Sunday, December 03, 2006
Setting the record straight on sleet
Andrew Freedman @ 10:50 AM
To: American PublicFrom: Meteorological Community
Re: Sleet
Dear all,
We hope this holiday season finds you in good health. It is with a heavy heart that we bring up the following matter, but it is our duty as members of the community at large to raise concerns we have in order to continue to coexist peacefully. We hope this memo is of some assistance in your development.
It has come to our attention that many of you continue to confuse sleet and hail, oftentimes thinking that all frozen precipitation other than snow is considered hail. That view flies in the face of decades of meteorological learning and is an affront to meteorologists everywhere.
Jason Samenow's Forecast
Today: Partly to mostly cloudy. High 50.Tonight: Mostly cloudy. Lows 33-37.
Tomorrow: Morning clouds, partly sunny in the afternoon. Brisk, with highs in the low 40s.
Check back tomorrow for Jason's week-ahead forecast.
How many times do we have to explain to you that there is a difference between sleet and hail? Frankly, it's getting tiresome and is quite unattractive. It makes us feel like you don't care about our feelings. We work hard to understand and predict the weather to enhance your quality of life and keep you safe. We're human, and we make mistakes sometimes, but at least we learn from them. It's things like this that make us think you don't even deserve to know what the weather is going to be.
Think for a second about what would happen if we suddenly stopped working. You won't know what to wear! Worse yet, you won't know whether to seek shelter from a hurricane or tornado, or when it's okay to fire up the backyard BBQ without the fear of an approaching thunderstorm. You'll be a mess! Like Judith Regan's publishing career in the wake of the recent O.J. Simpson book deal fiasco.
All we're asking for is some basic understanding. Realize that if you say that "The snow just turned to hail," as a friend said to me during the Chicago snowstorm on Friday, it's the equivalent of us calling you a racial slur, as well as fat. And a drunk. It's offensive to us that you won't bother to learn a basic meteorological distinction and yet you'll memorize and then use nauseating nicknames from Grey's Anatomy as if you had thought of them. So lets tackle the basics:
Sleet is a type of ice pellet that is 5mm or less in diameter. It is formed when raindrops or melted snowflakes fall through a layer of cold air near ground-level, causing them to refreeze. If the layer of cold air were deeper you'd have snow rather than sleet.
Sleet is a funny name for a precipitation type that evokes the tap-tap-tapping sounds of the ice pellets on a window. It probably would be named "sonofabitch" if it were to be named after the reaction from someone stung by one of the ice pellets on a windy winter day. When you think of sleet, think of the word "shallow," as this represents the depth of cold air aloft. You could also think of the word "sleeve" or the name "Steve" but neither of those would make any sense.
Sleet is a nuisance, an interloper of a precipitation type that doesn't accumulate in a beautiful form like snow or freezing rain. It's a sign of an atmosphere in transition rather than one that is truly comfortable with its own temperature profile. In Washington, sleet is a snow lover's sworn enemy, often slashing snow totals with each passing hour. During the blizzard of 2003, for example, a few hours of sleet in D.C. left the city with about ten inches less than areas thirty miles to the North, such as Baltimore.
Hail is formed within towering cumulonimbus clouds, more commonly known as thunderstorms. It never occurs in the absence of convection. Or almost never. As meteorologists it's difficult to say "never" because sometimes things happen that you didn't foresee and then people get angry at you, but it's a safe bet that if it's not thundering, it's not hailing.
Hail can destroy crops and batter airliners. The largest hailstone ever recorded
dented a field in Aurora, Colo. in 2003 and measured seven inches in diameter with a circumference of 18.75 inches. Sleet, if you've been paying attention, is 5 millimeters or less in diameter. So hail is a bit larger than sleet, don't you think?
Sleet and hail feel very different as well. You don't ever want to be outside when it's hailing unless you have a death wish. Sleet, on the other hand, is merely annoying.
If you continue to disregard the key precipitation differences you may soon find yourself left with a nationwide network of unmanned Doppler radars and a whole bunch of moving bright colors on TV that mean nothing to you.
Regards,
Your friendly neighborhood weather person
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