CLEVELAND — On January 15, 2022, an undersea volcano near the Tongan Islands in the Southern Pacific Ocean suddenly exploded.
This violent eruption sent tsunami waves racing around the world and created a sonic boom that circled the globe, twice.
It also hurled an unprecedented amount of water vapor up through the troposphere (a five-mile-thick layer of air next to the Earth's surface where all of our weather occurs) and into the stratosphere.
The stratosphere sits on top of the troposphere.
At 30 kilometers thick, it is very dry and is home to the ozone layer.
That immense amount of water vapor is now spreading out through the stratosphere around the globe.
So, what does a volcano 7,200 miles away have to do with predicting weather patterns for the coming winter months here in Northern Ohio? Well, possibly a lot!
While it's impossible to accurately forecast specific temperatures and precipitation amounts more than a few weeks out, it is possible to look for trends in weather patterns that could give us an idea of what the winter of 2022-23 has in store for all of us in Northern Ohio.
In other words, will it be warmer or colder in the coming weeks or months? Can we expect above-average rain or snow this winter?
To find those trends, we first look at current ocean temperature patterns plus pressure/temperature patterns above the Earth as well.
Large pools of warm and cold water in our world's oceans can and do affect the positions of high and low-pressure systems at the surface.
High pressure is generally fair weather; low pressure is generally rainy or snowy weather.
These warm and cold areas often change positions from year to year.
If we look back in history at years with similar ocean temperature patterns, we can see how those ocean-air "teleconnections" affected our seasonal weather patterns back then.
In turn, we can formulate a general forecast for the near future based on these weather patterns of the past.
So, what's happening right now in and above our oceans? Figuring out a forecast is like baking a cake. Let's start!
GATHER THE INGREDIENTS:
TRIPLE-DIP LA NINA
Water temperatures in the Pacific Ocean near the equator are cooler than normal. This is called La Nina. Most La Ninas last for several months to about two years. But this is the third year in a row for La Nina conditions. Pretty rare! In fact, it's only happened two other times in the last 55 years: 1974, 1975 and 1976; and 1999, 2000 and 2001. Not a lot of history to lean on here.
NEGATIVE PACIFIC DECADAL OSCIALLATION
Water temperatures south of the Aleutian Islands in Alaska are warmer than average while the water temperatures closer to the Canadian West Coast are cooler than average. This is known in meteorology as the "negative" phase of the Pacific Decadal Oscillation (-PDO). Negative and positive phases tend to last for years at a time. History shows us that typically, a La Nina plus a negative PDO during the Northern Hemisphere winter combine to favor warm, dry high-pressure systems near the U.S. West Coast and colder, unsettled weather across the Northern Plains into the Great Lakes.
THE POLAR VORTEX
The much-hyped Polar Vortex is a circulation of winds in the stratosphere above the north and south poles. The polar vortex sits generally between nine and 18 miles above the Earth's surface. During the fall months, the Polar Vortex typically strengthens. In October, it's usually a tight circle of wind that keeps most of the cold, arctic surface air trapped neatly underneath it. But not this year. For the past couple of weeks, the polar vortex has been weak and wavy. This has allowed several waves of arctic air to plunge southward into the Great Lakes and the northern U.S. as well as portions of Northern Europe. The result was this week's cold and sometimes snowy weather with temperatures a full 20 degrees below average.
The weaker Polar Vortex has also allowed more snow to accumulate over larger areas of Canada and Siberia. As of October 1, Siberia had the sixth most snow by area in the last 55 years. Canada sat at 15th most. More snow in these areas during fall can lead to more frequent cold air outbreaks over the USA in November and December.
THE MADDEN-JULIEN OSCILLATION (MJO)
This ocean-atmosphere interaction is based on large clusters of thunderstorms that travel along the equator starting over Africa and then moving east into the Indian Ocean and over the Pacific. It takes 20 to 60 days for these storms to circle the globe. The location of these storms near the equator will often tell us where the high and low pressures will be even over the United States. For instance, when we see that large cluster of equatorial thunderstorms sliding slowly east of Papua New Guinea, that usually means a couple of weeks of warmer, drier weather for the Eastern United States.
MIXING THE INGREDIENTS
Typically, a La Nina plus a negative PDO pattern favors a stronger Northern Jet Stream and a warm high pressure in the Western United States. That, in turn, supports colder air outbreaks sliding down out of Western Canada into the Northern United States and the Great Lakes.
As for precipitation, La Nina Winters favor a storm track that slides Southeast out of Canada and into the Ohio valley/Lower Great Lakes. We should see above-average precipitation for the Pacific Northwest and the Great Lakes, Ohio Valley, and Northern Ohio. But that may not mean more snow! In fact, snowfall totals during La Nina Winters often end up below average for most of us in Northern Ohio. La Nina Winters are wet here. But we often get more rain than snow.
Now, let's get back to the Tongan Volcano eruption. That extra water vapor caused serious cooling in the stratosphere over the Southern Hemisphere. When we look back at past years with cooler-than-average stratospheric temperatures over that region, we notice that winter surface temperatures over the Eastern United States were often on the cold side!
THE FINISHED FORECAST
La Nina Winters here in Northern Ohio are often wet and wild, characterized by big swings in temperature, above-average rainfall and bursts of moderate to heavy snow. Snowfall usually ends up below average for most of us. For the winter of 2022-23, I expect a colder and snowier start to winter thanks to a weaker, wavy Polar Vortex and extra snow across Canada. That makes it easier for Arctic Air to slide south into our area. The Lake Effect Snow Machine should get cranking, and I wouldn't be surprised to see a Panhandle Hook take aim at our area before Christmas!
The MJO will then disrupt the cold to start 2023 bringing us a long January Thaw. Only to be followed by a battle between cold and warm in February and March. The extra moisture from the Tongan Volcano eruption in the stratosphere should encourage frequent blocking high-pressure patterns over Greenland. This would force a couple of extra cold air outbreaks to slide south out of Canada and into the Great Lakes and Ohio Valley. The last half of winter will likely include at least one significant snow event, as the storm track parks over Ohio from February into March.
TEMPERATURES
Despite a nice January Thaw, cold December temperatures and a chilly February should tip overall winter averages to BELOW NORMAL for the season.
PRECIPITATION
The average winter snowfall for Cleveland is 64 inches; for Akron/Canton is 47 inches. During La Nina Winters, we typically see more rain and less snow than average. With the scales tipped toward cold this season, I would expect we should be able to get closer to those averages. For Cleveland, I look for between 55 and 65 inches of snow. For Akron, we'll shoot for between 45 and 55 inches of snow!
Get those shovels ready!
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