428
FXUS65 KPSR 060947
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
247 AM MST Sun Jul 6 2025

.KEY MESSAGES...

- Above-normal temperatures return, with many lower desert
  locations hovering close to 110 degrees this afternoon

- Further warming, and generally dry conditions, are expected
  into next week with highs around 115 degrees for lower desert
  locations by Wednesday

- Rising temperatures will result in widespread Major HeatRisk,
  prompting the issuance of Extreme Heat Warning for much the
  region between Tuesday and Thursday

&&

.SHORT TERM /TODAY THROUGH MONDAY/...
Morning 500mb RAP analysis reveals sub-tropical high pressure
continuing to build across the southwestern CONUS while a weak
disturbance spins off the California Coast. These two features will
have a brief period of interaction, with the latter feature helping
to keep the westward progression of the former at bay, at least
temporarily. With the high being the dominant of the two features,
its regional influence will be greater and will continue to help
the promotion of the increasing temperatures. Even with heights
aloft projected to be slightly lower (591-593dm) compared to where
they were yesterday (593-595dm), typically signaling at least
steady, if not slightly cooler, day-to-day temperature
variations, an increase in 850mb temperatures will be why this
warmup continues. Forecasted highs this afternoon are expected to
return to above-normal levels, with many locations across the
lower deserts hovering around 110 degrees.

By Monday, the aforementioned high will start to force its will on
the Pacific Low and resume its migration further over the Desert
Southwest, eroding the trough and keeping it well north of our
forecast area. In turn, very little, if any, changes in conditions
are expected heading into the start of next week. Temperatures
Monday afternoon for lower elevation locations will range between
106-112 degrees. Any rain chances over the state during the near-
term will be focused over southeastern Arizona as moisture profiles
across most of the region remain underwhelming for robust and
widespread monsoon related convection.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Models continue to remain in excellent agreement regarding the
spatial progression of the sub-tropical ridge during the remainder
of the upcoming week. With projections continuing to show further
enhancement of this feature (heights pushing 597-599dm) and it
eventually becoming parked virtually right on top of Arizona and
southern California, conditions will remain hot and dry through
this timeframe. Temperatures will continue to rise and peak on
Wednesday, where lower desert highs will hover around 115 degrees,
resulting in widespread Major HeatRisk. In turn, an Extreme Heat
Watch was issued for portions of the region (Phoenix metro and
surrounding areas) Tuesday, while most of south-central and
southwestern Arizona, along with southeastern California, will
join in on the watch Wednesday. These products will initially
last until Thursday (except for higher terrain zones east of
Phoenix which last just for Wednesday), but some uncertainty in
temperature forecasts may limit the temporal extent of a future
Extreme Heat Warning to just Wednesday as well for those areas in
southwestern AZ and southeast CA. The one caveat is a projected
low-level moisture increase, thanks to a surge from the Gulf of
California, may limit daytime heating. However, the added
moisture will push heat indices upward, making the ambient temps
Wednesday and apparent temps Thursday about equal. Height
anomalies are shown decreasing toward the end of the week,
indicating a the potential for a slight cooldown, but MaxTs should
remain above normal through this period as the high remains
overhead.

As mentioned above, with the high parked right over us, and
unfavorable flow aloft preventing increased moisture flux,
conditions are expected to remain mostly dry. Best chances
rainfall will remain over Tucson`s area, where slightly better
moisture profiles will be present. There are hints at that towards
the weekend, we could see some slightly better moisture that
could help induce some terrain influenced convection, but plenty
of uncertainty remains so chances remain fairly low (20-30%) at
this time. As for lower desert areas, moisture looks to remain too
minimal to get any activity by the weekend so it appears that any
more rainfall will have to wait at least another week or so.

&&

.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...
Above-normal temperatures will prevail over the next several
days, with lower desert highs approaching 110 degrees by this
afternoon. MinRHs values over the next several days will range
around 10-15%, with lower values closer to 5-10% today across the
deserts of California. MaxRH values are not expected to offer
much relief as readings near 20-45% can be expected. Winds will
follow familiar diurnal trends, with typical afternoon breeziness.
Minimal chances for rainfall exist across the region through the
week, with CWR <10% through Friday.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Watch from Wednesday morning through Thursday
     evening for AZZ530>533-535-536.

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

     Extreme Heat Watch from Wednesday morning through Wednesday
     evening for AZZ541-545-547-549-552-556-560>562.

CA...Extreme Heat Watch from Wednesday morning through Thursday
     evening for CAZ560>570.

&&

$$

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