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460
FXUS65 KPSR 262200
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
300 PM MST Sun May 26 2024

.SYNOPSIS...
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Generally quiet weather conditions will continue over the next
week, with temperatures warming to above normal as early as
tomorrow and continuing into the weekend. Typical afternoon
breeziness will become somewhat stronger going through the middle
of the week, but nothing out of the ordinary.
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&&

.DISCUSSION...
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Persistent troughing has finally exited the region, as latest
satellite shows the trough axis over eastern New Mexico this
afternoon. Clear skies will continue through most of this week as
ridging builds over the region. Temperatures will warm as a
result, with highs reaching above normal levels (upper 90s for
this time of year) as early as tomorrow. Thus, expect afternoon
temperatures in exceed 100 degrees, with chances for 105+ the
greatest for Tuesday. Typical afternoon breezes will continue
throughout the week, with some enhancements with the next weak
trough that moves across western CONUS mid-week.

Mid-level heights will build to around 585-588 dam across Arizona,
peaking on Tuesday, as the main ridge axis sets up east of the
region across the Rockies. The ridging will weaken going through
the middle and latter portions of the week as the next troughing
feature traverses across western CONUS, with the strongest
negative height anomalies remaining well off to the north across
the Pacific Northwest. As a result, generally zonal flow across
the Desert Southwest will enhance the afternoon breeziness
starting Tuesday, and continue through the rest of the week as
zonal flow persists. Temperatures will cool slightly, but either
neutral or slightly positive height anomalies persisting across
the region will only result in cooling of a few degrees (highs
will remain a few degrees above normal). Chances of 105+ degrees
are currently greatest on Tuesday across the lower deserts
(30-70%), with 20-40% chances Wednesday-Saturday according to the
latest NBM guidance. Thus, areas of Moderate HeatRisk (20-40%
coverage) continue to be advertised for Tuesday across the lower
deserts, with smaller areal coverage (10-20%) of Moderate
HeatRisk, confined to southeastern California, through the rest of
this week.

The latest ensemble guidance is in excellent agreement through at
least Wednesday, so the sensible weather impacts of Minor-Moderate
HeatRisk and increasing breeziness across the region, are expected
to come to fruition. For the winds, afternoon gusts are certain
to range between 20-30 mph for most areas, with some localized
higher gusts (probabilities of 35 mph or greater are highest in
the southwest corner of Imperial County at around 40-60%) peaking
on Wednesday. Some more noticeable spread begins on Friday, where
either the troughing feature lingers over western CONUS, or
retreats northward going into this weekend as ridging builds back
into the region. The trend seems to be some rebound in mid-level
heights, which would suggest temperatures warming again going into
next week. Currently, these slight differences are only resulting
in NBM interquartile spreads of 3-5 degrees for the high
temperatures going through this weekend, where highs for central
Phoenix would remain in the mid-100s should the middle of the road
(i.e. 50th percentile) solution occur.
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&&

.AVIATION...Updated at 1700Z.

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

No aviation concerns are expected during the TAF period. Winds
will follow light and diurnal tendencies, with occasional
afternoon and evening gusts in the mid-teens to near 20 mph. Other
than a few passing high clouds moving over the region late in the
forecast, skies will be mostly clear.

&&

.FIRE WEATHER...
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Hot and dry weather will persist through this week with temperatures
topping out around 5 degrees above average. Daily highs will reach
the century mark in most lower desert locations starting on Monday
and readings will generally top out between 100-105 through the
remainder of the week. MinRH values will range between 10-15% today
before falling to 10% or less across the central and western deserts
from Monday onwards. Overnight recoveries will continue to range
from poor to fair at around 25-40%. Winds are expected to remain
lighter through tomorrow, but a bump in breeziness could result in
pockets of elevated fire weather concerns going through the
middle of the week (peaking on Wednesday) ahead of tamer afternoon
breeziness heading into this weekend.
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&&

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

$$

DISCUSSION...Young
AVIATION...RW
FIRE WEATHER...Young/Salerno