017
FXUS65 KFGZ 210534
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1034 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.

&&

.UPDATE...The showers and thunderstorms today brought some much-
welcomed precipitation to central and northern Arizona, with local
accumulations of over 0.5"+ in the heavier storms. Several reports
of small hail were also received this afternoon. Activity has
decreased this evening, with the remaining scattered showers and
thunderstorms moving northeast through Navajo and Apache
Counties at this time. Most of the precipitation should dissipate
or move out of Arizona by midnight.

The current forecast is on track, and only minor updates were made
this evening to account for the evolution of the storms this
evening and overnight. Expect another round of thunderstorms
tomorrow (most numerous along the Utah border), with more
widespread storm coverage on Saturday.

&&

.PREV DISCUSSION /450 PM MST/...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 21/06Z through Saturday 22/06Z...Only a few
isolated showers expected overnight, with generally southerly
winds decreasing to 5-15 mph most areas. 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, and gusty
around thunderstorms.

OUTLOOK...Saturday 22/06Z through Monday 24/06Z...Showers and
thunderstorms will develop again on Saturday and Sunday (30-60%
chance) with MVFR and local IFR conditions in the stronger
storms.

&&

.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...BAK/McCollum
AVIATION...BAK
FIRE WEATHER...BAK

For Northern Arizona weather information visit
weather.gov/flagstaff