725
FXUS65 KPSR 060501
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1000 PM MST Sat Jul 5 2025

.UPDATE...
Updated Aviation

&&

.KEY MESSAGES...

- Temperatures warm through the remainder of the weekend with lower
elevation highs hovering around 110 degrees by Sunday resulting in
widespread moderate HeatRisk

- Further warming, and generally dry conditions are expected into
next week with highs pushing close to 115 degrees for some lower
desert locations

- Extreme Heat Watches have been posted for the Phoenix metro, along
with surrounding areas of Maricopa and Pinal counties for Tuesday
through Thursday

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
Some cumulus fields are building in southern Maricopa and
southwestern Pinal Counties early this afternoon as some enhanced
moisture remains in place across southern Arizona. Thus, cannot rule
out some isolated shower and storm activity later this afternoon and
evening in this general area tied mainly to higher terrain features
as CAM`s continue to show some level of activity possible. Typical
gusty outflow winds and brief downpours will be the main concerns
with anything that develops.

Subtropical ridging will become the dominant weather regime for our
region over the next several days as it continues to build and
migrate further west In its current stage, with heights aloft
between 592-594dm, day-to-day temperatures compared to yesterday
will be a few degrees warmer, but hover right around seasonal
levels. Highs across the lower deserts this afternoon are expected
to range between 101-109 degrees.

Model guidance does bring a quick developing area of low pressure
just off the California Coast over the weekend, which could inhibit
the progression of the ridge ever so slightly, and perhaps even
lower heights aloft into Sunday. Typically, when heights remain
steady or drop slightly, this translates to a similar trend in day-
to- day temps, but in this case, afternoon highs for Sunday are
forecasted to rise to between 106-111 degrees for the lower deserts.
The reason for this can be found in the trends of our regional 850mb
temperatures, as they are forecasted to increase from today into
Sunday.

Moisture content this weekend will be lacking and it does not appear
a better influx can expected as we remain under unfavorable flow
aloft. This will largely keep any monsoonal related shower and
thunderstorms at bay through the rest of the weekend, except in
southeast Arizona, where better moisture is available. However, hi-
res guidance does hint as some short-lived activity along the
Maricopa, Pima County border, but chances are slight at best (10-
30%).

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Looking beyond toward the upcoming week, the aforementioned ridge
will continue to build and eventually park itself over Arizona and
southeast California. With heights aloft projected to climb to 597-
599dm, temperatures will continue their upward climb with most lower
desert locations ranging between 108-116 degrees through most, if
not all of the work week. Tuesday through Thursday looks to be the
hottest period as the ridge peaks in strength and sits virtually
right on top of our CWA. MaxT values of 110-116 will be common for
the lower elevations, translating to areas of major HeatRisk. In
turn, an Extreme Heat Watch has been issued for the Phoenix metro,
and the surrounding areas of Maricopa and northern Pinal Counties
for the above-mentioned timeframe. Additional Extreme Heat Products
will likely be needed in the next 12-24 hours for areas in
Southwestern Arizona and Southeastern California. It would also not
be surprising, depending on subtle forecast shifts, if products for
some areas are extended into Friday, but uncertainty regarding
strength and positioning of the high will delay that decision at
least for a few more days.

For the fans of monsoon rainfall, you may want to look away. Due to
the expected subsidence aloft and the continuation of unfavorable
flow, rain chances will be limited to far Southeastern Arizona
through the end of the work week. Confidence is high that most of
the region will remain dry through this period, with very few (if
any) ensemble members showing measurable rainfall through Friday.

&&

.AVIATION...Updated at 0500Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
No major weather concerns will exist through Sunday night under a
few occasional mid/high cloud decks. Confidence is very good that
trends in wind directions and speeds will be similar to the past 24
hours with modest uncertainty that some terminals will have variable
winds rather than a distinct easterly switch during the morning
hours. Afternoon/evening gustiness should remain limited.


Southeast California/Southwest Arizona including KIPL and KBLH:
No weather concerns will exist through Sunday night under clear
skies. Confidence remains very good that trends in wind speeds and
directions will be similar to the past 24 hours with only
occasional, minor gustiness.

&&

.FIRE WEATHER...
Temperatures continue their warming trend toward above normal levels
through the remainder of the weekend as high pressure builds
overhead. Relatively high moisture across the eastern districts will
translate to MinRHs between 15-25%, but further west, values will
range closer to 10-15%. Those lower values become more common Sunday
across the region as drier air spreads further east. Overnight
recoveries will only offer marginal relief, as MaxRHs hover between
20-45% over the next several days. Winds will follow familiar
diurnal trends, with typical afternoon breeziness. Rain chances will
be confined to high terrain areas of the far eastern districts, but
CWR are <10%.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Watch from Tuesday morning through Thursday evening
     for AZZ534-537>540-542>544-546-548-550-551-553>555-559.

CA...None.

&&

$$

SHORT TERM...Young/RW
LONG TERM...RW
AVIATION...18
FIRE WEATHER...RW