It's June in the Tennessee Valley. We are past Memorial Day, and we are into the unofficial start of summer. Not just that, but today is the first day of meteorological summer, based on weather/climatology records. So, what exactly can we expect this time of year across our local area when it comes to the weather?
Already at the start of the month, our average daytime highs are in the mid 80s. As early as June 1st, our average high is 85 degrees, and by the time we end the month, we average a daytime high of 90 degrees. Taking the month as a whole, our average high temperature is 88 degrees and average low is 66 degrees. We are certainly no stranger to hot weather this early in the season though, with the monthly record high for June at the Muscle Shoals climate reporting station being 108 degrees, set back in 1914. And while it was unusually cool globally the year of this following record low, we can't rule out bouts of cooler air this time of year either (although it's usually coming to an end now or before now). The record monthly low for June was 42 degrees, set back in 1894!
June also starts one of the more frustrating parts of forecasting the local weather here in the Tennessee Valley... dealing with the almost daily chance of pop-up hit-and-miss afternoon showers and thunderstorms. There is no rhyme or reason to the exact placement of these storms. Sure, such as days like tomorrow and Thursday, there can be a larger weather system that moves through the area with a more organized rain chance that is easier to predict, but most of our rain during the summer months comes from these backyard scattered pop-up storms. Unfortunately, it is currently beyond the capabilities of the science for me to be able to tell you the morning of or the night before, exact which communities will or will not see a storm in the afternoon. It just does not work that way. Period. And it's even more unfortunate because this is the time of year when folks get outdoors the most. This time of year, you just have to keep an eye on the radar and be aware of your surroundings. The FREE Tennessee Valley Weather App is a great way to do that! Not only does it have real-time interactive radar built in, but you get push notifications for lightning alerts, storm approaching alerts, and watches and warnings. Just search for "Tennessee Valley Weather" if your appropriate app store.
As we work into June and summer as a whole, we are leaving the core of the tornado season in the Tennessee Valley behind us. No, that does NOT mean that tornadoes stop happening. What it DOES mean is that they are a lot less frequent and it's a lot harder for them to happen. They're also a lot less likely to be of the stronger variety, but we never say never to that either. The atmosphere can and often does things we think it shouldn't! Tornadoes during this time of year are most likely in the outer rain-bands of landfalling tropical systems. These are often shorter-lived and smaller (most of the time, but not always), but are still capable of damage. Very occasionally, a mesoscale low pressure area formed by a complex of storms the day before can move into our area and produce added spin in the atmosphere that would give more classic wind profiles for a "traditional" type of tornado threat. However, this doesn't happen all that often.
This time of year, our severe weather threat shifts away from supercells and long-track tornadoes toward sudden downburst damaging winds from the pop-up afternoon storms AND complexes of thunderstorms that produce widespread straight-line winds. We frequently see these during the warmer months. They often move in from the northwest, meaning that we often watch upstream across areas like Missouri, Kentucky, Illinois, and Arkansas for storms that may move into our area. These can often happen at any time of the day or night, not relying on daytime heating from the sun.
June also begins the official start of the Atlantic Hurricane Season. The Atlantic hurricane season runs from June 1st through the end of November, although there can be named storms before it starts and after it ends. Storms in June are most likely to form in the Gulf of Mexico, western Caribbean, or off the Southeast Coast in the western North Atlantic. June storms usually aren't on the higher end of the scale, but we can definitely have fully formed hurricanes this year. So far in 2021, we have already crossed Ana off our list of names. Having a named system before the start of the season does not give an idea of how active the season as a whole might or might not be. Having said that, there are larger scale weather patterns in place now that suggests the 2021 Atlantic season at least has the potential to be somewhat above normal in terms of activity.