Fall will feel like WHAT? Chief Meteorologist Heather Haley forecasts the season

Source: WVLT News
Published: Aug. 29, 2019 at 10:27 AM EDT
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Are you ready for cooler days and nights? Maybe it's the fall colors you're most looking forward to.The autumn months are a busy time of year, from football to tourism to the Smoky Mountains, especially.

Meteorological fall is September, October and November. The autumnal equinox is September 23 this year. We'll see and feel some changes as we move through September.


First, we are still dealing with hurricane season. In fact, the tropics in the Atlantic are most active in September. This means the odds of tropical storms developing, reaching hurricane status, and even becoming a Category 3 or higher are all greater in September. Hurricane season continues through the end of November.

The rest of this season is also trending to be slightly above normal for having an active season. The National Hurricane Center expects 10 to 17 named storms in the Atlantic, five to nine of which are hurricanes, and two to four becoming at least a Category 3.


It has been a hotter than normal year, and precipitation has been well above average. (Knoxville has a 14+ inch surplus in rainfall as of the end of August.)

So, it probably doesn't come as a shock that the temperature trend for September, October and November is looking to be slightly above average, with September averages highs in the low 80s and lows near 60. Look for October average highs in the low 70s and lows near 50 degrees. November slides down to average high of 60 degrees, and lows closer to the 40s.

A trend change for fall that is hopefully good news, is that the fall precipitation trend is to be average. The tropics keep the above average rainfall East of the Smoky Mountains. Knoxville's average rainfall is 3.24" for September, 2.51" in October and 4.01" in November.


The temperatures and precipitation ultimately impact the changing of fall leaves. With the cooler weather, the tree's chlorophyll breaks down, leaving other chemicals that trigger color change to yellows, oranges and reds.

The vibrant colors are more likely when late summer is dry, but the rest of the year has come with plentiful rain. So, we are definitely on track for a rich spectrum of fall foliage.

As we move into fall, the weather has to continue to accommodate this change. Clear weather is a big help! Sunny days and cool, clear nights encourage that chemical change in those leaves. Sticking with at least average rainfall in the fall has the potential to help, as well.


With a national view, the area from Eastern Kentucky to East Tennessee is known for mid-October being a great time for fall colors. The trick here is our beautiful elevation changes. The higher the elevation, the earlier the change in color. Early- to mid-October, the color slowly creeps down from the highest peaks of the Smoky Mountains. By mid-October, elevations above 3,500 to 4,000 feet will already put on a show. The color then slides down the Smokies and spreads across the mountains, plateau, and hills of East Tennessee and Southeastern Kentucky for late October. The Valley generally has the peak fall color by November.

With the slightly above above average temperature trend, this can delay the fall leaves changing color a bit. Anytime heavier rain or stronger winds come in, it can knock a lot of leaves off the trees.


It's time for ragweed season. The plant grows easily along roadways, riverbanks and open fields, making our area a perfect breeding ground.

Ragweed has already started blooming around our area, with the high rainfall this year. The high ragweed counts will stay high, especially in September and October. With some slightly above average temperatures, grasses can still bloom and add to the itch for allergy sufferers through October.

By November, the colder average temperatures help to slow the weeds and grasses, but after a good rain we can still have high mold counts.