799
FXUS65 KPSR 121820
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1120 AM MST Sun Jul 12 2026

.UPDATE...Updated 18Z Aviation Discussion.

&&

.KEY MESSAGES...

- Scattered showers and thunderstorms will develop over the high
  terrain of southcentral AZ this afternoon with much higher
  chances for storms surviving into the lower deserts. There is
  also a slight risk for severe thunderstorms in Maricopa and
  Pinal Counties today.

- With high pressure shifting into the Great Plains, daily shower
  and thunderstorm chances will continue over the Desert Southwest
  through much of this week.

- Seasonably hot temperatures will persist through the next several
  days resulting in a widespread Moderate Heat Risk.

&&

.SHORT TERM /Today through Monday/...
Latest IR satellite imagery shows a decaying complex of
thunderstorms progressing through Sonora MX. Gusty outflow winds
from this complex may reach the Lower Colorado Valley early this
morning causing winds to increase and generating patchy blowing
dust in Yuma and Imperial Counties. It is possible a few showers
and even some embedded lightning strikes could occur early this
morning over southcentral AZ where a pocket of higher mid-lvl
instability is present. As we progress into this afternoon, high
pressure currently located over the Rockies will continue migrate
into the Northern Plains. This pattern shift will allow 500 mb
steering flow over AZ to transition from E to SE allowing for much
better moisture to advect into central portions of the state.

Most of the CAMs indicate storms initiating along the Mogollon
Rim and S Gila County this afternoon and generating a strong SW
moving outflow boundary which will encroach on the lower deserts
late this afternoon into early this evening which will likely
generate additional showers/storms and areas of blowing dust. The
environment across the lower deserts will consist of modest
instability with ML CAPE values ranging between 500-800 J/kg and a
narrow axis of higher values up to 1000-1200 J/kg mainly over the
foothills E of Phoenix. Forecast soundings also indicate ML CIN
values around 50-70 J/kg which may inhibit greater storm coverage
across the lower deserts. Overall this setup poses a much more
conditional severe threat depending on the strength of the
initial outflow. Nevertheless, any storm that does develop could
produce strong wind gusts up to 50-60 mph due to high DCAPE up to
1200-1500 J/kg. The Storm Prediction Center has still maintained a
slight chance (15%) for severe level wind gusts (>58 mph) which
includes the Phoenix Metro and the I-10 corridor south to Tucson
this afternoon/evening. By late this evening into the overnight,
colliding outflows from storms in Pima county and western Maricopa
County will likely generate additional showers/storms across the
lower deserts east of the Colorado River, where NBM PoPs are
30-40% after 00Z.

The upper-lvl pattern is not expected to change heading into Monday
which will result in a very similar evolution as storms first
develop over the high terrain E and SE of Phoenix and attempt to
survive into the lower deserts by the later afternoon/early evening.
The environment will be similar to today with maybe slightly less
overall wind shear. Thus, a few strong to marginally severe storms
will be possible Monday afternoon. NBM PoPs are indicating 30-40%
coverage across southcentral AZ and up to 20% for the lower deserts
E of the Colorado River.

Due to the increase of boundary layer moisture and 500 mb hghts
ranging from 593-595 dam, high temperatures will run near to
slightly above normal with lower desert locations hovering between
102-109 degrees each afternoon. The added humidity will
unfortunately make it feel worse with apparent temperatures (heat
index) reaching 110-115 degrees across the lower deserts.
Moderate HeatRisk will remain widespread across the region, so
heat precautions should continue to be exercised if plans take you
outside.

&&

.LONG TERM /Monday through Friday/...
There is still excellent agreement within the EPS and GEFS members
regarding the placement of the upper high over the northern Plains
and Upper Midwest through midweek before retrograding over the
central Rockies by the latter half of the week. The overall position
of the 500 mb high will maintain deep easterly flow across the
Desert Southwest, helping enhance moisture transport. Latest EPS and
GEFS continue to show PWATs hovering around 1.5"-1.8" through the
entire week with low-level mixing ratios remaining between 10-12
g/kg. Therefore, conditions will continue to remain conducive for
daily thunderstorm activity with variations in the overall coverage.
Both the mean of the EPS and GEFS show an uptick in QPF across the
region by the end of this week due to an easterly wave/inverted
trough approaching the area by Thursday-Friday. If this occurs, this
troughing feature will likely enhance convective activity
potentially introduce a risk for heavy rainfall across portions of
AZ. This will have to be monitored closely in the coming days.

Temperatures through the first half of the workweek will generally
remain steady state at near to slightly above normal with highs
generally between 102-110 degrees, resulting in the continuation of
widespread Moderate HeatRisk. The NBM continues to indicate
temperatures cooling to well below normal by the end of the week
with highs falling into the 90s to around 100 degrees across the
lower deserts by Friday. This is likely due to the increased signal
for thicker cloud cover and the potential for more widespread rainfall.

&&

.AVIATION...Updated at 1818Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The primary concern during the TAF period will be the potential
for strong gusty outflow winds and TS impacts at the terminals
late this afternoon into the evening. Westerly winds will continue
through the afternoon hours with speeds hovering around 10kts with
periods of gusts in the mid teens this afternoon. Confidence
remains high that showers and storms will develop over the eastern
higher terrain and to the southeast of the terminals where an
outflow boundary from the NE is expected to push into the metro as
early as 22-00Z but most likely around 00-03Z as is reflected in
the TAF. Wind gusts during this time remain in high agreement
(70-90%) that speeds in excess of 30 kts will be possible in the
Phoenix Metro. Unfortunately confidence remains low on locations
where new storms might develop and the coverage of additional
storms along and behind the outflows. As such, continued the
PROB30 group at each of the terminals. A strong outflow out of the
northeast is not favorable for producing blowing dust and thus
causing reductions in visibility, but the possibility for some
areas of blowing dust, VIS restrictions, and hazy conditions
cannot be ruled out, especially at KIWA. Skies will be mostly
SCT- BKN mid-high level clouds with the exception of any storm
development where FEW low level clouds (050-060 kft) will be
possible.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation concerns are expected through the TAF period.
Winds at KIPL will remain SE`rly with winds generally between 8-14
kts, with a period of possible gusts in the upper teens near
10-13Z tomorrow morning. KBLH will maintain generally a southerly
flow with gusty conditions over the overnight hours out of the
ESE, otherwise continuing teetering between SSW and SSE with
speeds hovering around 10 kts. Skies will remain SCT-BKN, with
bases mostly above 15 kft AGL.

&&

.FIRE WEATHER...
Seasonably hot temperatures will prevail through the next several
days as readings will be near to slightly above normal. Scattered
showers and thunderstorms will be possible this afternoon and
evening bringing a threat of strong winds. Daily thunderstorm
activity will be possible through this week with the potential
for wetting rainfall increasing across the high terrain later in
the week. Due to increasing boundary layer moisture, afternoon
humidity levels will remain in a 20-30% range which will keep any
fire weather concerns at a minimum. Overnight recoveries will be
fair to good, or between 40-70%. Outside of any thunderstorm
driven outflow, winds should favor diurnal trends with the typical
afternoon breeziness around 20-25 mph.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Blowing Dust Advisory from 4 PM this afternoon to 8 PM MST this
     evening for AZZ539-553-554-559.

CA...None.
&&

$$

SHORT TERM...Salerno
LONG TERM...Salerno
AVIATION...Ryan/Whittock
FIRE WEATHER...Salerno

NWS Phoenix (PSR) Office