AUSTIN (KXAN) — The first weekend of the 2021 Austin City Limits Music Fest was unseasonably hot. Austin reached 88° on Friday, despite the heavy rain that brought more than six inches to portions of Central Texas. We climbed to 88° again on Saturday and 90° on Sunday. Keep in mind, our average for this time of the year is only 86°.
If you’re looking for a cool down, we have some bad news for you. Temperatures are forecast to get even hotter for this upcoming weekend, the second weekend of ACL Fest.
As of now, high temps for this Friday-Sunday are predicted to range from 93° to 95° with heat indices, also referred to as “feels like” temps, climbing to as high as 101°.
What is the difference between regular temperatures and ‘feels like’ temperatures?
A temperature is a physical reading, or quantity, of how hot or cold it is, measured by a thermometer. “Feels like” temperature, however, is the measure of how hot it feels for you factoring in the temperature and the relative humidity — how much moisture is in the air.
As you head outside Sunday afternoon, “feels like” temps could climb as high as the triple digits, even in the shade. More moisture means when you sweat, the air can’t evaporate it off your body as quickly as usual. This is problematic as the process of liquid evaporating off your skin actually cools you. A dry day with low humidity allows for more evaporation, and therefore, more efficient cooling. That won’t be the case for the thousands of people out at Zilker Park over the weekend.
Here is a look at the “feels like” temps each afternoon this weekend:
What’s the atmospheric setup?
A cold front from the north and west will be moving south and east towards Central Texas during the day Sunday. Just before the cold front passes, a good amount of compressional heating, or air being squeezed ahead of the front, will occur. Physics and the Ideal Gas Law prove that as air sinks, it compresses and warms as the air particles collide more with each other. You may have experienced this warming first hand with a bike pump. As you pump air into your bike, the hose typically warms up. We see compressional heating typically on a sunny day with high pressure in place. High pressure causes air to sink and get squeezed as it runs into the ground, resulting in a rise in temps.
This setup, combined with increasing winds from the south and west, will bring in moisture from the Gulf. Higher dew points or humidity being factored into rising temperatures will make the “feels like” temps reach the upper 90s by Sunday. So you’ll want to plan ahead with the proper clothing attire to stay cool. Take frequent breaks in the shade and stay hydrated. Don’t forget a hat as well.
There is some good news though. As the cold front pushes through our area by Monday, you can expect the humidity and temperatures to drop. Highs on Monday will be near 90 degrees, but with low humidity to kick off the new week.