643 
FXUS65 KFGZ 100337
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
837 PM MST Sun Jan 9 2022

.SYNOPSIS...Look for dry conditions, light winds and cool but
seasonable temperatures through Tuesday. Gusty northeasterly winds
will continue into Monday primarily from Flagstaff to the Grand
Canyon and locations to the southwest. Uncertainty grows towards
the end of next week when rain and mountain snow showers may
return on Friday.

&&

.UPDATE...Light east-northeasterly breezes persist into this
evening and will strengthen a bit overnight for areas immediately
along and southwest/west of high terrain features. Wind gusts up 
to 25-30 mph are expected overnight in these areas. No major grid 
updates were made this evening with northern Arizona on track for 
a quiet start to the work week beginning Monday.

&&

.PREV DISCUSSION /130 PM MST/...High pressure has continued to
build in across the southwest today with increasing easterly
gradients with breezy east to northeast winds. Expect these
easterly breezes to continue overnight, especially along and south
of the high terrain. This will likely keep overnight lows from
bottoming out quite so low for areas from Flagstaff to Grand
Canyon again tomorrow morning. As mentioned in previous
discussions, consensus still lies in developing a cut off low that
meanders off the West Coast dipping southward through Monday and
Tuesday. Trends have now take that low a bit further south than in
previous runs, further complicating the forecast for late next
week.

Wednesday through Friday...Long range models continue to indicate
that the closed low will drop south into the Pacific off the coast
of Baja California (albeit, a bit further west and south than in
previous runs.) Late Wednesday, it begins to be pulled northward
by a deepening trough across the Pacific Northwest. Here is where
the problems with the forecast begin. The GFS develops a much
deeper Pac NW low which attempts to absorb the cut off low and
bring it across the AZ/Mexico border on Friday with rain/snow
showers. The Euro has dry solution with the cut off low being left
off the southern California coast through the Friday period with
no precipitation. WPC Clusters seem to favor this outcome of the
cut off slow staying west of the area through Saturday and Sunday
until a secondary wave pulls it back into the main flow. In
either solution, cold air knocks right on our border which will
have to remain in close watch, should the wetter GFS be the
winner. The trend in the ensemble data is also to reduce
precipitation amounts with a few more members coming in dry. For
now, we have taken precipitation chances back conservatively from
the NBM, especially along the Mogollon Rim. We will hold for now
to see if models can come into better agreement on the handling of
the cut off low, ridge, and PNW trough.

Beyond Friday, long range models split over breezy, cold, and
stormy or a strong ridge rebuilding across the desert southwest.

&&

.AVIATION...For the 06Z package...VFR conditions prevail through the 
TAF period. East winds 10-20 kts, primarily across and downwind of 
the higher terrain, with light and variable winds expected 
elsewhere. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...The east-northeast winds of 10-20 mph continue for 
Monday, becoming a bit lighter on Tuesday. Under stable conditions, 
afternoon mixing heights will decrease resulting in marginal to fair 
ventilation, becoming poor by 1700 MST, for Monday and Tuesday.
Temperatures are expected to remain near average for both days. 

Wednesday through Friday...An unsettled weather pattern is possible 
for the second half of the week with increasing cloud cover, near 
average temperatures, and variable winds. Rain and high elevation 
snow showers are still forecast for Thursday into Friday, however 
liquid amounts at this time look to be up to 0.25" along higher 
terrain, with most locations near or below 0.10".

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

PUBLIC...NL/ET
AVIATION...Humphreys
FIRE WEATHER...LaGuardia


For Northern Arizona weather information visit weather.gov/flagstaff