Severe Weather 11 on how early October weather could affect fall foliage

PITTSBURGH — Tuesday marks the official start of fall, and as the cooler weather sets in, the leaves will soon be changing.

Meteorologist Adis Juklo is breaking down how the weather is going to impact this year’s fall foliage.

It has felt more like summer lately, but in the next few weeks, our area will start to see the first signs of fall as our weather cools down and the leaves change color. But with all of the rain in recent weeks and months, the upcoming weather will have a huge impact on not just how vibrant the colors are but also how long they stick around.

Last year’s colors were dull in our area because of excessive rain early in the summer, followed by long spells of drought. This year, it was the opposite, with around a foot of rain since Aug. 1, the most on record during that time. This raises the risk for some fungal diseases, but also allows healthy trees to hold onto their leaves longer.

“In general, what I’m seeing throughout our region is pretty healthy foliage moving into the fall season,” David Planinsek said.

Planinsek is a forester for the Pennsylvania Department of Conservation and Natural Resources. He says the change in daylight is the primary driver of fall foliage.

This time of year, as days get shorter, trees stop producing chlorophyll, which causes the green color in leaves to break down, revealing other pigments beneath. Too much rain will still let color show up, but the more vibrant reds, purples and burgundies are dependent on more sunlight.

“The best weather in these next couple of weeks that would provide bright fall color would be warm, sunny days, cool nights,” Planinsek said. “Not necessarily heavy frost because a heavy frost would cause the trees to go into dormancy very, very rapidly.”

Regardless of the outcome, time is on your side. Our area has such diverse geography and trees. The first change in color will appear by very early October over the Laurel Highlands. So it’s just a matter of timing where you want to go.

“You’re going to see fall color start there earlier, and then more extreme Southwestern Pennsylvania,” Planinsek said. “You’ll see fall color turn a little bit later. So we really have a full month or even up to six weeks of viewing.”

There’s high potential for some vibrant fall color this year as long as our weather can cooperate in the next few weeks. Once we get past some of the damp weather now, things will start to improve as we push into early October.

A lot of that warm air will start to push west of us as we head into the new month. You don’t want it too warm this time of year, and it does look like our weather will turn more seasonable as we head into early October.

Even more importantly, we’ll get a push of drier air. That allows for more sunshine and also allows for those cooler overnight lows. Look for those vibrant colors to really pop as we head into mid-October.

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