High Wind and Strong Wind in Arizona, December 24, 2016

Area Forecast Discussion
National Weather Service Tucson AZ
920 AM MST Sat Dec 24 2016

.SYNOPSIS...A quick moving storm system will move across the area
this afternoon and evening, exiting to the east Christmas Day. This
system will bring strong winds, valley rain, lower elevation snow
with cold temperatures for Christmas Day. Dry and warmer conditions
return to the area early to mid next week with the potential for
showers again near the end of the coming week.

&&

.DISCUSSION...Clear across most of the area at 9 am. The exception
was extensive low level cloud cover across the western areas or west
of a Casa Grande to Kitt Peak line. Latest surface obs indicate that
the approaching cold front extended from southern Nevada south along
the Colorado River. Regional radars depicted a narrow band, around
50 miles wide, of showers across eastern Imperial county and western
Yuma county. As the cold front pushes east, it will pick up
additional low level moisture from the Gulf of California which will
result in an expansion of showers later this morning as the cold
front moves into western Pima county. Latest high resolution model
runs of the HRRR and RAP are moving showers east across Pima and
Pinal counties this afternoon a smidge slower than the 00z UofA runs
of WRFGFS/WRKNAM. Overall the forecast for the afternoon hours looks
on track.

Strong gusty winds out ahead of cold front with local gusts up to 50
mph possible. Wind advisory area wide goes into effect at 10 am and
will run thru 8 pm. With the passage of the front the winds will
immediately shift to west and drop 10-15 mph in speed then gradually
diminish.

The following is from the midshift discussion.
While there will be decent shower (some heavy) activity with the
front, the main band will be fairly narrow lasting 3-4 hours before
tapering off. The snow levels will be dropping quickly behind the
front but should only drop to around 4500 ft before it begins to
taper off, although higher elevation locations near the mountains
such as Oracle stand a good chance of seeing accumulating snow early
this evening before the initial band moves east. In the midst of
this, the mountains will pick up a quick hit of snow falling at the
rate 2-4 inches per hour at its peak.

A Winter Weather Advisory is in effect to cover the expected
accumulating snow, basically 3-6 inches between 5000 and 7000 ft and
6-12 inches above 7000 ft.

As the night wears on, the cold air will continue to flood across AZ
with nearly every model indicating one or more bands of showers
moving across the area throughout the night. This will be at a time
when the low and mid levels of the atmosphere will be at its coldest
with light snow accumulations possible in the heavier showers down
as low as 3000 ft with mixed rain and snow showers below that later
tonight into the early morning hours on Christmas Day.

Christmas Day the system continues to move quickly to the east with
the air mass drying out so any rain/snow showers should come to an
end by afternoon from west to east. It will remain rather cold with
high temperatures peaking 10-15 degrees colder than normal.

&&

.AVIATION...Valid through 25/12Z.
An approaching cold front will bring rapidly deteriorating
conditions west of Tucson thru 24/20z. Expect widespread -SHRA,
ocnly heavy at times, with ocnl MVFR cigs and vsbys associated with
this cold front. At this time the latest high resolution models are
all in agreement on bringing these conds to KTUS and KOLS between
24/22Z and 25/00Z. These conds will continue to move east affecting
KDUG around 25/02Z-25/04Z. The 24/12Z TAFS reflect this timing.

Sfc wind early this morning generally less than 12 kts. However
strong winds are forecast to increase in advance of an approaching
cold front. South wind 15-20 kts this morning, then increasing
during the afternoon to 20 to 30 kts with gusts to 45 kts. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...A cold and fast moving weather system will track
across Southeast Arizona from the northwest today through Sunday
morning. Expect valley rain, mountain snow and a rain/snow mix
possible for some valley locations above 3000 ft. Strong and gusty
20-ft southwest winds are expected today. Wind speeds of 20-30 mph
with gusts up to 50 mph are expected as the storm tracks through the
area. The upcoming week will begin cool and dry, but yet another
system could bring precipitation to the region by the middle of next
week.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...

 Wind Advisory from 10 AM this morning to 8 PM MST this evening for
  AZZ501>515.

 Winter Weather Advisory from 2 PM this afternoon to 5 AM MST Sunday
  for AZZ510>515.

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