Official Fall, Bringing Chill: Weekend Weather for Yorktown

, NY — Summer gives way to autumn at 10:21 a.m. Sept. 22, but will hang on in the Hudson Valley until Friday night.

"The fall season officially begins on Thursday, but we’ll have to wait about 48 hours for mother nature to catch up," said Bill Potter of Hudson Valley Weather. "Some beautiful late summer weather is lined up for the Hudson Valley on Thursday and Friday, with rather comfortable humidity levels… and afternoon highs in the mid 80s on average."

Then things will begin to change. A cold front — accompanied by some isolated showers and thunderstorms — will sweep across the Hudson Valley Friday night and bring much cooler temperatures, with highs only in the 60s in the day time, and in the lower 40s both Saturday and Sunday nights.

Here's the National Weather Service forecast for northern Westchester County:

Today
Sunny. Highs in the lower 80s. Northeast winds around 5 mph...becoming southeast this afternoon.

Tonight
Partly cloudy. Lows in the mid 50s. Southeast winds around 5 mph in the evening...becoming light and variable.

Friday
Partly sunny. Isolated showers and thunderstorms in the afternoon. Highs in the lower 80s. West winds around 5 mph. Chance of rain 20 percent.

Friday Night
Mostly cloudy with scattered showers with isolated thunderstorms. Lows in the mid 50s. North winds 5 to 10 mph. Gusts up to 20 mph after midnight. Chance of rain 30 percent.

Saturday
Mostly sunny. Highs around 70. North winds 5 to 10 mph.

Saturday Night
Mostly clear. Lows in the mid 40s.

Sunday
Sunny. Highs in the upper 60s.

Sunday Night
Mostly clear. Lows in the mid 40s.

MAP: AccuWeather.com