BETHLEHEM, Pa. — Has September felt a little on the cool side?
Entering Friday, the average monthly temperature in Allentown was 65.3 degrees, or 1.7 degrees below average, with a cold front pushing southward into the area.
“It certainly will be feeling like fall, with cloudy and cool conditions expected for the first half of next week,” the National Weather Service said in its latest forecast discussion.
"Outdoor projects and activities which you would typically see winding down during the fall season will continue well into the season for many areas."AccuWeather lead long-range expert Paul Pastelok
Temperatures are expected to be a few degrees below normal for late September/early October, with highs in the upper 60s and low 70s.
With that in mind, you may wonder exactly what the Lehigh Valley can expect as we move into meteorological fall.
The National Oceanic and Atmospheric Association recently published its seasonal outlook, which features warmer-than-average temperatures expected for much of the country.
Seasonal temperature outlook
The latest map releases from NOAA’s Climate Prediction Center shows parts of 46 states expecting warmer temperatures.
Areas including New England, Florida and much of the Southwest have the best chance for a warmer fall, forecasters said.
The Lehigh Valley falls within an area where we’ll have a 40-50% chance of above-average temperatures this fall, and NOAA’s experts aren’t the only ones on board with that outlook.
AccuWeather forecasters also are calling for fall to feel more like an extended summer for millions of Americans this year, according to lead long-range forecaster Paul Pastelok.
"Outdoor projects and activities which you would typically see winding down during the fall season will continue well into the season for many areas," Pastelok said.
What about precipitation?
All of Lehigh County now is considered “abnormally dry” by the U.S. Drought Monitor.
“Due to short-term rainfall deficits, abnormal dryness (D0) and moderate (D1) drought conditions were broadly introduced or expanded in parts of the Northeast and along much of the northern Atlantic Coast,” an update said Thursday.
With just one inch of rain so far in September (as of Sept. 27), the Allentown area had a rainfall deficit of 3.12 inches for the month.
According to NOAA’s outlook, while a damp fall is potentially on tap for parts of the Northeast, the Lehigh Valley falls within an area where equal chances of above-or-below-average precipitation is possible.
That’s not good news after a bone-dry September, and could exacerbate drought conditions across the region.
What about La Niña?
La Niña is expected to form later this fall, and is a climate pattern marked by a natural cooling of the tropical Pacific Ocean.
Just like [the opposite pattern] El Niño, La Niña is considered one of the main drivers of weather in the United States, especially during the fall, winter and early spring.
Typically when La Niña emerges, winter temperatures are warmer than normal to our south and colder to our north, with the Lehigh Valley in more of a neutral area.
According to the Climate Prediction Center, there is a 71% chance La Niña will emerge during the fall, persisting through January-March 2025.
However, a strong event is unlikely, and more neutral conditions are favored by the spring.
