June 18th, 2025: When Will Our Monsoon Get Going?
Synopsis The typical late June extreme heat will continue through Friday as high pressure aloft dominates the Desert Southwest. This weekend into early next week an anomalous synoptic scale pattern is expected with a deep mid latitude trough along the West Coast and a high amplitude subtropical ridge east of the Mississippi River. This will allow high temperatures to cool by a few degrees and below excessive heat criteria, but will delay the onset of the monsoon in Arizona. By late next week, ensembles show moisture gradually moving northward toward Southeast Arizona. At this time, the onset of our monsoon could occur as early as the last few days of June. The Pre-Monsoon Heat Tis the season to sit in a pool or in the AC all day. The typical June heat has arrived which is usually a sign the monsoon is knocking on the door of Arizona. As of 2:45PM MST this afternoon, surface observations show temperatures between 105 and 110 degF across the lower deserts with a few ...