Strong Wind in California, December 3, 2016

Area Forecast Discussion
National Weather Service Phoenix AZ
441 AM MST Sat Dec 3 2016

.UPDATE...Updated Aviation and Fire Weather Discussions...

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.SYNOPSIS...
A strong surface pressure gradient will continue to produce gusty
northerly winds across a large portion of southeast California and
the Colorado River Valley through this afternoon. Otherwise, high
pressure building into the region will result in warmer conditions
through Tuesday. Another low pressure system will bring a brief cool
down Wednesday before a return to near-normal temperatures late in
the week and into the weekend.

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.DISCUSSION...
Closed upper low is clearly evident on water vapor imagery early this
morning across northern Sonora, though there is little to show for it
in terms of precipitation across Arizona. Latest regional MRMS
depicts only scattered light showers across eastern Arizona.
Consensus amongst the hi-res WRFs including the HRRR is that a brief
shower or sprinkle will clip southern Gila County early this morning.
Otherwise, main impact from this system will be a continuation of the
windy conditions down the Colorado River Valley. Gusts as high as 35
to 40 mph will be possible in these areas, before winds subside late
in the afternoon. Patchy dust in these areas may also result in
reduced visibilities and hazardous driving conditions.

As the upper low drifts eastward this morning, strong subsidence
will overspread Arizona yielding mainly sunny skies. Meanwhile, a
ridge in the eastern Pacific will migrate eastward resulting in
increasing height/thicknesses and consequently temperatures generally
3 to 8 degrees warmer than those observed Friday. Additional
warming/drying is likely Sunday as the axis of the aforementioned
ridge moves into the Desert Southwest. Little change is then expected
Monday.

Latest operational models are in generally good agreement through the
week, showing a weak short-wave trough moving through the region
Tuesday. A broad trough will then settle across the central states,
ushering in anomalously cold arctic air. The coldest of the air will
be displaced well to our east. Nevertheless, a weak short-wave trough
will result in cooler conditions and below normal temperatures across
the region Wednesday. Latest operational ECMWF suggests that light
precipitation will be possible across eastern Arizona including
portions of Gila County. However, this solution is supported by none
of the GEFS members. Late in the week and into the weekend, a warming
trend is likely as high pressure and ultimately zonal flow becomes
reestablished across the intermountain West.

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.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:

Skies to remain mostly clear through the period with the exception of
some FEW to SCT Cu development during the daytime hours today. Light
winds this morning will be quite variable, but mostly out of the west
at KSDL and KPHX. Confidence in wind direction becomes somewhat low
by mid morning as winds should switch around to the northeast and
increase. These winds may last through mid afternoon before again
switching back to the northwest. Confidence is moderate to high winds
will shift back to the east mid to late evening and remain fairly
light overnight.

Southeast California/Southwest Arizona including KIPL and KBLH:

Clear skies to persist into Sunday, but winds will remain breezy to
windy through this afternoon. Northerly wind gusts will at times
reach 25-30 kts at both KBLH and KIPL, especially late morning
through mid afternoon. Moderate to high confidence winds will begin
to diminish shortly before sunset today, becoming light overnight.

Aviation discussion not updated for amended TAFs.

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.FIRE WEATHER...
Monday through Friday:
Near normal temperatures and mostly dry conditions are likely for
next week. A passing weather system to the north on Tuesday and
Wednesday will bring breezy afternoon winds in some areas Tuesday
and then down the Lower Colorado River Valley on Wednesday. Minimum
humidities on Monday and Tuesday will range from 25 to 35 percent,
but then drop starting Wednesday with readings down into the teens.
Generally light winds are expected for Thursday and Friday with
minimum humidities again mostly in the teens over the deserts.

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.SPOTTER INFORMATION STATEMENT...
Spotters are encouraged to report according to standard criteria.

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.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Wind Advisory until 9 PM MST this evening for AZZ020-025.

CA...Wind Advisory until 8 PM PST this evening for CAZ030>033.

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DISCUSSION...Hirsch
AVIATION...Kuhlman
FIRE WEATHER...Kuhlman