The 1-day Average 4-inch Percent Plant Available Water map is derived by dividing the current daily 4-inch Plant Available Water value by the theoretical maximum 4-inch plant available water amount for each individual Mesonet site. The percent reported is for the soil column from the soil surface down to the 4-inch depth. Percents may go above 100% or below 0% due to variation between individual sensors and sensor locations. The theoretical maximum plant available water was calculated from depth specific soil analysis for each Mesonet site. Plant Available Water values are 24-hour averages, updated each day after midnight. Most plants experience water stress when less than 50% of the maximum plant available water remains in the active root zone.