928
FXUS65 KPSR 261107
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
407 AM MST Sat Jul 26 2025

.UPDATE...Updated 12Z Aviation Discussion.

&&

.KEY MESSAGES...

- Near normal temperatures will warm to slightly above normal by
  the beginning of next week, resulting in widespread Moderate
  HeatRisk.

- Very dry conditions will greatly inhibit any rain chances
  through the weekend.

- Monsoonal activity should increase again across portions of
  Arizona region by the middle of next week.

&&

.SHORT TERM /Today through Sunday/...
The unusual weather pattern with a near persistent upper level
trough along and just off the West Coast is likely to continue
influencing our weather through the upcoming week. The main
trough is still situated off the coast of southwest Canada, but a
secondary trough remains over California where H5 heights are
currently below the 10th percentile of climatology. These lower
heights aloft have provided the Desert Southwest with cooler than
normal temperatures much of time over the past week and a half,
but the close proximity is also a big negative for our monsoonal
pattern. The last few days have seen very dry air from the
southwest spread over our region, cutting off any monsoon activity
and this is forecast to last through Sunday. However, we will
start to see the subtropical ridge, which is positioned over the
Southeastern U.S., to begin to shift westward by Sunday. This
will in turn raise our heights aloft and boost temperatures a few
degrees. Forecast highs for today will be very similar to the last
couple of days with highs right around normals and lows a few
degrees below normal. By Sunday, daytime highs are expected to
reach near the 110 degree mark in the Phoenix area to 105-108
degrees across the western lower deserts.

&&

.LONG TERM /Monday through Friday/...
The first part of next week will see the trough to our northwest
gradually weaken and likely lift a bit more to the north. As we
begin to somewhat lose the dry westerly flow influence from this
trough, the subtropical ridge is forecast to continue to
retrograde westward. Previous guidance was fairly confident in a
meaningful inverted trough moving out of northern Mexico and
reaching southeast Arizona later Monday into Tuesday. This is
still somewhat the case in the latest model runs, but the inverted
trough looks weaker and now is likely to get held up, not
reaching past southeast Arizona.

The slight shift in the flow pattern should still allow for a
period of southeast semi-moist flow into much of Arizona starting
Monday, but the recent model shift now mostly keeps the better
quality moisture across eastern Arizona through Tuesday. Very
limited shower and thunderstorm chances will be possible across
the eastern Arizona high terrain on Monday with slightly better
chances on Tuesday, but still mostly relegated to the higher
terrain. The flow pattern is not likely to change much going
through the middle of next week and this should provide for daily
chances for higher terrain convection and eventually increasing
moisture into the south-central Arizona lower deserts via
outflows. Guidance does try to indicate just enough moisture
working as far west as the Phoenix area to provide for some very
limited (10-15%) chances by next Wednesday. These daily low end
rain chances may very well continue through the rest of next week
as ensemble output shows little change in the positioning of the
subtropical high to our east and the broad troughing to our
northwest.

Temperatures next week look quite stable with H5 heights mostly
hovering within the higher end of the normal range. This should
keep daily highs right around or maybe 2-3 degrees above normal
throughout the entire week. The increased moisture and clouds
should also lead to higher overnight lows across south-central
and eastern Arizona with readings within the Phoenix metro mostly
between 83-88 degrees each night. Lower humidities and generally
clear skies across the western deserts should provide for
overnight lows mostly in the mid 70s to lower 80s.

&&

.AVIATION...Updated at 1105Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation weather concerns under some passing high level clouds
are expected throughout the TAF period. The overall wind pattern
will continue to exhibit the typical diurnal tendencies with
speeds generally aob 10 kts along with some occasional
afternoon/early evening gusts into the mid to upper teens.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major weather issues under some passing high level clouds are
expected throughout the TAF period. Winds at KIPL will stay out of
the west while at KBLH winds will generally be out of the south to
southwest. Wind gusts upwards of 20-25 kts are expected at both
terminals this afternoon and evening. KIPL could potentially see
temporary gusts near 30 kts during the evening hours.

&&

.FIRE WEATHER...
Very dry conditions with zero rain chances and near to slightly
above normal temperatures will continue through the weekend. Some
lower desert location may reach 110 degrees starting Sunday before
moisture increases gradually across the eastern districts next
week. MinRHs through Monday will be in the 5-10% range across the
lower deserts with poor overnight recoveries of only 15-35%.
Winds will tend to follow their typical diurnal tendencies with
some afternoon upslope gustiness. With the increase in moisture
next week there will also be increasing shower and storm chances
across the eastern districts, especially later in the week.

&&

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

$$

SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...Berislavich/Lojero
FIRE WEATHER...Kuhlman