October was the coldest on record for Kalispell, Missoula, Butte and other communities across western Montana, according to the National Weather Service in Missoula.
Winter came early to the Northern Rockies and, if the short-term forecast is to be believed, won’t be leaving anytime soon as cold temperatures are expected to persist into early November. However, predicting what will happen for the rest of the winter is a little more complicated.
According to meteorologist Robert Nester, instead of an El Nino or La Nina weather pattern, we’ll experience what is called an “El Nino-Southern Oscillation,” also known as an ENSO weather pattern. An ENSO pattern is considered neutral, meaning it’s hard to predict what will happen over the course of the winter.
“During neutral years, there is no signal… There is variability,” Nester said. “We will have cold and snow but the frequency of events is uncertain.”
Seven of the 10 coldest temperatures recorded in Missoula have occurred during ENSO years, including the coldest ever back in 1957 when the mercury dropped to negative 33. The winter of 1996/1997 was also an ENSO year and saw a record-breaking snow event at the end of the December 1996 when 40 inches of snow fell in a week.
Weather service officials said the best way to keep track of upcoming weather patterns would be to pay attention to social media accounts connected to the National Weather Service in Missoula.