'Cold-dominated' winter ahead?
Though the weather between now and winter's onset will likely be mostly variable, a lot of signs point to another "cold-dominated" winter in the U.S., especially in the eastern third of the country.
The cold will enter the outlook in earnest next month, and the peaks on both sides of the spectrum will be far apart despite a generally colder-than-normal month, according to Commodity Weather Group, LLC's seasonal outlook for fall and early winter. Generally, the colder outlook hasn't changed much from earlier estimates, though the factors influencing what could be a highly variable season have adjusted, namely the lingering presence of a La Niña pattern in the Pacific and Atlantic oceans.
"The winter outlook is unchanged with this update as we still expect another cold-dominated winter. Forecast confidence is lower on the shoulder months of November and March than the core winter months as is usual," according to CWG.
Other factors that should contribute to the colder winter weather scenario for North America include snowpack in eastern Europe and Asia, sea temperatures in the north Atlantic and "stratospheric behavior," like solar activity.
But, CWG analysts are quick to say all of these factors won't necessarily align completely the way they're expected to now. In that event, there are some variations in at least temperature outlooks for the December-through-February period. The most likely possibilities revolve around the strength of La Nina; if the system continues "in its current weak state and the strong winter blocking of the last 2 winters underperforms expectations," the southern Corn Belt and mid-South could see a warmer winter than those further north. But, if La Niña strengthens, the bulk of the cold temperatures would be pushed west, leaving the eastern Corn Belt with a warmer winter.
If La Niña strengthens -- a scenario weather specialists say is unlikely at this point -- the entire Corn Belt would see a warmer winter. "The closest example of this type of year would be 2001," according to CWG.
The most likely outcome, though, is La Nina continuing in its current weakened state. Unlike the first possibility, this scenario would include a "super-blocking" La Nina pattern that keeps the entire eastern half of the country at temperatures below average. Overall, there's a 55% chance this outcome will reach fruition, CWG data shows.
"The average of these four forecasts is for a weak to right on the edge of moderate La Niña this winter. Historically, a weak-to-moderate La Niña in a cold Pacific, warm Atlantic, and easterly stratospheric wind favors a cold-dominated winter for North America," according to CWG.