Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 242145
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
245 PM MST Sat Oct 24 2020

.SYNOPSIS...Windy and cooler weather is forecast through Sunday
as a cold front approaches Arizona. The fastest winds will occur
Sunday afternoon, with southwest gusts from 35 to 50 mph. The
front will bring much colder temperatures Monday and Tuesday.
Areas of rain and snow showers are forecast, with light snow
accumulations above 6000 feet. A hard freeze is likely above 4000
feet Monday and Tuesday nights. Warmer and dry weather returns
starting Wednesday.

&&

.DISCUSSION... Extensive cirrus cloud covers northern Arizona
this afternoon. We are observing southwest wind gusts in the 20 to
30 mph range. The cold front forecast to arrive Sunday night is
now moving southward through the Pacific NW.

The forecast focus remains on impacts ahead of (SW wind) and
behind (rain and snow showers) the cold frontal passage Sunday
night. Forecast confidence is greatest in increasing southwest
wind speeds and gusts Sunday, and in the 20 to 30 degree cooling
in Mondays high temps versus today. Less confidence continues
in forecast liquid and snow accumulations.

The large scale picture this morning has a weak upper low off the
southern California coast. Sunday nights cold front is now
dipping into the Pacific Northwest.

For tonight, expect partly cloudy most of the night as cirrus is
directed overhead east of the weak low off the southern California
coast. Gusty downslope winds to persist tonight and Sunday
morning northeast of the higher terrain from the House Rock Valley
to Doney Park to Springerville.

On Sunday, A Wind Advisory is in effect for much of northeast
Arizona from 9AM to 6PM MST. This has been expanded to now
include most of Coconino County as well as the Chinle, Page and
Monument Valley areas. Southwest winds 20 to 35 mph with gusts to
50 mph are forecast. Areas of blowing dust are probable across the
northeast quarter of the state. We may see some low level cloud
cover stream into the Mogollon Rim as the weak low takes a path
across Baja Ca.

Sunday night and Monday - Progs are in good agreement with the
surface cold front moving southward from Utah into AZ Sunday
evening, and developing a closed low over us Monday. QPF trends
are going down, and model cross sections are on the skimpy side
with moisture depth, especially post frontal passage. At this
time, scattered rain showers are forecast to change over to snow
showers by Monday morning for most areas north of I-40 and above
6000 feet. Snow shower coverage to push southeast along the
Mogollon Rim during the day Monday. Current indications are for
the best time for light snow accumulations are Sunday night and
Monday.

Monday night, the upper low center should move south across our
state. At this time shower chances are forecast to decrease or end
from west to east overnight. We have decreased the forecast QPF
for the Monday night period, now following HPC`s forecast which
has .15" liquid in the White Mtns, and less across Navajo and
Apache counties. Very strong northeast downslope winds are
probable Monday night into Tuesday morning for areas along and
south of the Mogollon Rim.

Tuesday looks like a transition day to dry weather, as the low
center moves into SW New Mexico. Precip chances are ending west of
a Four Corners- Flagstaff- Phoenix line. East of this line,
moisture may wrap around the low center and bring widely scattered
showers.

Wednesday through Saturday - Dry weather is forecast as weak
ridging develops over the desert southwest. Max temps warm to a
few degrees above normal by Saturday. Overnight low should be a
few degrees below normal.

&&

.AVIATION....For the 00Z package...VFR conditions will prevail for
the next 24 hours. Southwest winds will weaken after sunset, but
remain gusty northeast of higher terrain features. Stronger
southwest winds of 15-25 kts with gusts 30-40 kts will develop mid
to late Sunday morning. Light shower activity is possible north of a
KGCN-KRQE line on Sunday afternoon. Aviation discussion not updated
for TAF amendments.

&&

.FIRE WEATHER...Expect strong southwest winds on Sunday. Relative
humidity values will be well above 15 percent in most places and
critical fire weather conditions are not expected. Much colder
temperatures will occur Monday as a cold front moves through. Areas
of rain and snow will develop later Sunday and continue on Monday.
The best chance for wetting precipitation will be east of the I-17
corridor. Strong northeast winds develop behind the front Monday.

Tuesday through Thursday...Rain and snow showers will linger on
Tuesday from Flagstaff eastward with continued gusty northeast
winds. Dry and warmer weather returns Wednesday and Thursday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...Wind Advisory from 9 AM to 6 PM MST Sunday FOR AZZ004>007-
009>017-039-040.


&&

$$

PUBLIC...DL
AVIATION...TPS
FIRE WEATHER...TPS


For Northern Arizona weather information visit
weather.gov/flagstaff


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