424
FXUS65 KPSR 210528
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1028 PM MST Thu Nov 20 2025

.UPDATE...Updated Aviation Discussion.

&&

.KEY MESSAGES...

- Rain showers have mostly moved into the higher terrain areas for
  the afternoon/evening, with a few lingering isolated cells in
  the eastern Phoenix Metro.

- Another weather system will then bring very good chances for moderate
  rainfall Thursday night and Friday across southeast California
  and southwest Arizona with light rain chances extending through
  the rest of southern Arizona on Saturday.

- Temperatures through the end of the workweek will be around 10 degrees
  below normal and steadily rise to near normal by early next
  week.

&&

.SHORT TERM /TODAY THROUGH FRIDAY/...
The upper level trough that has brought ample rainfall over the
past several days for much of central AZ will be exiting our
region by late tonight. Until then the higher terrain areas and
Gila County can expect additional light showers throughout the
afternoon, with some lingering isolated cells in the eastern
portions of the Phoenix Metro. This afternoon/evening will be
considerably drier for Central AZ and in the higher terrains as
PWAT values have already dropped to ~0.50", however moisture will
be advected back into region starting tonight in SE CA and SW AZ.
By Friday morning in the Imperial and Yuma County areas PWATs
will climb back to 0.80-1.00" or about ~200-225% of normal. This
comes from a deep trough off the coast of the Pacific NW that has
been diving southward and is expected to be to in our area as a
closed low as early as tonight into Friday morning.

This secondary upper level trough will bring additional rain
chances to the western portions of our region along the Lower Colorado
River starting tonight, with most of the activity expected Friday
morning. The 12Z HRRR forecasts this next system to stall over
these areas for several hours, leading to rainfall totals
forecasted to be in excess of 1" in some areas. For tomorrow, the
Lower Colorado River area, Imperial, Riverside and Yuma counties
are in WPC`s slight risk of excessive rainfall. Due to these
factors we have issued a Flood watch for much of SE CA and SW AZ.
However, Models show MUCAPE values of 100 J/kg or less, so most,
if not all, of the activity will remain as showers with little to
no thunderstorms expected (only a 10-20% chance of a few isolated
thunderstorms). Some of the shower activity will try to push into
portions of central AZ by Friday afternoon and evening. However
with PWAT values around 0.5-0.7" for Central AZ, minimal rain is
expected to reach the ground and most activity may just be virga
showers. Little to no accumulations is expected across central AZ
on Friday. The low will eventually start to move onshore and then
eastward into AZ by Saturday afternoon and into Sunday. Otherwise,
temperatures will continue to be well below normal due to these
low pressure systems, with highs for the lower deserts today in
the mid to upper 60s and a slight decrease tomorrow with highs
forecasted to be in the lower to mid 60s.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
As mentioned above, the second closed low, bringing shower
chances to SE CA and SW AZ late Thursday into Friday, will finally
start to move onshore by Saturday afternoon. The center of the
low will move into SW AZ by early Sunday morning and move
northeastward through the day. Activity will linger through
Saturday morning across SE CA and into Saturday afternoon across
SW AZ before ending as the low pressure system moves east of these
locations. Additional rainfall totals of 0.00-0.25" are expected
on Saturday.

As for central and eastern portions of AZ, PWAT values will remain
in the 0.5-0.7" range through Saturday morning, keeping rain chances
less than 30%. Minimal accumulations are also expected as most
activity may just be virga showers through Saturday morning. By
Saturday afternoon, when the center of the low pressure system moves
into central AZ, PWATs will raise to 0.7-0.9" range (180-210% of
normal). PWATs will be around 0.6-0.8" across the higher terrain in
eastern AZ. This is when the best chance for showers will be across
central (40-50%) and eastern AZ (60-70%). Models show no instability
with this round of activity, so it should remain as just showers and
no thunderstorms across central and eastern portions of the state.
The low will be east of AZ Sunday night and quickly advect into the
Plains on Monday. PWAT values will fall back below 0.7", and with
the low and its associated forcing east of us rain chances across
our region will be back to zero by Sunday night. For Saturday-
Sunday, rainfall totals of 0.00-0.30" are currently forecasted for
south-central AZ and 0.20-0.50" across the higher terrain of
eastern AZ.

With the low pressure system still in our area, temperatures will
remain below normal through the weekend. Lower desert locations will
see afternoon high temperatures in the mid 60s on Saturday and in
the low to mid 60s (south-central AZ) and upper 60s to around 70
degrees (SE CA and SW AZ) on Sunday. Higher terrain areas will see
afternoon highs in the upper 50s to low 60s on Saturday and in the
50s on Sunday. Morning lows, both days, will range from the upper
40s to mid 50s across the lower deserts and in the 40s across the
higher terrain areas.

With the low pressure system well to our east on Monday heights
aloft will rise leading to a gradual warming trend. Ensemble models
are in good agreement that no additional weather systems are
expected across our region through at least the middle of next
week, which means dry conditions are expected across the region
next week. Additionally models are in good agreement that heights
aloft will continue to rise next week leading to a gradual warming
trend, with temperatures returning to near normal by early next
week. This will result in afternoon highs in the low 70s across
the lower deserts and in the mid to upper 60s across the higher
terrain. Additionally morning lows will be in the 40s to low 50s
across the area next week.

&&

.AVIATION...Updated at 0530Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The only weather issues through the TAF period will be VCSH/-SHRA
conditions focused mostly west of the PHX metro Friday afternoon
and lower than usual confidence on winds late Friday afternoon
into the evening due to the nearby shower activity. Expect winds
to maintain an easterly component through the period. CIGs have
scattered out across the airspace temporarily, but mid and high
clouds will fill in overnight. Expect VFR CIGs by Friday afternoon
mostly AOA 7 kft AGL, but scattered decks down to 5 kft AGL are
possible.

Southeast California/Southwest Arizona including KIPL and KBLH:
A weather system will bring increasing cloud cover and extended
periods of SHRA to southeast California beginning within the next
several hours. Chances for MVFR CIGs will climb upwards of 30-50%
Friday morning at KIPL and late Friday morning through the
afternoon at KBLH, with 20-30% chances of temporary IFR CIGs.
Chances for isolated TS exist (around 15%), but confidence is too
low to include in the TAF. Current SE will continue to back out of
the NE overnight into Friday morning, with speeds increasing to
10-15 kts at KBLH for a period and generally staying below 10 kts
at KIPL. Gusty and erratic winds are possible if any convective
showers or TS pass near the terminals.

&&

.FIRE WEATHER...
Below normal temperatures and elevated moisture will remain in
place keeping MinRHs in a 40-70% range following excellent
overnight recovery greater than 80%. Locally gusty winds upwards
of 20 mph will be possible at times, though weaker wind speeds
will be more common through the period. Another weather system is
expected to move mainly across the western districts late tonight
and continuing through Friday leading to very good chances for
wetting rains with more scattered shower activity across the
eastern districts Saturday through Sunday. Temperatures will
mostly remain below normal through the weekend with humidities
staying elevated.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flood Watch through Friday evening for AZZ530>533-535-536.

CA...Flood Watch through Friday evening for CAZ560>570.

&&

$$

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