Stifling heat brings danger to Alabama this weekend

The intense heat dome building over Alabama from the west is prompting excessive heat warnings and advisories across the southeast. Heat indices soar above 100°F through the weekend. This level of heat requires extreme caution as it can be dangerous! RISING TEMPERATURES + EXTREMELY HUMID AIR = DANGER We are well acquainted with intense heat and humidity here in Alabama but rarely do temperatures soar near triple digits. Additionally, a heat index value as high as 110°F is uncommon. Only nine times since heat index has been measured has it reached that degree. The highest heat index on record for Birmingham came in 1999: 117°F. Heat index (apparent temperature) is a number representing what the air temperature “feels like” when combining the actual air temperature and relative humidity. Higher temperature air has the ability to hold more water vapor. Humid air feels hotter because of this reason. When relative humidity is high, your body's natural cooling processes are restricted because sweat cannot easily evaporate. Heat indices above 100°F require caution but values exceeding 105°F prompt excessive heat warnings and long-time exposure can be life-threatening. HUMIDITY VS. DEW POINT Relative humidity is relevant to the air temperature. It is a measure of the amount of water vapor in the air. Humidity can be high on a cool day because it takes into account the moisture combined with the air temperature. Dew point is the temperature of air once it becomes saturated. Higher levels of moisture in the atmosphere raise the dew point while lower amounts of moisture do the opposite. Dew point is a better indicator of how muggy the air feels as it reveals the temperature air must be for saturation to occur. This means the water vapor in the air is at full capacity. Wet-bulb globe temperature This term isn’t used often but is extremely important during the summertime, especially for those who spend ample amounts of time outside in the sun. Wet-bulb globe temperature (WBGT) measures heat stress on the body when in direct sunlight. While heat index is calculated using temperature and humidity, WBGT uses these parameters plus windspeed, solar radiation and cloud cover. WBGT exceeding 95 degrees are extremely dangerous. Your body absorbs excessive heat because sweat cannot evaporate to naturally cool effectively. WBGT between 80-90 degrees are still dangerous after brief exposure, however frequent breaks from the sun make the heat bearable. Finding WBGT in your neighborhood STAYING SAFE IN THE SUN There are plenty of ways to beat the brutal summertime heat! A complete list of dos and don'ts: RAIN RELIEF? Late this weekend, the intense high-pressure ridge will begin to weaken. Clouds will make a return with some scattered storms possible. Rain will help resume near-normal daytime highs for the first week of July. The full forecast here: