textproduct: NWS Flagstaff

SYNOPSIS

Although mainly hot and dry conditions are expected through much of the week, there will be daily chances for showers and thunderstorms over portions of eastern/central Arizona through at least the early part of the week. Dangerous heat is expected at the lower elevations of the Grand Canyon for most of the week.

DISCUSSION

A ridge is currently centered over eastern AZ into New Mexico, coupled with a surface low over the Lower Colorado River Valley. This opens a window for decent subtropical moisture advection into the region, with dewpoints nearing the 40s for much of northern AZ. The most ideal corridor for storms over the next few days will be along the higher terrain in eastern AZ. Convection is currently ongoing over the White Mountains and Black Mesa, though has remained fairly suppressed. Outflows from this activity will try to push moisture further west in the coming days, but this will battle against the large scale southwest flow. Isolated storms may push as far west as Flagstaff on Tuesday/Wednesday.

Later in the week, the ridge flattens and centers to our west. This will kill any moisture advection into northern AZ for the short term, and precipitation chances greatly decline by Thursday/Friday. By the weekend, there is decent agreement that a more favorable monsoon pattern will develop and PoPs begin to rebound.

Heat will also be a concern this week. The primary concern is the lowest elevations of the Grand Canyon, where temperatures are forecast to exceed 110 degrees each day this week. An Extreme Heat Warning is in effect for the Grand Canyon below 4000 ft through Wednesday, becoming an Extreme Heat Watch thereafter through Saturday.

AVIATION...Tuesday 07/06Z through Wednesday 08/06Z

Mostly VFR conditions. A few -SHRA NE of a KSJN-KPGA line through around 08Z then ending overnight. Brief MVFR possible in ISOLD-SCT SHRA/TSRA, again after 18Z Tue into Tue evening with the best coverage south of a KINW-KRQE line. Winds light and VRB overnight, then SW 10-20 kts after 18Z Tue. Gusty/erratic winds expected near storms. Light smoke impacts are possible at KFLG and KSEZ from a wildfire.

OUTLOOK...Wednesday 08/06Z through Friday 10/06Z...Mostly VFR conditions. Brief MVFR possible in ISOLD-SCT SHRA/TSRA Wed afternoon, primarily over southern Apache and Navajo counties, decreasing to isolated coverage on Thursday. Winds are SW-W 10-20 kts each day, becoming light and VRB during the overnight periods. Gusty/erratic winds expected near storms.

FIRE WEATHER...Tuesday and Wednesday

Most areas will remain hot and dry, with daily southwesterly breezes from 10 to 20 mph gusting from 25 to 30 mph. Limited moisture and storm chances may spread as far west as Flagstaff on Tuesday but then become more confined to the eastern Mogollon Rim and White Mountains on Wednesday. Isolated wetting rains are possible under the stronger storms.

Thursday through Saturday...Hot and mostly dry. Chances for afternoon showers and thunderstorms continue, mainly over the White Mountains region. Expect daily southwesterly breezes from 10 to 20 gusting from 25 to 30 mph.

FGZ WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 8 PM MST Saturday for AZZ006.