961
FXUS65 KPSR 172310
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
410 PM MST Thu Sep 17 2026

.UPDATE...00Z Aviation Discussion

&&

.KEY MESSAGES...

- The introduction of much drier air will result in tranquil
  conditions through the weekend with near zero rain chances.

- Near to slightly below normal temperatures today will warm to
  slightly above normal levels by the weekend.

- A low pressure system early next week may bring a return of
  moisture and rain chances to Arizona.

&&

.SHORT TERM /TODAY THROUGH FRIDAY/...

Much quieter conditions are settling in as subsidence behind the
remnant tropical circulation that aided with the heavy rainfall
yesterday lifts away and drier air aloft begins to settle in. This
will hinder the potential for any additional rain chances for the
rest of today. Even though the drier air aloft will settle in, the
boundary layer will remain moist the rest of today with surface
dewpoints in the 60s across much of the lower deserts. Further
drying will continue on Friday, which will help scour out the
moisture even more not only aloft but also in the low-levels as
surface dewpoints are expected to drop from the 60s early in the
day into the 40-50s by the late afternoon and evening in south-
central AZ and as low as the 20-30s across the western deserts.
Temperatures today will remain slightly below normal across
south-central AZ with afternoon highs stuck in the 90s whereas
readings closer to normal are expected out west as afternoon highs
top out around 100 degrees. Afternoon highs on Friday will
feature readings of around 100 degrees across much of the lower
deserts.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...

A more significant total column push of dry air is expected this
weekend, coinciding with a mid-level front moving through at the
base of the trough moving through the West. This will finally
scour out the lingering PBL moisture across south-central AZ.
PWATs are forecast drop as low as 0.4-0.7" across the southern
deserts by Sunday. With this dry of air you can count out any
chance at rain and count on plenty of sun. This trough will also
help moderate temperatures, keeping them near to slightly above
normal. There is good confidence that the trough moving through
the West will continue on into the Plains by Monday and another
Pacific low moves to the CA coast. What this next Pacific low does
once reaching the CA coast Monday is a little less certain, but
it may be what helps eventually drive moisture back up in the
deserts and drive the next chance at rain in the AZ deserts.
Latest NBM shows slight PoPs (10-30%) returning by Tuesday.
Average to slightly above average temperatures are forecast to
continue this weekend through the first half of next week with
this outlook, with afternoon highs around to slightly above 100
degrees. With the drier air coming in, the morning lows will
finally be more pleasant, consistently dropping into the 70s for
most lower desert locations.

&&

.AVIATION...Updated at 2310Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major aviation concerns are expected during the TAF window. The
one diversion from a typical diurnal forecast will be the absence
of a westerly shift this evening. Weak easterly flow will instead
be observed, along with perhaps extended periods of variability.
Typical east to west diurnal evolution should resume for Friday.
Other than some lingering low and mid-level cloud decks, mostly
clear skies will be common through the forecast timeframe.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation concerns are expected during the next 24 hours.
Outside of VRB conditions during the overnight and morning hours,
familiar diurnal trends will prevail, with southeast flow becoming
westerly at KIPL, and a southerly component being common at KBLH.
Other than lingering low CU this evening, skies will be mostly
clear through Friday afternoon.

&&

.FIRE WEATHER...
Overall there are no fire weather concerns through the next week.
Lingering wet grounds and elevated surface moisture will continue
into Friday, but a drying trend will begin today, initially
aloft, followed by a more significant drying this weekend. No
additional rain is expected through at least the start of next
week. Minimum RH values this afternoon will be around 25-45%, with
driest conditions in southeast CA. As drying continues, MinRHs
will dip as low as 10-20% during the weekend. Overnight recoveries
across south-central AZ will be good the next couple nights at
45-75% and then dry slightly over the weekend. Winds will mostly
follow typical diurnal patterns with modest afternoon
upslope/upvalley gustiness (15-25 mph).

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

$$

SHORT TERM...Lojero
LONG TERM...Benedict
AVIATION...RW
FIRE WEATHER...Benedict/Lojero