Saturday, July 23, 2011

7/23 - 1:15pm - Heat Continues, No End in Sight

The entrenched heat we've had over the eastern half of the nation has been making headlines for quite some time now and it appears that it will continue for a while more. The strong ridge of hot, stagnant air is staying firmly in place and most forecast models are keeping it over the same area for at least the next week or two. A big portion of the Plains, Midwest, and East Coast is covered in heat advisories and warnings, which you'll see shaded in orange and purple on left.

Around Louisville, temperatures are going to stay in the 90's for the foreseeable future. For some perspective, we're hotter right now than Jackson, MS, Birmingham, AL, Memphis, TN, Jackson, TN, and Nashville, TN. Cloud cover, surface winds bringing in cooler air, and easterly flow aloft is keeping these locations cooler than Louisville even though they're all to the south. This really highlights the Midwest and Plains as being the primary target for the heatwave since we have been and will continue to be feeding off of the entrenched hot air from those regions.

A few pop-up showers and storms are possible today in Louisville, but a bigger chance for storms comes tomorrow as a "cool" front approaches the area that will cross through on Monday. I think tomorrow afternoon and evening will be the best time period for storms, most likely lasting into the early part of Monday. Behind this "cool" front temperatures won't really drop much, but dew points will take a tumble.

Check out the dew point output from the GFS for early Wednesday on the left. Those dew points are a good 15 degrees lower than the average this week and that translates to markedly lower humidity. That won't last long though... higher dew points with the same old hot temperatures will be back before the weekend. Until then, remember that an Excessive Heat Warning continues for the Louisville area until Sunday night. Stay safe!

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