PHOENIX -- Yes, it’s only Tuesday, but we’re seeing some strong signs that Monsoon 2012 is making its way into Arizona for the first time this coming weekend. (The storms we had last weekend were kind of a moisture blip.) The pattern setting up for Saturday through Monday is textbook monsoon circulation.
For the Valley, we’ll start seeing an increase in humidity levels late Friday. On Saturday, most likely we’ll see some buildups to the east and south of the Valley in the afternoon hours and might see a dust storm.
Sunday and Monday our chances for thunderstorms increase rather dramatically, especially considering we’re in the first few weeks of the monsoon. Currently, we have a 30 percent chance for PM thunderstorms both Sunday and Monday for metro Phoenix. Hopefully, that number will continue to hold or, even better, trend upward, making our chances for rain even greater.
That being said, let’s put a little perspective on our optimism. It’s only Tuesday and history tells us a lot more thunderstorms never make it into the Valley than actually get here during the summer. In fact, in 2011 we had only nine days with measurable rain during the monsoon (June 15-Sept 30) and on only one of those days did we get over 1/2 inch of rain. Slim pickings.
An update on the heat: The Excessive Heat Watch for metro Phoenix Wednesday is canceled. It’s still going to be hot with a high of 110. However, Thursday may be a bit hotter and may require an excessive heat warning issued by the Weather Service.