655
FXUS65 KPSR 062321
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
421 PM MST Sat Dec 6 2025

.UPDATE...Updated 00Z Aviation Discussion.

&&

.KEY MESSAGES...

- Dry and generally quiet conditions will continue through at
  least the next 7 days.

- Temperatures will warm over the weekend and through the
  upcoming work week, likely reaching 8 to 12 degrees above daily
  normals.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
Clear skies and gradually warming temperatures will be the main
story through this weekend. Ensembles remain in excellent
agreement that the upper level pattern, characterized by broad
East Pacific ridging and longwave troughing downstream over much
of the CONUS, will persist and shift eastward. Over the next
36-48 hrs or so, the axis of the East Pacific ridge should settle
along or just off the West Coast and remain rather stationary as
we head into the upcoming work week. This will allow the eastern
periphery of the East Pacific ridge to encompass the Desert
Southwest, with positive midlevel height anomalies building into
the region from the west/northwest. As the region is influenced by
the building heights and anticyclonic subsidence more and more
over the next few days, expect temperatures to warm in response.
Afternoon highs today will be within a few degrees of normal,
generally in the middle to upper 60s across the lower deserts,
then warm into a decidedly above normal category Sunday onward.
Meanwhile, dry, northwesterly flow aloft will be maintained thanks
to the approaching anticyclone, precluding much in the way of
cloud cover other than perhaps some occasional passing mid level
cloud decks or high cirrus.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
The East Pacific ridge will keep much of western CONUS under the
influence of its eastern flank for the first half of the work
week. The ridge will be anomalously strong for this time of year,
with H5 heights fluctuating between 586-590 dm at its center (H5
heights of 582-585 dm over the southern half of Arizona and
southeastern California) through the first half of the week.
Multiple shortwaves will be moving from the Pacific NW/southern
British Columbia down into the Plains that will temporally dampen
the ridge, but, it will quickly rebound. If any of these
shortwaves are able to push into the Desert Southwest at all, it
would briefly stall our warming trend for a day. Nevertheless,
afternoon high temperatures, region wide, will gradually warm to
around 8-10 degrees above normal by the middle of next week.
Afternoon high temperatures are forecast to reach the mid to
upper 70s and near 80F in some places across the lower deserts,
with highs in the upper 60s to mid 70s across the higher terrain.

By the end of next week and heading into next weekend, the ridge
will finally push onshore with the center of the ridge eventually
moving over the Desert Southwest. The ridge will be weakening as
it moves onshore, however, with it moving directly overhead
temperatures will continue to gradually warm through at least the
end of next week. H5 heights will rise into the 583-586 dm range
by the end of next week. This will result in afternoon high
temperatures 10-12 degrees above normal and morning low
temperatures 6-8 degrees above normal. For the end of next week,
afternoon high temperatures are forecast to be in the upper 70s
to near 80 degrees across the lower deserts and in the low to mid
70s across the higher terrain. Morning lows are forecast to be in
the 50s across the lower deserts and in the 40s across the higher
terrain. Additionally with the ridge dominating the region, dry
and tranquil conditions will continue at least through next week
into the following weekend.

&&

.AVIATION...Updated at 2320Z.

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

No aviation weather concerns are anticipated through the forecast
period under clear skies. Winds will remain light, generally aob 5
kts, and continue to exhibit diurnal tendencies with periods of
VRB at all terminals .

&&

.FIRE WEATHER...
Dry conditions will prevail across the region through next week.
Temperatures will be within a few degrees of daily normals through
tonight then warm into a decidedly above normal category Sunday
onward. By the end of next week, temperatures will be 10-12
degrees above normal. Winds will generally remain light and
terrain-driven. Humidities over the next week will stay elevated
with afternoon MinRHs mostly ranging between 20-30%, followed by
good to excellent overnight recoveries.

&&

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

$$

SHORT TERM...Whittock
LONG TERM...Berislavich
AVIATION...Ryan/Salerno
FIRE WEATHER...Whittock/Berislavich