Dew Make Your Point

July 25, 2016 by  
Filed under Blogs, Hot Button / Lynn Ashby

 

By Lynn Ashby                                                             25 July 2016

 

THE TV – “It will hit a hundred and ten degrees, maybe a hundred and twenty, while in Dallas, well, two hundred even.” What? You mean this global warming farce is not a farce? But Marco Rubio and Rush Limbaugh assured me global warming is a hoax perpetrated by those clueless Nobel laureates. Wait. I peer at the TV screen. There, in little-bitty type, are the words “feels like.” Yes, it’s the old feels like ploy, which goes up there alongside the Easter Bunny, liberal Republicans and efficient Democrats. Feels like has been around for years, but now more and more of our TV weather wizards are using these scare tactics to get our attention. Then there are the meaningless dew point and wind chill factor, which we shall get to in a minute.

Pilgrim, this is summer in Texas. It is hot. If it were not hot – say in the low 90s — we would be comfortable but rather concerned about global freezing. So, in our simmering afternoons the temperatures rise to 90, then 95, then 100 or more. Big deal. Our local TV newscasters warn us about leaving children, pets and Godiva candy in cars with the windows rolled up. Reporters dutifully fry eggs on car hoods. They interview some guy in heavy clothes who works in a warehouse freezer and show shots of polar bears at the zoo frolicking in a pool. That’s standard. But when it comes to the true temperature, good luck. The meteorologist – well, actually they are rarely real meteorologists, but are sports jocks who need the job – stands in front of a big weather map and points breathlessly to the names of towns with horrifying figures beside them. “It will hit 120 in Waco and 130 in San Angelo, maybe twice that in Laredo.” Look for the small “feels like” in the corner.

How do they come up with these faux figures? The difference in the actual temperature and the feels like figure (also called the heat index) is determined by a complicated formula that includes the temperature, obviously, plus the humidity, cloud cover, wind speed, sun intensity and angle of the sun. A major component is the humidity. In Houston, where you can tie a knot in a Frito, we would normally be dry except there are nine large humidifiers placed around town to keep the air moist because dermatologists say moisture is good for the skin.

A day that is very humid may feel hotter than it really is outside because your body sweat does not evaporate and cool the body like nature intended. This last element is what we climatic scientists call the “deodorant factor.” But it is all a fake. The real formula for determining the feels like number is simple: the TV weather person takes the actual temperature and adds 20 degrees, and no one questions the higher figure. But when it’s 100 degrees it’s 100 degrees. On the other hand, my mother was born and grew up in Dallas, and when she would come visit us in Houston she would subtly mention the Houston humidity, remarking that Dallas wasn’t like that. “Mom,” I would say, “I grew up in Dallas, too, and those summers were blisteringly hot.” She would reply: “But it’s a dry heat.” I’d try again: “When it was 105 degrees it was 105 degrees, and that’s hot!” Never argue with your mother.

Let’s put our problems in perspective. On Aug. 5, 2015, the southeastern Iraqi city of Samawah reported a temperature of 119.5 degrees Fahrenheit and a dew point of 85.1 with a feels-like temperature of 159 degrees. In the southern Iraqi city of Basrah earlier that month the city’s high exceeded 120 degrees for eight straight days before falling to a cool 119.3. To the north, that same week Baghdad logged four consecutive days in the 120s. A question: Who wants Iraq anyway?

We just mentioned the dew point, another totally meaningless term unless you like to point to dews and need a stick. In simple terms, the dew point is the temperature at which water vapor in the air will form dew. More specifically, dew point measures moisture in the air. (Just how this differs from the humidity percentage is known only to meteorologists and my mother.) Let’s try again: It is the temperature to which air must be cooled at constant pressure and water content to reach saturation. A higher dew point indicates more moisture in the air; a dew point greater than 68 degrees is uncomfortable. Have you ever left an air conditioned building to enter the Texas summer and commented: “I’ll bet we broke a dew point record today.”? Of course not, it’s like using the metric system: “I’ll bet it’s 59 degrees Celsius today.”

One final unnecessary figure is the wind chill factor. It is the frozen equivalent of the heat index. On cold winter days, TV weathercasters play the same games as they did with the feels like fantasy. “In Amarillo it’s minus 40 while in Denver it’s minus any known reading.” Those are wind chill numbers. Hold the figures over a low flame to bring out the actual temperature. The wind chill factor measures the effect of wind speed cooling of the human body below 50 degrees. As airflow increases over the skin, more heat will be removed. This brings us to the question of what kind of dummy goes out in a blizzard with unprotected skin? OK, Green Bay Packer fans and Greenland flashers. Why are there a feels like figure, a heat index and a wind chill factor, and why do we care? It is simple self-importance and self-pity. We like to think we are suffering more than we really are. “Man, no wonder we’re miserable. It’ feels like it’s a hundred and twelve.” Or: “I heard on TV the wind chill factor is zero minus zero.” If you don’t understand these readings, go ask your mother.

 

Ashby’s cold at Ashby2@comcast.net

 

 

 

 

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