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2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan <br />Volume 2 — Hazard Inventory <br />which showed local evaporation also plays a role in causing high moisture values near the surface. <br />4.3.7.10. Detection & Warning <br />The two crucial values for the National Weather Service issuing excessive heat products are described <br />below in the definitions of advisory, watch, and warning criteria. <br />• Excessive Heat Advisory: The heat index will reach 95 °F for at least three hours one day. The <br />forecast maximum Wet Bulb Globe Temperature will reach 85 for three hours one day. The heat <br />index will reach 95 °F for two days in a row, along with an overnight low no cooler than 73 'F. <br />• Excessive Heat Watch: A possibility the heat index will reach 100 °F for one day and/ro the forecast <br />maximum Wet Bulb Globe Temperature could reach 87 for one day, and/or the heat index could <br />reach 100 °F for two days in a row, along with an overnight low no cooler than 73 'F. <br />• Excessive Heat Warning: Maximum heat index at MSP Airport reaches 100 °F or greater for at <br />least 1 day. The forecast maximum Wet Bulb Globe Temperature will reach 87 for one day. The <br />heat index will reach 100 °F for two days in a row, along with an overnight low no cooler than 73 <br />'F. Advisory conditions for at least four consecutive days. <br />4.3.7.11. Critical Values and Thresholds <br />The heat index is what gives us the critical values for indications and warnings. The Heat Index is <br />sometimes referred to as the "apparent temperature". The Heat Index, given in degrees Fahrenheit, is a <br />measure of how hot it feels when relative humidity is added to the actual air temperature. <br />Temperature (7) <br />�a <br />Likelihood of Heat Disorders with Prolonged Exposure or Strenuous Activity <br />Caution Extreme Caution M Danger M Extreme Danger <br />Another measurement that is used to describe how the human body reacts to extreme heat is the Wet <br />Bulb Globe Temperature (WBGT). This is different from the heat index because it factors in wind and solar <br />radiation along with temperature and humidity. The WBGT parameter has been used by the military for <br />heat safety since the 1950s as it is a better representation for individuals who are active in the heat, since <br />wind and sun factor into how out body cools itself off. Many athletic associations including the sports of <br />137 <br />