I’m off today, but I couldn’t help but post an entry. We’ve seen a few isolated t’storms pop up during the mid day hour around Hendersonville, and from Donelson to Hermitage to Mt. Juliet, and from Lavergne to Smyrna. Others are isolated along I-40 in Smith County and in Jackson, Macon Counties. After they go by, it’s nothing but steam.
Remember, a Heat Advisory is in effect for today. 97 degrees with dew points in the 70’s makes the heat index 105 plus. Please take care in the heat, especially high school football teams practicing this week.
This heat will be worse than two weeks ago because the humidity is higher.
Davis/Justin/Jeff — could someone explain the difference between humidity and dew point? A weather genius I am not.
Thanks!
Erin
I have traced the root of all this hot air. It seems to have coincided to when News 2 hired Steve Gill.
All that thunder I heard produced abosolutely NO RAIN! Wishful thinking on my part! Must have been the cell that you mentioned in the neighboring Jackson and Macon counties that I heard.
I’d like to offer a suggestion or two if I might. I don’t know if it should be done here or emailed to the weather email, but here goes……I’d like to see different ranges of the radar posted at the top of the main page if possible. The one that we have covers a large area and goes very fast once downloaded. There’s one local weather site (that will go unnamed) that does a good job of breaking down the radar into different ranges using the metro area, the middle TN area and the TN area. You can start and stop the radar in motion if you’d like too. I think it gives you a closer look at what the precip is doing. Is there any way that we could get that on here?
Nice observation Ben
Along the lines of what Mirgatroyd was saying, I have a radar link on my cellphone browser. If WKRN had one…animated, I would use it.
Erin: Great question! When it comes to describing the “mugginess” of the air, I love the dewpoint but I hate relative humidity. Unfortunately old habits die hard and the majority of people (even some tv folk) are used to relative humidity, so that’s what is used.
The dewpoint is the temperature at which dew will form. Let’s say your air temperature is 80 and your dewpoint is 75. If the air temperature dropped to 75 degrees, the moisture in the air would condense and dew would form. The higher the dewpoint, the more moisture is in the atmosphere. In the summer dewpoints are usually in the 60s, while in the winter they can drop down into the single digits on a cold and dry day. The nice thing about dewpoints is that they’re absolute (i.e. a dewpoint of 70 always feels muggy).
Relative humidity, by definition, is relative. A relative humidity of 100% means that the air is saturated and any moisture in the atmosphere will condense into a liquid. The problem with relative humidity is that it changes depending upon the temperature. A quick example: your afternoon temperature is 95 and the dewpoint is 70. That’s a heat index of 101! Going by the dewpoint alone, we know it’s a humid day and the air will feel thick and soupy. But the relative humidity only calculates out to 44%! I think that relative humidity is misleading and doesn’t accurately reflect how people experience the conditions outside. That’s why I prefer the dewpoint when describing how humid it is.
Mirgatroyd: we’re working on posting a Storm Tracker image on the blog; it involves a subtle change in our contract with our radar vendor so the process is slow as molasses. This is just me thinking…but given the “moving” radar on the top of http://www.wkrn.com I’d hope we could one day duplicate the feat here with Storm Tracker.