Weather

Anchorage just experienced its hottest month on record

Anchorage just recorded its hottest month ever, amid a statewide July warm spell that saw temperature extremes from Southeast all the way to Deadhorse.

That's according to National Weather Service meteorologists, who said on Facebook Tuesday that temperatures last month were searing throughout southern Alaska — Kenai also had its hottest month on record, while Homer and Sitka both posted their warmest July ever.

"Most other long-term climate observations locations in southwest Alaska reported the second-warmest July," meteorologists wrote.

Two spots on the North Slope saw their warmest single days on record as well, with the Deadhorse Airport hitting 85 degrees on July 13 and Kuparuk reaching 86 degrees on July 14.

Climate scientists said the warmth is due, in part, to above-average sea temperatures.

"All around Alaska, sea surface temperatures are much warmer than normal," said Rick Thoman, climate science and services manager for the NWS Alaska Region. "In the Bering Sea, especially south of St. Lawrence Island or so, they're really outrageously warm compared to normal."

"You still don't want to go swimming in that water," he cautioned.

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Elevated sea surface temperatures, almost by definition, mean warmer air temperatures, Thoman said. Coastal communities like Cold Bay and Kodiak are particularly affected, he said.

In addition to the heat extremes, July also delivered intense rain to parts of the state. Nome saw rainfall 81 percent above average for the month, while Eagle, near the Canadian border, reported 60 percent more rain than average.

Fairbanks, however, was in its own class, receiving 230 percent of its average July rainfall. That made the month Fairbanks' fourth-wettest July on record, with rainfall approaching 10 inches reported near the city.

Denali National Park also got drenched, with its Eielson Visitor Center recording 16.5 inches for the month. According to the weather service, the deluge contributed to a mudslide that temporarily isolated visitors and staff along the park road last weekend.

[Read more: Mudslide closes portion of Denali Park Road, temporarily maroons visitors]

That's not to say the Interior was untouched by above-average temperatures. Like much of the state, the region was warmer than normal, Thoman said, though it didn't rise to the same record-breaking levels of other places in the state.

"The records or near records were mostly confined to the south of the Alaska Range, and that really is also a function of it being so wet in the Interior," Thoman said. "Obviously, when it's raining and cloudy a lot it's hard to get very warm in the daytime, but temperatures have been significantly warmer."

A difference of more than 2 degrees is considered significant in the summertime, he said.

The warmth brings about the rain, according to Brian Brettschneider, climate scientist with the University of Alaska Fairbanks International Arctic Research Center.

Warm air can hold more moisture, Brettschneider explained.

"The air is like a sponge, and the sponge is a little bit wet, and if you squeeze out the sponge you get rain. Well, the warmer the air, the more water that sponge can hold," he said.

Jerzy Shedlock

Jerzy Shedlock is a former reporter for Alaska Dispatch News. He left the ADN in 2017.

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