985
FXUS65 KPSR 121724
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1024 AM MST Wed Nov 12 2025

.UPDATE...Updated Aviation Discussion.

&&

.KEY MESSAGES...

- Unseasonably warm weather will continue through Thursday with
  high temperatures around 5 to 8 degrees above normal.

- A strong storm system is expected to arrive by the weekend
  bringing breezy winds and widespread accumulating rainfall.

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

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...
The weather pattern is beginning to shift, but the warm and dry
conditions for our region will last for another couple of days.
Deep troughing remains positioned just off the West Coast and this
will continue to provide high amplitude ridging over the
Southwestern U.S. The close proximity of the trough is however
starting to push upper level moisture and abundant clouds into our
region and this will continue through tonight with a bit more
breaks in the cloud cover on Thursday. Expect daytime lower desert
highs mostly in the mid 80s for today and Thursday with mild
overnight lows around 60 degrees.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
An active period of weather is expected by the weekend and likely
lasting through most if not all of next week. Ensembles show at
least two weather systems that are likely to bring precipitation
to the region, the first one mainly over the weekend and another
one by around next Tuesday/Wednesday. It may not stop there as
guidance hints at another potential weather system by next
weekend.

The first weather system is already starting to take shape west of
Oregon/northern California with two shortwaves expected to merge
together on Thursday. A deeper low should then form which is
forecast to slowly drift southward off the coast of California
late Thursday and Friday before moving onshore on Saturday. The
low center is currently forecast to stay just to our northwest,
but the system will be large enough to impact the entire Desert
Southwest later Friday through the weekend.

Additional upper level moisture will begin to stream into the
region starting Friday with moisture gradually lowering into the
mid levels Friday night into Saturday. We will also see some
weak to modest moisture advection in the lower levels on Saturday,
but this will be limited by the southwest trajectory of the flow.
The overall slow progression of the weather system will at least
help to improve moisture levels by Saturday with a somewhat top
down saturation expected to occur as the low moves into the
region. The system will also provide plenty of upper level
dynamics for precipitation development, first over southern
California on Friday and then into Arizona Saturday into Sunday.

The peak of the rain potential, with PoPs currently as high as
60-80% should be over southeast California Friday night through
Saturday evening and then across southern and central Arizona
from Saturday morning through around Sunday afternoon. Forecast
PWATs are seen to increase to around 250% of normal for this
weekend, but low level mixing ratios will be slightly more limited
at between 6-9 g/kg. The event should bring periods of light
rainfall with the advancing cold front likely bringing a more
focused and shorter duration (maybe 3-6 hours) of more moderate
rainfall. The latest forecast rainfall amounts call for
0.50-0.75" over most of the lower deserts with higher amounts of
1.00-1.50" for higher terrain areas. Given the longer duration and
the expected lack of any heavy rainfall, we are not anticipating
much if any of a flood threat.

The weekend weather system will also usher in much cooler air
with highs falling into the 70s by Saturday and maybe into the
upper 60s starting Sunday. A second weather system is then likely
to move into the region at some point during the first half of
next week. A good deal of model spread is still seen with the
second weather system, but for now guidance somewhat agrees on
bringing it through the region around next Tuesday and/or
Wednesday. The trajectory with this one should be more out of the
west northwest with more limited moisture levels and precipitation.
The system will likely be a bit colder, but snow levels are still
likely to be fairly high at 6500-7500 feet. Temperatures are
forecast to stay below normal through the middle of next week with
the NBM even showing highs potentially dropping into the low to
mid 60s for a short period.

&&

.AVIATION...Updated at 1724Z.

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

No aviation weather concerns are anticipated at all terminals
through Thursday morning under SCT-BKN high clouds. Winds will
continue to follow light, diurnal tendencies with extended periods
of variable or calm conditions.

&&

.FIRE WEATHER...
Warm and dry conditions with above normal temperatures will
persist through Thursday before a strong weather system brings
cooler temperatures and very good chances for wetting rains to
the region mainly over the weekend. Over the next couple days,
MinRHs 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...Kuhlman
LONG TERM...Kuhlman
AVIATION...Smith/Benedict
FIRE WEATHER...Kuhlman