271
FXUS65 KPSR 161141
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
441 AM MST Sat Aug 16 2025

.UPDATE...12Z Aviation Discussion.

&&

.KEY MESSAGES...

- Rainfall chances decrease substantially starting today with
  storms primarily relegated to higher terrain areas of central
  and eastern Arizona.

- Temperatures will drop into a seasonal normal range through the
  weekend before readings rebound back above normal by the middle
  of next week.

- By middle of next week widespread Major HeatRisk will be common
  across the lower desert regions.

&&

.SHORT TERM /Today through Sunday/...
Water vapor imagery shows an upper level trough currently over
southern California. This feature will cause winds to shift out of
the S-SW, introducing much drier air into the lower desert
region, limiting precipitation chances starting today. The only
exception is the higher terrains in portions of eastern Arizona
this afternoon that has potential of initiating scattered storms
from lingering moisture. However only a few high res models are
showing activity for today.

By Sunday much of the moisture will be sufficiently mixed out
leaving the region dry, allowing for temperatures to begin to
warm. The afomentioned trough will shift towards the Pacific NW,
while the subtropical high begins to retrogrades back to the
west, with H5 heights between 588-591 dm. Thus the lower desert
regions will mostly be in the low to mid 100s while the higher
terrain areas will be mainly in the high 90s.

&&

.LONG TERM /Monday through Friday/...
Temperatures during the beginning portion of this upcoming
work week will be mostly near normal as the subtropical high is
still in the process of moving westwards towards the Desert SW.
This will lead to most of the lower desert regions to see
afternoon highs near 102-105 degrees. Overnight/morning low
temperatures during this time are expected to be in the mid 70s to
low 80s.

By midweek the subtropical high will strengthen over the region
with ensemble guidance showing H5 heights peaking near 595-597
dm. This will lead to afternoon highs across the lower deserts
between 110-115 degrees. consequently the overnight/morning lows
are also expected to climb to mid 80s to low 90s. The inevitable
strength of the ridge will lead to areas of Major HeatRisk again
beginning as early as Wednesday and persisting through the end of
the week. Although still fairly uncertain, models do show some
moisture beginning to creep back into the region late next week
into the following weekend which could provide a shot of some
isolated thunderstorm activity.

&&

.AVIATION...Updated at 1140Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Little to no aviation concerns are anticipated through the
forecast period under a few passing mid-high clouds. Winds will
continue to follow diurnal tendencies, with a 3-4 hr period of
southerly crosswinds anticipated at KPHX into the mid-afternoon
hours before fully shifting out of the WSW. Shower and storm
activity is expected to remain mostly over the higher terrain
areas the the NE of Phoenix. However there is a very low potential
(10% or less) of VCTS at any of the terminals this afternoon and
early evening. Due to the low probability of this occurring, have
precluded mention of any VCTS/VCSH in the TAF at this issuance.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns under clear skies can be
expected throughout the TAF period. At KIPL, winds will remain
southeasterly through most of today before shifting out the west
by sunset this evening. At KBLH, winds will remain primarily out
of the south with gusts into the lower teens possible during the
afternoon and early evening hours.

&&

.FIRE WEATHER...
Low confidence of possible storm activity sparking this afternoon
in the higher terrains of eastern Gila County. Winds will continue
to follow diurnal patterns except in the vicinity of any possible
thunderstorms where abrupt wind shifts with gusty outflows would
be common. Temperatures will continue to be near normal for the
weekend. Min RH levels are closer to a 20-30% range in eastern
districts, but remain 15-20% in western areas, but look to drop
considerably by Monday to near 10-20% region wide. Overnight
recovery vary but will begin to decay over the next few days as
dry air enters the region. Max RH levels today are generally
between 50-60% but drop to near 25-40% by Monday.

&&

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

$$

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