519
FXUS65 KPSR 110522
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1022 PM MST Sun May 10 2026

.UPDATE...Updated 06Z Aviation Discussion.

&&

.KEY MESSAGES...

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

- Widespread moderate HeatRisk will impact the majority of the
  region through the first half of the week with isolated pockets
  of major HeatRisk lasting through Tuesday.

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

&&

.SHORT TERM /TODAY THROUGH TUESDAY/...
Latest mid-lvl wv imagery and 500 mb streamline analysis reveals a
shortwave trough passing through the 4-Corners region while a ridge
of high pressure strengthens over SE California and the Great
Basin. This ridge will become the predominant feature over our
region for the next few days as it slowly migrates ewd. Due to
increasing mid-lvl hghts/thickness, temperatures are expected to
top out well above normal this afternoon. As of 2:00 PM, Phoenix
Sky Harbor has already reached 106 degrees. High across the lower
deserts will generally range from 102-108 today which is a solid
12-15 degrees above normal. An Extreme Heat Warning is now in
effect or the Phoenix Metro area and far W Imperial County in SE
California, so heat precautions should be taken, especially if
spending any amount of time outdoors. The one silver lining is
overnight lows will still remain comfortable in the upper 60s to
low 70s thanks to very dry air in place which will lead to ample
radiational cooling.

On Monday, the center of the ridge will migrate directly over N AZ
which will lead to 500 mb hghts approaching 590 dam or the 99th
percentile of climatology for mid-May. This increase in hghts
aloft along with clear skies and very low RH will result in the
hottest temperatures of the year so far. Highs across the lower
deserts are expected to reach upwards of 103-109 degrees and even
a few locations in SW AZ and the Lower Colorado River valley
hitting the 110 degree mark. Monday`s readings should fall just
shy of daily records by about a degree or two, however there is
still a low (20-30%) chance of at least tying the record high of
110F at Sky Harbor. The Extreme Heat Warning will also expand on
Monday to encompass all of the major populations centers including
Phoenix, Yuma, Blythe, and El Centro.

Short-range Model guidance continues to indicate a weak shortwave
trough developing west of Baja and being pulled nwd around the
western periphery of the ridge on Tuesday. This disturbance will
nudge the ridge axis further ewd, however positive hght anomalies
will remain in place across the eastern half of Arizona. Highs on
Tuesday will be slightly cooler, but still reach 103 to 107 degrees
in Phoenix. Therefore, the Extreme Heat Warning will remain in place
for the greater Phoenix Metro through early Tuesday evening. Areas
farther west including Southeast California will be noticeably
cooler due to the proximity of the passing disturbance with highs
dropping to 102-105 degrees. Winds are also expected to increase
Tuesday afternoon across the Lower Colorado River valley where gusts
could reach up to 25-30 mph. The elevated winds coupled with low RHs
during the afternoon hours will promote elevated to near
critical fire weather conditions.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
The latter half of the coming week will involve a larger Pacific
system moving into northern California on Wednesday displacing the
ridge over our region well to the east by Thursday. Wednesday
should be a bit of a transition day as heights really start to
lower, but daytime highs may react more to the influx of upper
level moisture and clouds. Forecast highs are still shown to top
100 degrees, but on average should be between 100-103 degrees
across the lower deserts. As the flow turns from the south on
Wednesday to more out of the west on Thursday, any moisture and
clouds will get pushed to the east out of the region. The Pacific
system is then favored to move east northeastward through
northern Nevada into Wyoming on Thursday, but it will also help to
further depress heights over our region lasting through Friday.
Models are now trending slightly cooler late this week with highs
potentially dipping into the mid to upper 90s on Friday. The
outlook for next weekend favors temperatures warming back up to
100 or just over 100 degrees as a brief ridge moves through the
region, while dry conditions and generally clear skies prevail.

&&

.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 the first half of
this week with lower desert highs in a well above average category.
Relative humidity will bottom out in the single digits each afternoon
with only very minimal improvement across the eastern districts
late in the week. Overnight recoveries will remain poor to fair,
averaging 20-35%. Winds will remain light and diurnal today,
before elevated easterly winds with gusts to around 25 mph impact
the eastern districts Monday morning. Tuesday will bring more of a
predominant southerly wind, particularly across the western districts
where afternoon gusts of 25-30 mph will be possible. The combination
of the hot temperatures, very low RHs, dry fuels, and breezy
conditions focused during the late afternoon hours should result
in elevated to near critical fire weather conditions for portions
of the area.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning from 11 AM to 8 PM MST Monday 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 to 8 PM PDT Monday for CAZ567-
     569-570.

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

&&

$$

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