639
FXUS65 KPSR 211829
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1129 AM MST Fri Nov 21 2025

.UPDATE...Updated Aviation Discussion.

&&

.KEY MESSAGES...

- Scattered showers, with pockets of moderate to heavy rainfall,
  will be common across southeast California and southwest
  Arizona today. A few isolated thunderstorms are also possible.

- A Flood Watch is in effect for southeastern California and
  southwestern Arizona through 11 pm PST Friday night/12 am MST
  Saturday morning.

- The weather system will then push eastward Saturday and Sunday
  bringing scattered showers to central and eastern Arizona.

- Temperatures will remain below normal this weekend and return to
  near normal as early as Tuesday.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
Early this morning upper level water vapor satellite imagery and
objective analysis show a deep upper level closed low straddling the
coast of central CA and a surface low straddling the southern CA
coast. This low will continue to dive southward through the day
today and eventually stall out just off the northern coast of the
Baja late tonight. This low has already brought scattered light
showers to SE CA and the Lower CO River Valley early this morning.
This system has raised PWATs into the 0.7-0.9" range across SE CA
and SW AZ, with the highest PWATs in SE CA. Even though PWATs have
been on the rise, the lower levels are still fairly dry. Forecast
soundings show this and it is evident in observed rainfall amounts,
over the past few hours, generally less than 0.1". The lower levels
will become more saturated throughout the morning as the low
continues to push moisture into the region. Once the lower levels
become saturated, that will lead to better/more efficient rainfall
rates. With the low staying along the coast today rain chances will
be confined to SE CA and SW AZ leading to prolonged periods of
rainfall across those areas. Forecasted rainfall totals of 0.50-
1.00" with higher amounts expected along terrain features and areas
that receive more moderate to heavy rainfall. Due to these QPF
totals and that the WPC has the area in a Slight Risk of excessive
rainfall, a Flood Watch remains in effect through 11pm PST/12am MST
tonight. MUCAPE values will be around 100 J/kg, so a few isolated
thunderstorms will be possible, but most activity will be just
showers.

PWATs will remain around 0.5-0.6" across central and eastern AZ
today. This in combination with the center of the low, and it`s
associated vorticity, remaining along the coastline no rainfall is
expected across eastern AZ and little to no rainfall is expected
across central AZ. Any activity will remain light/sprinkles and most
may only be virga showers. Western Maricopa County has the best
chance of picking up a couple hundredths of measurable rainfall
today.

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. 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 10%. Again, minimal accumulations are also
expected as any 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 (50-60%) and eastern AZ (80-90%).
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 the lower deserts of south-central AZ
and 0.30-0.60" across the foothills and higher terrain of eastern
AZ.

In addition to the rain chances, this low pressure system will also
keep temperatures below normal through the weekend. Lower desert
communities will see afternoon high temperatures in the 60s to
around 70 degrees today through Sunday. Higher terrain areas will
see afternoon high temperatures ranging from the upper 50s to the
upper 60s today through Sunday. Morning low temperatures will
range from the mid 40s to mid 50s across the lower deserts and
range from the upper 30s to mid 40s across the higher terrain.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As we move into next week calm and tranquil weather conditions make
a return to the Desert Southwest. The low pressure system that will
bring rain to the region this weekend will be well to the east of
the region by Monday. In the wake of the low pressure system,
heights aloft will be around 574-577 dm on Monday slowly rising to
around 578-581 dm by Thursday. This will result in a gradual warming
trend through the workweek, with temperatures returning to near
normal as early as Tuesday. Across the lower deserts afternoon high
temperatures are forecasted to range from the mid 60s to low 70s
rising to the low to mid 70s by the end of the workweek. For the
higher terrain areas, afternoon highs on Monday will be in the low
60s rising to the upper 60s to low 70s by the end of the workweek.
Additionally morning lows will range from the mid 40s to low 50s
across the lower deserts and in the low to mid 40s across the higher
terrain through the workweek. With rising heights aloft, forecast
confidence is very good that dry conditions will prevail through
this coming workweek.

&&

.AVIATION...Updated at 1828Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds will favor the E to NE through the afternoon and into this
evening with speeds aob 8 kts. Lower confidence exists in a
prevailing westerly switch this evening with better confidence in
seeing winds favoring a light W to NW component at times. Winds
will predominantly favor the E by around midnight becoming light
and variable at times through the overnight hours. CIGs are
expected to remain mostly aoa 10 kft through most of the TAF
period with FEW-SCT decks down to around 7-8 kft possible at
times. Overall dry conditions will be favored through the TAF
period, with virga or a few light showers possible at times today
before better rain chances move in by tomorrow afternoon/evening.

Southeast California/Southwest Arizona including KIPL and KBLH:
Moderate to heavy showers continue to push across parts of
southeast California this morning with lower CIGs in place over
the terminals. The primary concern with these showers will be
brief reduced visibilities down to 3-5 SM. The best timing for
showers will exist through this afternoon at KBLH, with a heavier
band now pushing over the terminal, before additional showers are
expected this evening at both sites. Can`t rule out an isolated
thunderstorm, which may result in erratic winds. MVFR CIGs will
remain an issue at KIPL with a 60-80% chance of these CIGs
persisting throughout most of the period. At KBLH, CIGs will
remain mostly aoa 4-5 kft with 30-50% chance for MVFR CIGs this
afternoon and evening. Winds at KIPL will continue to favor the E
through the afternoon before transitioning to the N this evening,
while winds at KBLH will predominantly favor the N to NE.

&&

.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. A weather system will be
moving mainly across the western districts today 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. Temperatures will return to near
normal as early as Tuesday.

&&

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

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

&&

$$

SHORT TERM...Berislavich
LONG TERM...Berislavich
AVIATION...Smith
FIRE WEATHER...Berislavich