Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 031034

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

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.


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

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.


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

No aviation concerns through this TAF period. Winds will stay out of
the northwest through around 03Z, then switch over to the northeast.
Speeds will remain light aob 6 kts. Skies will be partly to mostly
clear with few-sct clouds near 10 kft.

Southeast California/Southwest Arizona including KIPL and KBLH:

Breezy winds and localized blowing dust will be the two main
aviation impacts today. At KIPL, breezy northerly winds gusting up
to 30 kts will persist through early this evening, with lighter
winds aob 15 kts expected between the 00Z to 05Z time frame.
Thereafter, winds will pick up in speed again, remaining out of the
north-northwest and gusting up to 30 kts. At KBLH, sustained north-
northwesterly winds near 15 to 25 kts with gusts up to 25 to 35 kts
will be persist through the entire TAF period. Skies over both TAF
sites will remain mostly clear with few-sct clouds aoa 10kft.

Aviation discussion not updated for amended TAFs.


Sunday through Thursday:

There is a slightly elevated fire danger potential on Sunday for
Southeast California and parts of Western Arizona. The main concerns
will be windy conditions and relative humidities below 15 percent.
However, the duration of these conditions is short lived and the
overnight recovery for relative humidity is fair. In addition,
breezy conditions on the order of 10 to 20 mph are likely for much of
South-Central Arizona and Southeast California beginning Tuesday and
lasting through Wednesday. Minimum RH will stay in the 12 to 30
percent range with decent overnight recoveries.


Spotters are encouraged to report according to standard criteria.


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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