PHOENIX -- Thursday could be the 24th day of temperatures at 110 degrees or hotter for the year at Sky Harbor. The average number of days with this kind of heat in Phoenix is 19.
A ridge of high pressure over the region, combined with a drier air mass working in from the west, is to blame for this September scorcher. By noon, the temperature in Phoenix is expected to reach around 103 under sunny skies with an afternoon high of 110. Winds will be on the breezy side, reaching speeds of 10 to 20 mph.
A piece of energy moving across northern Mexico during the afternoon hours may be enough to produce a stray shower or storm in southern Maricopa County. Otherwise, the best chances for showers and storms will be along the Mogollon Rim and in northwestern Arizona.
Sun Devils kicking off the football season in Tempe at 7 p.m. will see a temperature of 103 in under mostly clear skies, a light breeze and a 10 percent chance of a storm.
Small storm chances are in the forecast for the Valley Friday afternoon with a high in Phoenix of 107.
This weekend, an area of low pressure moving through the Pacific Northwest will push our ridge of high pressure to the east. This will allow more monsoon moisture to move in from the southeast, increasing our storm chances. Temperatures are also expected to begin a downward spiral. By next week, afternoon highs in the Valley should top out in the upper 90s with an increase in humidity.