It's amazing to think about how far the science of weather has evolved over the years. As we learn new things from satellites and computer models, we can put some old superstitions to rest. But the proliferation of weather data and buzzwords can make it all feel even more confusing than before.
Here's my take on some common misconceptions about the weather.
From one season to another?
It seems like Mother Nature has a cruel sense of balance. Sunshine and 60s one day, then 30s and snowing the next. Or an unusually mild February followed by a bitter, blustery, bloom-freezing March.
So when one season stands out for being especially hot or cold, it's natural to wonder whether more extremes are lurking in an upcoming season.
Actually, the events we remember about a season, such as heat waves and winter storms, can be sparked by patterns that don't even last for the whole season. So no, there isn't any simple connection between winter and summer temperature anomalies.
Let's take Virginia's coldest winters, then check the summers that followed: Of those years, a handful of summers were warmer than average, a handful were cooler, and some were just normal. That's not much of a connection.
And the winters that followed our most brutal summers? They had an even mix of colder-than-average, warmer-than-average and normal temperatures.
The job of forecasting would be a lot easier if a warm winter meant a hot summer. But forecasting a few months out is done on a case-by-case basis, by analyzing what's changing with the El Niño-La Niña cycle, ocean temperatures and other patterns.
Variation is a part of nature, and those swings are what make weather interesting and frustrating.
Signs in the skies?
It makes you stop in your tracks: A bright moon shines through the milky clouds, with a giant halo beaming around it.
It must mean something. People remembered it and waited for what was next. Legends got created and passed down. Maybe Grandma said it meant bad weather was on the way in so many days.
That could be the case, but an ethereal halo simply means that moisture is returning several miles above ground level.
Tiny ice crystals inside thin, wispy cirrus clouds refract the moonlight to create the optical effect (no, the halo isn't around the moon – and you can occasionally catch the same effect around the sun during daytime). And though these clouds, which are blown off the top of storms, can precede a change in the weather, they don't guarantee foul or stormy conditions.
Mind you, the motion of clouds can provide clues about what's happening, especially if you see separate layers.
Say there's a patchy layer of puffy cumulus clouds or horizontal stratus clouds close to the ground, beneath a higher layer of cloudiness. If the lower clouds are moving from south to north, but the higher layer is moving from southwest to northeast, this is a more reliable signal that unstable weather is on the way. That usually means more warmth and humidity are moving in ahead of a storm system.
Buzzwords: science or hype?
Sure, weather makes for good ratings, but the explosion of social media is making it easier for people to learn about the science behind weather. Meteorology jargon has found a home at the watercooler.
Terms such as polar vortex, derecho and bombogenesis describe real things that have always been happening in our skies. In the pre-internet days, we'd have said "extreme cold snap," "sudden windstorm" and "nor'easter that came out of nowhere," respectively.
The three seemingly new terms have actually existed in weather textbooks for decades, but only in the past five years have they made it into widespread use – and occasional misuse.
For example, the polar vortex is a large circulation that always exists in the stratosphere, and its occasional fluctuations will send bitter Arctic air into the U.S. The polar vortex doesn't really "hit the U.S.," and it certainly doesn't "touch down."
Sometimes the descriptive language doesn't have a scientific basis. Many meteorologists backed away from the label "superstorm" for Hurricane Sandy. Unlike a hurricane or blizzard, there's no standard definition for superstorm. Yes, Sandy was a bad storm, but superstorm doesn't really convey a precise impact.
It makes you wonder about the next weather term that will capture the popular imagination. I don't think "positive vorticity advection" will catch on, but you never know.
Blowing hot and cold?
I've also heard that heat index and wind chill are inventions so the real temperatures sound worse. It's true ... but there's a good, scientific reason: Both are guidelines for how quickly the weather can harm your body.
Heat index is actually how hot it feels in the shade, because temperatures are measured in the shade. If you're in the direct sunshine on a steamy summer day, the risk of heat illness is even higher.
Wind chill is one simple number that comes from a very complicated formula. It's actually based on how quickly an average adult's face loses heat as he walks into the wind in a clear, dry and dark environment. That doesn't fit every situation, but it's a starting point.
Just like how a roomful of coworkers can have different opinions on the office thermostat, the true degree of heat danger or cold danger depends on the individual. Age, body type, clothing and level of exertion could make a person more or less vulnerable to heat illness or frostbite than another person.
No matter the exact number, when the heat index rockets into the triple digits or the wind chill blasts down below zero, everybody is better off taking it easy.