The National Weather Service announced a series of weather alerts affecting large swaths of Arizona from Thursday into Friday, warning of severe thunderstorms and flash‑flood threats. The alerts span both Mountain Standard Time (MST) and Mountain Daylight Time (MDT) zones, targeting counties that include Coconino, Apache, Navajo and several tribal lands.

Little Colorado River Valley Alert Runs Thursday 11 AM–8 PM MST

According to the National Weather Service, the Little Colorado River Valley – encompassing parts of Coconino, Apache and Navajo Counties – was placed under an alert from 11:00 a.m. to 8:00 p.m. MST on Thursday. The warning specifically cites the risk of flash flooding in low‑lying river corridors and the potential for hail and strong winds on elevated terrain. Residents were urged to monitor local forecasts, avoid driving through flooded roadways, and seek shelter if storms develop.

Friday MDT Watch Extends Over Chuska Mountains and Defiance Plateau

The service also issued a watch for areas observing Mountain Daylight Time, including the Chuska Mountains, Defiance Plateau, Black Mesa, and the northeast plateaus north and south of Highway 264. This watch runs from 12:00 p.m. to 9:00 p.m. MDT on Friday, covering tribal lands that straddle the Navajo Nation. The watch highlights the same hazards – severe thunderstorms, lightning, and flash flooding – but adds that high‑elevation wind gusts could pose additional danger to hikers and campers.

White Mountains and Mogollon Rim Added to Friday MST Alert

On Friday, the National Weather Service expanded its MST alert to include the White Mountains,the eastern and western stretches of the Mogollon Rim, and additional sections of the Little Colorado River Valley. The alert period mirrors Thursday’s timing, running from 11:00 a.m. to 8:00 p.m. MST. This expansion reflects the storm system’s eastward progression and underscores the monsoon season’s tendency to produce rapid, localized downpours that can overwhelm even well‑drained mountain streams.

Unclear Timing for Navajo Nation Residents Across MST/MDT Divide

One lingering ambiguity is how the split‑time‑zone arrangement will affect residents of the Navajo Nation,where both MST and MDT are observed. The alerts list separate time windows for each zone, but the report does not clarify whether a single storm could trigger overlapping warnings. emergency managers have advised locals to treat both sets of times as active and to follow tribal coordination centers for the most current guidance.

What Remains Unverified About the Storm System?

While the National Weather Service has detailed the geographic scope and timing, it has not disclosed the precise storm track or the expected rainfall totals for each county . Moreover, the report does not indicate whether any evacuation orders have been issued, leaving communities to rely on local officials for further directives. As of the latest update, no major road closures have been reported , but conditions could change rapidly once convection peaks in the late afternoon.