344
FXUS65 KPSR 052253
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
353 PM MST Fri Dec 5 2025

.UPDATE...Updated 00z Aviation Discussion...

&&

.KEY MESSAGES...

- Dry and generally quiet conditions will continue through at
  least the upcoming work week.

- Temperatures will warm over the weekend into the upcoming work
  week, likely reaching 8 to 10 degrees above daily normals.

&&

.SHORT TERM /TODAY THROUGH SATURDAY/...
With winds calmer than that of Wednesday night and skies remaining
mostly clear, many valley locations across the forecast area saw an
even chillier Thursday night/Friday morning. Temperatures around 6-8
AM MST this morning were between 1-8 degrees cooler than the same
time yesterday morning (except for sites that are positioned atop
prominent terrain features, at an elevation that is near or above
the top of the surface inversion.) Temperatures at or below
freezing (<=32F) were observed at several automated sites within
the higher elevation, populated valleys of Southern Gila County.
However, today will be the coolest day of at least the next 7
days, with forecast afternoon highs in the middle to upper 60s
across the lower deserts, near or even slightly below normal
values for the date. Then a warming trend commences this weekend.

The warming trend over the weekend and into the upcoming work
week will be a result of the current upper level pattern, which is
characterized by a broad ridge over the East Pacific and longwave
troughing downstream, persisting and gradually shifting eastward.
This will bring our region solidly under the influence of high
pressure, with positive midlevel height anomalies building into
the Desert Southwest from the west/northwest. The growing
influence of the ridge should allow for slight warming Saturday,
with temperatures generally 1-3 degrees warmer than today.

&&

.LONG TERM /SUNDAY THROUGH THE END OF NEXT WEEK/...
By Sunday the aforementioned high pressure system in the eastern
Pacific will have moved further south and east and will stall just
off the California coast. With the high pressure pushing further
east the longwave troughing, that had been keeping our region
cooler, will also move eastward and will finally exit our region.
Despite the center of the high pressure system remaining off shore
through the middle of next week, much of Western CONUS will be under
the influence of its eastern flank. H5 heights will rise to around
580-583 dm on Sunday and then rise to 582-585 dm by the middle of
next week. This will result in a gradual warming trend. However,
through early next week multiple shortwaves will be moving from the
Pacific NW/southern British Columbia down into the Plains that will
temporally dampen the ridge, but, the ridge will quickly rebound. If
any of these shortwaves are able to push into the Desert Southwest
at all, it would briefly stall our warming trend for a day.
Nevertheless, afternoon high temperatures, region wide, will go back
above normal on Sunday and warm to around 8-10 degrees above normal
by the middle of next week. Afternoon high temperatures are
forecasted to go from the low 70s (mid to upper 60s) across the
lower deserts (higher terrain) on Sunday to the mid to upper 70s
(upper 60s to low 70s) by the middle of the week.

By the end of next week and heading into next weekend, the ridge
will finally push onshore with the center of the ridge eventually
moving over the Desert Southwest. The ridge will be weakening as it
move onshore, however, with it moving directly overhead temperatures
will continue to gradually warm through at least the end of next
week. H5 heights will rise into the 583-586 dm range by the end of
next week. This will result in afternoon high temperatures 10-12
degrees above normal and morning low temperatures 6-8 degrees above
normal. For the end of next week, afternoon high temperatures are
forecasted to be in the upper 70s to near 80 degrees across the
lower deserts and in the low to mid 70s across the higher terrain.
Morning lows are forecasted to be in the 50s across the lower
deserts and in the 40s across the higher terrain. Additionally with
the a ridge dominating the region, dry and tranquil conditions will
continue through next week and into next weekend.

&&

.AVIATION...Updated at 2250Z.

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

No aviation weather concerns under clear skies expected throughout
the TAF period. The overall wind pattern will continue to exhibit
light diurnal tendencies along with extended periods of variable
to calm conditions.

&&

.FIRE WEATHER...
Dry conditions will prevail across the region through next week.
Temperatures will be near to slightly below normal today, warming
above normal during the weekend, and then peak 10-12 degrees
above normal by the end of next week. Winds will be light and tend
to follow their typical diurnal tendencies. Humidities over the
next week will stay elevated with MinRHs mostly ranging between
20-35% much of the time, with good to very good overnight
recoveries.

&&

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

$$

SHORT TERM...Whittock
LONG TERM...Berislavich
AVIATION...Lojero
FIRE WEATHER...Whittock/Berislavich