787
FXUS65 KPSR 302007
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
107 PM MST Wed Jul 30 2025

.KEY MESSAGES...

- Above normal temperatures with lower desert highs between
  108-114 degrees will prevail through next week, resulting in
  widespread Moderate HeatRisk with areas of Major HeatRisk across
  the south-central AZ lower deserts for Friday and Saturday with
  Extreme Heat Warnings in effect.

- Limited monsoon moisture will result in daily chances for
  thunderstorm activity across the eastern Arizona high terrain
  through Friday, with only a very slight chance for isolated
  activity across the south-central AZ lower deserts late Thursday
  afternoon and evening.

&&

.SHORT TERM /Today through Thursday/...
Latest water vapor satellite imagery shows a substantial amount
mid to upper-level dry air in place as a result of southwesterly
flow aloft enveloped across much of southern CA through western
and central AZ from a trough situated across central CA. As a
result of this pattern, moisture levels continue to be well-below
normal with the latest SPC mesoanalysis showing PWATs ranging
between 0.5-0.9" across the lower deserts of south-central and
southwestern AZ through southeast CA to as high as 1.0-1.3"
across the southeastern third of AZ. Given the meager moisture in
place, thunderstorm activity similar to the past couple of days
will be limited to the eastern and southeastern third of AZ this
afternoon through early this evening while the rest of the region
will remain dry with mostly clear skies. Heading into Thursday,
moisture levels do improve some as PWATs increase to 1.0-1.3"
across the south-central AZ lower deserts, which could allow for
some of thunderstorm activity that does develop during the
afternoon across the eastern third of AZ to spread westward.
However, it is still looking like any activity that attempts to
develop into the lower-deserts will be isolated at best with PoPs
at around 10%.

The main story will continue to be the hot temperatures as
temperatures will be a good 3-5 degrees above normal, ranging
between 107-111 degrees across the lower deserts through Thursday
as 500 mb height fields will range between 593-596dm. This will
result in widespread Moderate HeatRisk and thus anyone scheduling
outdoor activities as well as the most vulnerable communities
will need to take the necessary heat precautions.

&&

.LONG TERM /Friday through Tuesday/...
The upper-level ridge will strengthen across central and southern
AZ Friday and Saturday as 500 mb height fields increase up to
597-598dm. This will translate to hotter temperatures as highs
will range between 110-114 degrees across the lower deserts with
early morning lows between 85-90 degrees across the Phoenix metro
area. This will be enough to result in areas of Major HeatRisk
materializing across the south-central AZ lower deserts and as a
result, Extreme Heat Warnings have been issued for both Friday
and Saturday.

We are expecting some lingering moisture across the eastern 1/3rd
of Arizona on Friday, but with the high center setting up
directly over southern Arizona any chances for showers or storms
should be limited to higher terrain areas. More organized westerly
dry flow will also set up Friday into Saturday with PWATs quickly
dropping to around 0.75" on Saturday, mostly ending any rain
chances even over the higher terrain. This dry westerly flow is
expected to at least persist through Sunday, but by Monday models
begin to shift the high center more over New Mexico. If this shift
occurs, it may allow for some moisture to begin seeping back
northward into southern Arizona as early as Monday. Limited 10%
PoPs have added across the Phoenix metro for Monday and Tuesday
with chances closer to 20% over the eastern Arizona high terrain.

Temperatures are likely to take a slight dip of a couple of
degrees Sunday into Monday as the ridge shifts away from the area
and weakens slightly. However, we are still anticipating the
above normal temperatures to continue with highs between 107-111
degrees across the lower deserts. Looking out toward the latter
half of next week, guidance is still pointing at a restrengthening
of the ridge and the potential return of extreme heat.

&&

.AVIATION...Updated at 1753Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds have shifted W`rly early and will persist through this
evening, with some light variability still expected through noon.
Afternoon wind gusts up to 15-20 kts are expected. Skies should
remain clear over the Phoenix area through this afternoon, with
cumulus and isolated storms developing well to the east. There is
low potential for an outflow to move into the Phoenix area late
this evening, but if one does it will mostly just serve as an
E`rly wind shift. Similar conditions are expected tomorrow, but
with afternoon cumulus developing closer to or in the Phoenix
area.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns under clear skies can be
expected throughout the TAF period. Winds will favor southeasterly
during the day at KIPL, with westerly winds this evening, and S-SW
at KBLH. Periods of light variability can also be expected in the
mornings. A few gusts to around 20 kts will be possible at both
terminals this afternoon and evening.

&&

.FIRE WEATHER...
Limited monsoon moisture will provide for daily chances for
showers and isolated thunderstorms primarily over the eastern
Arizona high terrain. Chances for wetting rains will remain below
10% resulting in at least minor risk of dry lightning. Afternoon
MinRHs through Friday will remain between 10-15% across the lower
deserts to 15-20% in higher terrain areas. Outside of the
influence of thunderstorms, winds will generally follow diurnal
tendencies with typical afternoon upslope gustiness. Temperatures
will remain above normal with lower desert highs mostly between
108-112 degrees. High pressure will again take over across the
region by the weekend with conditions drying out further. This
will push humidities into the single digits and end any rain
chances.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning from 10 AM Friday to 8 PM MST Saturday for
     AZZ534-537>544-546-548>555-559.

CA...None.
&&

$$

SHORT TERM...Lojero
LONG TERM...Lojero/Kuhlman
AVIATION...Benedict/Smith
FIRE WEATHER...Kuhlman