740 FXUS65 KFGZ 120443 AFDFGZArea Forecast Discussion National Weather Service Flagstaff AZ 943 PM MST Thu Sep 11 2025
.SYNOPSIS...Windy conditions are expected through Friday, with lighter winds and cooler temperatures arriving over the weekend. Scattered showers and thunderstorms are forecast for this afternoon through Friday, mainly across eastern Arizona. Most location will see dry conditions move in over the weekend but a few showers could linger over far eastern Arizona into Saturday.
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.DISCUSSION...A long-wave trough over the western states will continue to produce windy conditions this afternoon through Friday with lighter winds due on Saturday as the trough moves eastward. In addition, moisture from the Gulf of California/northwest Mexico is being drawn northward across portions of central and eastern Arizona. The moisture combined with daytime heating and decent large-scale dynamics for upward motion will result in pockets of instability producing a good chance of showers and thunderstorms over eastern Arizona.
For this afternoon through Friday...With the arrival of additional moisture, large-scale upper dynamics and daytime heating, shower and thunderstorm activity will pick up this afternoon and continue into the evening. The cutoff line for this activity appears to be along and east of a Prescott to Flagstaff to Page line. The combination of increased instability and some vertical wind shear will introduce the chance that a stray thunderstorm or two could become severe producing near quarter size hail and/or wind gusts in excess of 60 mph. Models suggest activity will diminish to isolated showers/storms by midnight but the threat for isolated severe storms will remain as the flow aloft will continue to replenish moisture and instability. The same overall large-scale pattern remains in place on Friday with another round of activity similar in coverage and intensity anticipated.
On Saturday...There will remain a chance of showers and thunderstorms over far eastern Arizona but for much of the rest of the area a drier air mass will push in from the west as the trough heads eastward. It will turn a bit cooler behind the trough and with weaker pressure gradients winds will turn much lighter, generally from the west to southwest at 10 to 20 mph.
From Sunday onward...Mainly dry. There will be a slight chance of showers/thunderstorms across the White Mountains region on Tuesday and Wednesday as moisture is pulled northward by a weak passing trough. Otherwise, seasonable temperatures and light winds are forecast.
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.AVIATION...Friday 12/06Z through Saturday 13/06Z...Mainly VFR conditions, brief MVFR in heavier SHRA/TSRA. Isolated SHRA/TSRA over eastern Arizona tonight, becoming isolated to scattered SHRA/TSRA east of the Interstate 17 corridor starting as early as 12Z and lasting through 03Z-06Z Friday. Winds S-SW 5-10kts overnight, S-SW 10-20kts gusts to 30kts Friday after 15-18Z. Note: KSEZ Metars not coming in, amendments not scheduled at this time.
OUTLOOK...Saturday 13/06Z through Monday 15/06Z...Mainly VFR conditions, brief MVFR in heavier SHRA/TSRA. Isolated to scattered SHRA/TSRA possible over eastern Arizona mountains between 18Z-02Z each day. Winds SW 10-15kts, gusts to 25kts Saturday, SW 5-10kts Sunday. Light and variable or terrain driven each night.
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.FIRE WEATHER...Friday and Saturday...Slightly cooler and windy. Winds are southwest 15 to 20 mph with gusts to 35 mph on Friday, then southwest through west 10 to 15 mph with gusts to 20 to 30 mph on Saturday. There is a chance of showers and thunderstorms in eastern AZ, some storms could be strong. Storms will largely be confined to Apache and Navajo counties and become much more isolated on Saturday.
Sunday through Tuesday...Much drier with a return to seasonal daytime temperatures. Minimum RH is generally 10-20%, locally higher in the White Mountains. Daytime winds are south through southwest 5 to 15 mph. Slight chance for showers and thunderstorms return to the White Mountains on Tuesday.
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.FGZ WATCHES/WARNINGS/ADVISORIES...None.
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PUBLIC...McCollum AVIATION...Bernhart FIRE WEATHER...Lewandowski
For Northern Arizona weather information visit weather.gov/flagstaff
NWS FGZ Office Area Forecast Discussion