814
FXUS65 KPSR 042156
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
256 PM MST Fri Jul 4 2025

.KEY MESSAGES...

- Dry, along with cooler-than-normal, conditions are expected for
  the 4th of July.

- Temperatures warm through the remainder of the weekend, with
  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 near 115 degrees for lower desert
  locations.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
Afternoon showers and storms are firing off in southeastern
Arizona, but will remain well south of the region today, as much
drier air behind the decaying trough has a firm grip over western
and central Arizona. The exceptions to this will be around
enhanced terrain features of far southeastern Gila and Maricopa
Counties, where some very weak and short-lived showers may pop,
but chances for these areas max out at around only
20%.Temperatures this afternoon will reach into the lower to
mid-100`s across the lower deserts, with evening temperatures
cooling into the mid to upper 90s.

Building high pressure over Texas and Northern Mexico is
projected to strengthen over the remainder of the weekend, helping
to nudge the Pacific Low off to our west further north. This will
translate to warming temperatures during this timeframe, with
afternoon highs hovering near 110 degrees once again by Sunday.
Global models do indicate another Pacific Low developing just off
the California Coast by late Saturday, which presents an
opportunity for a limit on how far the region warms up. However,
by that point, the sub-tropical high will be the dominant feature
and will help to stave off any further advance eastward of this
follow-on disturbance, keeping us on an upward temperature
trajectory. In terms of rainfall, the strengthening high and a
relatively unimpressive moisture profile should suppress the
development of convection for most, if not all, of the region.
Only chances (20%) will be once again focused around high terrain
areas.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Exiting the weekend, the sub-tropical high is expected to continue
its westward migration while continuing to strengthen, resulting in
a persistent warming trend into the start of next week. It appears
that ensemble guidance has come into better agreement regarding
where this ridge will setup and how far temperatures will rise.
Previous runs had depicted discrepancies between the GFS and EPS,
with the latter leaning drier and hotter. Well, it appears the
GFS is now trending toward that drier and hotter solution. Heights
aloft will push toward 597dm, translating to temperatures at the
surface between 108-116 degrees through the middle portion of the
week. In turn, areas of Major HeatRisk begin to develop as early
as Monday, becoming more widespread by Wednesday. With increasing
confidence and coverage of Major HeatRisk, Extreme Heat Products
are likely to be issued over the next 12 to 24 hours. Along as
the high sits directly overhead, and we do not see a better of
influx of moisture, which does not appear will be the case,
convection is likely to be suppressed across the vast majority of
the region through at least the middle of next week, except the
typical high terrain spots of eastern Arizona.

&&

.AVIATION...Updated at 1735Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
No major aviation weather concerns under mostly clear skies are
expected throughout the TAF period. The overall wind pattern will
exhibit the more typical diurnal tendencies with winds slowly
becoming westerly through the early afternoon hours. The west
winds will persist well into the overnight hours. Winds will go
southeasterly at KIWA, whereas may just be more light and
variable at the other three TAF sites. Wind speeds will generally
remain aob 10 kts, although some occasional afternoon/evening wind
gusts in the mid to upper teens will be possible.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns under clear skies are expected
throughout the TAF period. At KIPL, southeast winds will prevail
through this afternoon with a period of southwesterly winds
expected this evening before going back south/southeasterly during
the overnight hours. At KBLH, winds will generally persist out of
a southerly direction throughout the period. Speeds at KIPL will
remain aob 10 kts while at KBLH, wind gusts upwards of 20-25 kts
will be common throughout the day, diminishing this evening.

&&

.FIRE WEATHER...
Near to below-normal temperatures will persist into the start of
the weekend, with above-normal readings returning by Sunday. Some
lingering moisture will result in relatively elevated MinRH
values with readings between 20-25% in the eastern districts and
15-20% in the western zones. Overnight recoveries Friday night
will offer some decent relief as readings hover between 40-60%.
However, drier air will lead RH values on a quick decline as
daily minimums fall to 10-15% by Sunday. As expected, MaxRHs will
follow a similar drying trend. Diurnal wind trends can be
anticipated, with typical afternoon breeziness. Rainfall activity
over the next several days will be quite limited, with only
minimal chances (<10%) of wetting rains over the eastern
districts.

&&

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

$$

SHORT TERM...Young/RW
LONG TERM...RW
AVIATION...Berislavich/Lojero
FIRE WEATHER...RW