Heat, Humidity Take Aim at St. Louis Park Area This Week

The National Weather Service in Chanhassen has issued a Heat Advisory for the seven-county Twin Cities area, including Hennepin. 

That advisory, which expires at 9 p.m. Thursday, warns of high heat and humidity combining to make deadly conditions this week. 

Temperatures are expected to reach the low 90s by mid-week with a potential for severe thunderstorms on Thursday.

The National Weather Service said heat combined with Gulf of Mexico air and its corresponding moisture will make dangerous conditions for those without air conditioning on today and Wednesday. 

Patch will keep you posted on the likelihood of severe weather and severe heat this week. 

In the meantime, the NWS offers these heat safety tips, including: 

Recognizing Heat-Related Illness

During extremely hot and humid weather the body's ability to cool itself is affected. When the body heats too rapidly to cool itself properly, or when too much fluid or salt is lost through dehydration or sweating, body temperature rises and heat-related illnesses may develop.

Heat-related illnesses can range from heat cramps to heat exhaustion to more serious heat stroke. Heat stroke can result in death and requires immediate medical attention.

Factors or conditions that can make some people more susceptible to heat-related illnesses include age (older adults and young children), obesity, fever, heart disease, mental illness, poor circulation, prescription drug and alcohol use, and sunburn. Sunburn, caused by ultraviolet radiation from the sun, can significantly retard the skin's ability to shed excess heat.

The sun's shortwave radiation (yellow in figure below) heats objects that it strikes.  For example, a dark dashboard or seat can easily reach temperatures in the range of 180 to over 200°F. These objects (e.g., dashboard, steering wheel, child seat) heat the adjacent air by conduction and convection and also give off longwave radiation (red in figure below) which is very efficient at warming the air trapped inside a vehicle.

Shown below are time lapse photos of thermometer readings in a car over a period of less than an hour. As the animation shows, in just over 2 minutes the car went from a safe temperature to an unsafe temperature of 94.3°F. This demonstration shows just how quickly a vehicle can become a death trap for a child.