Heat index values soar to dangerous levels Tuesday and Wednesday across southern MN

Excessive heat watch is in place for southern Minnesota and northern Iowa starting Tuesday... — Excessive heat watch is in place for southern Minnesota and northern Iowa starting Tuesday afternoon going through Wednesday evening as heat index values are forecasted to reach above triple digits.(KEYC Weather)

MANKATO, Minn. (KEYC) - The hottest day so far this year for Mankato, MN was June 5th when the high reached 99º F. The dew point, that day was in the upper 50′s, which is considered on the comfortable side. The heat arriving for Tuesday and Wednesday is going to be more miserable than that of June 5th due to the higher dew points.

The dew points Tuesday and Wednesday will climb into the low to upper 70′s with high temperatures reaching the mid to upper 90′s. These high temperatures paired with high dew points will cause heat index values to reach near triple digits across the area. With triple digit heat index values in the forecast the National Weather Service (NWS) has gone ahead and issued an excessive heat watch for Tuesday afternoon through Wednesday evening.

Remember a watch is issued because there is a potential for the type of weather to exist in the near future. For example the excessive heat watch means be aware that dangerous heat levels for Tuesday afternoon through Wednesday evening. A warning will be issued if and when values reach the warning criteria.

High heat index values will cause dangerous heat levels over the next couple of days. Be on... — High heat index values will cause dangerous heat levels over the next couple of days. Be on the watch for signs of heat illnesses.(KEYC Weather)

Dew points in the 70′s means there is a lot of moisture in the atmosphere. It is also a direct correlation of how muggy it feels outside. The higher the dew point the more muggy it will feel. When your body gets too hot it sweats. Sweating is a way for your body to cool off. When dew points are low the sweat evaporates more rapidly cooling your body off quicker. When dew points are higher the sweat can not evaporate as fast which causes your body to feel warmer than it is.