Published: Saat: 09:17 PM GMT Tarih: 18 Haziran 2013
Alaska Bakes with All-time Heat Records
A strong upper-air high-pressure ridge has brought all-time record heat to much of Alaska the past few days. Temperatures peaked at 96°F at Talkeetna north of Anchorage on Monday June 17 with unofficial readings as high as 98°. Here is a brief review of the record-setting temperatures.
Anchorage residents cool off in Goose Lake this past weekend. Temperatures reached 81° in Anchorage on Monday (short of the city’s all-time record of 86° set on June 25, 1953). Photo by Loren Holmes.
What is likely to have been the hottest day in Alaska for at least 44 years (since 1969) brought all-time record temperatures to a number of locations. These include:
96° at Talkeetna (previous record 91°F on June 14, 1969 and June 26, 1953 as well as last Sunday, June 16)
94° at McGrath (previous record 90° on June 15, 1969 as well as last Sunday June 16)
90° at Cordova (previous record 89° on July 16, 1995)
90° at Valdez city site (previous record 87° on June 25 and 26, 1953)
88° at Seward (previous record 87° on July 4, 1999)
84° at Nome (June monthly record only, all-time record remains 86° on July 31, 1977 and July 9, 1968. Previous June record was 83° on three occasions, the latest being June 7, 2004)
Other probable all-time records include 93° at Nikolai, 93° at Skwenta, and 88° at Unalakleet (this is a truly amazing figure since Unalakleet is located on the coast of the Bering Sea (Norton Sound) south of Nome.
Rick Thoman of NWS-Fairbanks notes that a couple of RAWS sites near Talkeetna reached 98° on Monday (June 17th) including Bentalit Lodge, and word has gone out to local COOP observers to check their equipment for any higher readings than the 96° officially measured at Talkeetna.
It is incredible how large the margin was between the record temperatures yesterday compared to the previous all-time records set at Talkeetna (by 5°) and McGrath (by 4°). The normal high for June 17th at Talkeetna should be just 64° and its previous daily record for June 17th was 85° in 1962.
The extraordinary heat was caused by a strong bubble of warm air associated with an upper-level high-pressure system that has become fixed over the state.
The heat dome over Alaska on Monday saw temperatures deviate 5 sigmas above the standard 500 mb height level. Thanks to Stu Ostro for this graphic.
Hottest Day on record for Alaska?
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 and NWS-Fairbanks employee Rick Thoman in his presentation Forensic Climatology in Alaska’ Please Google this for the PDF file report. After a thorough investigation Rick surmises the 100° reading at Fort Yukon to have been ‘plausible’ if not questionable. In the same report, however, Thoman categorically dismisses the 99° record for Fairbanks supposedly set on July 28, 1919. All evidence weighs against this reading being reliable. Therefore, the record for Fairbanks stands as 96° measured on June 15, 1969 (the last few days Fairbanks has only reached a high of 88°). The June 15, 1969 heat wave stands out as the last time such extreme heat affected Alaska as evidenced by the 96° in Fairbanks and a 98° reading that day in Richardson (near Fairbanks). Another heat wave in July 1955 brought a 97° reading to Fort Yukon on the 25th of that month. There are two other, but highly suspicious, hotter temperatures on the books for Alaska, this time in the southeastern peninsula area where, in 1976, temperatures of 99° at Tenakee Springs (on August 1st) and 98° at Haines (on July 31st) appear in the WRCC (Western Regional Climate Center) database. Neither of these figures seem credible; the Tenakee Springs reading is 13° warmer than their 2nd warmest reading on record. The Haines temperature is more credible but still a bit hard to believe.
All in all, I think it is fair to assume that the heat seen on Monday June 17th ranks as the warmest day in Alaska since June 15, 1969 and among the top five warmest days in the state’s history. If the 98° reading at RAWS Bentalit Lodge verifies then it might be argued that this ties the hottest reliably measured temperature in Alaskan state history (along with Richardson on June 15, 1969).
Last May saw Record Cold!
One thing that is so astonishing about the current heat wave in Alaska is how abnormally cold it was just a month ago. McGrath, which reached its all-time record high of 94° on Monday, recorded a 15° temperature on May 18th, the coldest temperature (by 4°) ever measured so late in the season there (McGrath went on to reach 86° on May 29th, its warmest May temperature on record!). Deadhorse (Prudhoe Bay) registered -12° on May 19th, the coldest temperature ever measured in the state of Alaska so late in the season.
During this past May McGrath set daily record lows for four consecutive days May 17-20 and daily AND MONTHLY record highs for four consecutive days May 28-31. Table from NWS-Fairbanks.
Christopher C. Burt