157
FXUS65 KPSR 041800
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1100 AM MST Sat May 4 2024

.UPDATE...Updated Aviation Discussion.

&&

.SYNOPSIS...
After another day of above normal temperatures today, a weather
system passing by to the north will help to bring cooler
temperatures Sunday into early next week. The system will also
lead to widespread breezy to windy conditions today across
southeast California and areawide on Sunday. Dry weather will
persist through next week, and temperatures are expected to
rebound into the low 90s by early next week.

&&

.DISCUSSION...
Temperatures will continue to run a few degrees above normal for
one more day ahead of an approaching Pacific low now moving into
northern California and the Pacific Northwest. Expect highs today
very similar to yesterday with readings mostly topping out in the
lower 90s across the lower deserts to as high as 95 degrees. The
approaching weather system will also increase the gradient across
the western deserts by this afternoon leading to increasing winds
and wind gusts likely reaching advisory level (40 mph) over
portions of southeast California by late this afternoon.

As the Pacific low moves inland across northern California into
northern Nevada tonight, it will start to weaken while also
bringing in some high level cloudiness through the Desert
Southwest. A dry cold front is also forecast to move through
southern California by Sunday morning with the front attempting to
move through much of Arizona, but it will likely somewhat wash
out as the system continues to weaken as it moves through Utah and
northern Arizona. Cooler temperatures will be realized on Sunday,
especially over the western deserts where readings will only top
out in the upper 70s to around 80 degrees, but the Phoenix area
will still easily reach into the mid 80s. Windy conditions will
also impact the region areawide on Sunday with gusts across the
Arizona lower deserts mostly between 30-35 mph to as high as 40-45
mph across southeast California and over portions of the higher
terrain north and east of Phoenix.

The weather pattern for a good portion of next week should see a
large trough set up from the Plains States through the Pacific
Northwest with the southern fringe of the trough setting up over
our region. This will allow for several days of seasonably dry
westerly zonal flow over the Desert Southwest with heights aloft
hovering near seasonal averages. As a result, temperatures will
recover fairly slow into next week, eventually warming back into
the normal range by around Tuesday or Wednesday. NBM forecast
temperatures show highs in the upper 80s to the lower 90s from
Tuesday through Thursday before warming a bit more by next weekend
as ensemble guidance shows a ridge potentially building in from
the west.

&&

.AVIATION...Updated at 1759Z.

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

Light winds will persist through the remainder of the morning before
veering toward the west this afternoon with some afternoon breezes
gusting upwards of 15-20 kts. Westerly winds will weaken this
evening but will persist into the overnight hours before making a
shift to the southeast after midnight. West to southwest winds
then resume Sunday morning around 16Z with speeds increasing. FEW-
SCT high clouds around 20 kft will pass over the region throughout
the period with lower bases to around 10 kft expected Sunday
afternoon as a cold front pushes through south-central Arizona.

Southeast California/Southwest Arizona including KIPL and KBLH:

Winds will be the primary aviation weather concern through the TAF
period. Strong westerly winds at KIPL and southwesterly winds at
KBLH will increase through the afternoon and evening. Winds will be
strongest at KIPL where gusts this afternoon will climb upwards
of 25-35 kts with gusts expected to exceed 35 kts at times this
evening. Meanwhile at KBLH, winds won`t be as strong but will see
gusts to around 25-30 kts through the evening before weakening.
Strong winds will promote the potential for some lofted blowing
dust, which could lead to surface/slantwise visibility reductions.
Wind speeds will remain elevated through the overnight period
before increasing again Sunday morning as a cold front passes
through the region. Otherwise, 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 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. Lighter winds are
expected by Monday, but some afternoon breeziness can be expected
during the first part of next week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory from 3 PM this afternoon to 9 AM PDT Sunday for
     CAZ560.

     Wind Advisory from 3 PM this afternoon to 8 PM PDT Sunday for
     CAZ563>567.

     Wind Advisory from 3 PM this afternoon to 11 PM PDT Sunday for
     CAZ562.

&&

$$

DISCUSSION...Kuhlman
AVIATION...Smith
FIRE WEATHER...Kuhlman