641
FXUS65 KPSR 042042
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
142 PM MST Wed Mar 4 2026

.KEY MESSAGES...

- Temperatures into early next week will fluctuate up and down
  with readings cooling into the 70s by Friday, warming back up
  over the weekend before cooling briefly again early next week.

- A dry weather system will bring widespread breezy to windy
  conditions on Thursday and lingering into Saturday across the
  western deserts.

- A stronger and slower moving weather system may bring some
  chances for rain showers Sunday into Monday.

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...
A slightly cooler airmass continues to move into the area which
will help keep afternoon highs in the mid-80s this afternoon,
still about 10 degrees above normal.

Strong height falls Thursday will lead to increased winds
throughout much of the daytime hours, especially across southeast
California where Advisory level winds are expected in some areas.
A Wind Advisory has been posted for eastern Riverside County
through northern parts of Imperial County for Thursday morning and
afternoon. Wind gusts outside of the Advisory area may also reach
25-35 mph during the afternoon hours. Drier air will also surge
southward on Thursday behind an advancing cold front dropping
surface dew points into the teens by early afternoon. The cold
front will keep daytime highs mostly in the upper 70s across the
lower deserts.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Models are finally starting to agree on the expected cut-off low
development by Saturday and its slow progression from
northern/central Baja across northern Mexico early next week. Even
with better agreement on the track and the timing, there are still
differences with how much moisture will advect into our region and
the exact placement of the moisture axis. The second shortwave
trough is shown to dive southward into the base of the trough
somewhere across southern California and/or western Arizona on
Friday triggering the development of a closed low. Continued
height falls on Friday and the core of the colder air aloft should
lead to highs only reaching into the low to mid 70s across the
lower deserts. Despite the low developing overhead, there will be
so much dry air in place skies should remain clear on Friday.
Winds will also continue to be quite breezy to at times windy
across southeast California into the Lower CO River Valley.

As the low continues to deepen Friday night into Saturday,
guidance agrees it will dig farther to the the southwest before
stalling out just off the central Baja coast Saturday night. Mid
level winds will also increase during this time leading to
moisture starting to advect northwestward into our region from
northern Mexico. The amount of moisture advecting into our area
does not look all that impressive, but ensemble mean PWATs are
shown increasing to between 150-180% of normal by Sunday evening.
The moisture will also be more elevated in nature with boundary
layer moisture likely be quite limited. Models have pushed up the
time line for potential rain chances with low end chances
starting as early as Sunday morning. The placement of the low well
to our south Sunday into Monday will also somewhat limit the
amount of forcing our region will have available. The best chances
for rain showers currently looks to occur from Sunday evening
through Monday afternoon with the highest PoPs of 30-40% over the
eastern Arizona high terrain. Ensemble QPF amounts remain quite
low across the region with lower desert amounts of around
0.05-0.15" to possibly 0.25" across much of southeast Arizona into
the higher terrain east of Phoenix. Models mostly agree on
ejecting the low to our east southeast Monday night into Tuesday,
likely ending any rain chances.

Temperatures late this week through early next week will be on a
bit of a roller coaster ride with highs warming back into the 80s
over the weekend, dipping back into the 70s Monday, before warming
back well into the 80s again by the middle of next week. Models
then favor further warming through the latter half of next week
with highs potentially topping 90 degrees again at some point.

&&

.AVIATION...Updated at 1750Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds will continue to follow diurnal tendencies with speeds
generally AOB 8 kts through Thursday mid morning. Confidence is
good that winds will then shift out of the west between 16-18Z
Thursday and become gusty by the afternoon across the terminals.
Gusts into a 20-25 kt range may become common Thursday afternoon.
Expect a few periods of passing high clouds through tonight
followed by SKC skies most of the day Thursday.

Southeast California/Southwest Arizona including KIPL and KBLH:
The primary aviation weather concerns during the period will be
the potential for brief LLWS conditions at KBLH early Thursday
morning followed by gusty northerly winds beginning Thursday mid
morning at both terminals. Confidence is low that LLWS criteria
will be met at KBLH, so it is not included in the TAF, but a front
is expected to sweep the area within a few hours of sunrise
Thursday morning. If the surface remains sufficiently decoupled,
the best timing for LLWS conditions would be 11-15Z Thursday.
Winds will remain light (under 10 kts) and generally contain a
westerly component until Thursday mid morning, with periods of
variability likely. Anticipate mostly clear skies other than some
passing high clouds this evening into the overnight hours.

&&

.FIRE WEATHER...

The weather pattern will become increasingly active through the
rest of the week as a series of dry disturbances cross the
Southwest. The current passing system continues to bring light
diurnal winds which will begin to strengthen bringing breezy to
windy conditions tomorrow. Dry conditions will persist across the
region with minimum relative humidity values staying entrenched
between 10-15% through Saturday, while overnight recoveries will
only reach the 30-50% range. Winds are expected to strengthen
significantly after sunrise Thursday, with west gusts of 25-35
mph in the Phoenix area and peak WNW gusts of 30-45 mph across
southeast California, leading to elevated fire weather concerns
before a potential slight increase in moisture arrives Sunday into
Monday.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory from 7 AM to 6 PM PST Thursday for CAZ560-561-564-
     568>570.

&&

$$

SHORT TERM...95/Kuhlman
LONG TERM...Kuhlman
AVIATION...Whittock
FIRE WEATHER...95

NWS Phoenix (PSR) Office