We open the week with the risk of a few strong to severe thunderstorms, and get much warmer thereafter as we say goodbye to June and welcome in July, with the first heat advisories of the season possible by the weekend.

Monday’s severe risk

Monday could start with a few showers in the area, but the overall thinking is that much of us get the bulk of the day in rain-free before showers and thunderstorms erupt in the afternoon and evening. It’s going to be a muggy day — we’ll top out in the low 90s with heat indices around 100° before storms fire.

Monday’s thunderstorm risk is somewhat complex, but the basic synoptics are that a cold front will be approaching the area from the west, with a trough of low pressure ahead of it at the surface as well as aloft. Impulses rounding the trough will interact with a rather unstable atmosphere to initiate convection, and sufficient shear should help organize storms somewhat. While the greater risk for wind damage will be well to the north in NC and VA, there will still be the potential for isolated to scattered severe thunderstorms capable of producing large hail and damaging wind across our area. Generally speaking, the further north you go, the greater your severe risk. The best severe probabilities appear to be along and north of a Givhans-Summerville-Huger-Awendaw line, but it’s important to reiterate a strong to severe storm could happen anywhere across the Tri-County.

As mentioned, there is the potential for some remnant activity from an upstream thunderstorm complex (currently moving through Kentucky as of this writing) to arrive in the area during the morning hours. It should be on a downward trend as it approaches the area, but some showers and maybe even a thunderstorm will be possible. We’ll be very interested to see how, if at all, this disturbance modifies the atmosphere; small local changes, such as tiny outflow boundaries, could be clues to how Monday’s thunderstorm risk evolves. If rain hangs around longer than first thought, it’s entirely possible we could miss out on much of the severe risk. Bottom line: Stay tuned to forecast updates throughout the day for possible watches and warnings.

Turning warmer with 105°+ heat indices this weekend

The front gets through the area Tuesday into Wednesday, and with it comes a slight reduction in dewpoint, but not much else. Expect highs in the low 90s each day with heat indices running in the upper 90s. We’ll likely not see too much relief from rain with high pressure at the surface and aloft keeping the kibosh on updrafts.

Moisture return improves beginning Friday, and with it likely comes the first Heat Advisory-level warmth of the season. Heat advisory criteria through June 30 is a 105° heat index for more than two hours, and we should meet or even exceed that in spots during peak heating Friday. While July 1 marks a change to 110° as the threshold heat index, NWS notes in its Sunday evening forecast discussion that it is possible they may keep Heat Advisories going as heat indices will still run well between 105-110° over the weekend for the first real strong heat blast of the summer. It’s been a mild June overall — the average temperature for the month so far has been 76.8°, putting it in the top 20 coolest Junes on record — so the advisories will certainly signal the return of real Charleston heat and humidity. Isolated to scattered showers and thunderstorms will be possible each afternoon, and given northwest flow aloft, we’ll want to keep an eye out for the potential for some “ridge-runner” thunderstorm complexes to make their way into the area.

Tropical update: Cindy has dissipated, no other areas of note

The National Hurricane Center has terminated advisories on Tropical Storm Cindy as of 11PM Sunday as it’s opened up into a tropical wave with no discernible center of circulation. Some guidance had been showing Cindy trying to redevelop once it got beyond Bermuda, but NHC notes that’s a very unlikely scenario at this point, and even still, it would have no bearing on our weather here. Otherwise, there are no areas of interest in the tropics as of this writing.

June got off to a bit of a busy start as we’ve gone through three named storms before the 25th. Bret and Cindy having both started in the main development region of the central and eastern Atlantic is certainly unusual for this point in the year, but the very warm Atlantic waters made it possible.

Whenever a new storm forms — and it will — it’ll get the name Don.

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