Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Flagstaff Arizona
453 am MST Monday Mar 2 2015
a Pacific storm system will bring widespread rain and snow to
northern Arizona today. Significant snow accumulations are
expected above the 6000 foot elevation level with hazardous
winter driving conditions. Precipitation will decrease tonight...though
a chance for showers remains in the forecast through Wednesday.
Drier and warmer weather returns by Thursday.
..significant winter weather across the high country today...
A robust cold front associated with a deep Pacific low pressure
system stretches from near Yuma all the way to the Utah border
early this morning with widespread rain being reported along the
front. Further east...scattered light to moderate convective
showers continue to develop across central Arizona in the warm
sector of the storm system with elevated snow levels ranging from
7000 to 8000 feet. Snow levels will remain high in the relatively
warm air ahead of the cold front this morning. Precipitation will
increase in coverage as the front moves into western Yavapai and
Coconino counties this morning...through central Arizona
midday...and into eastern Arizona this afternoon. Expect moderate
to periods of heavy rain and snow along the cold front with snow
levels dropping to around 5500-6000 feet behind the front.
The main updates this morning were to fine tune frontal timing and
transition of rain to snow in the higher elevations. The frontal
band of precipitation will likely start as rain for many areas
before transitioning to snow behind the front. A slightly later
onset of snow from the Grand Canyon to Flagstaff regions has
resulted in a slight downward trend in forecast snowfall amounts.
However...snowfall rates will be quite high along the frontal
zone...likely an inch per hour for at least a few hours. In
addition...strong southerly winds up to 40 to 45 miles per hour ahead of and
along the front will generate areas of blowing snow with very poor
visibility and hazardous Road conditions. Winter storm warnings
and advisories are in effect for much of the high country through
this evening. Winds will be even stronger gusting to 50 miles per hour north
of the Mogollon Rim this afternoon where a Wind Advisory is in
Additional precipitation totals (rain and melted snow) will
generally range from 1 to 1.5 inches from the Grand Canyon region
along the Mogollon Rim and south into Yavapai and northern Gila
counties. Already saturated ground from previous rainfall will
lead to a threat of some localized flooding in the lower
elevations of Yavapai and northern Gila County...especially during
the time of heaviest rain along the front.
Showers will decrease in coverage late this evening and especially
after midnight. A secondary shortwave moves through the Pacific trough
as it passes through Arizona Tuesday and Wednesday keeping the
chance for showers and cool temperatures in the forecast. A drier
weather pattern should return from Thursday through the weekend as
high pressure returns along the West Coast.
for the 12z package...a cold front will cross the state from west to
east today causing moderate to heavy precipitation with widespread
IFR/LIFR conditions along the frontal boundary. Snow levels 7-8 kft
mean sea level ahead of the front...falling to 5-6kft mean sea level behind the front.
Precipitation becoming showery and decreasing most areas by this
evening. Strong S-SW wind 20-30kt g40-45kt generally north of
Mogollon Rim 17z-00z. Aviation discussion not updated for taf
Winter Storm Warning from 10 am this morning to 7 PM MST this
evening for azz015.
Wind Advisory from 11 am this morning to 5 PM MST this
afternoon for azz010-012>014-040.
Winter Weather Advisory from 11 am this morning to 1 am MST
Tuesday for azz009-039.
Winter Weather Advisory from 2 PM this afternoon to 1 am MST
Tuesday for azz011.
Winter Storm Warning from 11 am this morning to 1 am MST
Tuesday for azz016>018.
Winter Storm Warning until 7 PM MST this evening for azz004-
Winter Weather Advisory from 10 am this morning to 7 PM MST
this evening for azz008.
For northern Arizona weather information visit