079
FXUS65 KPSR 111131
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
431 AM MST Tue Nov 11 2025

.UPDATE...12Z Aviation Discussion.

&&

.KEY MESSAGES...

- Unseasonably warm weather will persist through the middle of this
  week with high temperatures around 5 to 8 degrees above normal.

- A strong storm system is expected to arrive on Friday bringing gusty
  winds, widespread accumulating rainfall, and mountain snow.

- Temperatures are expected to cool well below normal this weekend
  with lower desert highs falling into the 60s and 70s and lows in
  the 40s and 50s.

&&

.SHORT TERM /Today through Thursday/...
Latest satellite wv imagery and 500 mb streamline analysis depicts
a highly amplified ridge-trough pattern across the lower 48.
Upper-lvl ridging continues to be the predominant feature over
the Desert Southwest this morning. Although the ridge has weakened
over the past 24 hrs, 500 mb heights will continue to remain in
the 587-589 dam range today which is above the 90th percent of
climatology for this time of year. This ridge will continue to
bring anomalous warmth to our region with lower desert highs again
reaching up to the mid 80s to around 90 degrees. Phoenix will
likely fall short of the 90 degree mark this afternoon, however
Yuma and El Centro will have a greater than 75% chance of reaching
90 degrees.

As the upper-lvl ridge continues to weaken and progress eastward
over the next couple of days, we will see southwesterly flow setting
up over SE California and southcentral AZ on Wednesday and Thursday.
This pattern change is in response to a large upper-lvl trough which
will be approaching the West Coast. Ahead of this trough, we will
begin to see abundant cirrus streaming over the forecast area with
cloud cover becoming thicker and more extensive with time. The
increased cloudiness coupled with an overall lowering in mid-lvl
heights/thickness will result in temperatures cooling by a few
degrees. Lower desert highs are expected to top out in the low to
mid 80s Wednesday and Thursday afternoon which is still around 5 to
8 degrees above normal. As the trough of low pressure draws closer
to the California Coast on Thursday, an increased 500 mb height
gradient will result in breezy conditions materializing across
southeast CA where gusts in the 20-30 mph range will be common.

&&

.LONG TERM /Friday through Tuesday/...
We then turn our attention to a very active weather period
beginning on Friday and persisting into the weekend. Since the
last forecast issuance, deterministic models and ensemble members
have now shifted to a slower and deeper track of the upper low
through SoCal on Friday. This solution is now being favored by
more than half of the GEFS and EPS members as well as the
deterministic GFS and ECMWF. If this solution were to come to
fruition, our forecast area would see a more prolonged period of
precipitation beginning late Thursday across southeast CA and
spreading ewd into southcentral AZ on Friday and Saturday. The
latest WPC 5-day QPF totals have increased dramatically across
southcentral AZ with widespread storm totals up to 1.00"-1.50".
This uptick in QPF is also reflected in the mean of the GEFS which
is showing a storm total of around 1.00" for Phoenix. Another
added element to this forecast will be increasing chance for
thunderstorms especially Friday night into early Saturday as mid-
lvl lapse rates steepen ahead of the approaching cutoff low. The
core of the closed low is projected to pass over central AZ late
Saturday into Sunday which will bring an end to the precipitation
for the lower deserts, but a few light showers could persist over
the AZ high terrain. It is important to note that we are a few
days out and there is still time for models to shift. For now,
precipitation chances peak at 20-40% for southeast CA and southwest
AZ and up to 40-60% for southcentral AZ late Friday into Saturday.

As the upper-low progresses through the forecast area, we will
see a noticeable drop in temperatures. Highs temperatures are
expected to fall from the mid 80s on Thursday to upper 60s to low
70s on Friday. Well below normal temperatures will carry into the
weekend making it feel much more fall-like. Overnight lows will
also tumble into the upper 40s to low 50s with some locations
across the high terrain areas NE of Phoenix bottoming out in the
upper 30s on Sunday morning. Well below normal temperatures will
likely persist into early next week as long range models indicate
a reinforcement of the upper-lvl trough Intermountain West Monday
into Tuesday. Although uncertainty is higher, this secondary
trough could also bring another round of precipitation to the
Desert Southwest by the middle of next week.

&&

.AVIATION...Updated at 1130Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation weather concerns are anticipated across the airspace
through tonight. Winds will remain light and follow normal diurnal
patterns with extended periods of calm and variable conditions.
A high cirrus shield will increase in coverage throughout the day
with skies becoming BKN to OVC late tonight.

&&

.FIRE WEATHER...
Warm and dry conditions with above normal temperatures will
persist through Thursday before a strong weather system brings
cooler temperatures and chances for wetting rains to the region
Friday into the weekend. Over the next couple days min RHs will
range between 15-20% before improving to 35-40% on Friday and
remaining above 35% through the weekend. Overnight recoveries
will remain poor to fair through Thursday but improve to an
excellent category by Friday night. Winds will be light, generally
less than 15 mph and follow typical diurnal patterns through most
of this week, however breezy to locally windy conditions are
expected to develop across the western districts Thursday and
Friday where gusts could reach 25-35 mph.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

$$

SHORT TERM...Salerno
LONG TERM...Salerno
AVIATION...Salerno
FIRE WEATHER...Ryan/Salerno