|Above: Lifeguard Luke Orot from Anchorage watches beachgoers at Jewel Lake on July 4, 2019 in Anchorage, Alaska, during the hottest day in Anchorage history. (Photo by Lance King/Getty Images).
The temperature in Alaska’s largest city of Anchorage soared to an astonishing 90°F on Thursday, July 4, smashing the city’s previous all-time heat record by a remarkable 5°F. Anchorage’s average high temperature for July 4 is 65°F; records for Anchorage date back to 1952. All-time heat records fell Thursday at all four Anchorage climate stations, and were set or tied at three other Alaska locations with a long period of record:
Anchorage Ted Stevens Airport: 90°F (previous record: 85°F, June 14, 1969)
Anchorage Merrill Field: 90°F (previous record: 87°F on June 27, 1953)
Anchorage Elmendorf Air Force Base: 87°F
Anchorage Lake Hood: 89°F
Kenai: 89°F (previous record: 87°F on June 26, 1953 and June 18, 1903)
King Salmon: 89°F (previous record: 88°F on June 27, 1953)
Palmer: 88°F (tied with 88°F on June 27, 1953 and May 27, 2011)
The hottest location I found in Alaska on Thursday was 94°F at Skilak Guard Station. This fell short of Alaska’s all-time highest reliably measured temperature of 98° measured at Richardson on June 15, 1969 (see the 2013 post by wunderground's weather historian, Christopher C. Burt). According to Mr. Burt, the official heat record for Alaska remains the 100° registered at Fort Yukon on June 27, 1915. However, there are questions concerning this figure as outlined by Alaskan weather expert Rick Thoman in his presentation Forensic Climatology in Alaska. He surmised that hot air had become trapped in the valley, and that the 100° reading at Fort Yukon was ‘plausible’, but not certain. In the same report, he categorically dismissed the 99° record for Fairbanks supposedly set on July 28, 1919.
Weather records expert Maximiliano Herrera emphatically argues that the 100° reading from June 27, 1915 is not reliable. In an email, Mr. Herrera detailed his objections: From June 27 to July 2, 1915, the Fort Yukon temperatures suddenly diverged by as much as 19°F with those of the nearby Rampart and University Experiment Station. Also, the spread between min and max temperatures grew abnormally during that period, with min/max spread as high as 55°F. Daily observations on June 27, 1915 showed cloudy and overcast skies at Fort Yukon, with a 51°F difference between the min and the max and 18°F to 19°F difference from the nearest stations. This is not compatible with Mr. Thomas’ theory of a "hot airmass being trapped in the Fort Yukon area”. The abnormal min/max spread (the min dropped as low as 38°F!) and the cloudy skies indeed suggest that those maxima in those 6 days are completely wrong, possibly by as much as 20°F.
On Denali, the highest peak in North America, the temperature rose to an astonishing 36°F at 5 pm local time at the weather station located at 14,200 feet. The snow depth is over 11 feet at the station.
The forecast: an extended heat wave for Alaska
The record-strength upper-level ridge of high pressure responsible for Alaska’s heat wave will slowly drift west and weaken slightly through Monday. This will allow at least four more days of record to near-record heat over southern Alaska, likely causing Anchorage to beat its all-time record for consecutive 80-degree days.
The record longest streak of days with 80 degree-plus highs at Ted Stevens Anchorage International Airport is just three, set in both June 2015 and 1954. Only once since 1953 has the city experienced four 80-degree days in a single year: 2015.
The Friday morning WU forecast for Anchorage called for 80-plus degree heat every day through Tuesday, with the hottest day of the heat wave coming on Monday, with a high of 87.
The Alaska Interagency Coordination Center @BLM_AFS estimates that as of July 04 wildfire in Alaska has burned 634K acres (256K hectares). This is significantly more than is typical for this point in the season, but not dramatically so. #akwx #Arctic #wildfire @Climatologist49 pic.twitter.com/sfuwNFyT6D— Rick Thoman (@AlaskaWx) July 4, 2019
The exceptional heat is combining with dry conditions to create significant fire danger. According to the Wildland Fire Assessment System, “Extreme” fire danger—their highest level of concern—was present over large areas of southern Alaska. Fortunately, winds have been light under the dome of high pressure responsible for the heat wave, keeping spread of the fires relatively slow. There is concern for Monday that enough instability may be present to allow thunderstorms to develop, which might bring gusty winds that would fan wildfires.
According to the National Interagency Fire Center, as of July 3, there were 36 large fires burning in Alaska; these fires had consumed a total of 427,000 acres, which is 37% of all the acreage burned in the entire U.S. so far in 2019.
#SwanLakeFire still active, 5 miles NE of Sterling, showing smoke-filled valleys. Main carrier of the fire is Black Spruce burning #Alaska #USA 4 July 2019 Enhanced nat. col. with IR overlay #Copernicus #Sentinel-2A Full-size https://t.co/24NTgXVOu6 #RemoteSensing #Wildfire pic.twitter.com/pAxPxQUQ4R— Pierre Markuse (@Pierre_Markuse) July 5, 2019
The Swan Lake fire burning on the Kenai Peninsula southwest of Anchorage has been sending smoke into the city in recent days, and brought another plume of smoke over the city on Friday morning. Last Saturday, the fire prompted the first-ever dense smoke advisory for Anchorage, according to Alaska climatologist Brian Brettschneider.
June 2019 sea surface temperature departures from 1981-2010 normal. Virtually entire Bering Sea north of 59N & Chukchi sea south of ice edge more than 2.5C (4.5F) & large areas much warmer. Impacts to communities & ecosystems continue. #Arctic #akwx @Climatologist49 @amy_holman pic.twitter.com/Udce3m0zrL— Rick Thoman (@AlaskaWx) July 2, 2019
Record warmth causing near-record sea ice loss
Alaska had its warmest March on record this year, followed by its 10th warmest April and 6th warmest May. June was the warmest and driest June on record in Anchorage, according to the National Weather Service, and Kotzebue, Talkeetna and Yakutat also had their record warmest June, according to Rick Thoman, an Alaska-based climatologist. The first six months of 2019 have been the warmest first half of any year on record in America's northernmost town on the Arctic coast, Utqiagvik (formerly known as Barrow), according to the Southeast Regional Climate Center.
All of this unusual warmth has led to significant losses of sea ice extent near Alaska, helping drive Arctic sea ice coverage to the second lowest June extent on record, said the National Snow and Ice Data Center. Water temperatures in the Bering and Chukchi Seas were running at least 4.5 degrees warmer than average, said Thoman, and sea ice extent in June in the Chukchi Sea off the northwest coast of Alaska was the lowest on recod.