This drought showed two signs this week that things in the mid-south are going to get much worse before they get better.
The first sign is the high temperatures Wednesday and Thursday. Computer model forecasts, which are not programmed to account for the bone-dry soil moisture conditions we currently have, predicted a high temperature of 99 F both days with a dew point in the upper 60s. Instead here in Bowling Green we got a record 104 F Wednesday and 106 F Thursday with dew points in the low 50s. Relative humidity during the afternoon each day was around 20%, which means that Bowling Green, KY was hotter and drier than Phoenix, AZ (High 104, dew point 57F, RH 22%). Yes, our current drought has essentially turned the mid-south into a desert for the time being. All available solar energy is able to go to warming the atmosphere instead of evaporating moisture from the soil and plants (evaporation is a cooling process).
The second sign is in the way that the excessive warmth over the mid-south found at all levels of the atmosphere basically has the ability to weaken thunderstorms as they approach the area. Thunderstorms in the summer occur where there is ample low-level moisture and relatively cool temperatures in the upper atmosphere (instability) that lead to rising motion. Our drought has removed all low-level moisture and the very warm temperatures aloft mean that any storm that approaches the area will be met with a very stable atmosphere and sinking motion.
I think that the hot and dry conditions will continue through the end of August and well into September, and I think we have definitely not seen the last of 100+ weather.
