Humidity and Your Racing Forecast

By: Cassie Behofist - Email

Updated: Sun 6:07 PM, Aug 09, 2009

Here in the Northern Shenandoah Valley, it's been quite humid lately! On the air every morning, I give the humidity as a percentage. That is actually the relative humidity. The National Weather Service defines relative humidity as "a dimensionless ratio, expressed in percent, of the amount of atmospheric moisture present relative to the amount that would be present if the air were saturated. Since the latter amount is dependent on temperature, relative humidity is a function of both moisture content and temperature. As such, relative humidity by itself does not directly indicate the actual amount of atmospheric moisture present." Fortunately for me, the computer automatically gives me the percentage. But if you are given a temperature and dew point in Celsius, you can use this equation to approximate the relative humidity. RH = 100(112-0.1T+Td/112+0.9T)^8 Remember, humidity is directly related to dew point, and you can read about that in a previous Weather Classroom blog. So why does humidity cause bad hair days? Well, hair tends to absorb the moisture in the air, which causes it to expand and twist, and therefore your hair will lose its shape and become frizzy. I'm not sure if there's a way to totally "humidity proof" your hairstyle, but many styling products claim to be able to stand up against frizz and other effects of humidity.

On a completely different note, my aunt Heidi went to see Kasey Kahne and Kyle Busch race in my hometown of Mechanicsburg, PA, at Williams Grove Speedway on Wednesday! I heard it was a warm evening. Here are some pictures.

Now here are this weekend's race forecasts:

IndyCar Series - Lexington, OH on Sunday (8/9) at 1 p.m. ET on VERSUS. A warm front is forecast to move through the region on Saturday. With the boundary in the area, there is a chance for some showers and thunderstorms. Look for a mix of clouds and sun for qualifying with a temperature around 84 degrees. Behind the front on Sunday, expect sunshine along with passing clouds. It will be warmer and more humid with a temperature around 88 degrees at the start of the race.

American Le Mans Series - Lexington, OH on Saturday (8/8) at 3 p.m. ET. *Televised Sunday at 2:30 p.m. ET on NBC. It will be partly cloudy on Friday afternoon for qualifying with a temperature around 78 degrees. There is a chance a shower or storm could develop in the area. On Saturday look for more of the same - partly cloudy with a chance of showers and storms. The temperature at race time will be around 85 degrees.

Grand-Am Rolex Sports Car Series - Watkins Glen, NY on Friday (8/7) at 6:30 p.m. ET. *Televised Friday at 8 p.m. ET on SPEED. Friday evening looks quiet with partly cloudy skies. The temperature will be a comfortable 75 degrees.

NASCAR Nationwide Series - Watkins Glen, NY on Saturday (8/8) at 2:30 p.m. ET on ESPN2. Things get a little tricky on Saturday at the Glen... right now it looks like most of the day will stay dry, but there is a chance of storms late as a warm front approaches the area from the south. Aside from the chance of showers and thunderstorms, look for mostly cloudy skies and a temperature near 79 at the start of the race.

NASCAR Sprint Cup - Watkins Glen, NY on Sunday (8/9) at 1 p.m. ET on ESPN. High pressure will build into New England, bringing warmer conditions through the weekend. On Friday, look for a mix of sun and clouds with a temperature around 77 degrees at qualifying. On Sunday expect a variably cloudy sky with a temperature near 83 at the start of the race. The threat of showers and thunderstorms remains in the forecast, however, as a warm front lifts north through the region. Some heavy downpours are possible within storms. **Sunday Update** So the race was rained out... rescheduled for Monday at Noon. It's going to be partly cloudy and warm with a temperature around 85 at the green flag. The threat of showers and thunderstorms remains, however, especially in the late afternoon.

PA Hillclimb Association - Flintstone, MD on Saturday (8/8) and Sunday (8/9). High pressure will build in over the weekend, however a few showers and thunderstorms could develop on Saturday afternoon. The high will be in the mid 80's. On Sunday, look for partly sunny skies with a warm high temperature near 91 degrees. I will be at this event on Saturday to see my dad race, so I'll have some pictures next week!

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