By Micah Prior
WKTV Contributing Writer
Michiganders know that spring is usually late to arrive, yet we’re nearly two months past the Vernal Equinox and it has felt as though spring is still a few more weeks away. Luckily, temperatures are predicted to be much more favorable later this week, but this unusual cold spell has left many Michiganders curious as to why the frigid conditions that are typically characteristic of Michigan’s winter months have continued through March and April.
There’s a few factors that can explain why this has occurred. The first of which is the fact that we are in the midst of a La Niña year. La Niña is the cold water phase of a temperature cycle in the Tropical Pacific called the El Niño-Southern Oscillation (ENSO).
According to the National Ocean Service, “During normal conditions in the Pacific ocean, trade winds blow west along the equator, taking warm water from South America towards Asia. To replace that warm water, cold water rises from the depths — a process called upwelling.”
During the infrequent La Niña years of this climate cycle, those trade winds are stronger, upwelling increases, and the prevalence of this cold water in the Pacific Ocean pushes the jet stream further north, which leads to colder temperatures and increased precipitation.
This time around, it seems as though La Niña is doing her a job a little too well.
“We have had a lot of precipitation, with an active storm track the past several weeks,” said Erin Ostuno at the Grand Rapids National Weather Service. “This has resulted in March and April being cloudy and much wetter than usual. The combination of March and April had over eight inches of rain/melted snow water. This ranks 11th wettest on record. April had 5.19 inches of precipitation, the 12th wettest April on record at Grand Rapids.”
Talk about a great deal of precipitation. To make matters more intense, the jet stream that divides the northern and southern half of North America appears to have been pushed south this winter by high pressure zones that have formulated in the early spring near Greenland during a prolonged negative phase of the North Atlantic Oscillation (NAO).
In a recent article from the Washington Post, “When the NAO is negative, the weather over the eastern U.S. tends to be colder than normal. Such a pattern was seldom seen during the core winter months, which resulted in generally above-normal temperatures.”
While we were fortunate enough to experience slightly warmer temperatures this past winter, it seems that inevitably, we would have to pay the price at some point, which we’ve been doing since late March. The tax for having such a mild winter and all that high pressure up north is the spilling of the jet stream further south, which is why we’ve seen frigid temperatures typical of January or February continue through March and April while the Pacific Southwest has experienced oddly higher temperatures.
Luckily for us, it’s not forecasted to continue this way for much longer. According to a 10-day forecast for Michigan Center from Weather.com, by the week of May 9th, we’ll see high temperatures begin to erupt into the 70s with lows persisting in the upper 50s, so it appears as though this wintry weather we’ve been experiencing will finally be behind us.
