805
FXUS65 KPSR 151800
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1100 AM MST Sat Nov 15 2025

.UPDATE...Updated Aviation Discussion

&&

.KEY MESSAGES...

- The first in a series of three weather systems will affect the
  region this weekend bringing fairly widespread light to moderate
  rainfall but little impacts.

- Temperatures are expected to cool well below normal starting
  Sunday and last through all of next week.

- A second weather system with rain more focused across Arizona is
  expected for Tuesday.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
A deep Pacific low pressure system is currently centered just west
of San Diego with strong southerly moisture advection and
rainfall impacting the coast of California. The slow progression
of the system has directed the bulk of the moisture and energy
into southern and central California with rain-shadowing keeping
most of the rain from getting over the interior mountains. For
today, the trough is set to slowly drift more to the east
allowing for better forcing and moisture to finally move into
southeast California and eventually into Arizona tonight into
Sunday.

Model guidance continues to lower expected rainfall amounts for
much of the area this weekend, especially across Arizona. Rain
should peak across southeast California later this morning and
through the afternoon hours with more scattered shower/embedded
thunderstorm activity eventually swinging through southern and
central Arizona Saturday night/Sunday morning. QPF amounts have
been lowered to show an average of 0.25-0.5" across the southeast
California lower deserts to 0.1-0.25" for the Arizona lower
deserts. Some lower desert areas may end up seeing between 0.5-1",
but that should be very localized. Higher rainfall totals are
still expected across JTNP where upwards of an inch is likely to
fall through this evening. Forecast totals for the Arizona higher
terrain have also fallen to between 0.25-0.5", with slightly
higher totals over ridgetop locations.

Temperatures today are still expected to be fairly warm across the
Arizona lower deserts with highs likely topping 80 degrees. More
cloud cover and the rainfall across the western deserts should
keep daytime highs today between 70-75 degrees. Once the cold
front pushes through the entire area by later Sunday morning, the
below normal temperatures will finally be seen.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
After this weekend`s weather system weakens and finally exits to
the northeast by Sunday night, a second shortwave will be
following behind within the broader trough which will remain in
place across the Western U.S. Guidance is now showing better
agreement with the progression with this second system with a
closed low first developing across California on Monday before
tracking south southeastward into our region on Tuesday. There is
still some slight timing and position differences within the
ensemble members, so that in turn means there is uncertainty with
the rainfall totals and exactly when the peak rain will occur.
Some showers may begin to develop late Monday and Monday night,
especially across higher terrain areas before more widespread rain
is likely to occur on Tuesday. This system should bring better
dynamics and forcing than the first, potentially allowing for a
more organized rain event. Forecast moisture levels will be lower
than this weekend`s system, but given the Tuesday system will be
colder that should compensate for the lower available moisture.
Potential rainfall amounts are still fairly uncertain, but the
higher end of potential shows upwards of an inch possible across
south-central Arizona to 0.25-0.5" across the southeast California
lower deserts. As of right now, we are going with a more
conservative 0.1-0.25" for SE CA and around 0.5" for the south-
central Arizona lower deserts. Higher terrain areas north and east
of Phoenix may end up getting another 0.75-1.25" by the time the
rain ends either Tuesday night or early Wednesday.

The active weather period is expected to continue through the rest
of next week with a third somewhat cold system quickly moving
from off the Pacific Northwest on Thursday into our region around
Friday or Saturday. Model uncertainty is even higher with this
third system, but it could end up being the best precip maker.
There are around 30% of the ensemble members that show a more
progressive system which would not provide much additional
precipitation, but another 30-50% show a much slower closed off
low which may stick around for a couple of days.

Temperatures next week will be fairly chilly all week with highs
mostly staying below 70 degrees each day. As of right now,
Wednesday may end up being the coldest day with highs only in the
lower 60s for some lower deserts locations. The persistent higher
boundary layer moisture and clouds should at least keep overnight
lows fairly close to normal readings most nights.

&&

.AVIATION...Updated at 1800Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The main aviation concerns during the TAF period will be the
introduction of VFR CIGS (6-8k ft) this afternoon and evening and
SHRA activity Sunday morning. In the short term, no major impacts
are expected with light winds and quiet conditions. The typical
W`rly wind shift may take longer than usual to become established
with some terminals potentially observing more of a S`rly
component through this evening. By Sunday morning (likely between
11-13Z based on current trends) a more pronounced W`rly component
will take hold with perhaps a few gusts around 15-20 kts. The best
chance to see rainfall activity over the terminals will also
concur with this switch which could result in some brief
reductions in VIS. Even though the chances for MVFR conditions
exist in conjunction with any SHRA activity, confidence is too low
to warrant any mention of impactful CIGs and VIS in the TAFs at
this time. A rouge shower also cannot be completely ruled out in
the vicinity of the terminals from this evening through early
Sunday

Southeast California/Southwest Arizona including KIPL and KBLH:
The main aviation concern during the next 24 hours will be -SHRA
activity through this evening that could lead to periods of MVFR
VIS. These reductions should be relatively brief in nature before
the region fully drys out by early tonight. Even though chances
for MVFR CIGs are too low to include in the TAFs at this time,
they cannot be completely ruled out through the evening timeframe.
Winds with the associated shower activity will contain a S`rly
component before a W/SW`rly shift takes place once the rainfall
coverage begins to diminish. Some periodic gusts 20-25 kts may be
observed through this afternoon.


&&

.FIRE WEATHER...
A large weather system will slowly move through the region
this weekend bringing cooler temperatures, increased humidities,
and fairly widespread rainfall. Rain chances will peak across the
western districts during the daytime hours today and during the
first half of Sunday for the eastern districts. A few isolated
thunderstorms will be possible, which may produce locally heavier
rainfall amounts. MinRHs today will range from 25-30% over the
eastern districts to 50-70% for the western districts. Sunday will
bring MinRHs of 40-60% areawide. Expect periodic breeziness over
the weekend. The active weather will continue through next
week with another weather system affecting the area by Tuesday and
another later in the week. Expect below normal temperatures and
elevated humidities for all of next week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Flood Watch through this evening for CAZ560-568.

&&

$$

SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...RW
FIRE WEATHER...Kuhlman