Dust Storm Warning 2, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
415 AM MST Wed Apr 18 2018

.SYNOPSIS...Expect cold morning low temperatures, followed by
warmer weather Wednesday afternoon with less wind. Strong winds
are expected again Thursday ahead of a cold front. There will be a
chance of rain and snow showers Thursday night into Friday, then
fair and warmer conditions return for the weekend.

&&

.DISCUSSION...
A quiet period of weather is expected for the area Wednesday as a
weak ridge of high pressure moves across the southwest today. Cold
conditions are occurring across the area, but should quickly
dissipate as most locations climb back up toward climatological
normals for high temperatures today.

With the ridge exiting the region Wednesday night, the next strong
shortwave system is expected to quickly sweep across the region
Thursday bringing the next round of strong southwesterly winds.
Timing of the winds maximum aloft with the diurnal heating looks
to be more in line this time, with daytime heating allowing for
maximum mixing of winds down to the surface.

A high wind warning, and wind advisory has been issued for
Coconino, Yavapai, Navajo, and Apache counties. The strongest
winds are expected to occur along and north east of the higher
elevations.

Winds will also combine with dry condition to create critical
fire weather conditions late Thursday morning through Thursday
evening. A red flag warning has been issued due for the entire
area because of this threat.

Strong winds are also expected to create blowing dust capable of
quickly reducing visibilities below one quarter mile Thursday. The
main area of concern is the from the Little Colorado River Valley
North and East to the Four Corners Region. This includes sections
of Interstate 40 east of Flagstaff, and Navajo and Hopi Nations.

As the low pressure system crosses the Four Corners region around
precipitation, will move into northern Arizona from the north.
While widespread precipitation is not anticipated, showers across
much of northern Arizona are a possibility. However this potential
has dropped from previous model runs as the position of the
trough has moved further north. Colder temperatures are also
expected on friday with this track.

Looking into the weekend, cooler temperatures on Saturday will
begin to warm up as a ridge of high pressure builds into the
region on Sunday and looks to remain in place through the middle
of next week.

&&

.AVIATION...For the 12Z package...Expect VFR conditions through
12z Thursday. Surface winds light easterly through 18z Weds then
shifting to southerly to southwest 5-15 kt. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...Expect very dry conditions through Thursday.
Cold temperatures this morning will warm considerably through the
day. Winds will be generally light northeast to easterly shifting
southeasterly, then south to southwesterly in the afternoon. A
strong cold front approaching the area Thursday will bring strong
winds and widespread critical fire weather conditions to nearly all
of the region.

Friday through Sunday...Scattered light rain and snow showers will
develop behind the front Thursday night and Friday, with much
lighter winds and higher relative humidities. Drying and warming
returns Saturday and Sunday, with generally light winds.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...High Wind Warning from 11 AM to 8 PM MST Thursday FOR AZZ012>017-
039-040.

Red Flag Warning from 11 AM to 8 PM MST Thursday FOR AZZ104>118-
137>140.

Wind Advisory from 11 AM to 8 PM MST Thursday FOR AZZ004>011-037-
038.

Dust Storm Warning from 11 AM to 8 PM MST Thursday FOR AZZ005-
009>014-039-040.

&&

PUBLIC...Suk
AVIATION...DL
FIRE WEATHER...DL

For Northern Arizona weather information visit
weather.gov/flagstaff