244
FXUS65 KPSR 140531
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1031 PM MST Fri Jun 13 2025

.UPDATE...Updated 06z 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 from Saturday morning
  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 decreasing
  temperatures by several degrees on Tuesday.

&&

.DISCUSSION...
Mid level objective analysis places the center of a subtropical
anticyclone approximately over central Baja California, shifting
into western Sonora this afternoon. Forecast confidence is
excellent that this feature will amplify and eventually settle
over Southern NM Saturday, with ensemble mean 500 mb heights
rising to around 591- 594 dam over the area and persisting through
Monday. In response, thermal profiles over the Desert Southwest
will warm; NAEFS and EPS mean 850 mb temperatures increase above
the 90th percentile of climatology Sunday-Monday. The trend in
ensemble mean 850 mb temperatures correlates quite well with NBM
highs as they heat up this weekend, reaching around 5F above daily
norms Saturday and around 6-10F above normal Sunday-Monday
(peaking between 110-114F across the lower deserts). Temperatures
this hot will result in areas of Major HeatRisk developing late
this weekend and lingering into early next week, and so an Extreme
Heat Warning will be in effect from 10 AM MST/PDT Saturday
through 8 PM Monday. Be sure to take all the pertinent heat safety
measures including staying hydrated and reducing time spent
outdoors during the heat of the day as much as possible.

Model guidance is still suggesting we will get a slight reprieve
from the extreme heat by Tuesday as a weak trough passes north of
AZ, but the latest trends (especially within the EPS) show a more
muted effect on our temperatures with highs only dipping to
between 105-109 degrees Tuesday. This will end the extreme heat
episode, but temperatures will still be at or even a few degrees
above normal. The other impact of this weak trough passing us to
the north will be increased afternoon breezes to between 20-25 mph
areawide by Monday and potentially up to around 30 mph over the
South-Central AZ high terrain on Tuesday. Though heights aloft are
not expected to rebound during the later half of next week to the
same levels that are forecast Sunday-Monday, H5 heights will
likely (>70% chance) exceed 590 dam and hover between 590-593 dam
Wednesday through at least Friday. As a result, NBM highs become
rather stable around 5F above normal, i.e., near 110F across the
lower deserts with fairly widespread Moderate HeatRisk. Continue
to heed all appropriate heat precautions even after the current
Extreme Heat Warning expires, as Moderate HeatRisk still indicates
a risk to the general population, especially visitors that are
not acclimated to the level of heat or people without adequate
hydration/cooling. The forecast area will remain seasonably dry
for mid June through at least the next 7 days.

&&

.AVIATION...Updated at 0530Z.

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

No aviation concerns are anticipated through the forecast period.
Winds will follow typical diurnal tendencies, with speeds
remaining mostly at or below 10 kts sustained with occasional
late afternoon and evening gusts up to 15-20 kts. Periods of
variability between transition periods will be common. FEW to SCT
high cirrus will overspread the region through tomorrow evening.

Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation concerns are expected through the TAF period. Winds
at KIPL will favor a southeasterly component, while KBLH will see
a predominant southerly 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 overnight
tonight. FEW-SCT high cirrus will progress over the area.

&&

.FIRE WEATHER...
Hot and dry conditions will prevail over the next several days
with lower desert high temperatures climbing to around or just
over 110 degrees starting Saturday. Winds will follow typical
diurnal (upslope and downvalley) tendencies with periods of modest
afternoon upslope breeziness (gusts upwards of 20 mph at times).
Minimum afternoon humidity will bottom out between 8-12% today
and 5-10% on Saturday and Sunday with poor to fair overnight
recovery mainly between 20-35% areawide. A dry weather system will
pass north of the region early next week, resulting in a slight
uptick in winds across much of the area by Monday. These gusty
winds combined with dry fuels and very low humidity could result
in elevated fire weather concerns.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning from 10 AM Saturday to 8 PM MST Monday for
     AZZ530>544-546>556-559>562.

CA...Extreme Heat Warning from 10 AM Saturday to 8 PM PDT Monday for
     CAZ562>567-569-570.

&&

$$

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