A heat wave unprecedented in the past 73 years has toppled weather records across Alaska, particularly in Southeast Alaska.
On Friday, the National Weather Service thermometer at Juneau International Airport hit 54 degrees, tying the highest temperature ever recorded in December there.
The airport is the city’s official measuring point, and according to records kept by the Weather Service since 1936, three of the 10 warmest December days in Juneau’s history have come in the past week. The city has set four daily high-temperature records.
It was warm elsewhere in the city, too. On Thursday evening, the temperature in the Mendenhall Valley reached 58 degrees. Downtown, it was 50. At the base of Eaglecrest, it was 47.
It was warmer in Juneau on Friday than it was in Houston. That’s the Houston in Texas, not the one in Southcentral Alaska.
It was warmer in Juneau than in Jacksonville, Florida or Monterrey, Mexico.
And Juneau wasn’t alone.
Sitka had an extraordinary event: The low temperature Thursday (53 degrees) was above the previous record high for the day (52 degrees).
“These are some fairly long-standing records that have fallen. Definitely the Sitka temperature you could say that about,” said Devid Levin, a general forecaster for the Weather Service in Juneau.
Southeast Alaska high temperatures (ºF) on Thursday, Dec 7th. Some of these are record highs for the date. For reference, highest reliable Alaska temperature in December is apparently 65F (18C) at Sitka on Dec 12, 1944.
According to Weather Service records, it’s the biggest December heat wave in Juneau since 1944, when the thermometer also spiked at 54 degrees and high temperatures stayed at or above 49 degrees for four days. Temperatures also reached 54 degrees in 1999.
Levin offered a clear explanation for the heat wave covering Southeast Alaska: “What we have is a big ridge of upper-level high pressure. The jet stream position has moved really far north for this time of year, and the jet stream kind of separates cooler air to the north and warmer air to the south.”
With the jet stream to the north, warm air from the tropics has moved north, covering Southeast Alaska — and to some extent, the rest of the state.
On the west side of the ridge, Southcentral Alaska has been enduring freezing rain and thawing conditions. In Fairbanks, temperatures reached into the mid-30s and rain fell on the state’s second-largest city.
Levin said the ridge isn’t going away any time soon, but temperatures will fall as heavy rain moves across the capital city. That rain arrived Friday morning, precluding temperatures from rising any higher than 54.
Levin said he expects temperatures to remain above normal through at least the first part of the week, with rain continuing throughout.
Juneau temperature records this week:
• Friday’s high of 54 blew past the old record of 46, set in 2002.
• Thursday’s high of 51 topped by 3 degrees the old record of 48, set in 1964.
• Wednesday’s high of 50 was 3 degrees higher than the old record of 47, set in 1964.
• Tuesday’s high of 46 was one degree higher than the old record, set in 1979.
• Contact reporter James Brooks at james.k.brooks@juneauempire.com or call 523-2258.
