123
FXUS65 KPSR 091701
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1000 AM MST Sun Nov 9 2025

.UPDATE...
Updated Aviation

&&

.KEY MESSAGES...

- Unseasonably warm weather will prevail through at least the middle
the week with record setting high temperatures possible today and
Monday.

- A cooler and wetter weather pattern will arrive into the Desert
Southwest by Friday and persist into next weekend.

&&

.SHORT TERM /Today through Monday/...
A highly amplified and well defined upper-lvl ridge has taken shape
over the Desert Southwest this morning. This ridge will be the
catalyst for near record to record breaking high temperatures over
the next couple of days. 500 mb heights are expected to top out
around 588-590 dam today, which is around the climatological maximum
for this time of year. H5 heights of this magnitude will result in
sfc temperatures reaching the upper 80s to 90 degrees across the
lower deserts which is around 8-10 degrees above normal. If we reach
the forecast high of 90 degrees at Phoenix Sky Harbor, it would
easily break the previous record of 88 degrees last set in 2005.

On Monday, the anomalously strong ridge of high pressure will become
more suppressed across the western CONUS due to a shortwave trough
traversing the N Rockies. Despite the slight reduction in heights
aloft, temperatures will still remain well above average. The best
chance of any records being tied will be across the western deserts
including Yuma and El Centro where 500 mb heights will be maximized.

&&

.LONG TERM /Tuesday through Sunday/...
Forecast confidence remains high that low amplitude ridging will
prevail over the Desert Southwest through at least the middle of
this week as the next storm system takes aim on coastal California
and the Pacific Northwest. Under the presence of this ridge, daily
highs across the lower deserts of AZ and southeast CA will continue
to top in the mid 80s or around 5 to 8 degrees above normal from
Tuesday through Thursday. The only sensible change in weather
conditions through the middle of this week will be the influx of
high cirrus streaming over the forecast area which will become
thicker and more extensive by Wednesday and Thursday.

Deterministic models and ensemble members are still in agreement
showing an upper-lvl trough deepening over the West Coast and
progressing inland beginning Thursday. As this occurs, a large plume
of Pacific moisture will overspread CA and slowly translate
southward into the Desert Southwest. PWAT values are forecast to
increase to around 0.8-0.9" across SE California and SW Arizona on
Thursday and 0.7-0.8" across southcentral AZ on Friday. These values
are around 150-200% of normal for mid November. With the combination
of moisture and lift ahead of the approaching trough, rain chances
will increase from W to E across our forecast area starting late
Thursday and persisting into Saturday. It is important to mention
that there are still differences in both the intensity and track of
this system. The deterministic ECMWF and EPS members continue to be
the most aggressive showing a deeper low and higher QPF totals for
our forecast area. Coincidentally, NBM PoPs have trended upward to
around 20-50% across much of the region. Due to the arrival of
negative height anomalies associated with core of the upper low, sfc
temperatures are expected to cool into the mid 70s on Friday and
potentially falling into the mid to upper 60s by the weekend.

&&

.AVIATION...Updated at 1700Z.

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

No significant weather issues will exist through Monday afternoon
under clear skies. Confidence is excellent that winds will retain an
easterly component across the PHX metro throughout the period with
some localized gusts near 15kt possible during the late
morning/early afternoon. Winds over SE California will maintain a
light N/NW fetch with extended periods of nearly calm conditions.

&&

.FIRE WEATHER...
Warm and dry conditions with above normal temperatures will prevail
through the much of the upcoming week before a weather system brings
cooler temperatures and chances for wetting rains to portions of the
area late in the week. Afternoon minRHs will mainly range between 15-
20% each afternoon through Thursday before improving above 30% on
Friday. Overnight recoveries will range from poor to fair over the
next several nights. Besides an uptick in breeziness across the
eastern districts this morning, winds will be light, generally less
than 15 mph and follow typical diurnal upslope/nocturnal drainage
patterns.

&&

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

&&

$$

SHORT TERM...Salerno
LONG TERM...Salerno
AVIATION...18
FIRE WEATHER...Salerno