Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Flagstaff Arizona
930 am MST Sat Jan 31 2015
Synopsis...scattered rain and snow showers will continue through
today...primarily along and south of the Mogollon Rim and White
Mountains. Expect strengthening high pressure with dry and warm
weather from Sunday through all of next week. Due to the wet
conditions...patchy fog and low clouds will also be possible through
Two area of precipitation ongoing this morning the first a east to
west fat band across the southern third of Arizona. This feature is
expected to push slowly east northeast and should bring scattered
showers to the south side of the Mogollon Rim that is east of I-17
today. The second is a band of showers covering SW Utah and
associated with upper level deformation. This band is expected to
move into Coconino County this afternoon and evening. We have
massaged the precipitation chances a bit for today...the main change to
west of line from Page to Williams this afternoon.
Fog is being observed at many locations this morning and it will be
prevalent for the next few days.
Previous discussion...345 am an upper level low pressure center is seen
on water vapor imagery near Las Vegas this morning...with a
secondary center over the northern Baja California. The main plume of
sub-tropical moisture that has been over Arizona since Thursday has
fragmented and moved into New Mexico. There has been some dynamical
cooling with this low over central and western Arizona...but the
saturated boundary layer has been difficult to overcome and snow
levels have hardly changed at all in the last 36 hours. A colder
boundary layer near the New Mexico border has allowed snowfall to
persist and light snow is still being reported this morning above
about 6500 feet. Organized precipitation has just about ended in our
County Warning Area...with convection and weak upslope being the primary forcing
We have pared back probability of precipitation and quantitative precipitation forecast for the next 24 hours...the heaviest
amounts are likely to be east and south of this County Warning Area. A west-southwest remains
in effect foe the Window Rock area and the White Mountains...we will keep
an eye on the dwindling precipitation rates in these areas and the
west-southwest may be canceled early.
After today...a major ridge builds into the west with above normal
temperatures and dry conditions for the at least the next week.
There is a possibility of more widespread fog and low clouds with
this ridge...especially to our east. We have added fog through
Sunday at this time...but it could end up being a much more
widespread and long-lived event.
Aviation...for the 12z package...expect continued MVFR/IFR
conditions in rain and high elevation snow along with extensive
lower cloud ceilings at or below 4000 feet. Periods of LIFR
conditions in low clouds and fog are also anticipated. Aviation
discussion not updated for taf amendments.
Winter Weather Advisory for Arizona public zone 011 through 5 PM
Winter Storm Warning above 8500 feet for Arizona public zone 017
through 5 PM Saturday.
For northern Arizona weather information visit