483
FXUS65 KPSR 131213
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
513 AM MST Fri Jun 13 2025

.UPDATE...Updated Aviation Discussion.

&&

.KEY MESSAGES...

- A ridge of high pressure will strengthen over the Desert
  Southwest this weekend, resulting in near record high
  temperatures and areas of Major HeatRisk on Sunday and Monday.

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

&&

.DISCUSSION...
The weather pattern over the next week and likely longer will
favor above normal temperatures and dry conditions across the
Desert Southwest. The main forecast concern during this time will
be the potential for high temperatures reaching or exceeding 110
degrees resulting in high-end Moderate and Major HeatRisk. The
weather pattern will favor a blocking pattern with a large cut-
off low sitting over the northeast Pacific and a sub-tropical
ridge dominating from the Southwestern U.S. into the Central and
Southern Plains.

The sub-tropical ridge is currently centered just to our south
southwest across central Baja, but by Saturday the center of the
ridge is forecast to move into southern New Mexico and west
Texas. The ridge will also strengthen this weekend as H5 heights
of 591-594dm expand into our region. Guidance seems to finally
have settled on how hot it should get for our area this weekend
into Monday with lower desert readings topping out near 110
degrees Saturday, between 110-114 degrees Sunday, and 109-113
degrees on Monday. For mid June, these temperatures fall short of
daily records, but only by 2-3 degrees on average. The near record
heat will also result in areas of Major HeatRisk, especially on
Sunday. As a reminder, an Extreme Heat Warning has been issued for
Saturday-Monday for the majority of southeast California and
southern/central Arizona.

Model guidance is still suggesting we will get a slight reprieve
from the extreme heat by Tuesday as a weak trough slides through
the region, 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. Once the weak trough slides to the northeast Tuesday
night, the ridge will begin to rebuild first to our south, and
then centered to our east starting Thursday. Ensemble mean
forecast H5 heights for the latter half of next week are shown to
mainly fall within a 590-593dm range across our region, only
slightly lower than what is expected for the weekend`s heat
episode. NBM forecast temperatures do climb upwards late next week
with some potential for another period of Major HeatRisk
developing. For now, lower desert highs mainly top out between
108-111 degrees late next week, but that is only a couple degrees
away from tipping into the Major HeatRisk category. The atmosphere
will continue to be dry through the entirety of this weekend and
next week with PWATs running between 50-70% of normal for this
time of year.

&&

.AVIATION...Updated at 1156Z.

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

A near persistence forecast for all terminals with winds
continuing to follow typical diurnal tendencies. There will be an
extended period of S/SSW from late-morning through early to mid
afternoon, with a more predominant W/SW not occurring until
23-00Z. Wind speeds will mostly remain at or below 10 kts
sustained with occasional late afternoon and evening gusts up to
15-20 kts. FEW to SCT high cirrus will pass over the airspace
through the TAF period.

Southeast California/Southwest Arizona including KIPL and KBLH:

Winds at KIPL will continue to favor a SE component through the
TAF period, while KBLH favors a S component. Wind speeds will
remain light at KIPL through most of the period, but with a period
of 9-12 kt breezes and gusts into the middle teens this evening.
KBLH will see 10-15 kt winds and gusts up to 20-25 kts this
afternoon and evening, with lighter speeds during the morning
hours. FEW-SCT high cirrus will pass 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% region-wide. By early next week,
the arrival of a dry weather system may result in an uptick in
winds across much of the area on 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...Kuhlman
AVIATION...Benedict
FIRE WEATHER...Salerno/Kuhlman