911
FXUS65 KPSR 091130
AFDPSR

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

.UPDATE...12Z Aviation Discussion.

&&

.KEY MESSAGES...

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

- A cooler and wetter weather pattern is progged to 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 1130Z.

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

No aviation weather concerns are anticipated through the forecast
period. Winds at the Phoenix Metro terminals will remain easterly
through tonight. Speeds will increase up to 8-11 kts later this
morning, with occasional gusts as high as 15-20 kt through early
this afternoon. Winds will remain light and diurnally driven at
the SE California TAF sites. Clear skies will prevail over the
region.

&&

.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...Salerno
FIRE WEATHER...Salerno