Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 121247
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ...coorectred
547 AM MST Thu Apr 12 2018

.SYNOPSIS...Expect very strong southwest winds today as a cold
front moves across the northland. Blowing dust and dangerous
crosswinds are likely across the northeast quarter of the state
through this evening. Friday will have cool temperatures and gusty
northwest to north winds. Dangerous fire weather conditions are
anticipated today and Friday. Expect warming temperatures and
lighter winds this weekend. Another bout of gusty southwest winds
possible Monday.

&&

.DISCUSSION...

The forecast focus has been on the very strong winds expected
across the northland due to a cold frontal passage today. Todays
forecast 700 mb (10000 ft msl) wind speeds are in the 95th-99th
percentile when compared to observed data for this time of year,
for the years 1979-2009.

At 3 AM MST, the surface front stretched from Provo Utah to north of
Las Vegas to just north of Los Angeles. Ahead of the front very
strong southwest flow covers the Desert Southwest, with 50 to 65 MPH
speeds at the 10000 foot MSL level. We have seen some isolated gusts
to 50 MPH already this morning on the Kaibab Plateau. As this
morning progresses, the current deck of high level cloud cover to
move east and we will see increasing mixing in the lower atmosphere
bringing faster wind speeds.

Todays High Wind Warning and Wind Advisory look good. Models have
been consistently showing central Navajo and Apache Counties to have
the fastest winds for this event, and we expect SW winds sustained
from 30 to 45 MPH with gusts to 65 MPH this afternoon.
Elsewhere winds from the southwest 20 to 40 MPH with gusts to 55
MPH. We have added a Dust Storm Warning for area east and north of a
line from Marble Canyon to Winslow to St Johns as visibilities
should go under one quarter mile at times. Travel today will be
difficult, especially across the northeast quarter of the state. The
winds direction to shift to westerly this afternoon across Yavapai
and Coconino County with speeds slowly decreasing.

For tonight, some skimpy mid level moisture to move into areas
north of a line from Supai to Window Rock and bring a slight
chance of a light shower. The upper trough axis will be moving
through and by sunrise Friday very fast northwest flow to affect
our area. Gusty northwest wind to blow on Friday and another wind
advisory may be needed for Navajo and Apache counties. Max temps
Friday to be around 10 degrees below normal for the date.

Saturday through Monday...High pressure moves in for warming
daytime temperatures Saturday and Sunday. North northeast surface
winds Saturday will slow with time. Winds at all levels become
southwest on Sunday in advance of another low pressure system.
Another wind event similar to todays is possible Monday afternoon.

&&

.AVIATION...For the 12Z package...VFR conditions will prevail over
the next 24 hours under periods of high clouds. A cold front will
move across the area today with increasing southwest winds. The
strongest winds will be east and northeast of Flagstaff where
southwest gusts into the 50 to 60 knot are possible. Blowing dust
and sand will lower the visibility...even above the surface. Winds
will become northwest behind the front starting around 00Z in
northwest Coconino County to around 06Z in southern Apache County.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...A Red Flag Warning remains in effect today  for all
of northern Arizona from Noon to 1900 LST. Winds will increase mid-
morning, with gusts into the 45 to 65 MPH range - strongest across
Navajo and Apache Counties. Much cooler weather is forecast Friday,
but gusty north-northwest winds and dry conditions will combine to
produce continued Red Flag Conditions for portions of the area.

Saturday through Monday...Dry conditions with less wind is expected
for the weekend. Another round of very strong winds possible Monday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...Red Flag Warning from noon today
to
7 PM MST this evening FOR AZZ104>118-137>140.

Red Flag Warning from noon to 6 PM MST Friday FOR AZZ108-113>117-
137-138.

Wind Advisory from 7 AM this morning to 7 PM MST this evening
FOR AZZ004>010-015-016-018-037>039.

Dust Storm Warning from 9 AM this morning to 7 PM MST this
evening FOR AZZ005-009>014-039-040.

High Wind Warning from 9 AM this morning to 7 PM MST this
evening FOR AZZ011>014-017-040.


&&

$$

PUBLIC...DL
AVIATION...MAS
FIRE WEATHER...MAS


For Northern Arizona weather information visit
weather.gov/flagstaff



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