Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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FXUS65 KFGZ 251736
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1036 AM MST Mon Mar 25 2024

.SYNOPSIS...Cold and unsettled weather, with periods of rain and
snow continue through Tuesday. Drier and warmer weather returns
mid-week, however winter weather potentially makes a return over
the weekend.

&&

.UPDATE...Forecast still on track for the afternoon: can already
see instability increasing to south/east of I-17/I-40. Stable
wave clouds are being observed along with some cumulus showing
signs of increasing heights along the southern Mogollon Rim and
White Mountains. This will be the concentration for showers and
storms today. With elevated snowlevels today, still expecting most
snow accumulations to be the higher elevations of the White
Mountains (greater than 8000 feet).

POPs were adjusted and brought further north to Flagstaff with
some isolated activity expected this afternoon: likely areas that
far north will fall as graupel instead of rainfall or snow.

Better forcing is expected Tuesday with continued instability.
Together, Tuesday afternoon still looks to hold greater coverage
of showers and storms with a hodge-podge mix of rain, snow, and
graupel expected for areas mainly SW and along higher terrain.

&&

.PREV DISCUSSION /410 AM MST/...through this morning...The earlier
band of moderate to heavy snow is moving southeastward through
the White Mountains and out of the area. Some lingering snow
showers look possible through around 4 AM MST near the Whites, but
most of this activity should be minimal.

Elsewhere, decreasing mid-level clouds should give way to clear
skies and cold overnight temperatures. However, areas of low clouds
and patchy fog look to remain over the High Country, which could
keep temperatures not as cold. Any untreated surfaces overnight will
likely be slick overnight as temperatures fall below freezing.

Today and Tuesday...Rain and snow-showers redevelop this afternoon
as Arizona remains within the grip of a longwave trough. Coverage
should remain a bit less than what we saw on Sunday, with the
greatest coverage and intensity expected to be concentrated south
and east of the Flagstaff. A few rouge showers will be possible
elsewhere, but mostly dry conditions are expected. Model soundings
show steepening low- and mid-level lapse rates (around 8-10 C/km)
into the afternoon hours, which should result in enough instability
for some more vigorous snow showers to develop. These showers will
have the potential to produce brief periods of whiteout conditions
and quick snow accumulations. Snow levels look to be around
5500-6000 feet, but warmer surface temperatures will likely result
in accumulations being minimal or at least not long lasting.
Nevertheless, the rapid onset of snow and quick accumulations will
still be impactful on the roads.

By Tuesday, another around of showers looks to develop, this time
with bit more add upper-level dynamics as a shortwave rotates
through the trough axis. Given the added dynamics, coverage and
intensity look to increase a bit for Tuesday afternoon. HREF
probabilities of greater than 1 inch per hour snowfall rates are
largely concentrated along the Mogollon Rim and eastward to the
White Mountains, thus the greatest impacts are expected for these
areas. Snow levels look to rise a bit, to around 6000-6500 feet.

Wednesday through Sunday...High pressure builds into the region
from the west, ushering in much warmer temperatures and drier
conditions to finish out the week. As the ridge peaks on Thursday,
temperatures look to be within about 5 degrees of normal, with
afternoon high temperatures in the mid 50s F to mid 60s F over the
High Country and low 70s F to mid 80s F over the lower elevations.

By the weekend, the latest guidance has pushed back the next storm
by about a day, with precipitation chances now looking to begin
on Sunday. Uncertainty with this system to remains, so confidence
in exact timing and impacts is low at this point in time. Gusty
winds still look to precede this system on Friday and Saturday.

&&

.AVIATION...Monday 25/18Z through Tuesday 26/18Z...Mainly VFR
conditions are expected across much of the region today. Periods
of MVFR/IFR VIS and CIGS are forecast from 20Z-02Z due to
scattered -SHSN/-SHRA along a KFLG-KSEZ-KPAN-KSOW line. SCT-BKN
low-level clouds will persist overnight. Anticipate west-
northwest winds for this afternoon, 15-25 kts, becoming 5-10 kts
after 02Z.

OUTLOOK...Tuesday 26/18Z through Thursday 28/18Z...Increased -SHRA/-SHSN
coverage is likely for Tuesday along and south of I-40 from 19Z-03Z.
Expect periods of MVFR/IFR conditions during this time. Widespread
VFR conditions return for Wednesday and Thursday due to a drying
trend. Anticipate breezier west-northwest winds on Tuesday, 15-30 kts,
becoming lighter, 10-15 kts, on Wednesday. Southwest winds, 15-25 kts,
return on Thursday.

&&

.FIRE WEATHER...Today and Tuesday...Expect scattered rain and
mountain snow showers this afternoon across the eastern Rim and the
White Mountains. Showers diminish later this evening with another
round likely for Tuesday afternoon along and south of I-40.
Anticipate temperatures 10 to 15 degrees below average with west-
northwest winds, 15 to 25 mph, each afternoon.

Wednesday through Friday...A warming and drying trend develops for
the latter half of the week as temperatures return to average.
Expect light west-southwest winds on Wednesday, followed by gustier
southwest winds, 15 to 25 mph on Thursday and 25 to 35 mph on
Friday.

&&

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

&&

$$

PUBLIC...RKR/Humphreys
AVIATION...LaGuardia
FIRE WEATHER...LaGuardia

For Northern Arizona weather information visit
weather.gov/flagstaff


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