The warmth felt across much of the Northeast the past few days will be quickly erased for the start of the new week as thunderstorms and a cold front sweep through.
T-shirts and shorts will again be replaced by jackets, sweatshirts, and pants as daytime temperatures dip into the 50s and low 60s.
Sunday will likely mark the last day of the warm stretch for many cities such as Pittsburgh, Pennsylvania; Erie, Pennsylvania; Buffalo, New York; Albany, New York; Charleston, West Virginia; Philadelphia, Pennsylvania; Washington, D.C.; and Baltimore, Maryland.
The cool shot of air will drop high temperatures 10 to 20 degrees between Sunday and Monday.
Pittsburgh will have temperatures rise to the mid-70s on Sunday, but those temperatures will drop to the upper 50s for Monday. Other cities across the Northeast will experience similar drops.
The clashing between the warm air mass currently in place and the cool air mass moving in will set the stage for thunderstorms, some of which could produce locally gusty winds and brief downpours.
Outdoor plans scheduled for Sunday will be at risk for delays or even cancellations as thunderstorms rumble through the region.
According to AccuWeather.com Meteorologist Brian Lada, "lightning will be the greatest danger for those unprotected in the outdoors."
With a number of professional football games on tap across the Northeast on Sunday, folks planning on attending may want to pack a poncho.
Showers and thunderstorms will impact games in Buffalo, Philadelphia, and the New York night game at MetLife Stadium.
Motorists may encounter downpours in their travels. Slow traffic and delays should be anticipated if thunderstorms are in the area.
The cool air will arrive just in time to usher in fall, which begins on Monday night at 10:29 p.m. EDT.
Temperatures closer to the coast will cool, but at a more gradual rate. New York City will drop from the upper 70s to low to mid-70s through the early week.
With the cold front and thunderstorms departing by Monday, high pressure will move back in for the rest of the week which will yield several days of dry and sunshine-filled weather.
Temperatures will work their way back to normal towards the end of the week.