FXUS65 KFGZ 192105

AFDFGZ



Area Forecast Discussion

National Weather Service Flagstaff AZ

205 PM MST Tue Aug 19 2025



.SYNOPSIS...Isolated showers and thunderstorms will continue into

this evening in eastern Arizona, with hot and dry conditions 

expected elsewhere. Monsoonal moisture looks to increase over the 

coming days. Scattered to widespread storms, some with heavy rain

and localized flash flooding, are expected to develop by weeks 

end and continue into early next week. 

&&



.DISCUSSION...Strong high pressure (500 mb heights 596-598 dam) is

forecast to be centered near the four corners through Friday

before gradually weakening and sliding southward into New Mexico

later this weekend/early next week. This will be a much more

favorable setup for transporting monsoon moisture into our region

than we have seen lately, and should set the stage for an active

period of showers and thunderstorms. With such a strong high

pressure system, heat will also be an issue through at least

Thursday or Friday. An Extreme Heat Warning is in effect through

Wednesday for the lower elevations of Grand Canyon, with a watch

for Thursday/Friday. We left the watch as is for now, as 

increasing clouds and precip chances could keep temperatures below

warning thresholds. The lower elevations of Yavapai County will 

also be quite hot through Friday (Verde Valley near 105F), though 

the same issues with cloud cover/precip may impact these areas 

each day by early/mid afternoon and keep temperatures down a bit. 

For today, the main area of moisture increase has been far eastern

Arizona, with isolated/scattered showers and thunderstorms in the

White Mtns, Chuska Mtns, and around Black Mesa. CAMS suggested 

that some of these storms near the White Mountains into eastern 

Gila County could become strong later this afternoon/evening and 

push an outflow boundary westward.



Wednesday - a continued westward push of moisture is forecast as

the large scale flow as well as outflow boundaries are favorable

for moistening up areas as far west as Flagstaff and at least the

eastern half of Yavapai County. Storm chances go up to 30-60%

along the Mogollon Rim to 20-30% in eastern Yavapai. By Thursday,

higher storm chances push even farther west and north, with 20-40%

chances all the way to the UT/AZ line.



Friday into early next week - shower and thunderstorm coverage is

forecast to remain high (50-80%) each day with some fluctuation

related to outflows and debris cloudiness though these are not

really predictable more than 24 hours out. With elevated precipitable

water values across the region, the threat of locally heavy rain

and flash flooding will increase. In addition, easterly steering

flow Fri/Sat will be favorable for pushing storms off the high

terrain westward into Yavapai County where moisture and

instability will be highest each afternoon. This pattern can

produce strong to locally severe thunderstorms with strong winds

and hail in this area. As the high gradually weakens and shifts

southward, high temperatures should fall back closer to normal by

the weekend and early next week.



&&



.AVIATION...Tuesday 19/18Z through Wednesday 20/18Z...VFR 

conditions with VRB winds 5-10 kts. ISOLD to SCT -SHRA/-TSRA with

MVFR conditions in the heavier showers east of a KPAN-KINW-KRQE 

line from 23Z to 07Z. Gusty outflow winds possible in and around 

TS.



OUTLOOK...Wednesday 20/18Z through Friday 22/18Z...Mainly VFR 

conditions with VRB winds 5-10 kts each day. ISO-SCT SHRA/TSRA 

possible each afternoon/evening, mainly over the higher terrain. 

MVFR conditions and gusty outflow winds possible in and around 

TS.



&&



.FIRE WEATHER...Wednesday and Thursday...Hot and mainly dry 

conditions continue. Isolated to scattered showers and thunderstorms 

expected Wednesday, most numerous across eastern AZ. More widespread 

showers and thunderstorms expected on Thursday. Winds generally 

variable 5-10 mph. Gusty and erratic winds possible in and around 

thunderstorms. Minimum afternoon RH values 10-30%, highest across 

the White Mountains. 



Friday through Sunday...Good chances (60-80%) for showers and 

thunderstorms each day. Winds will primarily be variable 5-10 mph. 

Gusty and erratic winds possible in and around thunderstorms. 

Minimum afternoon RH values 10-30%, greatest over the high 

terrain.



&&



.FGZ WATCHES/WARNINGS/ADVISORIES...

Extreme Heat Warning until 8 PM MST Wednesday for AZZ006.



Extreme Heat Watch from Wednesday evening through Friday evening 

for AZZ006.



&&



$$



PUBLIC...JJ

AVIATION...BAK

FIRE WEATHER...BAK



For Northern Arizona weather information visit

weather.gov/flagstaff