Area Forecast Discussion
Issued by NWS Flagstaff, AZ
FXUS65 KFGZ 130322
Area Forecast Discussion
National Weather Service Flagstaff AZ
822 PM MST Sun Feb 12 2017
.SYNOPSIS...Scattered to numerous showers will continue over
northern Arizona tonight, with isolated thunderstorms possible
through this evening. Scattered showers will gradually taper off
from west to east Monday through late Monday night. Snow levels will
generally be in the 7200 to 8500 foot range through Monday night.
A second disturbance will bring a chance for showers along the
Mogollon Rim mainly south of I-40 Tuesday afternoon with snow levels
around 7500 feet. A drying and warming trend is then forecast
through Thursday. Another cold front is expected to bring colder
temps and rain and snow Friday through the weekend.
.DISCUSSION...The showers and thunderstorms that moved north
into Yavapai, Coconino and western Navajo counties have consolodated
into more of an orographically-enhanced stratiform band, modified by
the decreasing stability and easterly upslope flow. Snow levels are
relatively high...currently around 8200 feet near Flagstaff, to
around 7500 feet near the New Mexico Border.
Scattered to numerous showers and high elevation snow will continue
overnight, with an enhancement of precipitation along the eastern
slopes of the higher terrain. The NAM appears to have a good handle
with the ongoing weather, with the primary area of precipitation
lifting northward to near the Utah border overnight. We expect the
convective activity to end in the next hour or two as the atmosphere
becomes more stable, with snow level slowly falling overnight. We`ll
likely see a mix of rain and snow down to about 7000 feet across
central and eastern Arizona by sunrise...but any accumulations
should be limited to elevations above 7500 feet.
The forecast was updated to reflect the increased precipitation
expected this evening and overnight, with slightly lower snow levels.
.PREV DISCUSSION /244 PM MST/...
SHORT TERM...(This afternoon through Wednesday night)
The latest water vapor imagery shows the center of an upper low
beginning to pivot into the Baja Peninsula. Moisture continues to
stream ahead of this feature over Arizona and New Mexico. Scattered
to numerous showers will continue over northern Arizona tonight,
with isolated thunderstorms possible through this evening. Scattered
showers will gradually taper off from west to east through late
Monday night. Snow levels will generally be in the 7500-8500 ft.
range through Monday night.
The GFS/ECMWF/NAM prog a second east-west oriented wave to rotate
south over northern Arizona Tuesday. This disturbance is progged to
bring a chance for showers along the Mogollon Rim mainly south of
I-40 Tuesday afternoon with snow levels around 7500 ft. Impacts
should be minimal. The aforementioned precipitation should begin to
taper off by Tuesday evening.
Upper level ridging will then build into the southwestern US late
Tuesday night and will continue building into the region through
Wednesday night. This will lead to a drying and warming trend,
with temperatures running about 10 degrees above normal by mid-
.LONG TERM...(Thursday through Sunday)
Ridging builds briefly over the state Thursday with mostly sunny
skies and temperatures several degrees above seasonal averages.
Winds aloft become southwesterly Thursday night ahead of a
broad trough moving onto the West Coast.
Friday through Sunday - Model consistency continues to be good
regarding a cold frontal passage late Friday through Saturday
across our area. Precipitation chances were increased again
with the afternoon forecast package, into the likely category
for much of the area. Model QPF amounts are also continuing to
indicate the possibility for moderate to heavy precipitation
Friday night through Saturday with significant winter weather for
the high country. Early projections for snow levels are 6500-7500 ft
Friday night and Saturday, 5500-6500 ft Saturday night. By Sunday,
the 12Z operational runs of most models show a cold and moist
northwest flow with another shortwave approaching or passing through
the area, with a continued chance of snow and lower elevation rain.
This stormy pattern for next weekend is still 5-7 days out, so it`s
too early to get specific with details and there will likely be
changes to the forecast through the week so stay tuned for the
.AVIATION...For the 06Z package...Scattered to numerous showers with
embedded thunderstorms will continue tonight. Expect mtn top
obscuration with MVFR conditions in/near showers. Snow levels
generally remaining above 8000 feet MSL with a brief rain/snow mix
possible to near 7000 feet MSL through early Monday morning. A slow
improvement to VFR conditions should develop from west to east late
Monday afternoon. Aviation discussion not updated for TAF amendments.
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