694 FXUS65 KFGZ 070009 AFDFGZArea Forecast Discussion National Weather Service Flagstaff AZ 509 PM MST Sat Sep 6 2025
.SYNOPSIS...Isolated showers and thunderstorms will continue into this evening before coming to an end overnight. Dry air starts to move in on Sunday leading to only isolated storm activity which is expected to last through Tuesday. Fall-like weather is forecast to set in from Wednesday onward with breezy and cooler weather along with the potential return for the chances of showers and thunderstorms.
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.DISCUSSION...Monsoon moisture will hang around through this evening with isolated showers and thunderstorms continuing, mainly east of a Prescott to Four Corners line. On Sunday a drier westerly flow will develop, lasting through at least Tuesday. Enough moisture will linger for a slight chance of showers and thunderstorms primarily toward the Arizona/New Mexico border. Our expectation for the remainder of the area is dry. From Wednesday onward the forecast models still diverge but overall have trended toward a drier solution for all but eastern Arizona. There are likely a few additional model twists and turns as we head into next week so check back for updates.
For tonight...Moisture will begin to dwindle overnight as a drier westerly flow develops across our area. As a result, isolated shower and thunderstorm activity in the early evening will come to an end by midnight.
For Sunday through Tuesday...The drier westerly flow will remain over northern Arizona and also deliver a capping warm layer aloft. The result will be much diminished shower and thunderstorms activity. However, enough moisture will linger and combine with daytime heating for isolated showers and thunderstorms, mainly toward the Arizona/New Mexico border. The remainder of northern Arizona is forecast to remain dry. Turning a bit warmer with winds remaining on the light side as pressure gradients remain weak.
From Wednesday onward...As a trough moves across the western states we are expecting that breezes will strengthen and temperatures will cool leading to a fall-like feel from Wednesday into Friday. The position of the eventual trough will be critical as to how much moisture gets pulled across Arizona. The most recent run of the forecast models have overall tended toward a drying solution. At this time we are thinking only an isolated threat with around 10 to 20 percent coverage of showers and thunderstorms.
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.AVIATION...Sunday 07/00Z through Monday 08/00Z...Mainly VFR conditions. Isolated to scattered SHRA/TSRA through around 03Z this evening. Brief/localized MVFR and gusty/erratic winds 25-35 kts in and near SHRA/TSRA. Wind becoming light/variable overnight. Isolated SHRA/TSRA possible again after 18Z Sunday, mainly along/south of a KFLG-KSJN line. SW-W winds 10-15 kts after 18Z Sunday.
OUTLOOK...Monday 08/00Z through Wednesday 10/00Z...Mainly VFR conditions. Isolated SHRA/TSRA through around 08/02Z. No SHRA/TSRA expected area-wide on Monday as drier air moves in, then very low chances (10-15%) return for Tuesday afternoon. Brief/localized MVFR and gusty/erratic winds 25-35 kts in and near SHRA/TSRA. Outside of storms, expect daytime SW-W winds 10-15 kts Monday, then 10-20 kts Tuesday.
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.FIRE WEATHER...Sunday and Monday...Only a few isolated storms are expected over the highest terrain Sunday as drier air moves into the region. By Monday things dry out enough that no storm activity is expected. Outside of storms, expect winds W 10-20 mph each day. Minimum RH values range from 20-30%.
Tuesday through Thursday...Drier conditions expected through much of the coming week with only isolated showers or storms expected across the higher terrain. Winds S-W 10-20 mph Tuesday, increasing to 15-25 mph on Wednesday and Thursday. Minimum RH values range from 15-30% each day.
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.FGZ WATCHES/WARNINGS/ADVISORIES...None.
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PUBLIC...McCollum AVIATION...JJ FIRE WEATHER...Bernhart
For Northern Arizona weather information visit weather.gov/flagstaff
NWS FGZ Office Area Forecast Discussion