GRAND RAPIDS, Mich. (WOOD) — After two tame winters, West Michigan looks like it will finally get its fair share of snow this season, with prevalent cloud cover and a mid-winter thaw.
Every winter, there are hundreds of factors at play that can determine how the season will go down, including La Nina, the jet stream and even what the snowpack is looking like on the other side of the world. Storm Team 8 considered those factors and compared them to years past to project the trends we’ll see this time around.
WINTER SHAPING UP TO BE WETTER THAN AVERAGE
One of the biggest indicators that we are going to have a wetter-than-average year is the moderate La Nina that has formed in the equatorial Pacific.
It may be hard to believe, but the ocean temperatures in the Pacific off the coast of South America can have a big influence on the storm track here in the United States.
This year, forecast models are fairly consistent in calling for a moderate La Nina. This will likely steer our storm track to give us wetter-than-average conditions by the time winter is all said and done.
A moderate La Nina also leaves room for several other players on the meteorological field. Last year, we had a moderate La Nina and it ended up being a quiet winter until February hit. This winter, we are looking at other variables that will likely kick winter off much sooner.
EXPECT A QUICK START TO SNOW
Last season, we had to wait until Christmas Eve until our first inch of snow. This winter season will likely hit harder and faster with a good chance of above-average snowfall for December.
Past years that are similar to this one are considered analog years. Storm Team 8 has identified several analog years that can help us piece together the forecast for this coming winter. Many of our La Nina analog years featured a single month with a lot of snow for West Michigan. This is likely because a moderate La Nina often allows for other factors, like blocking or the polar vortex, to dominate for a shorter period of time.
We are expecting something similar this year. A stratospheric warming event, better known as a “polar vortex” event and an interaction with the Madden-Julian Oscillation (a type of moving atmospheric disturbance) is forecast by seasonal experts to bring blocking cold to the central and eastern parts of the U.S.
This likely means a solid kickoff to wintry temps and snow for November and December here in West Michigan. The storm system that happened the last week of October in West Michigan increased our confidence in this. Late fall storm tracks often reveal where the jet stream is expecting to “sit” for early winter. The storm track that has developed is one that would favor a snowier and cooler start than average.
Cold air is already starting to generate with a solid seasonal snowpack in Siberia, which is another factor we look at. A healthy Siberian snowpack already this year means that when our jet stream does begin taking a dip over Michigan, the cold air will be present to drop our temps and trigger some lake-effect snow.
MORE LAKE-EFFECT SNOW THAN RECENTLY
Calling for more lake-effect snow in West Michigan this year than the previous two seasons is no stretch of the forecast.
Lake-effect totals were abysmally low the last two winters. Typically, lake-effect means we see higher amounts of snow near the lakeshore and almost double the amount of snow as in Wisconsin. The last two years, the lake-effect snow was wimpy at best.
This winter, we expect an average lake-effect snow generation. This should boost our snowfall numbers to the 70-inch range for most areas with higher amounts in the typical snowbelt areas.
There is a high chance for some big variability and a mid-winter thaw this season. A moderate La Nina often leaves room for other important variables to dominate from time to time. This usually means that moderate La Nina years feature a few solid pattern swings.
Typically, mid-winter thaws feature some rain and temperatures that are mild enough to eat away at our snowpack so grass can peek through.
We expect a healthy mid-winter thaw as a result before the cold of February returns.
When it comes to seasonal forecasting, it is rare for there not to be a few wildcards in the forecast that can completely change the outcome.
A solid stratospheric warming polar vortex event, for example, can completely shatter temperatures for a couple of weeks and pile on the snow. Events like a polar vortex are often forecast just a few weeks out. These can be huge game changers when it comes to seasonal forecasting.
One of the biggest wildcards this year is the same one that bit us last year: the cold pool of water that has developed in the Gulf of Alaska. This cold pool will is not a guarantee through the winter and it does affect our jet stream location. Last year, the cold pool flipped and we saw a big flip in the forecast.
We are watching the warm pool of water north of Hawaii to see if it moves to replace the cold pool. This can happen from time to time. If it does mid-season, we will likely see a sharp turn to colder than usual for the second half of winter.
All in all, we expect a typical wild West Michigan winter with a few curveballs and a few good winter storms.
We are expecting a wetter-than-average winter with accumulating snow arriving in November and a snowier-than-usual December. There should be a mid-winter pullback and some periods of rain. We are expecting close-to-average snow totals by the time the season is done, and we are expecting winter not to linger too far into spring.
We are also expecting a few wildcards to keep our job interesting along the way. Whatever the weather throws us, you can bet we will be working hard to get you the best breakdown of what we expect to see each day.