October Warmth: Will it impact fall colors?

BETHESDA, Md. (FOX 5 DC) - September has been a month of extremes. 

Extreme heat to start the month. We had our hottest stretch of weather for the entire year between Sept. 3 and Sept. 7 where the high temperature exceeded 97° each afternoon. Fall came in strong at the end of the month, although Saturday, Sept. 23 was the wettest day in D.C. since April. The morning of Sept. 28 was the coolest morning since early May. 

Tropical Storm Ophelia impacted our region the weekend of Sept. 23-24, bringing over two inches of rain to the region. 

The month had been running extremely dry until that point, as D.C. had picked up barely over an inch of rain in the entire three weeks preceding the storm. Even with all the rain that Ophelia brought, this September is likely to wrap up drier than average, which is 3.93." 

The dryness has been felt strongest just to the west of the D.C. region, near the Blue Ridge mountains and the I-81 corridor, many of which remain in a severe drought as of Sept. 26 when the latest dough monitor was released. 

These areas could use another soaking rain event or two to erode drought conditions in the region. A concern that many have is how this could impact the fall colors in the region, which is typically one of the best areas to view the fall foliage in the entire Mid-Atlantic.

It has not just been recently either. For much of the summer, the D.C. region was running abnormally dry with parts of Maryland and Virginia under a severe drought for most of it. 

As a result, a lot of trees in the areas that have been the driest are running at moderate to high-stress levels. This can mean more muted colors during peak foliage season here in the D.C. region. 

And when is the typical peak color for our region? 

According to data from ExploreFall, the average peak for the immediate D.C. area is pretty close to Halloween – during the last 10 days of October. Areas to the east near the Potomac River and Chesapeake Bay, where the overnight temperatures do not get as cool as quickly, thanks to their proximity to water, peak color is more typical during the first 10 days of November. 

The earliest color in our region is out in the foothills of West Virginia, which typically sees peak color during the middle of October. 

This may be further delayed though by a coming warm spell heading to the D.C. region to begin the new month. A feature known as an "omega block" will develop over the eastern half of the country during the beginning of the month. This extensive ridge will provide an extended stretch of dry and sunny weather, along with well-above-normal temperatures to start the month of October. It is similar to what happened at the beginning of September to power the strong heat but to less extreme. 

After the final nine days of September failed to cross the 80 °F mark, much of the first week of October will likely see 80s to start. While the warmer-than-normal nights might make you think that fall colors may be further delayed, the opposite is true. 

In fact, this stretch of weather could be very beneficial to bringing out some stronger color from the trees, despite the stress that many are under from dryness. 

According to the National Park Service, "A succession of warm, sunny days and cool, crisp but not freezing nights seems to bring about the most spectacular color displays. During these days, lots of sugars are produced in the leaf but the cool nights and the gradual closing of veins going into the leaf prevent these sugars from moving out. These conditions – lots of sugar and light – spur production of the brilliant anthocyanin pigments, which tint reds, purples, and crimson."

So the warm start to the new month could be just what the doctor ordered for trees, which have been struggling in our region. 

If you are heading out and trying to get an early view of some of the leaves, at the moment, there is not too much to see as far as color goes across the Mid-Atlantic region. Some light color out in the mountains to the west. But nothing too spectacular.  

And despite the favorable forecast, nothing too spectacular is expected through the first week of October either, according to the latest foliage forecast from ExploreFall. 

We'll likely have to wait until later in October for those colors to become vibrant in our region. But the good news is that the nice start to the month should help those colors pop quite a bit when they do begin to change — as long as we don't have a surprise early frost or freeze waiting for us later in October!