Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/07/22

Area Forecast Discussion

National Weather Service Phoenix AZ

 454 PM MST Fri May 6 2022

.UPDATE...Updated Aviation Discussion.

&&

.SYNOPSIS...
Strong high pressure over the region continues through Saturday
bringing the warmest temperatures so far this year with many
lower elevation communities likely reaching 100 degrees today and
Saturday. A large, but dry, weather system will begin to impact
the region over the weekend resulting in increased winds and a
slow cooling trend beginning Sunday. Temperatures around normal or
even slightly below normal are expected for much of next week
with dry conditions prevailing.

&&

.DISCUSSION...
A strong upper level ridge is now centered over the desert
southwest with 500 mb heights around 586 dm this afternoon. ACARS
soundings reveal that the entire atmospheric column has warmed
about 2C compared to yesterday at this time, which should allow
for temperatures to approach 100 F this afternoon. As of the time
of this discussion, PHX has climbed to 97 F. High temperatures
will be similar in our western zones, generally reaching 100-102
F. Temperatures will be similar to perhaps a degree warmer on
Sunday.

The weather pattern for Arizona will begin to shift Saturday as a
deep upper level trough settles in over the Pacific Northwest and
stalls out. Due to the enhanced pressure/height packing, wind
speeds will begin to increase across the area. On Saturday the
strongest winds will occur over Imperial County as cool dense air
builds up to the west of the area and spills over the mountains.
Wind gusts of 30-40 mph will likely develop there, with locally
higher gusts possible. These winds may contribute to some blowing
dust which could locally lower visibility. A wind advisory has
been posted for Imperial County for this period.

As the trough to our northwest sags a bit farther south on
Sunday, the gradient will tighten even more providing another
windy day. Guidance suggest winds Sunday will be around 5 mph
stronger than Saturday, so widespread wind gusts of 30-35 mph will
be possible with 35-45 mph gusts possible across Imperial County.
ECMWF EFI values reach 0.7 to 0.9 for much of the area
highlighting a somewhat unusual event for this time of year,
especially for the higher terrain north and east of Phoenix. The
slowly approaching trough will also dampen our heights aloft and
start a cooling trend. Forecast highs Sunday are shown to mostly
fall into the lower 90s for many lower desert areas with limited
spread in the NBM temperature percentiles.

For much of next week a blocking pattern encompassing the entire
CONUS will persist with the low pressure trough dominating across
the Western United States. During this time frame, the low
pressure center will slowly sag south and weaken very gradually.
WPC clusters continue to show modest uncertainty with respect to
this pattern progression, but overall ensembles have come into
better agreement than in the days prior. The sensible effects of
this pattern progression will mostly be cooler temperatures and
breezy conditions at times, with high temperatures hovering in the
lower 90s to upper 80s in south central Arizona, and low to mid
80s for southeast California. The remnants of the filling low will
finally eject inland near next Thursday. This will bring one more
push of breezy conditions and relatively cooler weather.

Clusters diverge for the end of next week, with the majority
taking the ejecting low and merging it into the mean flow. This
would lead to warmer conditions quickly returning. A minority
(40%) of ensemble solutions keep the low cut off over the Great
Basin, which would slow the return to average temperatures. Either
solution would result in continued dry weather.

&&

.AVIATION...Updated at 2350Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major aviation concerns expected through the period. Winds will
continue to follow diurnal tendencies. Some gusty winds near 20
kts are possible at times through sunset. Light winds aob 7 kts
expected overnight through tomorrow morning. Wind speeds will then
increase tomorrow afternoon with gusts likely exceeding 25 kts at
times, especially across KPHX. Mostly clear skies with FEW high
clouds will prevail through the period.

Southeast California/Southwest Arizona including KIPL and KBLH:
Breezy, southerly flow will predominate through this evening, with
some gusts around 20 kts, as a low pressure system moves towards
the Pacific Northwest. Winds will decrease to below 10 kts
overnight into tomorrow morning, with westerly winds expected at
KIPL and southerly winds expected at KBLH. Winds will then
increase from the west to southwest tomorrow afternoon with gusts
likely exceeding 30 kts at times, resulting in areas of blowing
dust. Mostly clear skies with FEW high clouds will prevail through
the period.

&&

.FIRE WEATHER...
Dry weather with above normal temperatures will continue through
the weekend. Starting Saturday, winds are expected to increase
with afternoon gusts in a 25-35 mph range, locally stronger in
the higher elevations north and east of the Phoenix area and
across much of Imperial County. Winds on Sunday will increase by
another 5 mph areawide. Minimum afternoon humidity levels will be
reduced mostly into a 5-12% range through the forecast period with
poor overnight recovery generally topping out in a 15-30% range.
The higher winds Saturday and especially Sunday are likely to
create elevated fire weather conditions for much of the area, with
critical fire weather conditions expected on Sunday across
southern Gila County. A cooling trend is expected during the first
half of next week, but day to day gusty winds and dry conditions
will continue.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Red Flag Warning from 10 AM to 8 PM MST Sunday for AZZ133.

CA...Wind Advisory from 11 AM to 8 PM PDT Sunday for CAZ560-561-
     563>568.

     Wind Advisory from 3 PM to 11 PM PDT Saturday for CAZ563>567.

     Wind Advisory from 3 PM Saturday to 5 AM PDT Monday for CAZ562.

&&

$$

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DISCUSSION...Hodges/Kuhlman
AVIATION...Lojero/Hirsch
FIRE WEATHER...Hodges/Kuhlman