734
FXUS65 KPSR 031121
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
421 AM MST Fri May 3 2024

.UPDATE...Updated Aviation Discussion...

&&

.SYNOPSIS...
Slightly above normal temperatures are expected today and tomorrow,
with afternoon highs peaking in the low to mid 90s across the lower
deserts. A dry weather system will traverse the Intermountain West
this weekend leading to widespread breezy to windy conditions
Saturday evening and Sunday, as well as cooler temperatures on
Sunday and Monday. Dry weather will persist through next week, and
temperatures are expected to rebound into the low 90s by Tuesday.

&&

.DISCUSSION...
Quasi-zonal flow currently exists over the Desert Southwest while
the persistent troughing feature over the Intermountain West
gradually begins to push east this morning. Though a weak upper
ridge will traverse the Pacific Northwest later today and continue
eastward, heights aloft will be relatively unchanged over the
forecast area through tomorrow, and so afternoon high temperatures
will be stable in the low to mid 90s across the lower deserts.

The trough evident in current mid-lvl wv imagery off the Pacific
Northwest Coast is expected to dive south along the West Coast
Saturday, move inland, and traverse the Great Basin Sunday. The
tightening pressure gradient ahead of and along the southern
periphery of this trough will bring widespread breezy to windy
conditions Saturday afternoon/evening and Sunday. A dry cold
front associated associated with this system will also sweep
through the CWA Sunday, leading to high temperatures dropping
between 5-10 degrees across the lower deserts (and potentially
more in the western deserts) on Sunday compared to their forecast
values on Saturday.

NBM guidance continues to show upwards of 80-90% probability for
gusts to 40+ mph across Southwest Imperial County including the
Imperial Valley Saturday afternoon/evening. As a result, Wind
Advisories have been issued for portions of Imperial County late
Saturday afternoon into the evening, with the Advisory over far
southwestern Imperial County remaining in effect through Sunday
afternoon. Global models depict 700 mb winds peaking around 40-50
kts early Sunday morning over Southeastern California, so the
strongest winds aloft will not coincide with peak daytime heating
that would allow higher momentum air to mix down to the surface.
Thus, the strongest winds will be confined to high terrain
locations overnight. Strong winds spread east across Arizona
Sunday with afternoon gusts to 30-40 mph likely (>70%) across
portions of South-Central Arizona. Additional wind headlines may
be needed for portions of Imperial County on Sunday, as well as
the high terrain zones of South-Central AZ within and around
Southern Gila County. Dust channels may develop across dust prone
areas as a result of the strong winds this weekend, which can
reduce visibilities and make travel hazardous.

Longwave troughing will continue to be reinforced over the
Intermountain West through Monday which will also feature near to
slightly below normal temperatures and continued daytime breeziness
across the region. Heading into the middle of next week,
temperatures look to slowly rebound to slightly above normal,
however the overall longwave troughing pattern across the Western
CONUS looks to persist.

&&

.AVIATION...Updated at 1120Z.

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

No aviation weather concerns under clear skies are expected
through the TAF period. Wind pattern will continue to exhibit
diurnal tendencies, with easterly winds this morning
transitioning to a period of southerly winds through the early
afternoon hours before a full transition out of the west. Wind
speeds will generally remain aob 10 kts.

Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation weather concerns under clear skies are expected
through the TAF period. Winds will generally be southerly through
the period at BLH aob 10 kts, while southeasterly winds at IPL
are expected to become westerly during the evening hours.

&&

.FIRE WEATHER...
Warm and dry weather will persist into this weekend, with light and
diurnal winds expected today. Afternoon highs will be slightly above
normal today and tomorrow in the low to mid 90s across the lower
deserts. A dry weather system will pass to the north of the region
this weekend, leading to gusty winds, as well as cooler temperatures
on Sunday and Monday. Winds could gust in excess of 40 mph across
parts of SE California Saturday afternoon and evening and again
Sunday morning/afternoon, while gusts climb to 30-40 mph across
southcentral AZ on Sunday. Afternoon min RHs will bottom out around
10-20% over the next few days, while overnight recoveries remain in
the poor to fair category between 30-60% for most areas.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory from 3 PM Saturday to 5 PM PDT Sunday for CAZ562.

     Wind Advisory from 3 PM to 11 PM PDT Saturday for CAZ563-566-567.

&&

$$

DISCUSSION...Whittock
AVIATION...Young/Kuhlman
FIRE WEATHER...Whittock/Smith