We’ve made it at last to our first full Weekend of June, and we’re definitely kicking off this first portion of Meteorological Summer (which begins on June 1st) with a thunderous bang, so to speak. In continuing the trend of a relatively active pattern of late, more strong to severe thunderstorms look possible, if not likely, through this afternoon and into this evening. Moreover we don’t necessarily shake thunderstorm chances after today, either, with persistent shower and thunderstorm chances possibly lingering into next weekend. Let’s break the forecast down here, starting with what we can expect for our Saturday.
Of note to start is the areawide LEVEL 3 of 5 risk areawide across the Tennessee Valley (in fact, extending from Atlanta, Georgia to near Fort Smith, Arkansas). This is a change from previous outlooks which featured a LEVEL 2 of 5 risk for most of us, indicating increasing confidence of the possibility of severe weather locally through this afternoon. Fortunately for us forecasters, models are beginning to hone in on how this will evolve as we come within 6-8 hours of the event unfolding.
To boot, today will be another sticky, humid day, with widespread 80s across the TN Valley and high dewpoints – perhaps up to the mid-70s once again – by early this afternoon ahead of an evolving line of thunderstorms. This is one of the handful of favorable factors that make us think the thunderstorms could sustain and be fairly intense; with moisture like this locally, instability will be relatively high, though fortunately we don’t have substantial levels of shear (a crucial ingredient for a higher tornado threat) to work with, though some is present nearby the line.
Taking a look at a couple of our near-term models, we see that aforementioned increasing consistency as far as the timing and storm structure is concerned this afternoon. Our current thinking is that the highest chances for strong to severe thunderstorms will be from 1-4pm with a fast moving line of storms, known as an MCS, sweeping from west to east. Models, as well as current trends evolving to our west, seem to favor the idea that this will be centered up across our area, so a good majority of us will likely as a baseline see thunderstorm activity. As for the damaging wind threat, the highest potential will be within bowing features within the line where the winds push out, which many models are projecting, where we could see winds up to 60-65mph. This appears to be the main round, but later this evening we could see thunderstorms redevelop further south, and those could become fairly strong if they have energy to work with, but there is a bit more uncertainty with those (though, they have a lower ceiling than this afternoons round).
Granted not all of us will see those winds, but the level 3 of 5 risk is for the elevated potential of those damaging winds areawide (and do keep in mind, it won’t take 60-65mph winds to take a tree down with how saturated some of us are). As far as the tornado threat goes, its on the lower end of the scale, but of COURSE that is still not zero, especially if curly-cue type features evolve in the line, which would increase tornado potential somewhat in the line. As far as hail goes, this doesn’t look like an event that is particularly favorable for that, as supercell-type storms tend to favor hail more than lines do. Localized flash flooding remains possible as we have a decent precipitation surplus to work with and are expecting high rain rates from the most intense thunderstorms today.
Also as mentioned we stay quite wet for the next 7 days, though it becomes more scattered to isolated as we head deeper and deeper into the week – really, it’s today and Monday with the highest potential of widespread potentially strong thunderstorm activity across the area (yes, with a bit of a break on Sunday!).
Wrapping that all up into the 7 day forecast, you can really see the ‘status-quo’ so to speak for the next 7 days – we stay humid and hot (thanks to the higher heat index values) effectively all week, indicating just how persistent that moisture is in our area which is aiding the development of those storm chances. All of this combined will likely add up to an additional 2-3 inches of rain widespread across the area, so keep that umbrella on hand, and stay with us especially today as we keep you updated as storms evolve.
