321
FXUS65 KPSR 050553
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1053 PM MST Sat May 4 2024

.UPDATE...Updated Aviation Discussion.

&&

.SYNOPSIS...
Slightly above normal temperatures will continue today,
before a dry weather system passing to our north ushers in cooler
temperatures by Sunday. This weather system will lead to breezy
to windy conditions today across southeast California and across
the majority of the area on Sunday. Heading into next week,
temperatures will slowly rebound while remaining seasonably dry.

&&

.DISCUSSION...
Latest water vapor satellite imagery shows a very potent upper-level
low pressure system just off the Oregon coast as of this morning.
This system during the next 24-30 hours will move through the
Great Basin and Intermountain West. Out ahead, temperatures today
will continue to run a few degrees above normal with highs across
the lower deserts topping out in the low to locally mid 90s. As
the low pressure system moves inland later today, a tightening
pressure gradient will lead to strong gusty winds later this
afternoon and evening across portions of southeast California. The
strongest winds are expected across Imperial County, where gusts
in excess 40 mph are likely and where a Wind Advisory is in
effect. The strong gusty winds can lead to areas of blowing dust,
resulting in temporary reductions in visibilities.

Heading into Sunday, as the low pressure system moves through the
Great Basin and Intermountain West, the pressure gradient will
tighten across the entire area leading to widespread breezy to
windy conditions. Widespread afternoon and early evening gusts
upwards of 30-35 mph are likely across the Arizona lower deserts
while locally higher winds in excess of 40-45 mph are likely
across portions of southeast California and the higher terrain to
the north and east of Phoenix. Along with the gusty winds, cooler
temperatures are expected with highs only topping out in the upper
70s to low 80s across the western deserts while the south-central
Arizona lower deserts will see higher temperatures in the mid
80s.

The weather pattern through a good portion of next week will feature
a general large trough extending from the Plains through the
Pacific Northwest with the southern fringe setting up across the
Desert Southwest. As a result, a mostly zonal flow will set up
over the region with temperatures gradually rebounding into the
low 90s across the lower deserts heading through the middle of
next week. Heading into the end of next week through next weekend,
as the troughing pattern dissipates, a ridging pattern is being
hinted by the ensembles in building in from the west. This would
result in temperatures rising a bit more, potentially into the mid
to upper 90s across the lower deserts with a 20-30% chance of
approaching 100 degrees.

&&

.AVIATION...Updated at 0552Z.

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

Westerly winds will continue at all terminals through 08-10Z
before shifting E to SE. E to SE, 5-8 kt, winds will prevail
between 10-15Z. By 15-16Z Sunday, S to SW winds increase with
speeds initially around 8-12 kts. W to SW winds further increase
by 20Z, with sustained speeds up to 15-20 kts and gusts to around
25-30 kts. Between ~22-02Z, occasional gusts may reach 30-35 kts.
A cold front will move through around 3-4Z, which may also lead to
a brief spike in winds. Following the front winds should gradually
subside. SCT to BKN high clouds around 20 kft will pass over the
region throughout the period with lower bases to around 8 kft
expected Sunday afternoon.

Southeast California/Southwest Arizona including KIPL and KBLH:

Winds will be the primary aviation weather concern through the TAF
period. There will be a small reprieve from the winds tonight
through early Sunday, more so at KBLH. Slightly stronger winds
than Saturday are then expected during the day at the terminals,
with westerly to southwesterly gusts mostly to 30-35 kts.
Occasion gusts may reach up to 40 kts. The strong winds will be
capable of generating blowing dust which will likely lead to
slantwise visibility reductions at a minimum, but could also
briefly reduce surface visibility as well. A cold front will
eventually pass through KBLH around 01Z and shift winds to the NW.
Winds subside at both terminals after sunset. Expect to see
fluctuating coverage of high clouds throughout the period.

&&

.FIRE WEATHER...
A weather system moving just to the north this weekend will bring
breezy to windy conditions focused more during the afternoon and
evening hours along with cooler conditions starting Sunday. Wind
gusts above 30 mph are likely later today across much of the
western districts and then areawide on Sunday. The strong winds
and dry conditions will lead to elevated fire weather conditions
over much of the area this weekend. Min RHs through the weekend
will be around 10-20%, while overnight Max RHs will be around
30-60% for most areas. For next week, weak high pressure will
remain over the region allowing for temperatures returning to
slightly above normal, while seasonably dry conditions persist
with MinRHs dropping to around 10%. Lighter winds are expected
into next week, but some afternoon breeziness can be expected
each day.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 9 AM PDT Sunday for CAZ560.

     Wind Advisory until 8 PM PDT Sunday for CAZ563>567.

     Wind Advisory until 11 PM PDT Sunday for CAZ562.

&&

$$

DISCUSSION...Lojero
AVIATION...Benedict
FIRE WEATHER...Lojero/Kuhlman