751
FXUS65 KPSR 250000
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
500 PM MST Fri Jul 24 2026

UPDATE...Updated 00z Aviation Discussion...

&&

.KEY MESSAGES...

- Much above normal temperatures will continue through the weekend
  with readings approaching near record levels and Extreme Heat
  Warnings in effect.

- The high pressure system responsible for the extreme heat will
  also restrict thunderstorm development with minimal chances today.

- Temperatures will cool slightly early next week as increased thunderstorm
  coverage returns to the region.

&&

.SHORT TERM /Today through Sunday/...
Upper level water vapor satellite imagery early this afternoon shows
a broad area of high pressure sprawled across southern CONUS with
the ridge axis across western CONUS. The center of the high
pressure system is currently centered over the the northern AZ-NM
boarder. The main story through the weekend will be the extreme
heat that this strong high pressure system is bringing to the
area. This high will remain around 596-598 dm through tomorrow
before beginning to weaken slightly and shift north/northeastward
slightly on Sunday. Model guidance continues to show temperatures
peaking today and tomorrow with afternoon highs around 10 degrees
above normal (in the 112-120 degree range across the lower
deserts and in the 100-110 degree range across the higher terrain
areas) and morning lows of 8- 12 degrees above normal (in the 90s
across the lower deserts and in the mid to upper 80s across the
higher terrain). Record morning warm lows were either tied or set
this morning at all three climate sites (Phoenix Sky Harbor,
Imperial, and Yuma) , and in fact Phoenix Sky Harbor tied their
all time record warm low (97 degrees originally set on July 19,
2023). Similar morning lows, if not a few degrees warmer, are
expected again tomorrow morning. Phoenix Sky Harbor could also tie
or break today`s record high temperature this afternoon, which is
116 degrees set in 2014, 2018, and 2023. However, the other two
climate sites are expected to fall a few degrees shy of their
record highs for today. An increase in moisture on Sunday paired
with the high weakening slightly and moving further
north/northeast will lead to temperatures cooling around 3-5
degrees on Sunday, but remain around 5 degrees above normal. An
Extreme Heat Warning remains in effect for most of the area
through the weekend. The Extreme Heat Warning for the locations in
southern Gila County is set to expire tomorrow evening.

Some shower and thunderstorm activity has already popped up along
the higher terrain features across eastern AZ. Much like
yesterday, activity will be isolated and short-lived in nature.
But, shower and thunderstorm activity is expected to gradually
increase this weekend as a well defined easterly wave/inverted
trough comprised of tropical remnants cross through northern
Mexico. The northern extent of the inverted trough and jet streak
is expected to cross into southern AZ tomorrow afternoon providing
ample lift for storms to develop in SE AZ tomorrow. While mixing
ratios languishing under 10 g/kg and a warm midlevel thermal layer
should preclude storm development over most lower elevation
locations, DCape values 1500- 2000 J/kg will promote strong, long
lived outflow boundaries racing into lower deserts creating
elevated chances of dense blowing dust (primarily over Pinal
County). This outflow will also enhance and deepen the moisture
pool bringing boundary layer mixing ratios back into a 11- 12 g/kg
range and spiking total column PWATs near 1.75". Depending on how
Saturday`s activity pans out will influence activity on Sunday.
The environment on Sunday remains fairly favorable for
thunderstorm development with MLCAPE exceeding 1000 J/kg, and
DCAPE around 1500 J/kg. Forecast BUFR soundings suggest low
elevation CinH in excess of 25 J/kg. However, if outflow
boundaries collide they should be able to break the cap.

&&

.LONG TERM /Monday through Thursday/...
Strong, expansive ridging will remain nearly in place next week
across the southwest and central United States with the anti-
cyclone center rotating back from central Colorado into New Mexico
and Arizona. Early in the week, sufficient easterly flow will
prevail over the region juxtaposed with marginally supportive
mixing ratios of 9-11 g/kg for scattered storms. There remains
considerable uncertainty regarding a more preferred time frame for
higher POPS in any given location with mesoscale details likely
becoming more important towards convective evolution.
Unfortunately, the mandated NBM/WPC forecast during this time only
further complicates and diminishes the forecast confidence with
numerous instances of spurious QPF forcing procedural, un-
scientific higher POPs spread over uncommon time periods based on
climatology and the preponderance of trusted model output. In
reality, this appears to be a very typical monsoon pattern with
alternating convectively active and inactive days. By the latter
half of the week, there are a handful of NAEFS members indicating
notable strengthening of the high pressure with 600dm H5 heights
materializing over northern AZ/southern UT. It appears the NBM/WPC
forecasts are latching onto this scenario as POPs dwindle to much
lower than expected values given the ensemble mean synoptic
pattern. The larger impact of this outcome would be a return to
major HeatRisk and extreme heat thresholds towards the end of the
week.

&&

.AVIATION...Updated at 2355Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major aviation weather concerns are expected through Saturday
afternoon under FEW-SCT mid to high-level cloud decks. Winds will
generally maintain a westerly component across most of the
terminals throughout the period, with the exception of KIWA where
an easterly shift is likely overnight. There is also a low
potential of a decaying outflow boundary to move in early Saturday
morning, which will temporary enhance the westerly winds.
Otherwise, overall wind speeds will remain aob 10 kts with some
afternoon gusts into the mid to upper teens.

Saturday evening outlook: Hi-res guidance continues to be
consistent in indicating two distinct outflow boundaries affecting
the area terminals. The first outflow will likely come in from the
northeast from thunderstorm activity developing over the higher
terrain to the north and east with potential gusts upwards of 25
kts. Another outflow, likely to be more impactful, will move in
from the south during the late evening hours, with BLDU reducing
visibilities to at least MVFR conditions and potentially stronger
gusts in excess of 25-30 kts. There is also the potential for
VCSH/VCTS to materialize along the second outflow, however, this
aspect of the forecast is highly uncertain at this time.


Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns under FEW mid to high-level
cloud decks. Overall wind pattern will continue to fluctuate
between southeast to southwest. At KBLH, some gusts of around 20
kts will continue through sunset with the potential of another
round of elevated gusts briefly Saturday morning as a result of a
decaying outflow boundary moving in from the south.

&&

.FIRE WEATHER...
Thunderstorm chances will remain low today with only isolated
showers and storms expected over the high terrain areas in eastern
Arizona. These storms are expected to be short-lived. Better
chances for more expansive storm coverage and wetting rainfall
will arrive later in the weekend and early next week with activity
focused over higher terrain locations. With temperatures hovering
much above normal and near record levels the next several days,
minimum afternoon humidity in a 10-25% range will improving closer
to a 20-30% range next week. Correspondingly, overnight recovery
will mostly be in a fair to good range of 30-60% with somewhat
higher values next week. Temperatures are expected to cool back to
near to slightly above normal early next week. Outside of
thunderstorm outflows, wind speeds should be fairly light through
the period with only local afternoon gusts 20-25 mph.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning until 8 PM MST Monday for AZZ530>555-559.

     Extreme Heat Warning until 8 PM MST Saturday for AZZ556-560>562.

CA...Extreme Heat Warning until 8 PM PDT Monday for CAZ560>570.

&&

$$

SHORT TERM...Berislavich/18
LONG TERM...18
AVIATION...Lojero
FIRE WEATHER...Berislavich/18