Although early speculation suggests a winter on the mild side, informed sources believe that eventually, it will get cooler.
Whether it will get wetter is a whole other matter, and the rapid browning throughout the region is a growing - or, in some cases, a nongrowing - concern.
"Farmers are working their butts off to keep the crops watered," said Paul Hlubik, executive director of the U.S. Department of Agriculture's Farm Service Agency, which is seeking disaster aid for drought-affected farmers.
The government has declared most of New Jersey and Delaware to be in "severe" drought, and all of Eastern Pennsylvania in "moderate" drought. Pennsylvania and New Jersey have asked residents to cut back on water voluntarily.
Hlubik said crops such as corn and soybeans, along with pasturing hay, had been especially affected.
Drought conditions also are taking a toll on the homefront, evidenced by an outbreak of balding lawns.
"I've never seen anything like this year," said Anna Hillman, 80, who has lived in Narberth for 43 years. She said her husband had installed water-saving devices in their toilets, and the couple splash dishwater on their plants.
The conditions in the mid-Atlantic region aren't surprising, given the rapid cooling of surface waters across the tropical Pacific, said Matt Rogers, a meteorologist with the Commodities Weather Group in Washington.
"In La Niña patterns, you tend to have a long, slow burn-off of the summer," he said. In the last four autumns characterized by La Niña - 1995, 1998, 1999, and 2007 - September temperatures averaged above normal in Philadelphia. In 2007, the temperature hit 89 on Oct. 8.
That September - as is this one so far - was bone dry. That's no coincidence.
"Hot days and dry days go together," said Al Cope, senior science officer at the National Weather Service office in Mount Holly.
That said, one of the greatest rainstorms in Philadelphia history was in September 1999, from the remnants of Hurricane Floyd.
This season, however, tropical-storm remnants have been missing in action, as upper-air currents have steered storms away from the U.S. coasts.
That could change, and the government's Climate Prediction Center is saying odds favor some rain next week.
Scrolling even farther into the future, early forecasts suggest the region should expect no precipitation windfall from cosmic snows during the winter.
The commodities service in Washington is calling for a warmer and drier-than-normal winter, with energy demand across the country down about 10 percent from last year.
AccuWeather Inc. in State College, Pa., expects winter temperatures in Philadelphia to be slightly above normal, with snowfall about normal.
Both services forecast that winter will get off to a cold start in December, as does WSI Corp., in Massachusetts, which serves energy interests.
WSI hasn't ventured deep into the winter yet, but it predicts continued warmth in October and November. Whether that means continued dryness is unclear.
So far, the impacts of the dry spell have been mitigated by a long reign of generous precipitation. The last seven years have constituted the wettest such period in 137 years of recordkeeping in Philadelphia. Since Jan. 1, 2003, rainfall has been 8.5 percent above normal.
In its drought assessment last week, the National Weather Service noted that, in general, stream flows were near normal, and groundwater near to below normal.
That is little consolation to the plants, however. In the last 30 days, they have been rain-starved, with precipitation totals under a third of normal in every county in the region except Burlington, which was at 36 percent. Chester County was at 18 percent of normal; Cape May, 30.
Tonight, the spectacular harvest moon may cast its magnificent silvery glow on the foliage, but Friday morning, the sun will reveal that the leaves are brown.
Said Anna Hillman, as expert as any: "It doesn't look good."
Contact staff writer Anthony R. Wood at 610-313-8210 or firstname.lastname@example.org.