610
FXUS65 KPSR 101105
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
405 AM MST Sun Aug 10 2025

.KEY MESSAGES...

- Above normal highs and warm overnight lows will continue to
  yield widespread Moderate to localized Major HeatRisk through
  early this week.

- Major HeatRisk will be concentrated particularly over the
  central AZ lower deserts, the Lower Colorado River Valley, and
  Imperial Valley where Extreme Heat Warnings remain in effect
  through Tuesday evening.

- Chances for showers and thunderstorms will continue to remain quite
  limited through the first half of this week, generally favoring
  the eastern Arizona high terrain.

- Increasing moisture by late week will result in better coverage
  of thunderstorm activity across much of the region including
  the lower deserts

&&

.SHORT TERM /Today through Tuesday/...
Latest IR WV satellite imagery and 500 mb streamline analysis
reveals an elongated ridge of high pressure stretching from
southeast CA into west TX while a trough of low pressure is
present over the Intermountain West. A large complex of
thunderstorms over northern MX has sent an outflow boundary into
our region, resulting in overnight convection and areas of blowing
dust. Shower activity with a few embedded lightning strikes will
continue to track through southcentral AZ overnight but this
activity is expected to diminish around sunrise.

Heading through the rest of today, the aforementioned high
pressure center is projected to reposition over the CA/NV border
resulting in upper level winds shifting from westerly to northerly
across our forecast area. Hghts aloft will still remain around
593-594 dam allowing highs to again reach the 105F-112F range
across the lower deserts this afternoon. Another round of
convection is expected to fire up over the higher terrain areas,
mainly across the Mogollon Rim and White Mountains, as well as
across portions of southeast AZ this afternoon. The convection
that fires up around the vicinity of the Mogollon Rim will move
southward into portions of southern Gila County as well as into
northeast Maricopa County but will likely not survive into the
lower deserts due to greater inhibition in place. Thus rain
chances for the Phoenix Metro will remain below 15% through this
evening. Despite the low rain chances, there is still a moderate
chance (30-50%) for gusty outflow winds up to 35 mph to reach E
Maricopa and N Pinal Counties.

On Monday and Tuesday, dry N-NE flow aloft will prevail over the
state as ridging continues to strengthen over the Great Basin
region. In response shower and thunderstorm activity will remain
isolated and confined to the AZ high terrain of eastern and
southeastern AZ. Due to a slight increase in hghts aloft and
warming of 850 mb temperatures, we will see sfc temperatures
climb by a degree or two with highs reaching 108F-113F on Monday
and 108F-114F on Tuesday across the lower deserts. The Extreme
Heat Warning has remain unchanged and will continue through
Tuesday evening.

&&

.LONG TERM /Wednesday through Saturday/...
Starting Wednesday, ensemble guidance continues to indicate a
trough entering the Pacific Northwest while the ridge over the
Great Basin begins to weaken and shift eastward toward the Four
Corners area. This will allow a more favorable E-SE flow to set up
over the forecast region. Despite some model uncertainty between
the EPS and GEFS regarding timing of the better moisture return,
the overall trends during the latter half of next week favor
increasing moisture (PWATs reaching 1.4"-1.6") followed by a
return of monsoon rain chances by the Thursday through Saturday
timeframe. NBM PoPs continue to trend upward by the latter part of
this week, peaking around 20-40% across the lower deserts on
Thursday and Friday. Due to the increasing moisture, a cooling
trend is expected to transpire from Wednesday-Saturday, with highs
falling back into the normal range by next weekend.

&&

.AVIATION...Updated at 1105Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:

Southerly winds initially are expected to shift more westerly
after sunrise and likely stay out of the west through this
evening. Any convective potential today is expected over the
higher terrain with only minimal chances of an outflow out of the
northeast by mid to late evening. If the outflow doesn`t occur,
winds should eventually turn back to the east later Sunday night.

Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation weather concerns are expected over the next 24 hours
under generally clear skies. Winds at KIPL will generally remain
out of the SE through Sunday afternoon, while KBLH will continue
to see more S`rly winds with some occasional afternoon gusts
around 20 kts.

&&

.FIRE WEATHER...
Above normal temperatures will continue through the middle of this
week. There will continue to daily thunderstorm activity over the
high terrain through the first half of the week followed by a better
potential for scattered shower and thunderstorms across much of the
region late in the week. Chances of wetting rainfall will remain
below 10% over the next few days, resulting in potential for dry
lightning and new fire starts. Minimum afternoon humidity levels
will mostly range between 15-20% with fair to good overnight
recoveries. Winds will retain an afternoon upslope component with
gusts to 15-20 mph common.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning until 8 PM MST Tuesday for AZZ530-532-534-
     537>544-546-548>551-553>555-559.

CA...Extreme Heat Warning until 8 PM PDT Tuesday for CAZ562-563-566-
     567-569-570.

&&

$$

SHORT TERM...Salerno
LONG TERM...Salerno
AVIATION...Kuhlman
FIRE WEATHER...Salerno