563
FXUS65 KPSR 311100
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
400 AM MST Sun May 31 2026

.UPDATE...
Updated Aviation

&&

.KEY MESSAGES...

- Temperatures today will be near normal before warming to slightly
above normal later this week.

- Lighter, more seasonable wind speeds with only modest afternoon
breezes will be common and likely persist through much of the week.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Upper-level imagery and 500mb RAP analysis show quasi-linear flow
over AZ and southern CA, with a swath of dry air over the region.
The low that has been progressing northeastward to the north of our
region over the past few days is now well into central WY. This has
helped alleviate the breezy to windy conditions, returning the
region to a more typical pattern of light winds with an occasional
breezy afternoon for the upcoming week.

Quasi-linear flow will persist throughout today leading to near
normal temperatures across the lower deserts ~100F. By Monday an
omega block pattern will begin to develop as high pressure builds
centered over the central Plains, and a deep low pressure system
develops in the Gulf of Alaska area. By Monday, as this high
pressure builds, H5 heights over the lower deserts will climb into
the 585-588 dam range, resulting in afternoon highs slightly above
normal or between 101F-105F degrees. This pattern will remain in
place through at least mid week, and due to this, temperatures day
to day will only vary by 1F-2F degrees. With temperatures returning
to the above normal category, isolated areas of moderate HeatRisk
will develop across portions of the lower deserts (most notably
across the Lower CO River region). Remember to practice smart heat
safety by drinking plenty of water and electrolytes and limiting
your time outdoors (especially during the afternoons). Otherwise,
the ample dry air aloft along with calmer winds will keep skies
mostly clear and aid in radiational cooling at night. Expect morning
low temperatures to be in the mid to upper 70s through much of the
upcoming week.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
Model ensembles are in good agreement that the upper level ridge
over the Central Plains will begin shifting eastward as early as
Wednesday, then afterwards a cut off low will develop Thursday in
Northern Mexico and is what will help temperatures trend back
towards normal late next week. Afternoon highs Thursday will not
feel the full effect of this developing low as H5 heights will
remain between 582-585 dam. While these heights will be slightly
lower than earlier in the week, temperatures will remain generally
between 101F-104F degrees. Starting Friday temperatures will begin
returning to near normal, ~100F, as heights continue to lower
slightly in response to the developing low to the south of the
region. These near normal temperatures are likely to persist through
next weekend.

&&

.AVIATION...Updated at 1100Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:

No significant weather issues will exist through Monday morning
under clear skies. Wind speeds and timing of directional shifts will
be nearly identical to the past 24 hours. Extended periods of nearly
calm conditions may be common.

&&

.FIRE WEATHER...
Light winds will mainly follow their diurnal upslope/upvalley and
nocturnal drainage patterns through most of this upcoming week. Some
occasional breeziness is expected as well. Near normal temperatures
today with temperatures rising to slightly above normal by Monday
and will stay slightly above normal through at least the upcoming
workweek. MinRHs will be around 5-10% today and are expected to
remain in that range through the workweek. Overnight recoveries will
will be around 20-35% throughout the workweek, with the driest day
expected mid week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.

&&

$$

SHORT TERM...Ryan/Berislavich
LONG TERM...Ryan
AVIATION...18
FIRE WEATHER...Ryan/Berislavich

NWS Phoenix (PSR) Office