459
FXUS65 KPSR 081700
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1000 AM MST Sat Nov 8 2025

.UPDATE...
Updated Aviation

&&

.KEY MESSAGES...

- Unseasonably warm weather will prevail through at least the middle
of next week with some local daily high temperature records possible
Sunday and Monday.

- A cooler and wetter weather pattern may 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 into early next week. Latest IR satellite
imagery and objective analysis indicates upper level 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 south-
central 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 1700Z.

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

No major weather issues will exist across the region through Sunday
afternoon under clear skies. Winds patterns today will be nearly
identical to Friday with extended periods of calm conditions. Some
local gusts around 15kt will be possible late Sunday morning across
PHX area terminals, but should have little affect on operations.


&&

.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...18
FIRE WEATHER...Salerno