126
FXUS65 KPSR 271200
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
500 AM MST Wed Aug 27 2025

.UPDATE...Updated 12Z Aviation Discussion.

&&

.KEY MESSAGES...

- Isolated showers and a few thunderstorms will remain possible
  today areawide with light shower activity then affecting
  southeast California and southwest Arizona Wednesday night and
  Thursday.

- Expect near to slightly below normal temperatures today and
  Thursday before temperatures warm to slightly above normal by
  the weekend. Widespread Moderate Heat Risk is expected for this
  weekend.

- Overall dry conditions will prevail later this week and likely
  through the weekend before rain chances gradually increase
  during the first half of next week.

&&

.SHORT TERM /Today through Thursday/...
Moisture levels continue to slowly decrease as the Pacific trough
to our west sends drier southwesterly flow over much of our
region. However, there is still enough low and mid level moisture
to support periods of isolated to scattered showers and
thunderstorms. A cluster of showers and storms is currently
working it way into the high country north of the Phoenix area and
Hi-res CAMs suggest this should be the last of the activity we
can expect tonight.

The drier air aloft will continue to bring down overall moisture
levels through the rest of today with any afternoon redevelopment
of showers or storms being quite limited in scope and focused
more across the western deserts and the Arizona high terrain.
Attention then turns toward the remnant mid and upper level
moisture from the slowly decaying TC Juliette that is forecast to
stream northeastward into southern California and western Arizona
starting tonight and last through Thursday night. Even though
this moisture will be concentrated aloft it will be quite robust
sending PWATs back up to between 1.4-1.7" at least into Imperial
Co. Upper level forcing should also be present across southern
California as the moisture streams over the area providing thick
mid and high level clouds and likely periods of light shower
activity from late tonight through at least Thursday evening. Rain
chances for southeast California and far western Arizona have
been trending upward during this time, but any rainfall amounts
are expected to be quite light. Locations farther to the east in
Arizona should just see the mid and higher level clouds on
Thursday with virtually no chances for rain.

Temperatures for today will warm slightly from what we saw
yesterday, but highs should mostly fall 2-4 degrees below
normals. Once the cloud cover moves in tonight and Thursday,
locations across southeast California should see a somewhat cooler
day Thursday with highs only in the 90s. For south-central and
eastern Arizona, temperatures should see readings closer to
normals as some peaks of sun should be seen throughout the day.

&&

.LONG TERM /Friday through Tuesday/...
By Friday, the remnant moisture from TC Juliette is expected to
shift out of the region with drier westerly flow taking over as
the subtropical ridge centered near El Paso becomes the main
driver of our weather. We should return to full sunshine on Friday
with boundary layer moisture gradually getting mixed out,
lowering surface dew points down into the low 50s and then into
the mid to upper 40s on Saturday. The ridge will bring some
increasing heights over the region Friday into the weekend and
helping to bring hotter conditions as highs warm to just above
normal starting Saturday. We are expecting to see widespread
Moderate HeatRisk develop by Saturday and possibly some very
localized Major HeatRisk on Sunday as some of the lower deserts
could top out near 110 degrees.

Eventually ensemble guidance shows the ridge center shifting
northward to over or near northern Arizona early next week
allowing some weak southeasterly moist flow back into at least
southern Arizona. There is still a good deal of uncertainty with
the timing of the moisture return and the NBM tries to even
introduce slight chance PoPs already on Sunday, but that seems too
early. Our thinking is we may see some high terrain convection
return by Monday and then potentially into the lower deserts
around next Tuesday or Wednesday. Temperatures early next week are
likely to start to trend downward with the increase in moisture,
but more than likely will remain at least a couple degrees above
normal into the middle part of next week.

&&

.AVIATION...Updated at 1200Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Light and variable winds will likely continue into the early
afternoon, with speeds generally aob 5 kt. However, winds should
tend to favor a southeasterly/southerly direction. Winds will then
go westerly early this afternoon (18-20Z), with a later than
normal switch to easterly during the overnight hours. Wind speeds
are expected to be aob 10 kt through the period. Any showers or
storms that develop today are expected to remain away from the
Phoenix Metro and over higher terrain areas. Increasing mid and
high level clouds are anticipated through the period.

Southeast California/Southwest Arizona including KIPL and KBLH:
Winds overall will favor their diurnal tendencies (SE`rly/S`rly
through the afternoon switching to SW`rly this evening). Speeds
will generally be aob 10 kt through the period. VCSH/SHRA may
start to move into the KIPL area at the tail end of the TAF
period. However, better confidence for the arrival of SHRA is
after 12Z, so have left VCSH/SHRA out of the KIPL TAF at this
time. Mostly clear skies this morning will see increasing cloud
cover through the TAF period.

&&

.FIRE WEATHER...
Moisture levels will stay somewhat elevated through Thursday, but
rain chances will continue to decrease. Wetting rain chances will
mostly stay below 10% today and Thursday before rain chances end
completely for all but the far eastern Arizona high terrain
starting Friday. MinRHs today and Thursday will mostly range
between 20-30% before gradually decreasing into the teens by the
weekend. Temperatures will remain near to slightly below normal
through Thursday before rising to slightly above normal by
Saturday.

&&

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

$$

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

NWS Phoenix Office