Falling temperatures, snow, sleet and a freezing rain forecast grab my attention, courtesy of the local TV weather prognosticator, as I daydream of spring emerging from its annual state of hibernation. After a brief period of warmth, in contrast to a long one for which I had hoped, I realize that winter has returned.
I’d like to forget what the groundhog predicted. Someone in that state east of us, the one that calls itself a commonwealth, needs to teach Phil, whose first name no one seems able to spell, forecasting.
Contrasted with our local weather forecaster and Phil, the National Oceanic and Atmospheric Association (NOAA) adds theirs. They’ve indicated we could be in the middle of a La Niña, a Pacific Ocean weather phenomenon off the coast of South America that determines when spring arrives in northeastern Ohio.
If so, then why all the snow?
Because a late spring is caused by a weather pattern called an El Niño. But an early spring is one caused by La Niña, and this year, despite the cold spells we’ve had, it’s La Niña that’s been in existence.
Our local weather prognosticators have nothing in common with La Niñas. Well, actually, Phil and his kin have one thing in common. Their long term forecasting is good only locally? The reason is that wind is involved. You’re just never 100 percent sure on the when, where, what, how or why.
Phil’s silly forecast that we all know and seem to love depends heavily on weather patterns. On a worldwide scale they’re somewhat predictable. But the smaller the area, the harder it is to determine the right forecast. The same goes for any long range forecast, including La Niñas.
To clarify this weather phenomenon, in the Pacific there’s a large variance of temperature. According to the NOAA, a cold ocean means dry, sinking air. In contrast, a warm ocean makes for moist, rising air that turns into precipitation. The top level’s heated by the sun while the lower levels remain cold.
If a strong enough wind blows across the surface, it pushes that warm layer in the same direction. At the same time it displaces the cold under-layers. These winds are called trade winds. They’re consistent and they flow in predictable patterns. As such, they were used by trade ships in the days of old to sail quickly from one country to another; thus their name.
In the Pacific, close to the equator, the trade winds blow from east to west. Warm waters travel towards the East Indies, and the deep, cold waters near the Americas rise up in their place.
Because the surface temperature of a body of water has a big impact on local precipitation, that patch of abnormally cold ocean is what creates La Niña weather. This, in turn, affects global wind patterns. A weak year, which is what scientists have predicted for the 2017-18 season, means the change in temperature is between 0.5 and 1 degree Celsius below average. A moderate year is between 1 and 1.5 degrees colder, and a strong year is anything greater than that.
Therefore, despite all the snow and bitter cold weather we’ve been having, it looks as if we’ll still be able to enjoy a weather breaking, warm spell. In other words, La Niña’s are predictable . . . except when they’re not.
So, after reading this weather explanation, if I’ve left you in a quandary about who to believe - the TV weather lady, Phil or La Niña - it may still help if you know which one I favor.
But since the NOAA is not even quite sure it’ll be a La Niña, to play safe, perhaps I ought to order my tomato plants now.
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