642
FXUS65 KFGZ 121536
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
836 AM MST Sun May 12 2024

.SYNOPSIS...Warmer temperatures arrive today and persist, with
slight chances for showers and storms each afternoon through
Thursday. Anticipate typical afternoon breezes through the
forecast period.

&&

.UPDATE...Clear skies are in place this morning across northern
Arizona with little to no wind. Heights will increase throughout
the day today as a shortwave ridge moves into the region from the
west. The PWAT value from this morning`s sounding here in
Bellemont was quite similar to yesterday`s, 0.25"-0.26", with a
bit more moisture in the lower-levels. However, with warming aloft
as the ridge builds in from the west resulting in less instability
overall, shower and thunderstorm activity should be much less in
coverage for this afternoon, mainly confined to the higher terrain
(10-15% chances) according to recent hi-res model guidance.
Cumulus clouds will likely begin to bubble up along the higher
terrain later this morning, but shouldn`t amount to much. Winds
will be out of the north-northwest for this afternoon, 10-20 mph.
Temperatures will be warmer as well, forecast to be a few degrees
above average for this afternoon.

The forecast remains on track with no changes needed at this time.

&&

.PREV DISCUSSION /438 AM MST/...The upper low that brought fairly
widespread light showers and a few thunderstorms to our region on
Saturday continues to exit to the east, leaving us with clearing
skies this morning. Weak ridging will develop over the southwest
for the next few days, with mid-level (500mb) temperatures warming
by 2-5C which will result in a decrease in afternoon instability.
It still looks like enough moisture lingers for a 10-20% chance
of light showers during peak heating over the higher terrain, but
it should be much less coverage than what we saw Saturday.
Afternoon highs will be near normal today, then warm to around 5
degrees above seasonal norms by Tuesday. Northwest winds today
become west to southwest Mon/Tue with speeds 10-20 mph.

Wednesday through Thursday - the combination of a weak low passing
across southern Arizona and a shortwave trough diving in from the
north will bring a pause to the warming trend. Slight increases in
moisture and instability will also bring a bit higher chance of
afternoon showers (20-30%), along with more cloud cover.
Precipitation amounts are forecast to be light, with a tenth of an
inch or less in most spots, up to a quarter inch for isolated
locations that see a heavier shower.

Friday into next weekend - there is good support in the ensemble
data for a trough developing off the west coast and a warmer
southwesterly flow for our region. Dry weather is forecast, with
daytime highs 5-10 degrees above normal (mid 70s mountains, low
80s Prescott, low-mid 90s Verde Valley/LCR Valley).  As the
trough gets closer to Arizona, winds will gradually increase by
the weekend with gusts 25-35 mph in our latest forecasts.

&&

.AVIATION...Sunday 12/12Z through Monday 13/12Z...VFR conditions
will prevail through the period. ISOLD -SHRA/-TSRA will be mainly
confined to the Mogollon Rim, Kaibab Plateau, White Mountains, and
the Chuska Mountains. Outside of any erratic outflow gusts from storms,
expect northwest winds of 15 to 25 mph on Today, followed by
west- southwest winds on Monday.

OUTLOOK...Monday 13/12Z through Wednesday 15/12Z...ISOLD to SCT
afternoon -SHRA/TSRA will continue through Wednesday, mainly
confined to the high terrain. Brief periods of MVFR conditions are
possible in any storms, with much of the region remaining in VFR.
Daytime winds will blow from the southwest-west with gusts 15-25
kts.

&&

.FIRE WEATHER...Today and Monday...Isolated afternoon showers and a
few high-based thunderstorms will be mainly confined to the Mogollon
Rim, Kaibab Plateau, White Mountains, and the Chuska Mountains.
Wetting rain is unlikely. Outside of any erratic outflow gusts from
storms, expect northwest winds of 5 to 15 mph gusting to 25 mph
today, shifting to west-southwest on Monday. Look for Warm
temperatures each day with minimum humidity of 10 to 20%.

Tuesday through Thursday...Shower and thunderstorm chances persist
each afternoon through Thursday with the greatest coverage likely on
Wednesday. Afternoon winds will be out of the west each day at 5 to
15 mph gusting to 25 mph.

&&

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

&&

$$

PUBLIC...LaGuardia/JJ
AVIATION...MAS
FIRE WEATHER...McCollum

For Northern Arizona weather information visit
weather.gov/flagstaff