097
FXUS65 KPSR 220517
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1015 PM MST Wed Jan 21 2026

.KEY MESSAGES...

- High pressure will keep dry, tranquil conditions and above normal
temperatures in place through Thursday with increasing high level
clouds.

- A weather system will affect the region Friday and Saturday
bringing heightened shower chances to south-central and eastern
Arizona along with cooler temperatures.

- Dry conditions with temperatures slowly warming back above normal
will return to the region during the first half of next week.

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...
The latest water vapor satellite imagery as well as streamline
analysis depict upper-level ridging remaining in place across the
Desert Southwest while a closed off upper-level low, which will
bring unsettled weather to close out of the week, is beginning to
take shape off the central CA coastline. While the upper-level ridge
will continue to keep weather conditions dry and tranquil through
Thursday, an abundance of high clouds along the eastern periphery of
the closed low will continue to stream in across the region during
the next couple of days. Although temperatures will still be above
normal through Thursday, due to the increase in the higher level
clouds, afternoon highs will be slightly cooler compared to the last
couple of days with readings topping out mostly in the lower 70s
across the lower deserts. The abundance of higher level cloudiness
will also result in warmer than normal early morning lows, with most
areas only bottoming out in the middle 40s to lower 50s through the
end of the week.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Unsettled weather conditions are expected for portions of the region
on Friday and Saturday with the first closed low passing by just to
our south and a second follow-on disturbance quickly diving
southward through the region later on Saturday. Moisture advection
into the region Thursday into Friday will come in two different
waves with one slug of moisture moving out of northern Mexico into
eastern and central Arizona and another along and out ahead of the
closed low.

The best moisture corridor is expected to be from just south of
Phoenix through the eastern Arizona high terrain where PWAT
anomalies are likely to reach 200-225% of normal. We will also
mostly have to rely on top-down saturation of the atmosphere
resulting in an initial dry boundary layer for a good portion of
Friday. Upper level forced ascent along with increasing orographic
lift should help to develop light rain shower activity by Friday
afternoon, but this first batch of rain is not likely to amount to
much due to the dry boundary layer. By later Friday evening through
the overnight hours Friday, increasing moisture in the low levels
are expected to allow for the measurable rainfall to become more
widespread. The best area of rain is expected to fall mainly east of
the Phoenix area, while very little is expected to the west of
Phoenix. Forecast rainfall amounts have trended up since yesterday
with Phoenix potentially seeing between 0.10-0.25" to 0.25-0.75"
over the eastern Arizona high terrain.

Saturday may also bring some convective potential as colder air
aloft moves overhead significantly increasing lapse rates by the
afternoon. Forecast soundings still do not show much available CAPE,
but this scenario is quite common for our area and may result in
some convective showers producing small hail and maybe an isolated
thunderstorm Saturday afternoon. Once the second shortwave moves
through the area late Saturday into early Sunday, much drier air
will quickly usher in from the north ending any rain chances by
Sunday morning. Temperatures over the weekend are forecast to dip
into the normal range with highs mostly between 65-70 degrees across
the lower deserts. Upper level ridging should overtake the region
during the first half of next week likely leading to a warming trend
beginning by Tuesday.

&&

.AVIATION...Updated at 0515Z.

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

No major weather concerns will exist through Thursday night under
periods of thick mid/high level cigs. Wind speeds under 10kt will be
common across the region with extended periods of nearly calm
conditions. Typical diurnal/nocturnal wind shifts will be absent or
temporally limited with a light easterly fetch more prevalent around
the Phoenix metro, and a light north wind across SE California
terminals.

&&

.FIRE WEATHER...
Dry conditions with above normal temperatures will persist through
Thursday before a weather system moves into the region starting
Friday bringing increasing rain chances. Chances for wetting rains
will mainly exist across eastern Arizona from Friday night through
Saturday afternoon. Daily MinRH values are expected to remain
generally near 15-20% through Thursday before rising to 30-50% for
Friday and Saturday. Expect light and diurnally driven winds through
Thursday before more dominant southerly winds move in on Friday.
High pressure with drying conditions will then settle back into the
region early next week.

&&

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

&&

$$

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