159
FXUS65 KPSR 152104
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
204 PM MST Fri May 15 2026

.KEY MESSAGES...

- Breezy to locally windy conditions return over the weekend with the
  strongest gusts across Southeast California and the Arizona
  high terrain.

- Elevated to critical fire weather conditions this weekend,
  particularly on Sunday for the Eastern Arizona higher terrain
  where a Red Flag Warning has been issued.

- Afternoon high temperatures 4 to 8 degrees above normal through
  Saturday will drop into a near to below normal range Sunday and
  early next week.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
Mid level WV imagery shows mostly quasi linear flow across the CONUS
with a weak ridge over the southern Gulf states, and a weak
shortwave trough over the Desert SW. This shortwave trough has
been lingering over the region for the past couple of days and has
been responsible for temperatures cooling in comparison to the
beginning of the week, however afternoon highs remain 4-6 degrees
above normal today and Saturday. Forecasted high temperatures
today across the lower deserts will mostly be in the upper 90s
with areas along the Colorado River Valley reaching triple digits.
Saturday will be a case of deja vu with almost identical temperatures,
with the exception of the Colorado River Valley cooling to under
the century mark.

By Saturday afternoon a stronger troughing feature will dive down
the western CONUS, starting from the Pacific NW states, and will
extend down into the Great Basin region by Sunday evening, which
will help cool the region by 4-6 degrees, or to below normal.
Ensembles continue to show small discrepancies in the depth of
this next system, while the GEF and GEP showed little change from
the 00Z to 12Z run, the ECMWF has weakened in strength and depth
in comparison to the 00Z run. However, there is enough consistency
to be confident that widespread breezy conditions (15-25 mph
gusts) will develop by Saturday afternoon, and more locally windy
conditions in SW Imperial County where a wind advisory will begin
to take effect Saturday starting 2PM PST and lasting through
Sunday night. Winds will relax for most of the region during the
overnight period before ramping back up Sunday afternoon when peak
gusts are expected. Much of the lower deserts can expect peak
gusts Sunday afternoon between 20-30 mph, the eastern higher
terrain between 30-40 mph, and the SW portion of Imperial County
between 45-55 mph.

Elevated fire weather concerns in the eastern higher terrain area
will begin to develop Saturday afternoon due to increased wind
speeds, reaching critical conditions by Sunday with the peak
gusts, in conjunction with MinRH values near 10%. Due to these
conditions a Red Flag warning has been issued for Southern Gila
County and Tonto National Forest foothills starting 11 AM MST on
Sunday.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
The aforementioned second, more potent piece of energy will rotate
through just north of the area Sunday night into Monday, with
several global models depicting an associated front being sent down
the Lower CO River Valley, resulting in locally windy conditions for
portions of Southeast CA Monday morning. This is the final
anticipated impact from the system that deepens over the Western US
this weekend, as negative height anomalies retreat to the north and
east heading into the middle of the upcoming workweek. Monday is
also shaping up to be the "coolest" of the next 7 days, with
afternoon highs potentially struggling to reach 90F across the lower
deserts, around 5F below daily normals. Forecast uncertainty remains
moderate to high Monday onward, however, as the core of the weekend
system departs northeastward, some measure of broad cyclonic flow
over the Western US will remain and likely evolve into quasi-zonal
flow through the middle of the week. Heights aloft will rebound
closer to seasonal averages and so temperatures are expected to warm
through the middle of the week, with dry conditions continuing.

&&

.AVIATION...Updated at 1700Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major weather issues will exist through Saturday afternoon under
clear skies. A brief period of variable winds (140v230) may exist
during the switch to westerly today, however speeds should be
limited under 10kt. Any stronger wind gusts early this evening
should be rather weak with good confidence of the nocturnal switch
back to easterly occurring after midnight. Heightened wind speeds
and increased gustiness will return Saturday afternoon.

Southeast California/Southwest Arizona including KIPL and KBLH:
Some occasional stronger wind gusts will be the only weather issue
through Saturday afternoon under clear skies. While some wind
variability will be common during the morning, confidence is good
that south winds will be preferred at KBLH while west winds become
more common at KIPL. Late afternoon/evening gusts 20-25kt will
affect the area with more pronounced gusts likely at KIPL.

&&

.FIRE WEATHER...
Slightly above normal temperatures and generally light winds with
typical afternoon upslope/upvalley breeziness will prevail today.
A weather system will move onshore along the Pacific Northwest early
Saturday and deepen over the Western US resulting in increased winds
across the area this weekend. Afternoon/early evening wind gusts
will commonly peak between 20-35 mph Saturday, with locally stronger
gusts in Southeast CA. The strongest gusts by Sunday will likely be
confined to Eastern AZ higher terrain, where gusts between 30-40
mph will be common. This has lead to elevated to locally critical
fire weather conditions across the region both days, and a Red
Flag Warning has been issued starting Sunday 11 AM MST in response.
Afternoon minRHs mostly between 8-12% today will increase by
several points this weekend, with values 7-15% areawide Saturday,
then 10-20% Sunday. Overnight recoveries ranging from 25- 45%
across the area and improving only slightly from there on Saturday
and Sunday nights.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Red Flag Warning from 11 AM to 11 PM MST Sunday for AZZ133.

CA...Wind Advisory from 2 PM Saturday to 11 PM PDT Sunday for CAZ562.

     Wind Advisory from 4 PM to 11 PM PDT Saturday for CAZ566.

&&

$$

SHORT TERM...Ryan
LONG TERM...Whittock
AVIATION...18
FIRE WEATHER...Ryan/Whittock

NWS Phoenix (PSR) Office