How quickly things can change.
Just a couple of days ago, it appeared that hot and dry weather was with us to stay for a while, with at least one forecast model consistently showing even hotter weather next week. The GFS forecast model was promising high temperatures topping 100 degrees even here on the northern Cumberland Plateau and less than an inch of rain through the remainder of the month.
Now that same model has done an about-face, and it looks like the breakdown of the heat ridge this weekend will usher in a return to cooler-than-average and wetter-than-average weather, similar to what we've experienced for much of the summer thus far.
We'll be very hot Wednesday-Friday, with virtually no rain chances, before thunderstorm chances begin to increase Saturday and Sunday as the ridge breaks down. After that, the GFS is now showing anywhere from 2-3 inches of rain from July 26 through August 3 as we fall back into the familiar pattern we've been in.
In fact, there are actually some signs that rain chances may return as soon as Friday, which was not previously expected. The National Weather Service at Morristown is now forecasting a 20% chance for thunderstorms in Oneida on Friday; previously the forecast was for hot and dry weather to continue on Friday.
Any showers that do develop Friday should be limited to the Cumberland Plateau and to the mountains, where the terrain will help provide a spark for possible convection. Then a closed low pressure system to the south over the weekend will help beat back the ridge to allow for better rain chances.
Ordinarily, such a rapid flip of the models would raise red flags, but this has been a very progressive summer, weather-wise, and it's also been a summer where those heat ridges have a hard time establishing their grip in the eastern U.S., so it isn't really a surprise.
Given how consistent the GFS was in showing continuing heat next week, it would be easy to dismiss the about-face if the GFS were on this train by itself...but it isn't. The European and Canadian models are very consistent with their American counterpart, showing cooler-than-average temperatures for much of the eastern U.S. next week.
With the new model data in mind, the NWS's Climate Prediction Center is forecasting below-average temperatures for Tennessee for the Days 6-10 period, which is July 24-28. The same time period should feature above-average precipitation for just about everyone south of the Mason-Dixon Line.
The bottom line? If you're enjoying this hot, sunny weather we're experiencing, soak up every minute of it...because changes are on the way. If we don't see the fruits of those changes by Saturday, we'll certainly begin to experience them by Sunday and Monday.
Eye to the Sky is a weather blog by Independent Herald editor Ben Garrett. Garrett is a weather enthusiast who has long blogged about interesting weather on his personal website. He is not a professional forecaster or a meteorologist and information on this blog should not be considered a substitute for forecasts, advisories or other products from the National Weather Service.