Wow! We have seen 2-6” of rain across most of Yavapai County in the past 10 days since the monsoon began. Deep moisture continues to hang around today, and will likely remain in place through about Friday. The upper-level high pressure system is strengthening to our north (over Utah and Nevada) the next few days, bringing 20-30 mph easterly winds across northern Arizona. The winds aloft will help steer thunderstorms southwestward or westward at 10-20 mph. They will also provide ample low-level shear for thunderstorms to organize into lines. Some of the storms could produce frequent lightning, gusty winds and possibly hail up to half-inch diameter…but the main threat will be heavy rainfall on already saturated ground. Make sure to stay away from low-lying areas, washes, slot canyons, and don’t drive through flooded roadways!
Starting on Saturday, we will see the high pressure aloft begin to shift into New Mexico, providing less vertical wind shear, plus a change in storm propagation to a more northward direction and a downward trend in the amount of moisture present over Arizona. Nevertheless, at least a slight probability of thunderstorms each day will continue into next week.
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