The National Oceanic and Atmospheric Administration (NOAA) upgraded their previous La Niña Watch to a La Niña Advisory on Thursday.
According to a discussion released by the Climate Prediction Center yesterday, "La Niña conditions are present and are likely to continue through the Northern Hemisphere winter". The CPC scientists say there is a 75% chance that these conditions will be in place from December 2020 through February of 2021.
So what is La Niña and why do we care in Mid-Michigan? Those answers are below.
What is La Niña?
La Niña occurs when cooler-than-average sea surface temperatures develop across the central and eastern Pacific Ocean, near the equator. This is the opposite of El Niño, which features above-average sea surface temperatures in this region.
What Does It Mean For Mid-Michigan?
When you hear La Niña or El Niño in our weather forecast close to home, it's usually being talked about when it comes to seasonal outlooks. Although they can play a role in the summer, there is usually far more interest for what it means for our Michigan winter.
While all La Niña or El Niño winters aren't created equal, and can have a variety of different outcomes, they can mean that certain outcomes are more likely.
Typically, La Niña brings above-average precipitation and colder-than-average temperatures to the northern tier of the US, which of course includes us here in Mid-Michigan. The southern states are typically drier with above-average temperatures.
What Happened Last Time? 2017-2018
The last time we observed La Niña was in 2017-2018, and it was considered a weak La Niña.
When it came to temperatures around Saginaw, Flint, and Houghton Lake, there wasn't much change from the usual. Temperatures were incredibly close to average (within 1 degree) in all three locations.
- Saginaw 24.6° (Avg: 24.6°)
- Flint 24.3° (Avg: 23.8°)
- Houghton Lake 20.8° (Avg: 20.6°)
Snowfall on the other hand, had a little bit of everything!
Flint checked in with its snowiest season on record (July to June), and a big reason for that was the huge winter season. Flint averages around 35.7" of snow from December to February. But in 2017-2018, they nearly doubled that mark with 65.3" between the three months.
Saginaw, who usually sees around 31.1" of snow during that time, was just a shade below average with 29.5".
And Houghton Lake was on the opposite side of the spectrum, checking in with their 5th least snowy winter on record with only 29.5" of snow, well below the average of 47".
Looking Back At Past La Niña Years
If you're curious of more previous La Niña years, check out the graphics below put together by NOAA's Tom Di Liberto back in 2017 ahead of that season.
He examined the precipitation and temperature outcomes from all previous La Niña winters on record before 2017-2018.
One thing you'll notice after looking at these maps, like mentioned above, you'll see that La Niña patterns aren't always "typical". While the odds usually suggest cool and wet for us here in Mid-Michigan, we've had our share of above-average temperatures and below-normal precipitation.