Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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FXUS65 KFGZ 271033

Area Forecast Discussion
National Weather Service Flagstaff AZ
333 AM MST Mon Feb 27 2017

.SYNOPSIS... An wet unsettled pattern will continue through the
first half of the week, with breezy and cool conditions combined
with widespread rain and snow showers. Dry weather and a warming
trend is then forecast Wednesday through the end of the week.


.DISCUSSION... An active short term period is in store for
Northern Arizona to start the work week. Winds overnight have
remained relatively quiet, however some locations on the downwind
side of the higher terrain have experienced some gusty winds due
to ducting of stronger winds aloft down to the surface. These
gusts are not expected to be widespread and will hold off against
a warning at this moment. However the occasional gust up to 40 mph
will be possible through the early morning hours.

As daytime heating begins and the nocturnal boundary layer
dissipates wind speeds will increase across the area ahead of the
cold front that will usher in the next winter storm. Some showers
are expected to occur this afternoon and evening ahead of the main
precipitation later tonight. Models continue to show a tight but
significant moisture plume that will supply the bulk of this
storms moisture. Integrated water vapor transport analysis
continue to shows a plume of moisture that is capable of produce
areas of 2 to 3 inches of precipitation over parts of the Mogollon
Rim. While this idealized solution will be likely be above what
actually precipitates out, it is worth noting the incredible
precipitation efficiency and this winter event is capable of
especially since the bulk of the precipitation is likely to fall
between 5 pm Monday night and 11 am Tuesday Morning as the storm
quickly moves eastward across the state.

Model confidence on timing and location is relatively high at this
point with strong model agreements over most aspects of the storm.
Have continued with the previous timing of the winter storm
warnings and winter weather advisories with only minor tweaks to
the snowfall and rainfall totals for most locations. Snowlevels
continue to remain consistent from model run to run with only
slight deviations from previous solutions noted on this shift.
Most snowfall is expected to fall above 5500 feet with this event.

This will mean that the lower elevations of Yavapai and Gila
counties will see mainly liquid precipitation across their areas
with most locations seeing between 0.75 to 1.5 inches. Some
favored locations will possibly see amounts approaching 2 inches.
All this precipitation will create some hydrologic concerns across
the area, while now widespread flood concerns exist, expect creeks
and washes to run by this Tuesday with some low water crossings
becoming unpassable.

As the system exist the area Tuesday evening precipitation should
end. Cool temperatures are expected to remain around the area
through Wednesday with warming occurring through the end of the
week. As a ridge builds in over the area, and zonal flow returns
by this weekend. Temperatures are expected to remain above
seasonal averages Thursday through this weekend.


.AVIATION...For the 12Z package...An approaching storm
system will produce widespread MVFR conditions with areas of IFR
conditions across the mountains. Surface winds southwest 15-25 knots
gusting locally to 40 knots. Rain and snow showers on the increase
18Z-00Z west of a Prescott-Flagstaff-Grand Canyon line. Snow level
around 6000 feet. Aft 00z Tues Widespread rain and snow, heavy at
times,  over most or northern Arizona, producing IFR/LIFR
conditions. Snow level 6000-7000 feet. Aviation discussion not
updated for TAF amendments.


.FGZ WATCHES/WARNINGS/ADVISORIES...Winter Weather Advisory from 5 PM this afternoon to 5 PM MST
Tuesday FOR AZZ011-039.

Winter Weather Advisory from 11 AM this morning to 11 AM MST
Tuesday FOR AZZ004.

Winter Storm Warning from 5 PM this afternoon to 5 PM MST
Tuesday FOR AZZ016-017.

Winter Storm Warning from 11 AM this morning to 11 AM MST
Tuesday FOR AZZ015.




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