494
FXUS65 KPSR 221132
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
432 AM MST Sun Jun 22 2025

.UPDATE...Updated Aviation Discussion

&&

.KEY MESSAGES...

- Below normal temperatures today through at least the first half
  of next week, followed by a return to above normal as early as
  Thursday and lower desert highs back around 110 degrees next
  weekend.

- Dry conditions will prevail, under mostly clear skies, and with
  afternoon and evening breeziness (15 to 25 mile per hour gusts).

- Slight chances (10 to 20 percent) for afternoon storms in parts
  of Southern Gila County beginning Tuesday.

&&

.DISCUSSION...
Widespread heat alerts are seen from the Midwest through the
Northeast, while there are winter weather and freeze alerts in
parts of the Northwest. The yin and the yang, with a large area of
high pressure across much of the eastern CONUS and an anomalously
cool trough across the western CONUS. This trough across the West
will lead below normal temperatures today through at least
Tuesday, with today expected to be the coolest day in the
forecast. Most lower desert locations will come up short of 100
degrees this afternoon, which is rare for late-June. Phoenix has
only observed a sub-100 degree high 7 times between June 20th-30th
during the 2000s (Yuma 11 times & El Centro 13 times). The morning
low temperatures will also be more pleasantly in the upper-60s to
middle-70s through mid-week.

Unfortunately, the sub-seasonal temperatures will not last as
global models continue to show the trough in the West gradually
weakening and negative height anomalies disappearing by Thursday.
The negative height anomalies will not be immediately be replaced
by positive anomalies and strong high pressure, as the blocking
high/heat dome in the East is expected to persist through most of
the week. H5 heights are still expected to slowly rise across the
Desert Southwest, however, and so will surface temperatures as a
result. Latest NBM forecast has a return to above normal as early
as Thursday and then 110 degree highs by next weekend.

With the trough still in the West, daily breezy conditions will
continue across the region, though winds will not be as strong as
the past couple of days. Winds are actually still quite breezy
(25-35 mph gusts) across Southeast CA early this morning, with
westerly downsloping winds in Imperial County and northwesterly
winds behind a dry cold front that has dropped down into eastern
Riverside County, but these winds will subside through the morning
and become light by this afternoon. Afternoon 15-25 mph gusts will
be common through the next several days.

So, when will monsoon storms get going here? Well, while the
western trough lingers across the area through early week it will
maintain dry southwest flow across Southeast CA and most of AZ and
keep a deeper moisture axis off to the east and southeast in
New Mexico and northern Mexico. As the trough weakens by midweek
moisture levels are expected to start rising across southeast and
south-central AZ, more to seasonal levels (lower desert PWATs of
0.7-0.9"). This looks like it will lead to at least some isolated
storms developing in parts of southeast AZ beginning around
Tuesday, including as far north as the White Mountains and into
Gila County. Grand ensemble probabilities >50% for MUCAPE >200
J/kg suggests afternoon and evening storms will mostly stay east
of a line from Tucson through Globe Tuesday through Friday. The
MUCAPE probabilities then drop heading into next weekend,
suggesting a decrease in activity. NBM PoPs in southern Gila
County only peak around 10-20% Tuesday-Friday.

Looking a little further ahead, long-range models are not
indicating any strong signals for anymore negative height
anomalies across the West and there is consensus for the monsoon
high becoming established in the Desert Southwest around or just
after July 4th. Overall, it is looking like we will slowly ease
our way into the monsoon stormy season with moisture levels slowly
creeping up.

&&

.AVIATION...Updated at 1130Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
No major aviation concerns under clear skies can be expected
throughout the TAF period. Winds will follow familiar diurnal
trends, with a longer than usual window of S`rly crosswinds at
KPHX and KDVT. Gusts in the mid-teens to near 20 kts will develop
this afternoon before then diminishing after sunset.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation concerns under clear skies can be expected
throughout the TAF period. Winds should generally contain a W`rly
component at both terminals through much of the forecast, with
some variability during the afternoon hours. Cannot rule out the
potential for some windows of reduced visibility at KIPL due to
wildfire smoke, but confidence surrounding any surface reductions
remains too low to warrant inclusion in the TAF at this time.

&&

.FIRE WEATHER...
There are no considerable fire weather concerns through the next 7
days, aside from perhaps some isolated dry thunderstorm impacts
in parts of southern Gila County (toward the White Mountains)
beginning Tuesday. Winds will be lighter than the previous couple
of days, but still breezy in the afternoons and evenings with
daily peak gusts up to 15-25 mph. Conditions overall will remain
dry with daily minimum RH values down to 5-15% and overnight
recoveries only to 20-40%. Near to below normal temperatures are
expected through the first half of the week, but will warm through
the end of the week and lower desert highs will push back to
around the 110 degree mark by next weekend.

&&

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

$$

DISCUSSION...Benedict
AVIATION...RW
FIRE WEATHER...Benedict