Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Flagstaff Arizona
305 PM MST Wednesday Dec 17 2014
showers will continue at times across northern Arizona through
Thursday. Expect areas of accumulating snow above 5500 feet. Dry
weather will return for Friday...with gradually warming daytime
temperatures through early next week.
Discussion...the second in a series of three shortwave troughs is
moving across western Arizona this afternoon. Showers continue along
and ahead of this feature...with the highest concentration south of
I-40. Will drop the winter weather advisories from Flagstaff
northward...and keep them going from the Yavapai Colorado mountains...
along the eastern Mogollon Rim to the White Mountains through 8 PM.
Showers are expected to decrease in coverage as this wave passes
by...though some light showers could linger overnight. Fog
development is also likely overnight as low levels remain moist and
we get some middle level drying...so areas of fog were added to the
forecast tonight through Thursday morning. The third and final wave
is forecast to move across the area Thursday... beginning around
sunrise in western Arizona and spreading eastward through the afternoon.
Probability of precipitation were increased for this period in the latest forecasts...but
precipitation amounts appear light at this time...mainly an inch or less of
snowfall for the higher terrain. This wave exits the region rapidly
Friday through Wednesday. Dry through the period. Models are much
weaker with saturdays disturbance which should only bring partly
cloudy skies. For Sunday and Monday look for cool northerly surface
winds and fast northerly flow aloft. A large and warm ridge along
the California coast will push into the Desert Southwest Tuesday
allowing maximum temperatures to start a strong warming trend.
Aviation...for the 00z package...two weather disturbances will move
across Arizona over the next 24 hours with widespread and mixed MVFR
and IFR conditions continuing through this period. The first wave
was over SW Arizona this afternoon and moving east. The second was
off the central California coast and will move across Thursday
morning. Expect several hours of -shra/ -shsn with each wave...and
stratus with mist and fog between waves. Snow levels from 5k feet mean sea level
on the Kaibab Plateau to 6k feet mean sea level in the White Mountains aviation
discussion not updated for taf amendments.
Winter Weather Advisory until 8 PM MST this evening for
For northern Arizona weather information visit