466
FXUS65 KPSR 092041
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
141 PM MST Tue Dec 9 2025

.KEY MESSAGES...

- Above-normal temperatures will be common across the region over
  the next several days with some locations event flirting with
  record highs by late week.

- Dry and tranquil conditions will prevail for at least the next
  7 days.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Current objective analysis reveals the Desert Southwest located
under the eastern fringes of a broad upper-level anticyclone,
helping to keep all any active weather well off to the north over
the Pacific and Intermountain West. What this means for our little
slice of the CONUS is a continuation of dry and tranquil
conditions over the next few days, with gradually increasing
daytime temperatures through the middle portion of the week.
Afternoon highs for this afternoon will be generally in the middle
to upper 70s across the lower deserts with perhaps a few spots,
mainly in and around the Imperial Valley, reaching the 80 degree
mark. Increasing temperatures aloft will translate to a few
degrees of warming at the surface heading into Wednesday as
readings hover around the middle 70s to lower 80s. Higher
elevations will see very pleasant conditions as well as MaxTs
range in the middle 60s to lower 70s.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Afternoon high temperatures 8-13 degrees above normal will
continue through the long term forecast, peaking Thursday and
Friday when global ensembles show highest 850mb temperature
anomalies at around the 95th to 97th percentile. Latest forecast
highs from the NBM are also within a couple degrees of daily
records, including in Phoenix Thursday through Sunday. It is not
tremendously uncommon to reach 80 degrees this time of year, as
most daily records are around 80-85 degrees in December and
January. It is actually somewhat common for lower desert
communities to reach 80 degrees a few times each Dec-Jan, and it
has become more common during the last 10-20 years.

Heading through this weekend global ensembles show the large scale
pattern across the Southwest becoming flatter, with more westerly
flow, for at least a few days. This reduction in 500mb height
anomalies will result temperatures a smidgen cooler heading into
the beginning of next week, but still well above normal. Overall,
the long term outlook does not support a lick of rain. The desert
is gonna desert while this La Nina atmospheric pattern persists.

EXTENDED LOOK: Looking out at longer range models there is still no
sign of any significant weather pattern change. Ensembles maintain
positive height anomalies through week 2, which means a continuation
of above normal temperatures.  The NBM shows very little spread
in the temperature forecast (4 degrees max) through December 19th,
indicating a high confidence forecast. There is also no sign of
rain still. Global ensemble 90th percentiles do not show any
measurable precipitation until December 20th, which is not saying
much when the 90th percentile is mostly outliers. So, it may be
even longer before the next rain in the lower deserts.

&&

.AVIATION...Updated at 1728Z.

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

No aviation weather concerns will exist through Wednesday
afternoon under clear skies. Winds will continue to follow light,
diurnal tendencies with extended periods of variable or calm
conditions. Speeds will mostly remain aob 7 kts.

&&

.FIRE WEATHER...
Warm and dry weather will prevail across the region through this
week. Temperatures will be above normal and gradually warm to 8-13
degrees above normal by the end of the week. A dry weather system
toward the middle of next week may enhance winds. Otherwise,
winds will remain light every day and follow diurnal tendencies.
Humidities over the next week will stay above critical levels with
afternoon MinRHs mostly ranging between 20-25%, followed by good
overnight recoveries to around 50-70%.

&&

.CLIMATE...Daily Record Highs

   Phoenix
   -------
12/11  81 (1977)
12/12  79 (2010)
12/13  82 (2010)
12/14  78 (2010)
12/15  79 (1969)

&&

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

$$

SHORT TERM...RW
LONG TERM...Benedict
AVIATION...Smith
FIRE WEATHER...Benedict
CLIMATE...Benedict