The dew points have dropped (a tad) compared to Monday, but yet, we're still seeing heat index values in the 90s this week. What gives? Areas like Bradley, and McMinn counties will get a higher heat index than most in the Tennessee Valley today and tomorrow. Here's why.

Over the last week you may have noticed more of a haze in your yard. On a less humid morning, after rainfall the day before, typically after a cold front has moved through, you'll notice evapotranspiration taking place! Evapotranspiration is the transpiring (water release) from the stoma or stomata (a pore or pores that release gas exchange). The plant is releasing water making areas with higher vegetation like farms, more of a scorcher, as more moisture is being released.

Here is the rainfall over the last 24 hours. Notice Bradley county picked up near 0.70" on Monday, and eastern McMinn picked up 0.50" total. Farms in Athens and Spring City will get a heat index over 90 the next few days as crops transpire, even if the dew points lower to the low 60s. 

You'll notice the transpiring less on more muggy and humid days. On a windy day, the transpiration is higher, however less noticeable. Try to view it tomorrow morning! It will look like steam coming off your plants.