DISCUSSION: On the week of July 15, A massive humid heatwave struck much of the Central United States from Kansas and Oklahoma to Ohio and West Virginia. The heatwave started after the remnants of Hurricane Barry was absorbed by a trough of low pressure that came from Canada. After the trough moved out towards New York and the East Coast, a strong ridge of high pressure built over the area which cleared the skies mostly. In addition, the ridge of high pressure brought a strong southerly flow of warm moist air from the Gulf of Mexico all the way up to Minnesota, Wisconsin and South Dakota.
The warm humid air led to Excessive Heat watches and warnings across the areas. The warnings were issued as the heat index values for much of the Central United States were in the triple digits. The heat index is an apparent temperature which factors in temperature and humidity and the higher the humidity, the higher the heat index feels like. However, the extreme heat and humidity led to afternoon thunderstorms across some of the region due to the large amount of Convective Available Potential Energy (CAPE) that was present for much of the region. CAPE is the buoyancy of a parcel of air and is related to the vertical motion of thunderstorms. CAPE is higher when there is more warmth and temperature in the atmosphere. The area of the extreme heat also happens to be where most of the corn is growing in the United States, click here to find out more about how corn plays a factor in the humidity.
The hot and humid weather pattern expanded to New York and the East Coast by Friday and persisted for the weekend. However, the pattern shifted to be cooler as the new week began and the ridge of high shifted eastward. We at the Global Weather and Climate Center would like to remind you to stay hydrated and cool especially during the summer heat by drinking at least 8 cups of water a day especially during the warmest time of the day as well as staying in the shade as much as possible and to try to not do too much outside especially between the hours of 10 am and 5 pm as that is when the heat and sun is at the highest points.
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©2019 Meteorologist JP Kalb