A significant cooldown will slash a brief midweek warmup in the northeastern United States late this week.
The impending cooldown is expected to be even more notable than the cool air that moved into the region earlier this week.
Prior to the additional shot of cooler air, however, temperatures and humidity will rise to summerlike levels through Wednesday.
The most significant warming will take place on Wednesday along the Interstate-95 corridor, where highs will range from the middle 80s near Boston to the middle 90s F near Washington, D.C.
Record highs may be challenged in Baltimore; Philadelphia and Harrisburg, Pennsylvania; Washington, D.C.; and Trenton, New Jersey, on Wednesday.
Beyond midweek, temperatures will begin to tumble.
"The [midweek] warmup will be reversed following the arrival of another cold front," AccuWeather Chief Meteorologist Elliot Abrams said.
Along the front, spotty but locally drenching thunderstorms may erupt from Maine to the Ohio Valley during Wednesday afternoon. Storms will exit the Northeast coast overnight.
Behind the storms, high pressure will build over the Northeast from Thursday into Friday. This will open the door for cooler and less humid conditions to prevail across the region, AccuWeather Senior Meteorologist Matt Rinde said.
On Thursday and Friday, highs in the 60s will be common in New England. Highs in the 70s and lower 80s are expected across the mid-Atlantic and along the coast.
Humidity levels will be noticeably lower from Wednesday to the end of the workweek.
"Temperatures will fall closer to average overall, perhaps a few degrees below normal," Rinde said.
He added that it will feel cooler given the recent warm spells across the region.
Jackets and sweatshirts may be needed for evening sporting events as lows are expected to dip into the 40s and 50s.
"This pattern will be a nice reminder that September weather does include occasional crisp mornings giving way to sunny and comfortable afternoons," Rinde said.
Dry weather is expected to hold from Thursday into the weekend, giving area residents an excellent opportunity to enjoy the comfortable conditions.
The up-and-down trend in temperatures will continue through the month of September and into October as summer and fall battle for the upper hand during the transition of seasons.
"This roller coaster-type weather pattern is typical for autumn months and will only increase in frequency and magnitude through November," AccuWeather Meteorologist Jordan Root said.