As winter is creeping into Alaska The climate pattern called El Nino is back, cycling warmer water across throughout the Pacific Northwest.
National Weather Service climate researcher Brian Brettschneider — back to our Ask an Climatologist segment He says that that a normal El Nino winter Alaska is usually warmer and is characterized by lower snowfall.
And Brettschneider states that the current El Nino is expected to be more powerful than it was previously.
Listen:
The transcript below has been lightly edited to improve clarity.
Brian Brettschneider The possibility is that it could take on the form of an extreme El Nino, which has only been seen a handful of times over the past 50 years. The winters that are typically very poor in snow. This is true across the majority across the entire state but especially in the southern regions in which temperatures tend to be warmer in winter than for instance the Interior. Actually the last time we saw an extremely El Nino develop, in 2014-15and 2015-16, these were among our worst snowy winters, as well as the smallest snow winters ever recorded across the entire state.
Wesley The Early Years: You mentioned that most of the time that an El Nino means a warmer winter, however it’s not always a sure sign. Why wouldn’t it cause the winter being warmer?
Brian Brettschneider: Right. Actually, it’s an statistical correlation. You know, often these things don’t play out the way we think they should. Sometimes, the atmosphere doesn’t as we would call it, join with the ocean. In this case the reaction of the atmosphere to the warm temperatures is quite insignificant. It’s less than what we would think. It happens often, and has been observed in many of the more recent events, notably La Ninas over the last couple of years. There was an insignificant relationship between the way the atmosphere reacts to these temperatures in the ocean.
In the present, as well it’s an extremely weak coupling. One of the biggest mysteries is that the oceans globally are significantly warmer than normal. So it is true that central Pacific is significantly warmer than normal should be viewed in relation to the activities that other areas are doing, and how the warm oceans are likely to impact the atmospheric flow. This leaves a lot of questions. It can happen in many ways. In reality, however historically it is a driver of southerly flow throughout the state.
Wesley The Early Hour:And how do these weather patterns compare to the previous year, when much areas of Minnesota were dry and saw below-normal precipitation, however Anchorage witnessed a massive dump of snow several dumps of snow in a short time? Does it appear that something similar to that could occur this year?
Brian Brettschneider It is true that precipitation can be more difficult to predict on the seasonal and monthly timescales than temperature, and by an enormous amount. We are able to predict temperatures every all day. If it’s cold in Anchorage is likely to be cold in Palmer and, if it’s cool, it’s probably in, say, King Salmon, whereas the precipitation is often inconsistent. It’s just every three days. That’s something to be aware of.
In Anchorage I’m guessing that in 12 days that we saw three snowstorms that were almost historical. However, that was local. If you take a look regionally it was a fairly boring winter snow in Southcentral. The snow across the state was fairly typical for a typical winter. Therefore, we must be aware that it was very local as a myriad of extraordinary things combined to produce the big three snowstorms of the early and mid-December months.
Wesley early:You mentioned that ocean temperatures that are warmer could result in an upcoming warmer winter. You also stated that El Ninos can result in an energizing winter. There’s also less sea ice on the coast. Does that affect how cold winter will be?
Brian Brettschneider: Right. You know that a major factor in climate prediction center’s seasonally-based forecasts is the tardy beginning of sea ice on both the West Coast and the North Slope. Particularly within regions like the Chukchi Sea, working your all the way into the Bering Strait the sea ice is set to come in earlier than normal and it’s also much drier when it is. If you experience one of a particular kind, such as an eddy flow that flows south which is a southerly flow, it could push the thin ice far north even in mid-winter. If there isn’t any sea ice covering the ocean, this enables all the warmth that is absorbed by the water to escape to the air and is, naturally, going to travel over ground. Thus, the change in sea ice regime can have a significant impact on temperatures, particularly during the beginning of winter.
Wesley The Early Hour:We are less than an entire week away from Halloween. What should children be prepared for? to be to wear thick coats with heavy hoods to match their costumes? Will it be an icy Halloween?
Brian BrettschneiderWell there in Fairbanks, they have already got 9 or 10 inches of winter snow on their ground. If anyone is watching from central Interior I’d expect that it’s going be a full-on winter on Halloween, which is what it usually is. Up until in 2015 Fairbanks was on a track record of snow falling everywhere on Halloween. But then they didn’t have it for four of the five years. However, they’re now back in the winter rhythm.
In the past, in Anchorage it’s about a 50-50 chance of snow falling on the ground in time for Halloween. It’s been the norm for a few decades, but it’s become slightly less snowy over the last 10-15 years. However, looking at the current forecast it appears that we’re not likely to see a snowy holiday in Anchorage. Also, no snow suits for kids going out trick-or-treating.
