320
FXUS65 KPSR 020515
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1015 PM MST Mon Jun 1 2026

.UPDATE...06Z Aviation Discussion.

&&

.KEY MESSAGES...

- Slightly above normal temperatures will prevail throughout the
  week before retreating closer to normal over the weekend.

- Other than a slight chance of a thunderstorm in eastern AZ
  during the middle of the week, dry conditions under mostly sunny
  skies will prevail through the next several days.

&&

.SHORT TERM /Today through Wednesday/...
Latest water vapor satellite imagery as well as streamline analysis
show an omega blocking pattern centered over central Canada with
troughing along the northeastern CONUS and over the northern
Rockies. Meanwhile, over the Desert Southwest, southwesterly flow
aloft prevails with weak troughing noted just off the southern CA
coast. This weak troughing feature will continue to slowly
progress east-southeastward into northern Mexico through midweek
and thus will not have any significant sensible weather impacts
for our region. Thunderstorm activity materializing across New
Mexico through the middle of the week will likely send a westward
propagating outflow boundary into far eastern Arizona, increasing
low-level moisture somewhat. Thus, isolated thunderstorms are
likely to materialize near the White Mountains Wednesday
afternoon, potentially impacting far eastern Gila County.
Otherwise, fairly tranquil weather under mostly clear skies will
prevail throughout the majority of the region.

With 500 mb height fields ranging 582-585dm, lower desert highs
today and tomorrow will generally be in the low 100s and will rise a
couple of more degrees to around 105 degrees by midweek as 500 mb
heights rise closer to 585-587dm. These temperatures will be around
3-5 degrees above normal for early June. The overall HeatRisk
through Tuesday will remain in the minor category before
increasing into the moderate category midweek as temperatures rise
into the mid 100s. Therefore, if planning in any outdoor
activities, make sure to take the necessary heat precautions to
avoid any heat-related illnesses.

&&

.LONG TERM /Thursday through Sunday/...
During the latter half of the week, NAEFS members are in fair
agreement showing weak southern stream troughing slowly translating
into the southern plains as deep negative height anomalies approach
the western Conus. The primary uncertainty is the forward speed at
which this occurs, and how quickly the forecast area falls under
anti-cyclonic subsidence. The preponderance of ensemble output
suggests the trough axis not passing into the southern Rockies until
Friday, thus keeping modest ascent mechanisms into eastern Arizona
Thursday with a continued slight chance of storms over mountainous
areas. Regardless, the pattern evolution late in the week will
promote height falls and dry westerly flow with H5 readings
retreating closer to 580-582dm by the weekend (and possibly much
lower early next week). While numerical guidance spread widens
during the evolution, an increasing number of ensemble members
indicate deeper troughing and more robust cooling arriving over the
weekend such that temperatures should return to near normal, or
even into a slightly below normal category.

&&

.AVIATION...Updated at 0515Z.

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

No aviation concerns are expected during the TAF period. Winds
will follow light and diurnal trends with periods of VRB
conditions during directional shifts. Occasional breeziness may be
observed Tuesday afternoon, but observations should remain aob 20
kt. Other than FEW high clouds exiting the region tonight, and
some distant, high terrain CU later in the forecast, skies will be
mostly clear.

Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation concerns are expected during the next 24 hours. Winds
will follow familiar diurnal trends, with some periods of VRB to
calm conditions during the overnight and morning hours. Skies will
be mostly clear through Tuesday evening.

&&

.FIRE WEATHER...
The threat for a few lightning strikes with little rainfall in far
eastern Gila County Wednesday and Thursday is the main fire weather
hazard this week. With temperatures hovering slightly above normal,
winds will maintain a diurnal upslope/nocturnal drainage pattern.
Gusts will be limited the first half of the week, then increase
later in the week, particularly across the lower Colorado River
valley and over mountainous locations. Minimum afternoon humidity
levels will generally fall in a 5-15% range following a widely
ranging poor to fair overnight recovery of 15-45%.

&&

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

$$

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