Just a friendly warning: It doesn’t appear we will ease into fall. It’s not going to arrive gently in the night, a little cooler each day, the proverbial frog boiling in the pot — but in reverse.

Nope, it’s going to come barreling in like a mean cold front, and the time is nigh. Those who brag that they have yet to turn on their furnace or light the wood stove may capitulate by next weekend. Those who still have vegetables in the garden may want to harvest them. Those who still have air conditioners in the windows certainly won’t need them.

But first, we get to enjoy a terrific, summer-like weekend. The high temperature will flirt with 80 degrees Saturday, with moderate humidity, and there’s even a 40 percent chance of an afternoon shower or thunderstorm to round out that summer feel. A cold front (not this coming week’s mean one) will snuff out the humidity Saturday night, drop temperatures into the high 40s and set up an absolute perfect dawn for the DeMar Marathon and Half Marathon Sunday morning.

Sunrise Sunday is 6:44 a.m., 16 minutes before the marathon begins in Gilsum, and temperatures should be ideal for running. There’s a slight chance of a shower, but the latest trends show most of the precipitation turning off by midnight. The day will warm into the high 60s with a little bit of a breeze.

Warm weather will continue into this coming week, with temperatures increasing every day and peaking in the high 70s by Wednesday. And then the hammer falls. A strong cold front is expected to push across late Wednesday, and by Thursday, the high will barely make it to 60.

The downward trend continues into next weekend, with temperatures struggling into the mid-50s. High temperatures the first week of October usually average in the mid-60s, but we’ll probably be a good 10 degrees below that. At night, lows may fall below freezing, so the first frost of the season is possible.

It could be much worse, of course. Folks in the Northwest are under a winter storm warning, with an early-season snowstorm barreling down from Canada. Heavy precipitation, bitterly cold temperatures and tropical-storm-strength winds are expected this weekend in parts of Washington, Montana, Wyoming and Idaho. On Friday afternoon, officials at the National Weather Service warned that the storm and cold temperatures to follow could be “historic.”

That’s the cold air that will trek east during the week, although the temperatures will moderate by the time it reaches New England.

At the other extreme, with hurricane season just beyond its peak, the tropics have been bustling with tropical systems over the past two weeks. The good news is most of the bustling has been taking place way out over the ocean, and storms that are heading toward the U.S. are continually being turned around by prevailing west-to-east winds long before reaching land.

As of Friday afternoon, Lorenzo was a major Category 3 hurricane, but it’s in the middle of the Atlantic and won’t come anywhere near land, the National Hurricane Center says. And former Tropical Storm Karen was dying out with 35 mph winds.