Fall Is Finally Here!

Chief Meteorologist Craig Carnesi here...

Well, Mother Nature has finally decided to give us a break. The first big cold front of the Fall season has arrived.

R&B joked in a comment that he only went from 99 to 81 in a couple of hours in Sweetwater and it didn't seem very cold. I know you were just kidding R&B, but I want folks to think about that for a minute. I'll use the numbers from Abilene Regional Airport as an example.

At 7:00 p.m. it was 99 degrees at ABI. (ABI is the 3-letter airport identifier code for Abilene Regional Airport) Now, at 9:00 p.m., it is 79 degrees. That's 20 degrees in only two hours. That is a massive amount of cooler air to do that much work, in that short of time. I won't get into physics here, but wow, that's a lot of energy to cool off the air that quickly. Think about coming home from work or school and you've had the air conditioner off all day and your house has warmed up to 85 degrees. You turn the AC on and set it to 75. Depending on the size of your house and the strength of your AC, it generally will take about 30 minutes to cool the house down to 75. Tonight, Mother Nature has turned her AC on and cooled the entire Big Country 20 degrees in just two hours. Even though I've studied it and forecasted it, it's still amazing to see that kind of energy at work.

Incidently, there were calls made to the KRBC newsroom and the Abilene Fire Department tonight about the smell of smoke in the air as the cold front arrived. The front actually blew in smoke and haze from North of Abilene. There were small fires in Hamby and that smoke was carried into the city with the front.

Unfortunately, this cold front will only cool us down for a couple of days. I don't expect to see any 100 degree afternoons anytime soon, but I don't think we've seen our last 90 degree day of 2005 just yet. By Friday afternoon winds will swing back around to the South. That will allow our highs to creep back into the lowers 80s. The weekend looks dry with highs in the mid to upper 80s.

We had mentioned a chance for rain this weekend, unfortunately it looks like we will remain too dry in the lower levers of the atmosphere and more importantly the upper-level disturbance that was going to produce the lift for the showers looks like it will move farther North than earlier expected. There will still be a slim chance for a shower North of IH-20, but not enough of a chance to throw a percentage up on the forecast pages.

Now to a question posted a little while ago...

Eileen said...
Now, how is it calculated into the total precipitation for a year. What I mean is, if we had let's say 26.95 inches of rainfall and 10 inches of snow, how would they come up with the total amount of precipatation for the year.

Depending on the snow type (wet snow, dry snow etc...) the average equation that is used is a 10 to 1 formula. So, your 10 inches of snow would equal 1 inch of water when melted. As before, this is a topic that I could go into detail with, but I'll refer those interested to the website of one of my professors at Mississippi State University, Meteorologist Jeff Haby. At the following link Jeff explains the different "average" equations for the different types of snow. Also, at the bottom of his page, he has a link to a National Weather Service website that will take you into even further detail on the subject. http://www.theweatherprediction.com/habyhints/346/

That's it for now. I'm off to enjoy the cooler air and the wonderful sound of silence as I shut my air conditioner off for the night!

Craig...