South West Weather

490
FXUS65 KPSR 182351
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
451 PM MST Sun Jan 18 2026

.UPDATE...00Z Aviation Discussion.

&&

.KEY MESSAGES...

- Strong high pressure across the region will persist for much of
  the coming week leading to above normal temperatures and dry
  conditions.

- Unsettled weather may affect the region by next weekend with
  rain chances potentially returning and temperatures dropping
  closer to normal.

&&

.SHORT TERM /TODAY THROUGH TUESDAY/...
An Omega blocking pattern with ridging throughout the Western
U.S. and southwest Canada and deep troughing across the eastern
CONUS and Canada can be seen on GOES satellite. Across the region
today H5 heights will be in the 90th percentile of climatology before
lowering on Monday to near normal. However, temperatures in the
lower deserts will continue to range between 72-77 degrees. Passing
high clouds have already began to move into the region and will
be common through Monday before clearing by Tuesday morning.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Upper level ridging is forecast to continue on Wednesday and
likely into Thursday before much of the Western U.S. begins to
fall under some modest troughing by Friday. At the same time, a
cut-off low will develop off the coast of California with the bulk
of the ensemble guidance pointing at this disturbance not gaining
much strength and eventually drifting southeastward by next
weekend. The shift away from the ridging later this week should
lower our temperatures modestly by Friday into next weekend, but
so far the NBM keeps our temperatures barely touching the normal
range. The cut-off low could get close enough to affect portions
of our region by next weekend, but model trends have been leaning
toward the system mostly bypassing our region to the south. Models
have a difficult time handling these cut-off lows, so forecast
confidence remains quite low for Friday into next weekend. Between
the GEFS and the EPS, around 25% of the members show decent rain
chances with the cut-off low. Models are not likely to have a good
handle on this system until at least the middle of the week.

&&

.AVIATION...Updated at 2350Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT and
Southeast California/Southwest Arizona including KIPL and KBLH::
No aviation concerns are expected during the TAF period. Winds
will follow light and diurnal trends with VRB to calm conditions
being common through the TAF period. FEW-SCT high cirrus decks
will be present during the forecast window, and may become BKN at
times.

&&

.FIRE WEATHER...
Strong high pressure will persist across the region over the next
several days keeping temperatures above normal and dry conditions
in place. Daily MinRH values will remain stable, falling to
15-20% each day with overnight recoveries of 30-50%. Winds will
overall be light through the period with only some periodic light
breeziness across the Lower CO River Valley and over the Arizona
high terrain.

&&

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

$$

SHORT TERM...Ryan/Kuhlman
LONG TERM...Kuhlman
AVIATION...Berislavich/RW
FIRE WEATHER...Ryan/Kuhlman