971
FXUS65 KPSR 291030
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
330 AM MST Mon Sep 29 2025

.KEY MESSAGES...

- A dry and quiet weather pattern will settle into the region
  beginning today and persist through the rest of this week.

- Temperatures will gradually warm from near normal to slightly
  above normal by the end of this week as a ridge of high
  pressure builds over the region.

- A dry weather system passing north of the region will bring
  breezy conditions and slightly cooler temperatures this
  weekend.

&&

.SHORT TERM /TODAY THROUGH TUESDAY/...
Latest mid-lvl wv imagery and 500 mb streamline analysis reveals
a shortwave trough progressing through Northern AZ. This troughing
feature will continue to weaken and exit the state by this
afternoon with shortwave ridging taking its place. Much drier air
will filter into the region this afternoon with PWAT values
expected to fall below 1.00" across the lower deserts. We will
start off this week with dry and tranquil weather across the
forecast area with high temperatures remaining slightly below
average. After the last few days with highs in the 80s, we will
see the return of 90 degree temps across the lower deserts this
afternoon. Overnight lows will remain seasonable in the upper 60s
to mid 70s.

On Tuesday, a broad mid-lvl trough will enter the Intermountain West
which will result in quasi-zonal flow developing over the Desert
Southwest. PWAT values across the forecast area will continue to
fall to around 0.6"-0.8" on Tuesday afternoon. The much drier air
combined with increasing mid-lvl hghts/thickness will result in
temperatures rebounding to near normal. Expect highs on Tuesday
afternoon to range from the mid 80s across the high terrain to mid
90s across the lower deserts.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
From mid to late week, ensemble and deterministic models are in
agreement that a high amplitude ridge will build over the Desert
Southwest while a cutoff low develops over California. 500 mb
hghts will gradually increase to around 588-590 dam by the end of
the week resulting in highs across the lower deserts increasing
from the mid 90s on Wednesday to the upper 90s to around 100
degrees by Thursday and Friday. Global models continue to indicate
the aforementioned shortwave trough eventually diving across the
Great Basin this weekend which will result in a slight cool down
and breezier conditions across southcentral AZ. Given the trajectory
of this system remaining north of the forecast area and the lack
of any adequate moisture return, dry conditions with near zero
precipitation chances are expected to persist.

&&

.AVIATION...Updated at 0515Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation concerns are expected during the TAF period. Winds
will mostly maintain a NW`rly component with periods of VRB. Wind
speeds will remain aob 10kts. Clear skies are expected through
most of the TAF period.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation concerns are expected during the next 24 hours. Winds
will follow light and diurnal trends, with extended periods of
variability. Clear skies are expected through most of the TAF period.

&&

.FIRE WEATHER...
Temperatures will gradually warm above normal through the middle of
this week as a ridge of high pressure builds over the forecast area.
Expect much drier conditions to materialize each day with MinRHs
ranging from 25-35% this afternoon and falling to around 15-25%
through the end of this week. Overnight recovery will range from
fair to good tonight and generally remain in the fair category
through this week. Winds will follow light and diurnal tendencies
for the next several days with some modest afternoon upslope gusts.

&&

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

$$

SHORT TERM...Salerno
LONG TERM...Salerno
AVIATION...Ryan
FIRE WEATHER...Salerno