There could be more warm and cloudy weather on Alaska’s coast and more wildfire danger in the Interior this summer if a temperature trend in the waters of the Pacific Ocean along the equator continues.
The National Weather Service’s Climate Prediction Center issued an El Niño Watch on Thursday, saying the weather pattern is more likely than not to develop this summer.
“At this point it does look quite likely that we’ll see that warmer water across the equatorial Pacific,” Rick Thoman, the Director of Climate Science and Services for Alaska, said. “That will influence where those big thunderstorms develop in the tropics over the summer, and that pushes lots of heat and moisture into the mid and high latitudes of the earth.”
The moisture transported to the north becomes clouds in Alaska.
El Niños were fairly common in the late 20th century but have only shown up twice since 1998. Thoman says because the jet stream is fairly weak in the summer, El Niño’s effects to the north can vary, but a general pattern can still be seen in records of past events that developed between spring and summer.
“When that’s happened in the past, that has correlated with active fire years,” Thoman said. ”It also does correlate to some extent with at least not cool summers, especially in coastal Alaska.”
The reason for the higher fire risk is thunderstorms.
“Because to get thunderstorms of course you need some moisture,” Thoman said. “Last year was a very warm summer across mainland Alaska, but there was unusually low thunderstorm activity and that was a result of the high pressure aloft and really a lack of low level moisture.”
“So to some extent we need that moisture to get thunderstorms across inland Alaska.”
The Climate Prediction Center says there is now a 65 percent likelihood of an El Niño developing this summer.