The probability that a La Nina dominated weather pattern will continue through the remainder of the 2022 Fall season, and possibly deep into the Winter 2023 season is relatively high.
Remember, the La Nina is one of two atmospheric patterns that are part of the El Nino/Southern Oscillation system that results in a shift of the jet stream, or storm track across the Northern Hemisphere. The other pattern is called El Nino.
These two atmospheric patterns cause a shift in the storm track across the United States, due to stronger or weaker trade wind flow in the tropics. A stronger trade wind environment pushes warmer oceanic surface water west into the Central Pacific, which leads to cooling of the Eastern Pacific Ocean, when colder water rises to replace the westward moving Pacific surface water.
The La Nina phenomenon causes the jet stream to shift well north to a position near the Gulf of Alaska and, as the high speed upper level winds shift southeast out of the polar region into the United States, much colder air impacts the Northern Plains, Great Lakes, and the Northeastern part of the country. In this pattern the Southern U.S. typically remains warmer, as the upper jet curves back north over the Mid Mississippi Valley carrying its frigid, polar air farther east across the Northeastern states.
The Four States region is positioned between these two extremes, but is a little closer to the milder, Southern U.S.; which would tend to keep a greater number of the extremely cold, arctic outbreaks from impacting the area.
This takes care of the temperature aspect of seasonal weather prediction. The other major aspect is precipitation. In similar fashion, the La Nina pattern impacts the northern states in a negative manner concerning precipitation, as the storm track brings more rain and snow to this particular region, while much of the southern part of the nation remains a little drier than what an average winter produces.
Here again, the Four States region sits in between these two extremes for colder season precipitation; remaining near the normal range for winter precipitation.
Now, the problem with being “in between” the extremes, is that the Four States region can be negatively impacted if there is a slight southward shift in the polar jet stream, and we end up experiencing an arctic outbreak, or we participate in a rather hefty 4-8 inch, or even 6-18 inch winter snowstorm event.
Remember, these forecasts that are based on La Nina, or El Nino winter patterns are just attempting to predict the “average”, or predominant winter conditions, that may occur in a particular region of the United States. We could still suffer through a larger snowfall event, or an arctic outbreak, but the frequency of these events is supposed to be reduced, according to the previously discussed La Nina winter weather pattern.
A final note of caution about the geographic position of the Four States region between the much colder northern tier of the U.S. and the warmer southern states, is that we may be at risk for something that unfortunately happens in this part of the country more often than we would like; and that is an ice storm. The Four States region is an area where shallow, arctic air masses can ooze south and remain trapped across broad regions of the south central U.S. for two to three days at a time.
Problems occur when a low pressure system develops over the Southern Plains, and then moves just south of us on its way toward the Mid Mississippi Valley. In this scenario, much warmer, moisture laden air is lifted just a few hundred feet over the top of the sub-freezing arctic air in place over Southwest Missouri, Southeast Kansas, Northeast Oklahoma, and Northwest Arkansas.
You know the rest of this story.
With temperatures just warm enough aloft to remain in the liquid state, precipitation falls as rain and then immediately freezes on contact with everything; including trees, power lines, structures, and roadways.
Simply put, we are hoping that the atmosphere doesn’t “arrange itself” to provide us with any major ice storms during the coming winter season. Some of us will desire the milder and, not quite as wet winter, the La Nina season generally produces. And some of us enjoy heavier snowfall that a more severe winter season can produce and will be rooting for more active weather this winter. It all comes down to what type of winter you prefer!