Record-breaking southwestern US heat wave to expand eastward this weekThe summer's most intense heat wave yet is expected to break a long-standing record of 110-degree days in one Southwest city. As of July 15, Phoenix had recorded 16 consecutive days of high temperatures at or above 110. Temperatures may have peaked during the heat wave this past weekend but may only slip back by a few degrees this week. High temperatures in the 120s are expected to persist through at least the upcoming weekend. In cities such as Las Vegas and Phoenix, record high minimum temperature records could be threatened," Johnson-Levine said.