By Mike Wilhelm
With record heat possible in the Tennessee Valley this week, this is a good time to review heat safety tips.
Believe it or not, heat is the number one weather-related killer in the United States. Excessive heat claims more lives each year than floods, lightning, tornadoes, and hurricanes combined.
The National Weather Service issues Excessive Heat Outlooks, Watches, and Warnings/Advisories when conditions warrant. These are designed similarly to severe weather products. Outlooks are designed to give advanced notice of 3-7 days. Watches are issued when an excessive heat is possible in 12 to 48 hours. According to NOAA, “Excessive Heat Warnings/Advisories are issued when an excessive heat event is expected in the next 36 hours. These products are issued when an excessive heat event is occurring, is imminent, or has a very high probability of occurring. The warning is used for conditions posing a threat to life or property. An advisory is for less serious conditions that cause significant discomfort or inconvenience and, if caution is not taken, could lead to a threat to life and/or property.”
The NWS does not solely use temperature to determine when heat products are necessary. Humidity is also factored in using the Heat Index. The Heat Index is the apparent temperature, or in other words, what the air feels like when humidity is factored in. The chart below from the NWS is used to determine the Heat Index.
For more on the forecast discussion, visit Valleywx.com.