【AZ】 ‘We can’t let our guard down’: Heavy rain, flash flood warnings remain in northern Arizona forecast | Weather – Arizona News

“Tuesday through Thursday, much of northern Arizona should see a half-inch to an inch of rainfall,” said NWS meteorologist-in-charge Brian Klimowski. “I will not be surprised if some areas see over two inches of rain by Thursday night.”

The heaviest rain events are expected to impact the Mogollon Rim and northeastern Arizona, Klimowski said, though Flagstaff should keep its head up for the threat of flooding beneath wildfire burn scars. Flagstaff and Coconino County have been battling with post-fire flooding for months, though recent weeks have provided some respite.

“We can’t let our guard down,” Klimowski said. “We’re going to see some heavy rain this week. There is a threat of flash flooding. We just need to stay alert to the conditions around us as the storms sweep through.”

As a whole, Klimowski said weather in the northern Arizona region is in a “transition season” that combines elements of monsoon and autumn storms. This week’s rainfall can be attributed to a low-pressure trough on the west coast.

“It isn’t atypical to see a strong trough come in and bring some resurgence of moisture,” Klimowski said. “What is unusual is how strong and deep this trough is and how slowly it’s moving.”

This strong, deep trough is also accompanied by high winds in the upper atmosphere, which will cause individual storms to move more quickly.

“They’ll have more of what we call ‘wind shear’ available,” Klimowski explained, “so the chance for severe storms is elevated as well.”

While August brought a remarkable amount of rain — almost double “normal” — to northern Arizona, truly severe storms have been rare.

When it comes to what these storms might tell us about forthcoming winter precipitation, Klimowski said, “we’ll have to wait and see.”

“There’s few indicators from the short-term forecast that truly parlay into the long-term forecast at this time,” Klimowski said. “It does look like the next couple of weeks will be pretty active. We’ll see what that brings for the rest of the fall and the winter.”