940
FXUS65 KPSR 142347
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
447 PM MST Sat Jun 14 2025

.UPDATE...Updated 00z Aviation Discussion.

&&

.KEY MESSAGES...

- Temperatures will heat up over the weekend, with highs peaking
  near daily records on Sunday, resulting in areas of Major
  HeatRisk.

- An Extreme Heat Warning is in effect through Monday evening for
  high temperatures ranging from 106 to 114 degrees across the
  lower deserts.

- A dry weather disturbance will pass north of the area early
  next week, resulting in breezy afternoon winds and a slight dip
  in temperatures into the middle part of the upcoming workweek.

&&

.DISCUSSION...
The current upper level pattern is characterized by a subtropical
ridge which has begun to settle to the southeast of our forecast
area, a concentrated area of negative height anomalies off the
British Columbia coast, and a broad swath of southwesterly flow in
between these features over much of the Western US. Ensembles
show this pattern remaining fairly stagnant through the upcoming
workweek (though slight variations in the subtropical ridge
positioning and strength will occur), yielding excellent forecast
confidence in continued dry conditions and above normal
temperatures. However, a weak, dry shortwave is expected to pass
north of the region early this upcoming workweek.

Under the influence of the subtropical anticyclone centered to
our southeast, temperatures will heat up to around 10 degrees
above normal by Sunday, with lower desert highs forecast to top
out around 110-114F. The latest probabilistic NBM gives a 24%
chance of reaching 115F at Phoenix Sky Harbor Airport, which would
tie the record for 15 June that was most recently set in 2021.
NBM highs are still in the lower 110s for much of the lower
deserts Monday as well, indicating a decrease of only a couple
degrees. Temperatures this hot translate to areas of Major
HeatRisk, more widespread Sunday and localized Monday. As such, an
Extreme Heat Warning remains in effect through Monday evening.

As mentioned previously, a weak shortwave will pass north of the
Desert Southwest late Monday/Tuesday, resulting in breezy
afternoon winds and a slight dip in temperatures. Over the last
several forecast packages, NBM highs have come up a few degrees
during the first half of the upcoming workweek, reflecting the
trend in global guidance showing a weaker shortwave passing the
region even further to the north. Despite this, HeatRisk should
drop into a Moderate category by Tuesday. The main concern Tuesday
will instead be elevated fire weather concerns, particularly over
the high terrain east of Phoenix, with gusts likely (50-60%
chance) to peak around 30 mph along ridgetops combined with
receptive dry fuels and afternoon humidities in the upper single
digits.

Ridging will reestablish east southeast of the forecast area
during the latter half of the workweek, allowing temperatures to
rise once again into the lower 110s for the typically hotter lower
desert locales. Heat headlines may need to be extended or
reissued as some areas of Major HeatRisk reassert themselves
across Southern AZ. Guidance then shows another trough moving into
the Northwestern U.S. by next Friday/Saturday, and if this holds
true, it should keep temperatures from getting any hotter and help
bring highs back to just below 110 degrees by next weekend.
Beyond next weekend, long- range guidance is still trying to
introduce marginal moisture from the southeast, but overall the
pattern still doesn`t look favorable for any meaningful monsoon
conditions for the forecast area.

&&

.AVIATION...Updated at 2350Z.

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

No aviation concerns are anticipated through the forecast period,
with wind speeds mostly remaining at or below 8 kts and following
typical diurnal directional trends. Periods of variability
between transition periods will be common. FEW high cirrus will
overspread the region through this evening.

Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation concerns are expected through the TAF period. Winds
at KIPL will favor a E/SE component, with a period of light S/SW
winds this evening, while KBLH will see a predominant S
component. Wind speeds will remain light aob 8 kts at KIPL through
most of the period, while KBLH will see 10 kt winds during the
daytime hours, with lighter winds during the overnight hours. FEW
passing high cirrus will progress over the area through this
evening.

&&

.FIRE WEATHER...
Strong high pressure will continue to bring hot and seasonably
dry conditions into early this upcoming workweek, with high
temperatures as hot as 110 to 114 degrees across the lower deserts
on Sunday. Winds will continue to follow typical diurnal (upslope
and downvalley) tendencies with periods of afternoon upslope
breeziness. Humidity levels through the entire upcoming workweek
show little variation, with poor overnight recoveries areawide,
generally between 20-30%, and afternoon minRHs dipping to between
5-10%. A dry weather system will pass north of the region early in
the workweek, resulting in a slight uptick in winds across much
of the area Monday afternoon/evening and mostly over the high
terrain of the eastern districts Tuesday. These gusty winds
combined with receptive dry fuels and very low humidity could
result in elevated fire weather concerns.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning until 8 PM MST Monday for AZZ530>544-
     546>556-559>562.

CA...Extreme Heat Warning until 8 PM PDT Monday for CAZ562>567-569-
     570.

&&

$$

DISCUSSION...Whittock
AVIATION...Young/Smith
FIRE WEATHER...Whittock/Kuhlman