163
FXUS65 KPSR 092306
AFDPSR

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

.UPDATE...
Updated Aviation

&&

.KEY MESSAGES...

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

- 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 2305Z.

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

No weather issues will exist through Wednesday evening under clear
skies. Winds will behave similarly to the past 24 hours with
prolonged periods of nearly calm conditions.

&&

.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...18
FIRE WEATHER...Benedict
CLIMATE...Benedict