512 
FXUS65 KPSR 282028
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
128 PM MST Sun Sep 28 2025

.KEY MESSAGES...

- Isolated showers and thunderstorms expected through this 
  afternoon across mainly the prominent terrain features, before 
  drying out by this evening.

- A dry and tranquil weather pattern expected through the 
  upcoming week.

- Below normal temperatures will prevail today before gradually
  warming up to more seasonable levels by the middle of the week.

&&

.SHORT TERM /TODAY THROUGH MONDAY/... 
Early afternoon water vapor satellite imagery as well as streamline 
analysis show the center of the upper-level low that has caused 
the very active weather during the last couple of days situated 
over the northwestern quadrant of AZ. Shower and thunderstorm 
activity once again is developing along the eastern flank of the 
low over the AZ High Country. Farther south, across south-central 
and southwest AZ, subsidence is in place and will hinder 
development across much of the region, with the exception over the
higher terrain features as enough moisture and instability 
remains in place to spark activity. The activity that develops 
should be short-lived given the subsidence in place, thus any 
sort of flooding impacts will be quite limited. Rain chances 
should completely end by this evening as the upper-level low 
gradually shifts eastward and drier air begins to filter in. 
Under the influence of the lowered upper-level heights from the 
low, temperatures will once again be below normal for today with 
afternoon highs expected to top out in the upper 80s to around 90 
degrees across the lower deserts.

Heading into Monday, the upper-level low will finally have exited 
the Desert Southwest while weakening and becoming an open wave with 
a quasi-zonal flow pattern in place. Much drier air will be in 
place and thus rain chances will virtually be nil everywhere along
with mostly clear skies. Afternoon highs will warm by about 3-5 
degrees with readings expected to reach the low to mid 90s across
the lower deserts. 

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/... 
A benign and dry weather pattern will take shape through the 
middle of this week as ridging aloft begins to build over the 
forecast area. 500 mb hghts will gradually increase to around 
588-590 dam by the end of the week resulting in highs across the 
lower deserts increasing from the mid 90s on Tuesday to the upper 
90s to around 100 degrees on Thursday and Friday. Global models do
indicate a shortwave trough diving into the Intermountain West by
next weekend which may result in a slight cool down and breezier 
conditions region-wide. Due to the trajectory of this system 
remaining well north of the area, dry conditions are expected to 
persist across the Desert Southwest. 

&&

.AVIATION...Updated at 1715Z. 

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation concerns are expected during the TAF period. Winds
will resume following diurnal trends with speeds remaining
generally less than 10 kts. FEW clouds with lowest bases around
7-8k ft will be present through sunset before clear skies take
over. 

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation concerns are expected during the next 24 hours. Winds
will follow light and diurnal trends, with extended periods of
variability. Other than a FEW afternoon CU, skies will be mostly 
clear 

&&

.FIRE WEATHER...
Temperatures will remain below normal today followed by a gradual 
warming trend through the beginning of this week. A low pressure 
system will continue to result in shower and thunderstorm 
activity, mainly across northern AZ through this afternoon. 
Isolated showers and thunderstorms will still be possible over the
high terrain of southwestern and south-central AZ this afternoon.
Rain chances will come to an end across the area by this evening 
with dry conditions prevailing everywhere throughout the upcoming 
week. MinRHs will range from 30-45% this afternoon, falling to 
around 25-35% on Monday and 15-25% on Tuesday along with fair to 
good overnight recoveries. Winds will generally be light and 
diurnal during the next several days with some modest afternoon 
upslope gusts. 

&&

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

$$

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