971
FXUS65 KPSR 090500
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1000 PM MST Mon Dec 8 2025

.UPDATE...
Updated Aviation

&&

.KEY MESSAGES...

- Temperatures will steadily warm this week with afternoon highs
reaching 8-13 degrees above the seasonal normal.

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

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...
Current objective analysis reveals a subtle disturbance traversing
the southwestern CONUS, with the wave axis centered over Arizona.
The most this system will do is generate some very marginal breezy
conditions across portions of the region with the strongest gusts
focused mainly along the Lower Colorado River Valley and higher
terrain areas east of the Phoenix metro.

Even with this system overhead, day-to-day temperatures are not
expected to cool at all; in fact, forecasted afternoon highs for
today are a few degrees warmer than what was observed yesterday.
This is thanks to more dominant eastern Pacific ridge that is in
place. Readings today for lower desert locations will range in the
middle 70s with a few areas, mainly out in SE CA due to their closer
proximity to the ridge axis, reaching into the upper 70s. Tuesday
MaxTs will tick up a degree or two more as the shortwave exits the
region and high pressure nudges further to the east.

&&

.LONG TERM /WEDNESDAY THROUGH THIS WEEKEND/...
A gradual warming trend will continue through late week as global
ensembles remain in excellent agreement in maintaining anomalous
high pressure over the central and southern Pacific coast with dry
northerly to northwesterly mid-level flow across the Desert
Southwest. Ensembles show 850mb temperature anomalies peak Thursday
and Friday, at around the 95th to 97th percentile. This will result
in temperatures up to 10-13 degrees above normal with lower desert
high temperatures forecast around 80 degrees to end the week and
start the weekend. 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 in slightly cooler temperatures heading into
the beginning of next week, but still above normal by up to 8-10
degrees. Overall, the long term outlook does not support a lick of
rain. The desert is gonna desert.

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 18th,
indicating a high confidence forecast. There is also no sign of rain
still. Global ensemble 90th percentiles do not show any measurable
precipitation until closer to December 20th.

&&

.AVIATION...Updated at 0500Z.

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

No weather concerns will exist through Tuesday night under clear
skies. Wind behavior will be similar to the past 24 hours featuring
a light easterly drainage component through mid afternoon around the
PHX metro, then only a limited late afternoon/early evening light
westerly trajectory. Winds across SE California will favor a N/NW
direction. Extended periods of nearly calm conditions will be common
across the entire region.

&&

.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 brief bout of gusty
winds, up to 15-25 mph, can be expected across the Lower Colorado
River Valley and AZ high terrain midday today through this evening.
There will also be some lingering gusts Tuesday morning through
early afternoon. Otherwise, winds will remain light and follow
diurnal tendencies. Humidities over the next week will stay above
critical levels with afternoon MinRHs mostly ranging between 20-30%,
followed by good overnight recoveries to around 50-70%.

&&

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

&&

$$

SHORT TERM...RW
LONG TERM...Benedict
AVIATION...18
FIRE WEATHER...Benedict