721
FXUS65 KPSR 311933
AFDPSR
Area Forecast Discussion
National Weather Service Phoenix AZ
1233 PM MST Sun May 31 2026
.KEY MESSAGES...
- Near normal temperatures today warm to slightly above normal
tomorrow and will be near to slightly above normal through this
upcoming week.
- Dry conditions with mostly sunny skies and light seasonal winds
with occasional afternoon breeziness are expected through this
upcoming week.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Upper-level water vapor satellite imagery and 500mb RAP analysis
show an omega block starting to develop with a strong closed low in
the Gulf of Alaska, another strong closed low over New England, and
a ridge starting to develop across central CONUS. With the omega
block starting to develop upper level heights across the Desert
Southwest have started to rise with flow aloft becoming more
southwesterly vs quasi-zonal. H5 heights across AZ and southern CA
range from 580-584 dm, which is around 4 dm more than H5 heights
yesterday. This increase in heights aloft will result in
temperatures continuing to warm. Afternoon high temperatures will be
near normal today with highs in the upper 90s to around 100 degrees
across the lower deserts and in the 90s across the higher terrain
areas.
The omega block pattern will continue to amplify and looks to
maximize during the middle of the week, when the hottest
temperatures of the week are expected. As a result of the amplifying
pattern H5 heights look to climb to 585-588 dm over our region and
thus temperatures will climb to slightly above normal on Monday and
then warm another degree or two for Tuesday and Wednesday. Afternoon
high temperatures will be in the 100-105 degree range across the
lower deserts and in the mid to upper 90s to around 100 degrees
across the higher terrain areas during the first half of the
workweek. Morning low temperatures will also be on the rise this
week with morning lows ranging from the mid 60s to mid 70s across
the lower deserts and the upper 50s to mid 60s across the higher
terrain areas. The combination of these morning lows and afternoon
highs will result in localized areas of Moderate HeatRisk developing
as early as Monday, mainly across the Lower CO River Valley. As
temperatures warm, remember to practice smart heat safety by
drinking plenty of water and electrolytes and limiting your time
outdoors (especially during the afternoons).
Aside from the warming temperatures, with high pressure building
over our region, dry conditions with mostly clear skies will
continue through at least the middle of the week. With no weather
systems moving through the region, wind speeds will follow typical
diurnal trends along with seasonal light wind speeds and occasional
modest afternoon breeziness.
&&
.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 1715Z.
South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns under generally clear skies can be
expected throughout the TAF period. The overall wind pattern will
follow the typical diurnal tendencies with speeds generally aob 10
kts along with extended periods of light variability to even calm
conditions.
&&
.FIRE WEATHER...
Light winds will mainly follow their diurnal upslope/upvalley and
nocturnal drainage patterns through most of this upcoming week. Some
occasional modest afternoon breeziness is expected as well.
Temperatures will be near normal today before rising to slightly
above normal for the majority of the upcoming workweek. MinRHs
will be around 5-15% through the upcoming week with poor overnight
recoveries (15-35%). The driest days (lowest humidities) are
expected mid week.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
SHORT TERM...Berislavich
LONG TERM...Ryan
AVIATION...Lojero
FIRE WEATHER...Berislavich
NWS Phoenix Office
Tucson, AZ 
