Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 102231
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
331 PM MST Tue Jan 10 2017

.SYNOPSIS...Expect fair weather today across northern Arizona
under partly sunny skies. A cooling trend starts Wednesday for all
with a chance of light showers across northwestern parts of the
state. A potentially stronger and colder weather system is
expected from Thursday through Saturday.

&&

.DISCUSSION...

Tuesday Afternoon through Wednesday night

Visible satellite shows gravity waves in the cloud field, indicative
of stable air and strong winds aloft. Forecast soundings show an
inversion height just above 700 mb overnight, which may be ideal for
bringing strong winds down to the surface to the lee of high terrain
features within the stable layer. GFS soundings indicate winds of 40-
50 kt within this layer. We have issued a Wind Advisory for
overnight tonight just to the east of Flagstaff, and in the western
Little Colorado River valley.

A fast-moving short-wave trough will make its way across far
northern Arizona on Wednesday afternoon. Expect breezy west to
southwest winds with this feature especially near and north of
Interstate 40, as well as rain and snow showers primarily along the
high terrain from about Heber northwestward. Mostly light
accumulations are expected, with up to 2-3" of snow possible on the
Kaibab Plateau.

Thursday morning through Wednesday

Models continue to show a significant spread in forecast
solutions for the passage of a closed low currently over the
Pacific Ocean off the Washington Coast. The low pressure system is
expected to move southeast down the Pacific Coast until it South
of California, off the Baja Peninsula by Saturday. From that
point the low pressure is expected to begin an eastward path
through Mexico before finally beginning to track back northward
around El Paso Sunday Afternoon.

While confidence is not high regarding this track, both
operational models of the GFS and ECMWF have a similar position
with low centers within 100 miles or so of each other. If the
eventual track is similar to these solutions, impacts to Northern
Arizona will be somewhat limited. Widespread snow accumulations
for the high country would be limited to advisory level or less.

There is still a few ensemble solutions that bring the low
pressure system closer to Northern Arizona, if that happens
precipitation amounts would likely increase dramatically in
proximity to the low, however a lack of cold air advection may
limit snow amounts. Again confidence remains low concerning the
track of this system, but consensus is trending towards a passage
further south, with less localized impacts to Northern Arizona.

Beyond Sunday, model consensus continues to degrade with time,
and have gone with a mean solution to provide a moderated forecast
for the eventual solution. Suk

&&

.AVIATION...For the 00Z Forecast...Largely VFR conditions
are expected through 09-12Z Wednesday with SCT to BKN MVFR to low
VFR clouds SW of the Mogollon Rim possible this evening. Localized
strong gusty SW winds are forecast northeast of high terrain
features overnight tonight. MVFR to low VFR ceilings possible near
and NW of a line from KPGA-KFLG-KSEZ starting at 12Z, expanding
farther south and east after 18Z. Aviation discussion not updated
for TAF amendments.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...Wind Advisory from 6 PM this evening to 8 AM MST Wednesday FOR
AZZ012-015.


&&

$$

PUBLIC...AT/Suk
AVIATION...AT


For Northern Arizona weather information visit
weather.gov/flagstaff



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