All is quiet across the Tennessee Valley on this early Tuesday morning. The frontal boundary that brought the storms to the area on Sunday has shifted south, and that’s allowed slightly drier air to temporarily filter into the region. Skies are clear this morning, and we expand that to continue through our Tuesday. Daytime highs will climb into the lower 90s by afternoon, although a few folks in northwest Alabama might briefly get close to the mid 90s. Fortunately, the lower humidity means that heat index values will be pretty close to the air temperatures… for now. That changes in a big way later in the week! Skies stay mostly clear to partly cloudy tonight with overnight lows falling back into the mid 60s.
That frontal boundary starts to lift back north as a warm front on Wednesday, and as early as Wednesday morning, that may provide a road map for a thunderstorm complex to dive out of the Plains from overnight Tuesday night into some portion of the Southeast on Wednesday morning. Almost all of the model data either keeps this complex off to our west and southwest and/or fizzles it completely before ever trying to reach our area. However, our in-house Baron Futurecast model is insistent upon this thunderstorm complex affecting parts of our area. We can’t completely rule that out, but it is the only model doing so, and it performed pretty poorly with the storms on Sunday. Still, we will hold low confidence rain and storm chances on the board for Wednesday just in case. As we head through Thursday and Friday, we just have typical summertime afternoon to early evening isolated storm chances on the board. Rain chances do look to increase a bit as we head into the weekend, especially by Sunday.
The big story going forward later this week will be the building heat and what will become dangerous heat index values for Thursday, Friday, and Saturday. Already, the local area National Weather Service offices have placed the entire region in an EXCESSIVE HEAT WATCH from late Thursday morning into Thursday evening. This is for expected heat index values to top out in the 110 to 113 degree range with afternoon highs in the upper 90s to lower 100s. Triple digit air temp highs and heat index values near or over 110 are also likely on Friday, and it will be near that for Saturday. All of this will be brought about by the upper-level high pressure ridge to our west building into much of the Southeast later in the week. This will also shift the main storm track north of our area until the ridge breaks down Saturday night into Sunday. That ridge relaxing its strength will also allow daytime highs to come back to the lower 90s, and maybe even the upper 80s, as we head into Sunday and early next week.
A quick look at conditions in the tropical Atlantic basin shows not a whole lot going on, despite there being a couple of areas of disturbed weather. Of particular interest though is the disturbance over the western Atlantic that was once Tropical Storm Cindy. It is still encountering strong vertical wind shear from the upper-level system that gave our stormy weather on Sunday. There is a CHANCE that the shear may relax enough in a few days for the disturbance to have at least a low chance of trying to regenerate back into a tropical depression or subtropical depression as it approaches Bermuda and then continues north into the open North Atlantic. Regardless of whether or not this is able to happen, this system will be no direct threat to the United States going forward.