968
FXUS65 KPSR 070922
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
222 AM MST Sun Sep 7 2025

.KEY MESSAGES...

- Drying conditions over the next several days will end rain
  chances altogether by Monday.

- Temperatures will briefly warm back into the normal range
  starting today and last through around Tuesday before dropping
  off again during the latter half of the week.

- Localized Moderate Heat Risk is expected mainly across the
  south-central Arizona lower deserts during the first half of
  this week with highs as warm as 105 degrees.

&&

.SHORT TERM /Today through Tuesday/...
The drying trend over the past day or so is now very noticeable
as satellite imagery shows clear skies over nearly all of southern
California and Arizona. Upper level ridging has also started to
build over our region in response to the deepening of the Pacific
low off the West Coast and heights over our area are forecast to
peak later today into early Monday. The strong drying aloft will
finally start to mix down to the surface this afternoon, but dew
points are likely to stay above 60 degrees for one more day.
The drying aloft has mostly ended the rain threat with only a few
widely isolated showers or weak storms possible over the Kofas
and over the far eastern Arizona high terrain this afternoon. The
increased heights and sunny skies today will help to push highs
across the lower deserts to between 99-102 degrees this afternoon.

Starting Monday, much drier air will finally work its way down
into the boundary layer, completely ending any rain chances and
lowering surface dew points into the 50s Monday afternoon and into
30s and 40s across the western deserts Tuesday afternoon. The
warming trend will also continue with highs likely peaking on
Monday between 100-104 degrees. By Tuesday, the southeastern
fringes of the Pacific trough will begin to shift into northwest
parts of our region. This will help to bring temperatures down a
few degrees across southeast California and likely also result in
some increased breezy conditions.

&&

.LONG TERM /Wednesday through Saturday/...
The Pacific trough will become the main driver of our weather
starting Wednesday as the low center moves into northern
California and the base of the trough moves over central and
southern California. This should push daytime highs well into the
90s across southeast California, but highs across south-central
Arizona are still likely to top 100 degrees on Wednesday. Breezy
conditions areawide are also expected Wednesday (and possibly
Thursday) with afternoon gusts to around 25 mph. Guidance is also
indicating some very modest moisture across eastern Arizona for
Wednesday and Thursday, but it is expected to be quite shallow and
should at most bring 10-20% PoP chances across the high terrain.

Ensembles are now in better agreement showing the Pacific trough
stalling out over the Western U.S. as it continues to weaken
before finally lifting the northeast next weekend. The lower
heights from the trough should keep highs in the 90s across most
of the lower deserts late this week to as high as around 100
degrees in the Phoenix area. Overnight lows should also continue
to improve later this week with lows dipping into the 60s across
the western deserts to the low to mid 70s in the Phoenix area.
Eventually by late next weekend and into the following week,
heights are favored to trend upward again after we lose influence
from the trough. This should lead to some slight warming and
highs back to just over 100 degrees.

&&

.AVIATION...Updated at 0530Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
An outflow boundary from distant storms is currently pushing nwd
into Maricopa County and is progged to arrive at KIWA by this TAF
issuance and KPHX at approx 07Z. This boundary will cause a brief
southerly shift at both terminals with gusts up to 18-20 kts.
Winds will return to the normal diurnal patterns later tonight,
however there will likely not be an easterly shift at KPHX tonight
and instead winds will go calm and vrb for a few hrs around
sunrise. Winds will shift back out of the WSW at all terminals by
16Z-17Z Sunday. Expect clear skies overnight with another round of
CU developing on Sunday afternoon.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns will exist over the next 24
hrs. Winds will generally favor SE at KIPL and S at KBLH, with
sustained speeds 5-11 kts through Sunday afternoon. Expect skies
to remain clear overnight with another round of CU developing
early Sunday morning.

&&

.FIRE WEATHER...
Drying conditions are expected over the next several days as high
pressure influences our region. Rain chances have essentially
ended and temperatures will briefly return into the normal range
early this week. MinRHs today will stay elevated at 25-35% before
gradually lowering to between 15-25% by Tuesday. Winds will
continue to be light and favor diurnal patterns through Monday
before a uptick in winds is likely during the middle part of the
week. By Wednesday into Thursday, an incoming low pressure system
mainly to our northwest may allow for some isolated shower and
thunderstorm chances largely over the eastern Arizona high
terrain. Temperatures will also cool back to slightly below normal
later this week with humidities staying stable through Thursday
before drying out even more Friday into next weekend.

&&

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

$$

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