This dangerous September heat wave will continue to bring peak heat index values of 100 to 110 degrees through Saturday, which may be the latest in the season that 105 degree heat index values have been recorded, and near 100 degrees Sunday. Wet bulb globe temperatures will peak at 85 to 90 degrees daily through Sunday. Overnight temperatures will be very warm for mid-September, in the lower to middle 70s during the worst of the heat.