in parts of the New York City region. Widespread readings in the mid-90s to around 100 are a good bet from North Carolina to southern New England.
This is on the heels of a number of record highs Thursday, a sample of which is below:
- Dulles, Va. — 100 degrees
- Newark — 98 degrees (tie)
- Lynchburg, Va. — 98 degrees (tie)
- Roanoke — 96 degrees (tie)
- Elkins, W.Va. — 92 degrees
- Islip, N.Y. — 90 degrees (tie)
In addition to record highs, extreme humidity has helped set a number of record-high low temperatures.
On Thursday, record high minimums were recorded in Bridgeport; Houlton, Maine; and Watertown, N.Y., among other locations. Places such as D.C. also recorded morning lows in the 80s on Friday, which is quite unusual historically. Additional record-high minimums are probable Friday and perhaps Saturday.
Saturday will feature cooler air spilling into western parts of the Northeast, while more typical summertime heat is squashed near the coast and deeper into the Mid-Atlantic and Southeast. Fairly widespread clouds and rain with the front should keep records to a minimum Saturday.
By Sunday, comparatively refreshing air will have taken over much of the northeast. That cooler air may be short-lived as warmer-than-normal temperatures are anticipated to return later next week.