031 FXUS65 KFGZ 111754 AFDFGZArea Forecast Discussion National Weather Service Flagstaff AZ 1054 AM MST Thu Sep 11 2025
.SYNOPSIS...Windy conditions are expected through Friday, with gradually cooler temperatures through the weekend. Scattered showers and thunderstorms are forecast this afternoon through Friday, mainly across eastern Arizona. Dry conditions return by the weekend.
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.DISCUSSION...A fairly strong closed low for this time of year was centered over northern California this morning. Increasing pressure gradients well ahead of the low brought windy conditions on Wednesday to our region, with gusts in the 35-50 mph range. As the low moves slowly eastward over the next couple of days, the windy conditions will persist with afternoon gusts mostly in the 30-40 mph range. Daytime temperatures will be a couple degrees cooler today through Saturday as well. With the increased south- southwest flow aloft, deeper moisture located over Sonora is being pulled northward into eastern Arizona. This will persist through Friday evening, with the best chance of showers and thunderstorms east of a Heber to Kayenta line affecting Apache and portions of Navajo counties. Farther west, a few showers or storms can`t be ruled out, but chances are only 10-20%. In Apache County, storm chances are 30-50% this afternoon and overnight, increasing to 50-70% on Friday. With deep layer wind shear present due to the approaching low, and increased instability in the moisture plume, there is a chance of a few strong to severe thunderstorms primarily in Apache County and southern Navajo County. The most favorable timing for the stronger storms appears to be on Friday as daytime heating increases instability, though there is a lower chance even Thursday night if storms manage to develop. Both damaging winds and large hail (1" or greater diameter) will be possible in isolated storms, and the SPC has placed this area in a marginal risk for severe weather.
By the weekend - much drier air is forecast to sweep eastward as the low advances into our region, ending the chance of storms. This will also cause southwest winds to diminish to 10-20 mph. Saturday is currently forecast to be the coolest day of the forecast period, with highs around 5 degrees below normal. With the drier air and lighter winds, overnight lows will be the coolest we have seen in some time, likely into the 30s Sunday and Monday mornings for many locations above 6500 feet. The usual cold pockets (Bellemont, Tusayan, Window Rock) may approach the freezing mark. Seasonable temperatures are forecast to return next week, with some indications that another moisture plume will move northward into the state and bring a chance of showers and storms back to the area. Still quite a bit of uncertainty in this scenario, so precip chances are only in the 10-20% range for now, and mainly for the eastern half of the state.
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.AVIATION...Thursday 11/18Z through Friday 12/18Z...Mainly VFR conditions. Isolated to scattered SHRA/TSRA after 19-20Z, primarily east of a KPAN-KINW-K0V7 line. Activity may continue overnight with the highest coverage in Apache county. Brief/localized MVFR in stronger storms with erratic winds gusting up to 40 kts and hail. Winds are S-SW 15-20 kts with gusts 30-35 kts, decreasing to 15 kts or less after 02Z.
OUTLOOK...Friday 12/18Z through Sunday 14/18Z...Mainly VFR conditions expected. Isolated to scattered -SHRA/-TSRA possible primarily east of a KPAN-KINW-K0V7 between 18Z-02Z each day. Winds are SW 15-20kts with gusts to 35kts on Friday, becoming S-SW 5-10 kts overnight. Winds are SW-W 10-15kts on Saturday, then light and VRB overnight.
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.FIRE WEATHER...Today and Friday...Slightly cooler and windy. Southwest winds from 15 to 25 mph, with gusts from 30 to 40 mph each day, from late morning through early evening. Some moisture being pulled into eastern Arizona will also allow for daily showers and thunderstorms, some storms could be strong. Storms will largely be confined to Apache and Navajo counties.
Saturday through Monday...Conditions will rapidly dry from west to east, with minimum relative humidity values mainly in the teens through the period. Seasonable daytime temperatures. Daytime south through southwest winds 10 to 20 mph.
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.FGZ WATCHES/WARNINGS/ADVISORIES...None.
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PUBLIC...JJ/Lewandowski AVIATION...JJ FIRE WEATHER...JJ
For Northern Arizona weather information visit weather.gov/flagstaff
NWS FGZ Office Area Forecast Discussion