Fall Chill Tumbling Southward into Northeast For Weekend Stay

Tom Moore
Published: September 23,2016
Fall officially began Thursday, but it felt more like mid-summer across the Northeast. However, some huge temperature changes will take hold overnight across the region.
(MORE: Four Things to Know About the 2016 Fall Equinox)
Several cities across the region encountered a top-five warmest meteorological summer (June through August) on record. The pattern of well-above-average temperatures continued into September, but that is all about to change this weekend. The warmth will come to an abrupt halt as a cold front pushes through the Northeast.
(MORE: August 2016 Global Temperatures Set 16th Consecutive Monthly Record)

Temperature Change Timing and Impacts

Northeast Forecast Highs

Saturday
Cool air will have taken a firm hold across most of the region Saturday. Highs will be mainly in the 60s and 70s. The front will not move through cities like Baltimore and Washington D.C. until later in the day, so highs there will still be close to 80 degrees.
You might want to keep a sweater or jacket handy if you are going to venture out on Saturday evening, as temperatures should fall off quickly.
(MORE: How Temperatures, Daylight 'Fall' From Late September to Late December)
Sunday
Sunday will feature a chilly start with lows in the 40s and low 50s over most of the region. Parts of northern New York and northern New England could get down around the freezing mark, and scattered frost can be expected. Sunday highs across the region will be mainly in the 60s to the lower 70s.
Portions of northern New York and northern New England will only see highs top out in the 50s, providing fall-like conditions.
Despite the significant temperature change, high temperatures will only be a few degrees below average for the date.

Northeast Forecast Lows

Setup For a Cooldown

As we move toward the weekend, there will be a major change in the jet stream pattern.

A dip in the jet stream will allow much cooler air to move down from Canada into the Northeast.

A ridge of high pressure (bulge in the jet stream) that was responsible for the well-above-average temperatures of late will weaken and move eastward.
Meanwhile, a trough of low pressure (dip in the jet stream) will be sinking southward from Canada to replace the departing ridge.
This will allow much cooler air from Canada to move southward over the northeastern U.S. through the weekend.
Your wardrobe of shorts and t-shirts will be replaced by jackets and sweaters in many locations.
Looking ahead, it appears that the excessively warm temperatures that have been experienced across the Northeast will not return next week.
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