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FXUS65 KPSR 042320
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
420 PM MST Tue Nov 4 2025

.UPDATE...Updated Aviation Discussion

&&

.KEY MESSAGES...

- Dry and tranquil weather will prevail across the Desert
  Southwest this week.

- High temperatures across the lower deserts are expected to
  slowly cool from around 90 degrees today to the mid 80s by
  Thursday.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Upper level water vapor satellite imagery and objective analysis
show quasi-zonal flow overhead with a high pressure system
centered over Texas and a low off the coast of the Pacific
northwest. The aforementioned high pressure is what`s influencing
the weather over our area causing heights aloft to be above their
climatological normals for this time of year (current H5 heights
around 588 dm this afternoon). This will result in temperatures
continuing to be 5-8 degrees above normal for early November.
High temperatures across the lower deserts early this afternoon are
already in the the mid 80s and are forecasted to warm to around 90
degrees this afternoon. As for the higher terrain, highs this
afternoon will warm into the low to mid 80s. The overall synoptic
pattern is not expected to change too much for tomorrow with the
aforementioned low starting to push onshore in the Pacific
northwest. This will result in heights aloft lowering slightly (to
around 586-587 dm tomorrow). As a result temperatures are
forecasted to be a degree or two cooler tomorrow. With afternoon
highs in the mid to upper 80s across the lower deserts and in the
upper 70s to low 80s across the higher terrain. Dry conditions
with light winds and mostly clear skies will persist.

&&

.LONG TERM /THURSDAY THROUGH NEXT WEEK/...
For late this week and through at least early next week, very little
will change. Initially, a passing trough well to our north will at
least suppress the ridge in place lowering H5 heights from the
current 587-589dm to 584-586dm by Thursday. The ridge is also
forecast to shift its high center to off the coast of southern
California. The brief dip in heights will help to bring temperatures
down a few degrees starting Thursday as highs are forecast to drop
to between 83-86 degrees. However, this will not last very long as
the ridge now centered to our southwest is expected to eventually
move over our region this weekend. As a result, temperatures will
gradually creep back toward the 90 degree mark by Sunday or Monday.

Model uncertainty begins to increase substantially by the middle
of next week as ensembles generally favor an upper level low
developing west of California by Monday before potentially
swinging through portions of our region by around next Wednesday.
This first weather feature will likely be on the drier side and
not bring much in the way of precipitation chances, but a
potential second follow-on system may be different. Uncertainty is
quite high for the second system later next week as it could end
up becoming cut off from the main flow and stay to our west, or it
could move on through shortly after the first system. Models do
at least indicate a much better chance of better moisture
associated with the second system. For now, guidance shows modest
rain chances for a good portion of Arizona by around next
Friday/Saturday timeframe with temperatures falling back closer to
the normal range.

&&

.AVIATION...Updated at 2320Z.

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

No weather issues should exist through Wednesday afternoon under a
few high cirrus decks. Winds will continue to follow light and
diurnal trends but a full W`rly shift is unlikely for metro
Phoenix terminals this evening. Rather, VRB to even calm
conditions will occupy most of the next several hours before E`rly
winds are established once again.

&&

.FIRE WEATHER...
Above normal temperatures and dry conditions will prevail through
this week. Minimum humidity levels around 15% midweek will rise
closer to 20% later in the week with fair overnight recoveries of 30-
60%. Winds will be light, generally 15 mph or less, and will tend
to follow a typical diurnal upslope/nocturnal drainage pattern
with limited afternoon gustiness.

&&

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

$$

SHORT TERM...Berislavich
LONG TERM...Kuhlman
AVIATION...RW
FIRE WEATHER...Kuhlman