Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 191044
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
345 AM MST Thu Jan 19 2017

.SYNOPSIS...A series of winter storms will affect the region from
today, through Monday or Tuesday of next week. These will be cold
systems, with heavy accumulations of snow across the high country.
Hazardous driving conditions should be anticipated for the next
several days.

&&

.DISCUSSION...The first in a series of pacific storms is already
bringing showers to the Lower Colorado River this morning. A shallow
saturated layer formed several hours ago as upslope flow increased
across the area. This layer will slowly deepen this morning as the
mid-levels moisten from the top down. We expect showers to move in
from the west shortly, as well as increasing activity along the
Mogollon Rim due to moist upslope flow. Trailing this initial area
of showers is a well defined s/wv over central California. This wave
will arrive this evening, spreading heavier rain/snow and falling
snow levels from west to east across the region.

Decreased shower activity is anticipated behind this first wave on
Friday, although moist and moderately unstable flow in the boundary
layer will keep showers going along and south of the Mogollon Rim
and other higher terrain features.

The second system arrives Friday evening and into Saturday morning.
This storm will be of a longer wavelength and will contain a better
and more prolonged moisture feed. This system will also contain more
cold air through the mid-levels, enhancing shower activity and
bringing lower snow levels. It is likely that the second storm will
add about double the QPF, compared to our first system today and
tonight.

Moist and moderately unstable air persists on Saturday as the main
system head east, s/wv ridging should end shower activity Saturday
night.

On Sunday, a large moisture fetch develops in the eastern Pacific
ahead of the third storm system. We expect warm advection showers to
develop as early as Sunday morning. Heavier precipitation develops
Sunday night and Monday as dynamics and cold advection increase
ahead of a cold trough due Monday afternoon. This could be the
highest QPF producer of all three storms, but it is just a bit too
early to tell.

Moist and unstable air persist Tuesday and possibly Wednesday, for a
continuation of cold temperatures and shower activity.

Additional impacts include possible flooding over Yavapai and Gila
counties, due to several days of rainfall.

Gusty winds will accompany each storm, especially Friday night and
Monday. Blowing and drifting snow could add to travel issues.

This will be a challenging 5 day period, persons with travel in
mind, or others with outdoor interests, need to take appropriate
precautions.

&&

.AVIATION...For the 12Z package...A storm system will move across
northern Arizona over the next 24 hours, with widespread MVFR
conditions in rain and snow showers spreading from west to east
across the area. Local IFR/LIFR conditions will also be possible
over the higher terrain. Aviation discussion not updated for TAF
amendments.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

Winter Storm Warning above 5500 feet from 6AM MST today until 12PM
MST Saturday for AZZ004-006>008-015-038.

Winter Storm Warning above 5500 feet from 12PM MST today until
12PM MST Saturday for AZZ016>018


&&

$$

PUBLIC...Peterson
AVIATION...KD


For Northern Arizona weather information visit
weather.gov/flagstaff


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