179
FXUS65 KPSR 170545
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1045 PM MST Sun Nov 16 2025

.UPDATE...Updated Aviation Discussion.

&&

.KEY MESSAGES...

- Another large Pacific weather disturbance will bring the next
opportunity for rain Tuesday and Wednesday with additional chances
arriving late in the week.

- Temperatures this week will hover below the seasonal normal with
readings at least 10 degrees below normal during the middle of the
week.

&&

.SHORT TERM /Today through Monday/...
Early afternoon WV imagery and objective analysis depicts a deep,
closed low over southern California accelerating northeast towards
southern NV as jet energy translates to the eastern periphery of the
trough axis while expansive, progressive Pacific troughing dislodges
this previously slow moving feature. The steep cold front associated
with this system has cleared the Phoenix metro, albeit losing
definition over the higher terrain as supporting energy becomes
separated. Although cyclonic vorticity was still passing over SW
Arizona and forced ascent lingers in the CWA, better quality
moisture was being shifted east and pinched away from forcing
mechanisms. In addition, increasing dry westerly sfc-H8 flow was
scouring mixing ratios closer towards 6 g/kg while jet energy
quickly lifting north was creating a midtropospheric subsidence
inversion further capping off any moist ascent. Thus, other than a
stray shower through orographic processes, confidence is good that a
period of dry weather will prevail into at least Monday afternoon.

However, this tranquil weather period will be short lived Monday as
the aforementioned Pacific wave will dig and intensify into the void
left by the departing negative height anomaly. Robust H5 height
falls will enter the forecast area Monday afternoon as strong jet
energy begins to materialize downstream of the cold core incurring
broad scale lift juxtaposed with modest sfc-H7 moisture return. Both
global scale and high resolution modeling have been consistent in
advertising building theta-e advection with broad scale moist,
isentropic ascent around the 300K layer. The greatest uncertainty in
this evolution is obtaining more precise timing and location as
model spread ranges from Monday afternoon over south-central Arizona
to late Monday night in western Arizona. NBM POPs appeared shifted
too far eastward, possibly tied to the influence from global
ensembles as HREF membership has solidly been focusing better
chances from the Phoenix metro westward through Monday evening
before spreading east Tuesday.

&&

.LONG TERM /Tuesday through Sunday/...
Models remain in good agreement showing the next weather system
moving into our region Tuesday with the low center moving through
southern California and Arizona as it weakens on Wednesday. The best
forcing and moisture is likely to align across central Arizona on
Tuesday bringing fairly widespread shower activity with chances for
embedded thunder. This weather system is likely to bring higher
rainfall amounts to southern and central Arizona than this weekend`s
system with QPF amounts averaging around 0.25-0.50" for Phoenix to
as high as 0.75-1.00" for higher terrain areas north and east of
Phoenix. The western lower deserts of southeast California and
southwest Arizona will mostly miss out on the best rain this time
with amounts generally less than a tenth of an inch. The slow
progression of the low should continue to bring some residual shower
activity across central and eastern Arizona Wednesday before
eventually coming to an end at some point later Wednesday or
Wednesday night as the low moves to the northeast of the region.

Even cooler air is anticipated Wednesday as the second system will
have a colder source region. Forecast highs begin to lower on
Tuesday with readings potentially only in the mid 60s before
bottoming in the lower 60s on Wednesday and/or Thursday. These well
below normal temperatures should also translate to overnight lows
well into the 40s across the lower deserts starting Wednesday night.

The active weather pattern may bring a third weather system at some
point later in the week or the weekend, but there is much more
uncertainty with the track of this potential third trough. Model
trends over the past 24-48 hours have been leaning more toward a
progressive system which may not end up bringing much additional
rainfall. The well below normal temperatures during the middle part
of the week should moderate by next weekend with the latest NBM
showing readings closer to normal.

&&

.AVIATION...Updated at 0545Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major aviation concerns are anticipated through Monday
afternoon under SCT to at times BKN low (bases 5-7 kft AGL) and
high cloud decks. Expect winds to return to typical E/SE drainage
directions within the next few hours. SE winds should then prevail
through most of the TAF period. Monday evening and overnight into
Tuesday, anticipate VCSH/SHRA conditions to once again develop,
with VFR CIGs around 050-060 filling in over the PHX airspace.
Scattered lower decks will be possible. The main concerns with
this initial round of showers Monday evening will be brief MVFR
CIGS (10-20% chance), the potential for MVFR or lower VIS during
rain (10% chance), brief gusty and erratic winds near showers, and
isolated TS (15% chance). Best timing of SHRA conditions for this
initial round will be 02-06Z.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation concerns will exist through Monday evening under
increasing high clouds and occasional FEW-SCT lower decks with
bases between 6-12 kft AGL. West winds at KIPL will relax
overnight, and winds have already begun to exhibit variability at
KBLH. Winds will then develop a southerly fetch by late Monday
morning and through the afternoon as another weather system
approaches the region from the west.

&&

.FIRE WEATHER...
A weather system will continue to move through the region today
bringing cooler temperatures, increased humidities, and shower
activity across the eastern districts. A few isolated thunderstorms
will be possible for the eastern districts producing isolated
heavier rainfall amounts. Monday will bring quieter weather
conditions, but still with a chance of isolated showers. Minimum
humidity values will range between 40-70% areawide through Monday
with good to excellent overnight recoveries. Locally gusty winds
upwards of 25 mph will be possible through this afternoon with
overall light winds tonight and Monday. The active weather will
continue for a good portion of the upcoming week with another
weather system affecting the area  Tuesday into Wednesday and
another potentially later in the week. Expect below normal
temperatures and elevated humidities to last all week.

&&

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

$$

SHORT TERM...18
LONG TERM...Kuhlman
AVIATION...Whittock
FIRE WEATHER...Kuhlman