202

Let it rain: Dry conditions could hamper local fall colors

The first hints of fall color are beginning to pop up along the Shenandoah mountains, but dry weather threatens to mute seasonal displays in the more urban parts of the D.C. area.

WASHINGTON — The first hints of fall color are beginning to pop up along the Shenandoah mountains, but dry weather threatens to mute seasonal displays in the more urban parts of the D.C. area.

“It certainly has been dry over the last 30 to 45 days or so, since the end of July,” said Michael Muccilli, a meteorologist with the National Weather Service. “As far as some of our forecast guidance going forward, it does look to continue to be a drier-than-normal period [into fall].”

Muccilli says August precipitation in the D.C. area was about 2.5 inches below normal.

In dry conditions, plants limit the water sent to leaves, photosynthesis slows and leaves begin to use reserves of carbon and sugars.

“Potentially, you have less sugar to make pigments and thus you have a less vibrant fall color,” said U.S. National Arboretum Director Richard Olsen.

But Olsen said many variables can affect a plant or tree’s color display.

“Warm days and cool nights is when you get the greatest concentrations of these sugars,” Olsen said. And that’s what tends to happen in the fall in the Shenandoah mountains that are about 75 miles west of D.C.

The park ranger who does the “Fall Color Report” for Shenandoah National Park isn’t overly concerned about dry conditions affecting the park.

“It’s not been an unusually dry summer. We had a lot of rain in the springtime and then spots of rain here and there, so it’s not terribly dry up there,” National Park Service Ranger Patressa Kearns said of conditions on the mountain.

Kearns said spots of color are beginning to appear on maple and sumac trees and on Virginia creeper, which is a vine.

“It’s just starting to turn in the higher elevations,” Kearns said. “There are little tiny spots of color here and there. On a maple, there’ll be a little orange spot.”

Historically, the most brilliant fall colors along Skyline Drive have appeared around the second and third weeks of October.

Follow @WTOP on Twitter and like us on Facebook.

© 2016 WTOP. All Rights Reserved.