Tornado in Arizona, November 19, 2023

Area Forecast Discussion
National Weather Service Flagstaff AZ
920 AM MST Sun Nov 19 2023

.SYNOPSIS...Rain and high elevation snow showers are expected
through tonight, along with gusty winds and colder temperatures.
Drier and warmer conditions return by the middle of the week.

&&

.DISCUSSION...A fast-moving s/wv trough, currently located at the
far southwestern corner of Utah, will dive through northern Arizona
today and into New Mexico this evening. This is not a particularly
strong trough, but what makes it interesting is the unusually moist
and unstable airmass ahead of the trough axis, as well as the cold
air behind the frontal passage.

Because of the moisture, QPF values have been a bit higher than what
one would typically expected, especially with the NW-SE trajectory.
Areas along the Utah/Arizona border are also seeing significant
convection along and just ahead of the frontal boundary, as well as
within the mid-level cold pool. This will translate to the southeast
through Arizona today, with the best forcing and instability mostly
north and east of Flagstaff. The frontal boundary will come through
the Flagstaff area at around 2 PM MST this afternoon, this is our
best shot for a brief period of snowfall, albeit mostly above 7000-
7500 feet.

Some of the convective showers have already produced accumulating
ice pellets near Kachina Village, so snow levels will need to be
watched carefully. However, current thinking of the most snow over
the upslope sides of the Kaibab Plateau, Chuska Mtns and the White
Mtns seems reasonable. A Winter Weather Advisory is in place.

This s/wv also features a tight gradient ahead of the front, with
the downslope side of the Mogollon Rim likely producing marginal
Wind Advisory gusts this afternoon. A Wind Advisory is in place.

Precipitation will end from west to east this evening, lingering the
longest along the New Mexico border. Winds then shift to the north
and northeast heading into Monday, along with cool and much drier
air. The northeast winds may become locally strong downwind of
higher terrain features, but does look widespread enough for
additional headlines at this time.

The remainder of next week features warming temperatures and less
wind, with a possible disturbance late in the period. Models are
handling this next potential trough quite different, so not much
confidence at this time.

These trends are reasonably handled in the current forecast package
and no short term updates are planned.

&&

.AVIATION...Sunday 19/12Z through Monday 20/12Z...Periods of MVFR
to IFR VIS and CIGS are expected through 00Z Monday due to
scattered showers mainly along and north of a KGCN-KFLG-KSOW line.
-SHRASN are forecast (30-45%) at KGCN-KFLG with no accumulation
expected. Low CIGS will lead to mountain obscuration throughout
the day. VFR conditions return after 00Z with -SHSN continuing in
the White and Chuska mountains. Gusty west-southwest winds, 25-35
kts, are expected after 16Z, becoming west-northwest after 21Z due
to a frontal passage. Winds weaken to 5-15 kts after 02Z.

OUTLOOK...Monday 20/12Z through Wednesday 22/12Z...Widespread VFR
conditions are forecast throughout the period with clear skies.
Gusty north-northeast winds, 15-25 kts, are likely on Monday,
becoming lighter for Tuesday and Wednesday.

&&

.FIRE WEATHER...Today through Monday...A trough of low pressure
moving from west to east across Utah and northern Arizona will bring
rain showers, high elevation snow showers, and thunderstorms through
this evening. Gusty westerly winds, 25-40 mph this afternoon, will
becoming lighter and more northerly this evening. Drier and colder
conditions on Monday, with breezy, 15-30 mph, north to northeast
winds.

Tuesday through Thursday...The drying trend continues with warming
temperatures likely through Thursday. Northeast winds, 10-25 mph,
persist on Tuesday, becoming much lighter and variable on Wednesday.
Breezy southwest winds return on Thursday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

Wind Advisory from 11 AM this morning to 6 PM MST this evening for
AZZ012>014-016.

Winter Weather Advisory above 8000 feet until 6 PM MST this evening
for AZZ004.

Winter Weather Advisory above 8000 feet until 3 AM MST Monday
for AZZ011.

Winter Weather Advisory above 8500 feet until 3 AM MST Monday for
AZZ017.

&&

PUBLIC...Peterson
AVIATION...LaGuardia
FIRE WEATHER...MAS

For Northern Arizona weather information visit
weather.gov/flagstaff