880
FXUS65 KPSR 220510
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1010 PM MST Tue Apr 21 2026

.UPDATE...
Updated Aviation

&&

.KEY MESSAGES...

- A weather system will traverse the Great Basin resulting in gusty
winds across portions Southeast California and the Lower Colorado
River Basin through tonight.

- Temperatures will cool back to near normal in the wake of the
passing weather system with continued breezy conditions for the
remainder of the week and into this weekend.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Current objective analysis reveals the Desert Southwest in a
transition zone as departing high pressure flanks us to the east and
an approaching closed low inches closer to the Pacific Coast. Our
forecast areas will find itself influenced by each of these weather
regimes this afternoon as the ridge helps keeps temperatures
relatively elevated while the western disturbance generates breezy
to locally windy conditions. Lower desert highs will remain 4-8
degrees or so above-normal for this time of year, which translates
to a continuation of afternoon highs in the 90s for the lower
deserts. As the latter feature pushes eastward, our regional
pressure gradient will tighten up, which will, as mentioned above,
usher in the return of enhanced winds for parts of the region,
especially out in SE California and the Lower Colorado River Valley.
Wind Advisories have been posted for Western Joshua Tree NP and SW
corner of Imperial County due to the high confidence of winds
exceeding 40 mph. Advisory level gusts will be possible over other
parts of SE California, but should be confined to higher ridge top
areas. Peak gusts for lower elevation areas should generally range
around 30-35 mph. These strong winds will also up the potential for
areas of blowing/lofted dust which could result in hazardous travel
along stretches of I-8 and I-10. Elsewhere, breezy conditions will
exist, but readings should be closer to 20-25 mph.

The previously mentioned low will eventually work its way onshore
early Wednesday, weakening as it does and transitioning to an open
wave trough. The base of the disturbance will pass well to our
north, but will have at least some influence on regional conditions
for at least one more day. One noticeable change from the day prior
will be the relatively cooler temperatures as highs for lower desert
areas will be mostly in the middle to upper 80s, much closer to
normal for mid to late April. This system will also provide one more
round of breezy conditions for parts of the region, but this time
the focus shifts more towards the high terrain of eastern Arizona,
where gusts will peak around 25 mph, with gusts closer to 30 mph for
the highest ridgetops. The typical wind prone areas of SE California
will see some residual gusts as well, but they will not be nearly as
strong as today.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Ensemble members and deterministic guidance continues to indicate
quasi-zonal flow returning to the Desert Southwest Thursday and
Friday which will result in temperatures remaining near to slightly
above normal. A compressed 500 mb height gradient will prevail over
the Desert Southwest resulting in continued breezy to locally windy
conditions through the end of this week with afternoon gusts
reaching 20-30 mph. A progressive pattern will continue into this
weekend as a series of mostly dry weather systems passes north of
the region. The strongest shortwave looks to arrive on Sunday which
will cool temperatures to around 3 to 5 degrees below normal across
the region. Both the mean of the GEFS and EPS show negative height
anomalies persisting over the Desert Southwest well into next week
which will keep temperatures at least near normal to slightly below
normal to finish off the month.

&&

.AVIATION...Updated at 0510Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Late afternoon/early evening wind gusts, along with west winds
persisting longer than usual into the overnight will be the main
weather issues through Wednesday night under passing high cirrus
decks. Confidence is good that the typical overnight easterly shift
will be delayed several hours, then revert back to W/SW earlier than
usual Wednesday late morning. Gusts 20-25kt should be common mid
afternoon though early evening, though may not be spatially and
temporally uniform across the entire valley.


Southeast California/Southwest Arizona including KIPL and KBLH:
Periods of strong, gusty winds will be the main weather concern
under occasional high cirrus decks. Confidence remains very high
that westerly winds at KIPL will remain in place through the period
with gusts relaxing late night and during daylight hours, but
redeveloping around sunset Wednesday. SW winds will be preferred at
KBLH though a periods of NW are likely around sunrise. Gusts should
be more intermittent and less pronounced at KBLH.

&&

.FIRE WEATHER...
A progressive pattern with multiple dry weather systems passing
north of the region will result in breezy conditions and periods of
elevated fire weather throughout this week. Relative humidity is not
expected to fluctuate much, bottoming out around 8-15% each
afternoon. Overnight recoveries will remain poor to fair over the
next several nights. The strongest winds will reside in SE
California this afternoon and evening where gusts up to 25-35 mph
(locally higher) will be possible. These stronger winds coupled with
very dry conditions (RH as low as 10%) will result in a brief period
of near critical fire weather conditions this afternoon. Widespread
breezy conditions with gusts around 20-30 mph will continue each
afternoon through the remainder of this week, resulting in
persistent elevated fire weather.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until midnight PDT tonight for CAZ560-566-567.

     Wind Advisory until 8 AM PDT Wednesday for CAZ562.

&&

$$

SHORT TERM..RW
LONG TERM...Salerno
AVIATION...18
FIRE WEATHER...Salerno

NWS Phoenix (PSR) Office