952
FXUS65 KPSR 130112
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
612 PM MST Sun Oct 12 2025

.UPDATE...Updated Aviation Discussion.

&&

.KEY MESSAGES...

- A Flood Watch remains in effect for south-central Arizona through
  Monday evening.

- Scattered showers and thunderstorms will affect south-central Arizona
  through Monday with the heaviest rainfall potential and
  greatest flood threat over higher terrain areas north and east
  of Phoenix.

- Below normal temperatures will be common throughout the week.

&&

.SHORT TERM /Today through Monday/...
A very active overnight and morning was observed across much of
south-central AZ as widespread showers and thunderstorms affected
the region with numerous reports of flash flooding. Rain gauge
observations indicated rainfall amounts ranging between 0.5" across
the Phoenix West Valley to as much as 2-3.5" across the Phoenix East
Valley with amounts of 1-3" across the higher terrain areas east
of Phoenix. Phoenix Sky Harbor Airport received 1.96 inches so
far today, which is the 4th highest one day rainfall in the month
of October. The rainfall activity for the most part has shifted to
the south with any additional activity through the rest of the
afternoon and evening hours expected to be concentrated mainly
across southeast AZ while most of south-central AZ should see
mainly mostly quiet conditions given the overturned atmosphere in
place from the morning convection.

Hi-res models indicate potentially another round of showers and
isolated thunderstorms affecting portions of the Phoenix metro and
the higher terrain areas to the east of Phoenix later tonight,
however, it does look like any activity will be more spotty and
not as intense as the activity from last night and this morning.
Hi-res models on the other hand are in decent agreement in
showing another round of more widespread showers and thunderstorms
across south-central AZ, with the heaviest activity expected
across the foothills and higher terrain areas to the north and
east of Phoenix. This additional round is in response to another
upper-level jet streak associated with a large scale trough over
the Pacific Northwest setting up just to the northwest providing
upper-level ascent and abundant low-level moisture remaining in
place with PWATs of 1.2-1.4" and low-level mixing ratios of 12-13
g/kg associated with the remnants of Tropical Storm Raymond. Given
the signal for another round of widespread showers and
thunderstorms with heavy rainfall being once again a major threat,
the Flood Watch has been extended across all of south-central AZ
through Monday evening as it will not take that much rainfall to
result in renewed flash flood concerns given the saturated soils
in place. In addition to the heavy rainfall threat, cannot rule
out isolated strong to severe wind gusts and marginally large hail
given that there will be around 40+ kts of 0-6 km shear in place
supporting some organized storm clusters.

&&

.LONG TERM /Tuesday through Saturday/...
Seasonally strong negative height anomalies along the central
California coast Tuesday will lift and fill into the Great Basin
during the middle of the week bringing pronounced, dry westerly flow
into the forecast area. Boundary layer moisture will rapidly be
scoured Tuesday with mixing ratios tumbling closer to 5-6 g/kg as
deep mechanical mixing promotes both horizontal and vertical
advection of dry air. While NBM output depicts enhanced POPs through
the western CWA as a Pacific cold front moves onshore, downsloping
and rain shadowing effects downstream of the coastal mountains
should preclude much, if any shallow Pacific moisture from breaching
into the leeward side, and appears this output is another typical
blended model artifact. The greater weather impact will likely be
gusty winds Tuesday afternoon and evening, primarily in the most
wind prone locations of SE California where midlevel height falls,
deepening marine layer, and enhanced H8-H& winds should promote
hydraulic jumps and downslope speeds.

Ensemble membership remains in excellent agreement during the latter
half of the week depicting a slowly progressive Conus pattern with
broad troughing somewhere in the northern Rockies/central Conus and
a lingering, positively tilted trough extended into the SW Conus.
This pattern will ensure H5 heights hover in a 572-578dm range into
the weekend, and narrow ensemble numerical spread yields very good
confidence temperatures settling 4F-8F below normal into the weekend
before a likely warming trend just beyond the scope of this forecast
period.

&&

.AVIATION...Updated at 0110Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Radar this evening shows the bulk of shower/storm activity is
currently across southeast Arizona with a few light showers
approaching the Phoenix area. Confidence in overall coverage and
timing in terms of shower activity is low through tonight with
better confidence in showers and storms tomorrow. SCT-BKN clouds
are expected to lower down to around 3-5 kft overnight tonight
with a 20-30% chance of MVFR CIGs overnight through early tomorrow
morning. Showers/storms are expected ramp up once again going into
Monday afternoon. Any activity is currently expected to last
through the afternoon before tapering off in the evening. Any
heavy showers/storms may result in brief MVFR visibilities.
Otherwise, SCT-BKN clouds are expected to remain mostly aoa 5 kft
during the afternoon. Winds will predominantly favor an easterly
component before transitioning to a breezy southerly crosswind
component with some gusts upwards of 20 kts.

Southeast California/Southwest Arizona including KIPL and KBLH:
No weather concerns will exist through Monday morning under clear
skies. Winds will predominantly favor the W at KIPL and S-SW at
KBLH. Speeds will remain light, aob 8 kts, through tomorrow
morning before gusts upwards of around 25 kts are expected to
develop tomorrow afternoon.

&&

.FIRE WEATHER...
Wetting rain chances will continue through Monday over eastern
districts with drying in SE California and SW Arizona. More
widespread drier conditions enter the region Tuesday. Rainfall in
eastern districts may be heavy at times resulting in localized
flooding, especially over higher terrain areas. Elevated moisture
levels will keep humidity levels in eastern districts above 50%
through Monday, then minimum values falling closer to a 30-40% range
during the middle of the week. Western districts will generally
experience afternoon humidity values 15-25%. Erratic and locally
gusty winds will common around showers and thunderstorms with
more widespread gusty winds affecting the region Tuesday
afternoon/evening.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flood Watch through Monday evening for AZZ534-537>563.

CA...None.
&&

$$

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