How’s this for perfect weather?

A breath of fall has replaced the muggies of this past week, introducing what could be one of the best summer weekends of the season — unless we get nicked by a wayward storm Saturday. As the sun goes to work after a cool morning, warm air will rise into a column of cold air high in the atmosphere, producing puffy white cumulus clouds, the cottony kind ideal for sky-gazing on a lazy afternoon.

However — and there’s always a however with the weather — there’s just enough energy to grow those cumulus clouds into pockets of cumulonimbus clouds. Those can climb past the 30,000-foot mark and beyond, turn gray and menacing, and unleash rain, lightning and thunder. That could happen later Saturday afternoon, but there’s only a 30 percent chance, according to the National Weather Service. Any storms that do develop shouldn’t be as strong as what we saw Wednesday and Thursday.

Sunday is supposed to be ideal, with a high of 77 and crisp, dry air with barely a cloud in sight. Most of this coming week should be in the high 70s, although there’s a chance of showers Tuesday. Still, it looks like another decent vacation week as summer winds down. Nights will be refreshingly cool with lows in the high 40s and low 50s, dreamy sleeping weather.

Meanwhile, a summer phenomenon sometimes called a “ring of fire” is setting up in the middle of the country this week. Think of it as a large, circular dome. Air travels clockwise around the periphery of high pressure while a dome of intense heat penetrates the core. In this case, the South will be in the center, sizzling hot, Florida to Texas, highs approaching 100 degrees in many locations. Already, excessive-heat watches and advisories have been issued by the weather service.

But folks on the periphery of that ring won’t have it great, either. Scattered thunderstorms will continually break out along the ring’s outer edge, putting a swath of the Midwest and Plains states in their path. Picture the active pattern in the shape of an arc rising diagonally from Arizona, up through Colorado and swinging east at about the Wisconsin-Missouri border, then cutting southeast through the likes of Kentucky and Tennessee and into Georgia and Florida.

Cut off from the ring, it’s all good for New England. We pay the price in other seasons when those closed, circular patterns trap cold and damp weather over us.

The other big weather news is the altered tropical storm forecast. Whereas it was initially thought this would be a below-average season, many agencies are now expecting it to be above average. NOAA (National Oceanic and Atmospheric Administration) Thursday announced it’s calling for 17 named storms compared to 12 it predicted in May. Of those 17, four could become major storms (winds above 111 mph), the agency said.

The reason is El Nino — or the lack of it. Forecasters in NOAA’s climate center released a statement that says El Nino has returned to “neutral status.” That lessens the chance of wind shear in the Atlantic, which tears off the tops of storms, preventing them from fully developing. With no wind shear and a warm ocean, conditions generally favor development.

Interestingly, conditions aren’t expected to be favorable in the next couple of weeks, but forecasters think hurricane season could last later than usual and really pick up at the end of August or in September. The season officially runs from June 1 to Nov. 1, with September the most active.