693
FXUS65 KPSR 110951
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
251 AM MST Mon May 11 2026

.KEY MESSAGES...

- An Extreme Heat Warning is in effect for portions of the western
  deserts today and for the Phoenix Metro area through Tuesday.

- Today will be the hottest day of the week with lower desert
  highs reaching 105-112 degrees, followed by a gradual cooling
  through the remainder of the workweek.

- Dry conditions will prevail all week under generally clear skies
  most days. Wednesday will be the only day with partly to mostly
  cloudy skies.

&&

.SHORT TERM /TODAY THROUGH TUESDAY/...
A strong upper level ridge is currently moving eastward through
the region with H5 heights expected to peak later today between
588-590dm, or near the 99th percentile of climatology for the
period. The higher heights will help to push temperatures even
hotter today with lower desert highs of 106-110 degrees, or
around 15 degrees above normal. The forecast high in Phoenix has
nudged up to 109 degrees today which is only one degree shy of the
daily record.

A weak upper level disturbance has also formed just west of
southern Baja, but there is currently no moisture connection or
clouds (other than marine stratus). However, as the disturbance
expands and the flow turns southeasterly across inland Mexico, it
should result in some convection today across Chihuahua and
eventually some mid to upper level clouds working their way into
southern Arizona tonight. Before this higher level moisture
advection occurs, a shallow low level east southeasterly jet will
affect eastern and southern Arizona this morning, bumping surface
dew points upward by around 20 degrees by mid to late morning.
Gusty easterly winds will also affect southeast Arizona into
south-central Arizona this morning with gusts over the higher
terrain upwards of 25-30 mph in some spots to 15-20 mph into
Phoenix. By mid to late afternoon, much of this boundary layer
moisture will get dispersed as much drier air mixes down. However,
some of the boundary layer moisture will remain and with the
southerly mid-level flow returning on Tuesday, some afternoon Cu
and potentially some isolated shower activity may develop across
southeast Arizona to as far north as eastern Pinal and southern
Gila Counties. Even if some showers do manage to develop, we are
not anticipating any measurable rainfall in our area.

The Baja disturbance is forecast to move northward later today
through Tuesday reaching southern California Tuesday afternoon.
Some mid and upper level clouds will be possible as this happens
along with height falls across southern California and western
Arizona. The height falls and increased gradient will help to
drive a decent push of southerly winds for Tuesday afternoon
across far southwest Arizona and southeast California. Wind gusts
may briefly reach 30 mph for some of these locations late Tuesday
afternoon. Temperatures Tuesday will react to the falling heights
mainly across southeast California and southwest Arizona where
highs will fall back to between 102-106 degrees. The Phoenix area
will only dip a couple of degrees from today`s highs with readings
topping out 104-107 degrees.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Wednesday will be a pattern transition day for the Desert
Southwest as upper level troughing from a much larger Pacific
trough nudges southeastward into the region while a sub-tropical
upper level jet comes on shore across northern Mexico into
Arizona. The jet will drive increased higher level clouds across
at least the eastern half of Arizona for much of Wednesday, while
the lowering heights will allow for cooling conditions. Forecast
highs Wednesday range from the upper 90s to around 100 degrees
across the western deserts to around 100 degrees in the Phoenix
area.

The main Pacific shortwave is set to miss our region well to the
north on Thursday, but the broader upper level troughing is still
favored to move through Thursday into Friday. This will drive
heights even lower while dropping highs more into a 95-99 degree
range for both Thursday and Friday. The pattern for the upcoming
weekend is likely to support a weak ridge moving through giving a
slight boost in temperatures as readings may top 100 degrees again
for some of the lower deserts. The westerly dry flow late this
week and through next weekend should provide for clear to mostly
clear skies.

&&

.AVIATION...Updated at 0520Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation concerns are expected throughout the TAF period. Winds
will tend to follow typical diurnal tendencies, with a later than
usual westerly shift late tomorrow afternoon (23-00Z). Some
occasional gusts into the teens are possible late tomorrow
morning, otherwise wind speeds will be aob 10 kt. Skies will
remain mostly clear for the TAF period.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation concerns are expected through the TAF period. At KIPL,
current W`rly winds will go light and variable in the morning
before developing a SE`rly component tomorrow afternoon. Winds
will then go SW`rly late tomorrow night. At KBLH, winds will
generally fluctuate between S`rly and SW`rly besides a period of
light NW`rly early in the morning becoming light and variable
into the early afternoon. Overall wind speeds, at both terminals,
will be aob 10 kts. Skies will remain clear throughout the period.

&&

.FIRE WEATHER...
Hot and dry conditions will prevail through Tuesday with lower
desert highs topping out 10 to 15 degrees above normal. Minimum
humidity levels will bottom out in the single digits each
afternoon with overnight recoveries remaining poor to fair,
averaging 20-35%. After a brief period of elevated easterly winds
across the eastern districts this morning, winds will become light
in the afternoon. Tuesday will bring more of a predominant
southerly wind, particularly across the western districts where
afternoon gusts of 25-30 mph will be possible. These stronger
winds coupled with very dry conditions will result in elevated to
near critical fire weather. The weather pattern will then shift
for the latter half of the week bringing temperatures down, but
still remaining above normal while dry conditions continue to
prevail.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning from 11 AM this morning to 8 PM MST this
     evening for AZZ530-532.

     Extreme Heat Warning until 8 PM MST Tuesday for AZZ537-540-
     542>544-546-548-550-551.

CA...Extreme Heat Warning from 11 AM this morning to 8 PM PDT this
     evening for CAZ567-569-570.

     Extreme Heat Warning until 8 PM PDT this evening for CAZ562-563-
     566.

&&

$$

SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...Berislavich
FIRE WEATHER...Kuhlman