Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 181632
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
932 AM MST Sun Feb 18 2018

.SYNOPSIS...Expect a very windy and colder period, with areas of
rain and snow, starting tonight and lasting through Tuesday.
Drier, but cool weather arrives Wednesday and Thursday, with a
chance of rain and snow again by the end of the week.

&&

.UPDATE...
The powerful cold front headed our way is now located from just
north of Salt Lake City through Reno thence to the west southwest.
Satellite imagery shows upslope clouds across the SW facing
slopes of central AZ. We are already seeing wind gusts in the
30-40 mph range around Show Low.

We are headed for a very windy period here in northern AZ from
this afternoon through late Monday afternoon. We will be tweaking
Mondays wind forecast upward a bit, and likely converting Mondays
high wind watch for the northeast quarter of the state to a
warning. Travel across the Navajo and Hopi nations, I-40 etc.,
Monday looks very dangerous.

No other changes planned at this time.

&&

.PREV DISCUSSION /415 AM MST/...A cold upper low over eastern
Washington early this morning will move into the northwestern
Great Basin later this afternoon and into the southern Great
Basin by Monday. A powerful cold front associated with this storm
will sweep through the state on Monday, preceded by upslope rain
and snow showers starting as early as this afternoon.

Pressure falls ahead of the front will allow for a moist return
flow to develop, especially along and south of the Mogollon Rim
and White Mountains. This will lead to a robust upslope shower
period as southwest winds strengthen, starting late today or
early tonight and continuing through Monday. Precipitation will
be enhanced along the cold front Monday afternoon, followed by
continued upslope flow and instability showers Monday night and
Tuesday.

The airmass behind the front is very cold, snow levels will reach
the valley floors Monday night. High temperatures Tuesday may be
close to the coldest this winter season.

A variety of headlines have been issued, for both wind and winter
weather. Travel conditions in northern and central Arizona Sunday
night through Tuesday will be poor, use caution.

Drier, but continued cold weather is expected Wednesday and
Thursday, with models showing potential for more rain and snow
Friday, perhaps yet another storm early next week.

&&

.AVIATION...For the 18Z Package...Gusty southwest winds will persist
and strengthen over the next 24 hours. Sustained wind speeds of 20-
30 kts with gusts of 35-45 kts. MVFR cigs will become more
widespread along the higher terrain from KFGZ southeast after 20Z,
with scattered showers developing by 00Z. After 06Z, showers will
increase in coverage and intensity with localized IFR conditions
above 6kft MSL due to snowfall and areas of blowing snow. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...On Sunday, gusty southwest winds return as a strong
cold front approaches from the northwest. The strongest winds will
be along and north of the Mogollon Rim, where wind gusts as high as
50 mph will be possible. On Monday, even stronger winds are forecast
as the cold front sweeps across the area. The strongest winds will
likely occur east of Flagstaff, where wind gusts as high as 60 mph
will be possible. In addition, rain and high elevation snow showers
will accompany the front as it moves across the area late Sunday
night through Monday with accumulating snow above 6,000 to 6,500
feet.

Tuesday through Thursday...Chances for snow showers linger into
Tuesday. Dry conditions along with a continuation of below normal
temperatures are forecast for Wednesday and Thursday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...Wind Advisory from 2 PM this afternoon to midnight MST tonight
FOR AZZ004-015>017-038.

Wind Advisory from 2 PM this afternoon to 7 AM MST Monday FOR
AZZ005-006-009>014-039-040.

High Wind Watch from Monday morning through Monday afternoon FOR
AZZ005-009>014-039-040.

Winter Storm Warning from midnight tonight to 5 AM MST Tuesday
FOR AZZ016-017.

Winter Weather Advisory from midnight tonight to 11 PM MST
Monday FOR AZZ004-015.

Wind Advisory from 2 PM this afternoon to 5 PM MST Monday FOR
AZZ007-008.


&&

$$

PUBLIC...DL/Peterson
AVIATION...TPS
FIRE WEATHER...MCT


For Northern Arizona weather information visit
weather.gov/flagstaff



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