612
FXUS65 KPSR 111148
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
448 AM MST Tue Aug 11 2026

.UPDATE...Updated Aviation Discussion.

&&

.KEY MESSAGES...

- Better moisture and more favorable conditions for monsoon storm
  development is expected through midweek with the most widespread
  activity across south-central and eastern Arizona.

- Locally heavy rainfall and gusty thunderstorm winds will remain
  possible through Thursday before drying conditions ends rain
  chances as early as Friday.

- Cooling temperatures are expected through midweek, briefly
  falling to below normal Wednesday through Friday.

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...
Scattered showers and elevated thunderstorms will continue to be
possible through around sunrise with the main area of focus across
Maricopa County. Despite fairly strong CIN in the lower levels,
the ongoing activity from the evening hours has allowed for the
elevated CAPE of over 1000 J/kg to be tapped into across the area.
The main concern over the next few hours will be lightning and
very localized heavy rainfall. A few spots could receive up to
around 1 inch of rain, but most locations will stay under 0.25"
through the rest of the night.

Looking at the larger picture, the subtropical high centered over
northwest New Mexico will gradually shift to the east as a weak
Pacific trough attempts to move in from the west starting
Wednesday. For the rest of today, a mostly overturned atmosphere
is likely to limit shower and thunderstorm activity compared to
the last couple of days. Hi-res CAMs show storms firing over the
eastern AZ high terrain this afternoon with a weak southeasterly
steering flow potentially directing some of the activity into the
south-central AZ lower deserts this evening. Despite ample
elevated instability, strong CIN is likely to be difficult to
overcome over the lower deserts resulting in PoPs of 10-20%.
Chances will persist into early Wednesday morning, but the
activity is expected to be much more sparse than what we are
receiving at the moment.

Uncertainty climbs on Wednesday as the weak trough begins to enter
western portions of the region turning the flow out of the south
southwest. The incoming trough is expected to increase upper level
forcing across much of the area for Wednesday into early Thursday,
but as the flow shifts out of the south southwest some dry air
will begin to filter into western and then south-central Arizona.
However, plenty of moisture will remain from around Phoenix and
areas to the east and northeast of Phoenix. The biggest question
will be the areas of focus for shower and storms from Wednesday
afternoon through Thursday morning. Guidance indicates the best
chances from northern and eastern portions of Phoenix into the
higher terrain with PoPs of 50-70% with decreasing chances to the
south and west. The southwesterly steering flow will direct any
activity toward the high terrain with some storms potentially
becoming anchored to a terrain feature and/or some potential for
training storms. A faster than normal storm movement should help
to limit the heavy rainfall threat, but the aforementioned
factors could still lead to some instances of flash flooding. The
activity is likely to persist during the overnight hours/Thursday
morning, but the threat for heavy rainfall is likely to gradually
decrease.

The increase in shower and thunderstorm activity and clouds over
the next couple of days will help to bring some relief from the
recent heat. Forecast highs today drop back to around normal and
then to below normal for much of Arizona starting Wednesday.
Forecast highs several degrees below normal are expected for
Thursday and Friday.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Drying is expected to pick up across the area during the latter
half of Thursday with most of the shower and thunderstorm
potential shifting to over the Arizona high terrain. By Friday,
enough dry air is expected to filter into the area to completely
end rain chances across the lower deserts while limited chances
are forecast for the high terrain. The subtropical high is
expected to stay centered across the Southeastern U.S. through at
least the weekend with broad troughing over much of the Western
U.S. This will keep dry air in place through at least the upcoming
weekend with at most slight chances for afternoon convection over
the far eastern Arizona high terrain. Ensembles do show the
subtropical high becoming more elongated late this weekend with
heights gradually increasing over our region. As a result,
temperatures are likely to climb back to around or even a few
degrees above normal by Sunday or Monday. The next potential for
rain could come as early as next Monday or Tuesday, but
uncertainty is quite high at a week away.

&&

.AVIATION...Updated at 1145Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
VCSH conditions will prevail for the next several hours with a low
chance (10-20%) of VCTS conditions developing. Confidence is very
low on wind directions and speeds the next few hours due to
clusters of showers/storms continuing to track across the region.
Directions will likely favor W/NW for the northern terminals
(KDVT, KSDL) and SE/S for the southern terminals (KPHX, KIWA) in
the immediate term. Confidence then grows late morning that winds
will settle out of the west and become gusty by the afternoon with
gusts 15-20 kts. A distant outflow from the NE may affect the
Phoenix airspace during the evening (02-05Z timeframe), but
confidence is too low for TAF inclusion at this time. Then, a
second distant outflow may reach the terminals late evening into
the overnight hours out of the SE. Another period of VCSH/VCTS
will need to be evaluated for the overnight period into Wednesday
morning, with 20-30% chances for spotty coverage of SHRA/TS across
the Phoenix airspace. Lowest cloud bases will mostly stay at or
above 10K ft AGL through the period.

Southeast California/Southwest Arizona including KIPL and KBLH:
The potential for strong outflow winds to once again reach the
terminals and VCSH/VCTS conditions this afternoon will be the
primary aviation weather concerns. Winds will favor a southerly
direction at KBLH with afternoon gusts to around 20 kts. VCSH/VCTS
may develop at KBLH Tuesday afternoon beginning around 22Z. At
KIPL, winds will primarily favor S-SE through the TAF period, with
potential for a period of W-SW later Tuesday afternoon and
evening associated with storm outflow. FEW to SCT clouds will be
common over the area with lowest bases down to around 10K ft AGL.

&&

.FIRE WEATHER...
Scattered showers and thunderstorms are anticipated each day
through midweek across the higher terrain areas of the eastern
districts, with slightly lower chances in the lower elevations.
The best chances will fall during the latter half of Wednesday.
Afternoon MinRHs will range between 25-40% through Wednesday with
good to excellent overnight recoveries. Aside from gusty and
erratic winds near thunderstorms, the overall wind pattern will
follow the diurnal trends with modest afternoon upslope gusts.
Near to below normal temperatures are expected through the rest of
the week with drying conditions by Friday and lasting through next
weekend.

&&

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

$$

SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...Whittock/Benedict
FIRE WEATHER...Kuhlman