Tuesday: Damaging wind threat in the afternoon and evening
A vigorous complex of showers and thunderstorms will traverse the Southeast tomorrow, arriving here in the Lowcountry around early evening with a risk of damaging wind gusts and a tornado or two.
Tuesday’s severe weather potential has a little different feel in that there’s a good chance more instability will be available ahead of the line, as it should be coming through right in that sweet spot time of 5-10 PM or so. (Stay tuned for inevitable tweaks to exact timings as the storm system gets underway.) Wind shear is plentiful, on the order of 50-60 knots, and if thunderstorm updrafts can take advantage of instability rooted in the surface, there will be plenty of available energy for strong to severe thunderstorms. (More on this in a sec, though.) Despite expected cloud cover, the heat pump is on, and warm and moist air will flow into the area readily during the day, allowing for highs near 80°. Winds outside of thunderstorms will once again be gusty as well, with gusts 30+ MPH not out of the question particularly on elevated surfaces.
Damaging straight-line wind gusts are certainly the main concern, with probabilities high enough to drive an Enhanced (level 3 out of 5) risk in tomorrow’s severe weather outlook. However, tornadoes will be possible with any discrete storms as well as embedded within a squall line (if that ends up being the storm mode).
There are possible failure modes here, though. Forecast soundings from this evening’s models do show some capping trying to hold across the Charleston metro with an inversion a few thousand feet up and dry air entrainment trying to put a damper on an even more unstable environment. This could act as a governor on a more substantially widespread severe threat. We can’t bank on this, though, especially as wind shear remains strong enough to keep thunderstorm updrafts healthy.
Bottom line: Be ready for possible watches and warnings tomorrow. Keep weather radios in the alerting position and phones charged. Know what you’ll do if a warning is issued for your area. If you live in a mobile home, be thinking carefully about where you’ll go if severe weather threatens. Damaging winds, tornadoes, and mobile homes can be a tragic mix. A site-built structure will give you more protection in situations like these.
With any luck, we’ll see another round of storms fizzle out as it reaches Charleston. But if that doesn’t happen, you’ll be glad you were prepared.