The winter of 2018-19 could be warmer with less snowfall than normal, if weather predictions hold true.
The National Weather Service in Missoula Monday released its winter outlook for the northern Rockies predicting a high likelihood for a weak El Niño system this winter. Bob Nester, climate program manger, said the last couple of years were marked by pretty harsh winters with near record snowfall and cold Arctic systems, but this winter is likely to be different.
“We’re expecting at or below normal snowpack,” he said. “And above normal temperatures especially with valley inversions.”
Nester cautioned that the forecast is a seasonal outlook for December to February and variations in that prediction are likely to occur.
A weak El Niño system for western Montana is likely to mean below average snowpack.
“For the basins in western Montana the average is 68 to 82 percent of normal,” he said. “That’s pretty low especially when last year we averaged over 140 percent of normal.”
During a weak El Niño year, the Flathead Basin averages 79 percent of normal snowpack on April 1 at the end of the winter season and average snowfall for December to February for Kalispell average 50 to 75 percent of normal.
Nester said that it doesn’t mean that western Montana won’t see precipitation, it just may not come in the form of snow.
“That is due to above normal temperatures over the winer,” he said. “So you get higher temperatures and not as much snow.”
“This does not mean we won’t see snowfall,” he cautioned. “Or perhaps have a big event here and there, but over the course of the season fewer events are expected.”
During El Niño, drier conditions are usually present in the Pacific Northwest and Alaska, he noted.
The confidence is high for above normal temperatures across much of the Western United States for the winter season based upon temperature records from 1950 to 2010 generally showing above normal temperatures during a weak El Niño. Precipitation varies at above, below or near normal.
The National Weather Service also recently released its winter outlook for the entire country for December through February, which is calling for a mild winter in store across the northern and western United States.
Forecasters are saying there is a 70 to 75 percent chance of El Niño developing.