Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 182233
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
333 PM MST Wed Jan 18 2017

.SYNOPSIS...A series of winter storms will affect the region from
Thursday through Saturday. Additional storms are anticipated
early next week. These will be cold systems, with significant
accumulations of snow across the high country. Hazardous driving
conditions should be anticipated for several days, beginning
Thursday.

&&

.DISCUSSION...

.SHORT TERM...Hazardous winter weather will arrive across the high
country Thursday and continue at times through Saturday...and a
Winter Storm Warning has been issued for areas above 5500 feet
elevation from the Kaibab Plateau along the Mogollon Rim to the
White Mtns...southward into Yavapai and northern Gila Counties.
Here are the latest details and forecast challenges. Wave #1 of
precipitation is expected to begin early Thursday morning across
Yavapai and Coconino counties with snow levels around 5500 ft.
Precip will spread east through the day...producing several inches
of snow above 5500 feet by Friday morning. The first wave exits
the region Friday morning, with precipitation intensity likely
decreasing. However, there is still a moist and cold westerly
flow during the day Friday, and periods of snow are likely to
persist especially over the higher elevations. The next even
colder wave arrives late Friday afternoon and moves slowly
eastward across northern Arizona through Saturday morning. This is
when the heaviest precipitation is expected, with snow levels
5000-5500 ft Friday afternoon falling to 4000-4500 ft by Saturday
morning. Travel conditions are likely to become hazardous, please
plan accordingly. Precip intensity will decrease Saturday
afternoon, though a cold northwest flow will allow for snow
showers to persist along the higher terrain. Total snowfall
accumulations for the 3-day event will be heavy, in general 1-2
feet above 6500 feet elevation, 8-16 inches 5500-6500, lesser
amounts down to around 5000 feet. Please check your point specific
forecast at weather.gov/Flagstaff.

.LONG TERM...From Saturday night through Tuesday - Models are in
good agreement showing clearing weather from west to east
Saturday night. From Sunday onward, timing issues and the number
of additional shortwaves bringing bouts of winter weather bring
decreasing confidence. The GFS has strong warm air advection
Sunday with rising snow levels and precip redeveloping across
Coconino county. This followed by a another strong cold front
passage Monday then a broad trough generating instability showers
through Tuesday. The ECMWF and to a lesser extend the Canadian
have two waves crossing our area. The first Sunday night and the
second Monday night. All 3 models have h5 temps near -30c over the
area on Tuesday. So we have kept scattered to numerous showers
going Sunday across Coconino county Sunday and expended them
across the area Monday. Tuesday should see decreasing shower
coverage. High and low temps to be well below normal.

&&

.AVIATION...For the 00Z package...A cold front will be moving
west to east across northern AZ on Thursday. Until 06z Thu Areas of
MVFR Cigs over higher terrain east of a KPAN-K0V7, with coverage
decreasing after 06z.

Areas west of a KPGA-KPRC line til 09z Thu bkn-ovc cigs developing
with bases down to 11 kft msl. Aft 09z Thu widespread MVFR with
local IFR in rain and snow. Sfc winds S-SW 10-20kt with gusts to
30kt. These conditions spreading eastward to K0V7-KPAN line by 18z
and to the New Mexico line by 00Z Fri.  Aviation discussion not
updated for TAF amendments.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...Winter Storm Warning from 6 AM
Thursday to noon MST Saturday FOR AZZ004-006>008-015-038.

Winter Storm Warning from noon Thursday to noon MST Saturday FOR
AZZ016>018.

&&

$$

PUBLIC...JJ
AVIATION...DL

For Northern Arizona weather information visit
weather.gov/flagstaff



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