Wet bulb temperature is a measure that combines air temperature and humidity, indicating conditions under which the human body’s ability to cool itself through sweating and evaporation is compromised.  While not a mass casualty event, over the next four days, places and pockets of the U.S. may be in wet bulb territory for a long enough duration to be of concern.  Consider this the first OODA Loop dispatch from the Ministry fpr the Future that is actually acting as a tactical advisory for the next four days as well.