266
FXUS65 KPSR 132118
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
218 PM MST Thu Nov 13 2025

.KEY MESSAGES...

- The unseasonably warm weather will again be seen today and again
  on Friday across much of Arizona.

- The first in a series of three weather systems over the next
  week or so will arrive over the weekend bringing widespread
  accumulating rainfall but little impacts.

- Temperatures are expected to cool well below normal this weekend
  with lower desert highs eventually falling to around 70 degrees
  by Sunday.

&&

.SHORT TERM /TODAY THROUGH FRIDAY/...
The deep upper level trough off the West Coast is continuing to
very slowly make its way onshore. Due to this, upper level riding
continues to influence temperatures over the lower deserts, with
afternoon highs today expected to be in the mid to upper 80s, and
Friday highs in the low to mid 80s as the ridge finally begins to
weaken. These temperatures are about 10 degrees above normal for
this time of year. As mentioned earlier the system off the West
Coast is moving quite slow, in turn pushing the bulk of the
expected activity now later into the weekend. Current guidance
shows the low center slowly drifting south-southwest as early as
Friday, but the trough will start to move into western portions of
our region at that time. By early Friday afternoon, strong
moisture advection will take place across southeast California and
southwest Arizona within the mid and upper levels, with 1000-700
MB mixing ratios increasing to around 7-8 g/kg. This increase in
moisture will bring the potential for some light showers across SE
California. However, Friday`s rainfall totals over SE California
are expected to be low, between 0.05-0.1 inch.

&&

.LONG TERM /SATURDAY THROUGH NEXT FRIDAY/...
A very active period of weather is expected for the weekend and
likely through all of next week. Guidance is currently showing at
least two and probably three weather systems bringing
precipitation to our region; the strongest over the weekend,
another one later Monday through early Wednesday, and a potential
third around next Friday/Saturday.

The first weather system is forecast move into our the region
beginning Saturday with the best upper level energy staying
across southeast California and western Arizona through Saturday
evening. PWATs of 250-275% of normal are forecast for this area on
Saturday, but some rainshadowing is likely to initially hamper
moisture in the lower levels. The slow progression of the system
will eventually help to create near saturated atmospheric profiles
across the western deserts by Saturday afternoon allowing for more
organized rainfall to develop. Rainfall rates of 0.10-0.25" per
hour will be possible during the afternoon and evening hours with
total amounts averaging between 0.5-0.75" across the lower deserts
of southeast California and southwest Arizona by around midnight
Saturday night. Localized higher amounts upwards of 1.00-1.25"
are expected, especially across JTNP, far western Imperial County,
and La Paz County. This may cause some minor flooding issues
across the more prone low water crossings. We also can`t
completely rule out a few embedded thunderstorms which will help
to bring some brief higher rainfall rates.

Eventually the weather system is expected to move inland across
southern/central California by Saturday night. Moisture advection
will spread eastward through the rest of Arizona Saturday
afternoon/evening with the first batch of rain showers likely
impacting the higher terrain north of Phoenix sometime Saturday
afternoon. Rain chances will gradually improve across the rest of
southern and central Arizona from Saturday evening through the
overnight hours, likely reaching their peak during the daytime
hours Sunday. Due to the low center missing our region well to
the northwest, there remains some uncertainty in the timing and
the rainfall amounts for south-central and eastern Arizona. The
advancing cold front late Saturday should help bring some more
organized rain and potentially some embedded thunderstorms with a
second round likely on Sunday associated with the main upper level
energy. The peak of the rain activity for south-central Arizona,
including Phoenix, should occur Sunday morning before it shifts
more over eastern Arizona through the afternoon hours. Forecast
rainfall amounts for these areas hasn`t changed much with lower
desert areas likely seeing 0.50-0.75" to upwards of 0.75-1.00"
across higher terrain areas. Similar to the western deserts,
locally higher amounts are likely to occur with area washes seeing
some flow, potentially causing some issues with low water
crossings.

By Sunday evening, any lingering shower activity will quickly be
diminishing as the weather system exits to the northeast of our
region. However, the next weather system is likely to not be far
behind. Model uncertainty with the second system is considerably
higher than the first with differences with the track and the
exact timing. For now, guidance is leaning toward a somewhat
organized system moving through the region on Tuesday bringing
another round of rain focused across the northeastern 2/3s of
Arizona. Additional rainfall amounts of 0.5-0.75" may be possible
from Monday night through early Wednesday across Phoenix and
areas north and east of Phoenix. There should also be some modest
rain chances across the western deserts, but amounts should be
much more limited.

Aside from the rain chances over the weekend and during the first
half of next week, temperatures will take a big hit with highs
dropping well below normal starting Sunday. The latest NBM shows
lower desert highs mostly in the upper 60s for Sunday and Monday
to as cool as the mid 60s during the middle part of next week.
These below normal temperatures are expected to persist through
the rest of next week with the potential for a third precipitation
producing weather system either moving through or just to the
north of our region on or around next Friday.

&&

.AVIATION...Updated at 1755Z.

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

No aviation weather concerns are anticipated at all terminals
through Friday morning under SCT-BKN high clouds. Winds will
continue to follow diurnal tendencies with light speeds, aob 7
kts. Expect extended periods of variable or calm conditions to
continue throughout the period.

&&

.FIRE WEATHER...
The quiet weather conditions will come to an end by the weekend as
a large weather system slowly moves into the region from the west.
Today will again bring above normal temperatures and dry
conditions. Above normal temperatures are expected again Friday,
however with rain chances beginning across the wester districts by
the early afternoon hours. Widespread wetting rains are then
likely for Saturday and the first part of Sunday for the rest of
the forecast zone. MinRHs today will continue to be in a 15-20%
range before rising to 40-60% by Saturday. Expect light winds with
fairly typical diurnal patterns through Friday before winds
become breezy at times over the weekend. The active weather is
expected to continue through next week with another weather system
affecting the area by Tuesday and another later the week. Expect
below normal temperatures and elevated humidities for all of next
week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Flood Watch from early Saturday morning through late Saturday
night for CAZ560.

&&

$$

SHORT TERM...Ryan/Kuhlman
LONG TERM...Kuhlman
AVIATION...Smith/Benedict
FIRE WEATHER...Ryan/Kuhlman