429
FXUS65 KPSR 081137
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
437 AM MST Sat Nov 8 2025

.UPDATE...12Z Aviation Discussion.

&&

.KEY MESSAGES...

- Unseasonably warm temperatures with dry conditions will prevail
  through at least the middle of next week.

- High temperatures across the lower deserts will peak Sunday and
  Monday with some local daily records possible.

- A potential cool and wet weather pattern will arrive into the
  Desert Southwest by the end of next week.

&&

.SHORT TERM /Today through Monday/...
An overall dry and benign weather pattern with unseasonably warm
temperatures will continue this weekend and into early next week.
Latest IR satellite imagery and objective analysis indicates
upper-lvl ridging remains firmly in place over the western CONUS.
This ridge will continue to be the predominant feature over the
next several days. H5 heights will range from 582-584 dam this
afternoon which is around the 90th percentile of climatology for
this time of year. These positive height anomalies will result in
another warm afternoon across our region with lower desert highs
topping out in the mid to upper 80s.

The upper-lvl ridge will become more amplified across the western
CONUS on Sunday as a deep trough of low pressure develops over the
Great Lakes/Upper Midwest. In response, model H5 heights will
rise to around 588-590 dam across the Desert Southwest which is
near the climatological maximum for early November. As a result,
highs across the lower deserts will climb into the upper 80s to 90
degrees. The record high on Sunday for Phoenix Sky Harbor is 88
degrees and NBM probabilities are still high (>70% chance) that
the record will be broken. Although the ridge will weaken slightly
on Monday, positive height anomalies will still result in highs
reaching within a degree or two of daily records across the lower
deserts. Due to these warm afternoons, a Minor HeatRisk will
exist for those that are not conditioned to the heat, so it is
important to continue to practice smart heat safety.

&&

.LONG TERM /Tuesday through Saturday/...
Confidence remains high that upper-lvl ridging will prevail over
the Desert Southwest through at least the middle of next week as a
trough of low pressure takes aim on coastal California and the
Pacific Northwest. Under the presence of ridging aloft, daily
highs across the lower deserts will continue to top out around 5
to 8 degrees above normal Tuesday through Thursday. Starting on
Wednesday we will also see an increasing fetch of high clouds
progressing into our forecast area ahead of the approaching trough.

Deterministic models and ensemble members are now coming into better
agreement showing the onshore progression of the upper trough and
displacement of the upper ridge ewd into the Southern Plains late
next week. As this occurs, a large plume of Pacific moisture will
begin to overspread CA and the Intermountain West from Thursday into
Friday. This system will likely bring widespread measurable
precipitation to coastal and interior California. The combination of
increasing mid-lvl southwesterly flow will transport moisture into
the Desert Southwest by Friday into Saturday and that is when we
will see rain chances increase from W to E across our forecast area.
There are still subtle differences in timing in model QPF fields,
however most members are now showing measurable rainfall in
southcentral AZ. Coincidentally, NBM PoPs have now increased up to
20-40% across much of the region late Friday into Saturday. Due
to the arrival of negative height anomalies associated with the
trough, sfc temperatures are expected to cool into the lower 80s
by Friday and potentially mid to upper 70s on Saturday.

&&

.AVIATION...Updated at 1135Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation weather concerns will exist across the airspace for
the entire forecast period. Winds will follow typical diurnal
trends with speeds remaining aob 6 kts. Extended periods of calm
and vrb conditions can also be anticipated.

&&

.FIRE WEATHER...
Warm and dry conditions with well above normal temperatures
will prevail this weekend and through much of next week.
Afternoon minimum humidity will bottom out between 15-20% over
the next several days with overnight recoveries ranging from
30-60%. Winds will remain light, generally 15 mph or less with
occasional afternoon gusts and will tend to follow a typical
diurnal upslope/nocturnal drainage pattern.

&&

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

$$

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