Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 03/21/22

Area Forecast Discussion

National Weather Service Phoenix AZ

 503 PM MST Sun Mar 20 2022

.UPDATE...Updated 00z Aviation Discussion...

&&

.SYNOPSIS...
A weather system will move through the region today and Monday
bringing cooler temperatures, very breezy to windy conditions, and
a slight chance of showers and thunderstorms. A gradual warming
trend is expected, especially by the middle and latter half of
next week. Forecast highs of 90 degrees enter the forecast for
many areas by next Friday.

&&

.DISCUSSION...
A deep elongated trough is centered directly over Arizona at this
time. It is slowing on approach, and beginning to partially close
off. A 100 kt 300 mb jet is rounding the base of the trough and
nosing into southeast Arizona. Diffluence in the left exit region
is allowing for broad lift across the forecast area. The upper
level trough axis is now overhead with ACARS soundings showing a
couple of degrees of cooling between 700 and 400 mb the last few
hours. In the lower atmosphere the main trough axis is still to
the west. Meanwhile, some increase in water vapor content has been
noted with precipitable water increasing to around 0.5-0.6 inches
per ACARS soundings. With these factors occurring during peak
heating, the ingredients are coming together to support scattered
showers and isolated thunderstorms this afternoon.

In terms of instability, SPC mesoanalysis shows around 100-300 J
of CAPE have developed with little in the way of inhibition
present. However, due to the very dry lower atmosphere LCLs are
near 750 hPa with 400-800 J of DCAPE. This should result in very
little rainfall reaching the ground except under the most intense
storms. Instead, gusty winds and patchy blowing dust are the more
likely hazards. HREF probabilities show a 10-30% chance of wind
gusts exceeding 35 kts near Phoenix with even higher probabilities
in the southwest portion of Maricopa Counties. Shower activity has
already developed over portions of La Paz and NW Maricopa
counties. This activity is expected to be the strongest and most
widespread over the higher terrain, with PoPs gradually
diminishing as one heads further to the south or west. With
positive CAPE values, isolated lightning strikes may also be
possible.

The other weather story will be the winds across southeast
California and southwest Arizona. Breezy westerly winds will
gradually shift to northerly today and Monday in response to
increasing high pressure over Nevada. Model guidance shows 850 mb
winds approaching 50 kts overnight with even 925 mb winds near 40
kts. During the overnight hours the strongest wind may stay
confined to higher peaks, but will likely spread into the lower
elevations as the sun comes up on Monday. Wind advisories have
been posted or extended for portions of Riverside, Imperial, Yuma,
and La Paz counties. A blowing dust advisory has also been issued
for the daytime hours on Monday to account for these threats.

By Monday night and continuing for the rest of the week the
weather system will depart with a large high pressure area
building into the region. High temperatures will climb into the
90s for most valley locations by Friday and continue through the
weekend. NBM probabilities show a 10% that 100F could be reached
in Phoenix next Saturday. WPC clusters show excellent agreement on
this progression with only some uncertainty with respect to the
ridges position and amplitude. If there is a limiting factor to
the potential heat it will be high clouds in advance of a weather
system that may impact the area early next week.

&&

.AVIATION...Updated at 0000Z.

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

VCSH will continue across the terminals through 03-04z. Otherwise,
breezy west to west-southwest winds sustained between 12-20 kts
with gusts mostly in the mid to upper 20s will continue through
the early evening hours. Brief gusts in excess of 30 kts will
possible near the SHRA activity. As the low-level wind flow
diminishes after 03-04Z, it will allow for an easterly wind shift
overnight with speeds ranging between 05-10 kts. North to
northwesterly winds then develop by Monday morning and will
strengthen throughout the day, resulting in breezy conditions as
early as 15Z-16Z. Gusts into the mid-20s will then be possible
Monday afternoon. SCT-BKN cloud deck between 07-09 kft will
prevail through the evening hours, gradually lifting to aoa 15 kts
overnight while diminishing to FEW.

Southeast California/Southwest Arizona including KIPL and KBLH:

Across KIPL, west winds of around 15 kts with gusts of up to 25
knots will be common through the evening hours with speeds
diminishing to around 10 kts overnight. Winds then become
northwest to north late Monday morning with speeds increasing to
around 15 knots during the afternoon.

Across KBLH, sustained winds from the north around 20-25 kts with
gusts of 30-35 kts will be common through this evening with some
diminishing of the speeds possible overnight. With low-level winds
of around 40 kts from the north expected through Monday afternoon,
gusts of this magnitude near the surface will be possible by the
mid to late morning hours and continuing into the afternoon hours.
This will likely result in areas of blowing dust that could
reduce visibilities to below 6SM at times.

&&

.FIRE WEATHER...
Tuesday through Saturday:
Dry conditions will prevail with highs as highs quickly warm
starting Tue. Above normal upper 80s and low 90s are likely by the
end of the week. Min RH`s near 10-15% on Tue will fall to the
single digits by Wed. Winds will be lighter although lingering
breeziness through the midweek cannot be ruled out. Overnight
recoveries will range in the low 20s to mid 30s percent range.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Blowing Dust Advisory from 8 AM to 8 PM MST Monday for
     AZZ530>533-536.

     Wind Advisory until 8 PM MST Monday for AZZ530.

     Wind Advisory from 11 PM this evening to 8 PM MST Monday for
     AZZ531>533-536.

CA...Blowing Dust Advisory from 8 AM to 8 PM PDT Monday for CAZ560-
     561-564-565-568>570.

     Wind Advisory until 8 PM PDT Monday for CAZ560-561-564-568>570.

     Wind Advisory until 8 PM PDT Monday for CAZ565.

&&

$$

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DISCUSSION...Hodges
AVIATION...Lojero/Benedict
FIRE WEATHER...Sawtelle