281
FXUS65 KPSR 292004
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
104 PM MST Tue Sep 29 2026

.KEY MESSAGES...

- A Flood Watch remain in effect for parts of the region through
  this evening, but most of the heaviest rain will be exiting the
  region through this evening.

- Lingering isolated showers and thunderstorms may pop across
  south-central Arizona this afternoon.

- Below normal temperatures will be common through the end of the
  workweek across the eastern portion of the forecast area, while
  near normal readings will return to the western deserts
  starting Wednesday.

- Dry conditions will prevail from Thursday though early next
  week as high pressure takes hold across the region.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Areas of light to moderate rainfall will continue across portions
of the region, mainly for Southern Gila, through this evening
before the majority of the shower and thunderstorm activity begins
to push of out of our forecast area. As expected, rainfall totals
over the past few days have varied greatly, with the driest spots
seeing only a few hundredths of an inch, while measurements
upwards of 2-2.5" have been seen so far in parts of south-central
Arizona. Accumulations will continue to rise for some areas, so it
is not out of the question that areas of 3+", mainly confined to
foothill and high terrain areas, will be seen once this is all
said and done.

Even though most of the lower desert rainfall has moved on, it may
not be the last of shower and thunderstorm activity seen over these
areas. With drier air surging behind the main rain bands, noticeable
clearing has taken place across most of the region. This dry air
advection will not completely scour out boundary-layer moisture
which, combined with day-time heating, should promote the presence
of some decent CAPE upwards of 500-1000 J/kg. With the best ascent
associated with the low removed from our area at this point, any
convection that can pop will be heavily dependent on orographic
influences. A sharp gradient of 0-6km shear will be located
overhead, so maybe some longer lived cells are be observed, but the
majority should be short-lived due to lack of mid and upper-level
support/lift. Even with the environment, confidence in this round of
activity is fairly low as CAMs have been inconsistent run-to-run on
where it places these showers and storms, with some keeping them
within the Flagstaff CWA, while others show the Phoenix metro and
even areas as far south as the I-8 corridor seeing something form.
Nonetheless, the main impacts will be brief heavy downpours, gusty
winds, and perhaps some isolated instances of small hail if storms
can become strong enough.

Today should feel a bit like fall across the portions of the region
as high temperatures will run a good 15 degrees or so below normal
across south-central Arizona. Readings for the lower elevations will
run in the 70s and low 80s, while the higher elevations will
struggle to get out of the 60s. The further west you go, the warmer
it will be as Southwest Arizona and Southeast California will reach
into the middle 80s and lower 90s, which is still a good 4-8 degrees
below normal.

Wednesday will be a transition day as the Pacific low gradually
exits the region. Some morning scattered showers are likely to still
be across the far eastern Arizona high terrain, but any activity
should quickly wind down in the afternoon. Elsewhere on Wednesday,
sunny skies and warmer temperatures are forecast for southeast
California and southwest Arizona while the south-central Arizona
lower deserts will see some lingering clouds and a continuation
of well below normal temperatures.

&&

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...

Model guidance shows upper level ridging fully moving into our
region on Thursday and likely staying put through the upcoming
weekend. This will lead to gradual drying and mostly clear skies
while temperatures slowly rise closer to the normal range for the
south-central Arizona lower deserts. The western lower deserts
may reach 100 degrees again starting Friday, but for the eastern
half of Arizona some reinforcing cooler air from the east Friday
through Saturday should keep daytime highs at or just above 90
degrees through Saturday. This cooler easterly flow may even
continue into early next week with temperatures in the Phoenix
area staying right near seasonal normals for early October.

&&

.AVIATION...Updated at 1740Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The main aviation weather concern throughout the TAF period will
be the lower CIGs through this evening. Most of the rainfall
activity that affected the area earlier this morning has pushed
well east of the terminals. There is a chance of a few spotty SHRA
later this afternoon/evening in the vicinity, however, chances of
occurrence is low at less than 20% and thus not mentioned in the
latest TAF package. The main issue through this evening will be
the CIGs with SCT-BKN coverage as low as 5-6 kft expected. Winds
this afternoon will be mainly out of the west with speeds aob 10
kts, with a return of the traditional nocturnal east component by
03-04z.

Southeast California/Southwest Arizona including KIPL and KBLH:
The main aviation weather concern throughout the TAF period will
be gusty north to northwest winds during the afternoon. Winds this
afternoon will be out of the north to northwest, shifting more out
of the west at KIPL early this evening. Afternoon gusts upwards of
20-25 kts are likely before subsiding by this evening.

&&

.FIRE WEATHER...
Widespread showers and isolated thunderstorms will affect much of
the area early today before mainly affecting the Arizona high
terrain this afternoon and evening. Moderate to heavy rainfall is
likely to impact the Arizona high terrain through at least early
afternoon. Humidities will begin to trend lower across the western
districts later today, but more so on Wednesday. Elevated
humidities will persist across the eastern districts through at
least Thursday. Winds will be breezy to locally windy at times
today before becoming light again on Wednesday. Drier conditions
and near to slightly above normal temperatures are forecast for
later this week and through the weekend.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flood Watch until 9 PM MST this evening for AZZ547-556>558-
     560>563.

CA...None.
&&

$$

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