936
FXUS65 KFGZ 290522
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1022 PM MST Sat Jun 28 2025

.SYNOPSIS...Warming temperatures and mainly dry conditions continue
through the weekend. Isolated to scattered showers around the White
Mountains through Sunday, then more widespread shower and
thunderstorm activity sets in through the week.

&&

.DISCUSSION...Ridging continues to set up over Arizona and New
Mexico. A mostly dry airmass will remain in place, and warm
temperatures will be the primary impact during this period with
daytime highs peaking 5-10 degrees above average on Sunday-Monday.
An Extreme Heat Warning is in effect for the Grand Canyon below
4000` today through Tuesday, where high temperatures are expected
to exceed 110 degrees. Physical activity is discouraged, but any
hikers in the Grand Canyon should be sure to carry adequate food,
water, and gear. Exercise enhanced caution elsewhere especially
for those who are sensitive to heat.

Weak southerly moisture advection is occurring with the building
high pressure, and higher PWATs are encroaching along the southern
periphery of our forecast area. Some scattered showers are being
observed today primarily in the White Mountains. Higher surface
dewpoints are lagging a little behind, and shower activity will
remain high based. There will be continued low, but increasing daily
chances for scattered showers/thunderstorms in this area.

Tuesday through Thursday...A mid-level trough will manifest off the
coast of California and quickly strengthen. This low pressure system
becomes cut-off and meanders eastward, pushing against the ridge
over New Mexico. This will set up an ideal axis for southerly
advection into northern Arizona, and moist dewpoints with high PWATs
will quickly entrain into our area. Expect widespread showers and
thunderstorms peaking on Wednesday-Thursday.

Friday and beyond... There is some uncertainty as to how persistent
the moisture will be after this initial surge. Some model solutions
bring a series of low pressure systems which follow a track more to
the north of AZ. This could set up a regime with flow that is a bit
more westerly and less ideal for moisture advection into our area.
Higher PWATs look to at least stick around to the south, but right
now showers look to decrease in coverage Friday through the weekend.

&&

.AVIATION...Sunday 29/06Z through Monday 30/06Z...Expect mainly VFR
conditions. Some local flight restrictions possible INVOF KRQE, due
to a wildfire. Areas of CU/TCU redevelop by 18Z-20Z Sunday, mainly
south/southeast of a KPRC-KFLG-KRQE line. ISOLD high-based -SHRA/-
TSRA possible over southern Navajo and Apache counties during the
time frame. Daytime sfc winds SW-W10-20kts.

OUTLOOK...Monday 30/06Z through Wednesday 02/06Z...Expect mainly VFR
conditions. ISOLD-SCT high-based -SHRA/-TSRA possible each day. Best
chances near the White Mtns Monday, spreading to the north and west
Tuesday. Daytime winds S-SW10-20kts both days, winds may be gusty
and erratic near any convective activity.

&&

.FIRE WEATHER...Sunday and Monday...Warm temperatures and low
RH continue. A slight chance of high-based showers and storms is
expected near the White Mountains Sunday afternoon, spreading west
Monday. Gusty and erratic winds are likely in the vicinity of
storms. In addition, dry lightning is a concern. Otherwise, SW-W
winds 5-15 mph with gusts to 15-25 mph each afternoon. Minimum RH
values 5-15% both days.

Tuesday through Thursday...Thunderstorm coverage increases Tuesday
and Wednesday, with the highest dry lightning risk Tuesday
afternoon. Increasing monsoon moisture will bring RH from 15-25%
Tuesday to 20-35% Wednesday. S-SW winds 5-15 mph with gusts to 20-25
mph each day, but strong outflow winds will be possible
near storms.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

Extreme Heat Warning until 7 PM MST Tuesday for AZZ006.

&&

$$

PUBLIC...Lewandowski
AVIATION...Peterson
FIRE WEATHER...RR

For Northern Arizona weather information visit
weather.gov/flagstaff