037
FXUS65 KFGZ 202350
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
450 PM MST Thu Jun 20 2024

.SYNOPSIS...Daily chances for showers and thunderstorms are
forecast through the weekend and into early next week, along with
warming temperatures.

&&

.DISCUSSION...Moisture from what is now Tropical Depression Alberto,
currently located over central Mexico, has pushed across the
eastern third of Arizona. The deepest moisture and most unstable
air mass according to model soundings will be along and north of a
line extending from Heber to Show Low to Springerville and
includes the Chuska Mountains, Defiance Plateau and the Chinle
Valley. Storms today will move generally from south to north and
will be capable of producing 0.50 to 1.00 inch downpours, wind
gusts in excess of 50 mph and localized storm runoff. The western
boundary of the moisture extends as far west as Flagstaff and Page
but a mid-level cap of relatively warm air will likely result in
extremely isolated storms that far west. Shower storm activity
will continue overnight but gradually diminish in coverage and
intensity.

On Friday...Moisture from Alberto spreads further north and west
with at least a slight chance of showers even across our lower
elevations locations of Bagdad and Black Canyon City. Elsewhere,
deep moisture and unstable lapse rates will result in a good
chance of showers and thunderstorm especially during the afternoon
with daytime heating. Activity will diminish but likely not end
overnight.

For Saturday into Tuesday...High pressure expands across Arizona.
The flow around the high will phase will the remnants of Alberto to
the south to induce our first surge of moisture from over the Gulf
of California. The onset of deep easterly flow over Mexico and the
predominate flow being from sea to land with daytime heating
indicates that our first monsoon pattern of the year will set upon
us. Look for daily chances for showers and storms with day-to-day
variations in storm intensity and coverage. Decent rainfall
accumulations will be observed during this period exactly where is
part of the mystery of the monsoon.

From Wednesday onward...A drying trough from the west will push
monsoon moisture eastward taking most of northern Arizona out of the
action. However, moisture will likely linger in the vicinity of the
eastern Mogollon Rim and White mountains for a continued shower and
storm threat.

&&

.AVIATION...Friday 21/00Z through Saturday 22/00Z...Expect
isolated to scattered -SHRA/-TSRA to continue this evening through
05Z with brief periods of MVFR VIS and CIGS, along and east of a
KPGA-KFLG-KPAN line. Showers and BKN clouds look to continue
through the night across much of NWS AZ. Storms will develop again
on Friday, with scattered to numerous storms along and near the
Utah border after 18Z, with MVFR and local IFR conditions. Expect
south to southwest winds on Friday 20-30kts.

OUTLOOK...Saturday 22/00Z through Monday 24/00Z...Showers that
develop on Friday will continuing into the night, with the greatest
coverage along the Utah and New Mexico borders. Moderate chances
for -SHRA/-TSRA continue through the weekend across all of
northern Arizona.

&&

.FIRE WEATHER...Friday and Saturday...With moisture increasing into
the weekend, expect rounds of scattered to widespread showers and
thunderstorms each afternoon. Wetting rains (>0.10") are likely with
any storms as well as gusty and erratic outflow winds up to 40 mph.
Showers could continue overnight with good humidity recovery.
Outside of any outflow winds, anticipate enhanced south to southwest
winds, 25 to 35 mph, on Friday followed by much lighter southerly
winds, 10 to 15 mph, on Saturday.

Sunday through Tuesday...The active monsoonal pattern persists
through Monday with 40 to 60% chances for showers and thunderstorms
along and south of the Mogollon Rim and White Mountains. By Tuesday,
chances decrease, however, isolated to scattered activity is
forecast at this time, mainly along the higher terrain. Temperatures
remain seasonal throughout this time with light southwesterly flow,
10 to 15 mph, each afternoon.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

PUBLIC...McCollum
AVIATION...BAK
FIRE WEATHER...LaGuardia

For Northern Arizona weather information visit
weather.gov/flagstaff