Westmorland, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

719
FXUS65 KPSR 181720
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1020 AM MST Fri Apr 18 2025

.UPDATE...Updated 18Z Aviation Discussion.

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.SYNOPSIS...
A weather disturbance will slowly track through the region today
into early Saturday bringing continued mild temperatures, periods
of breezy to locally windy conditions, and scattered showers this
evening and tonight across south-central and eastern Arizona.
Weak high pressure will eventually build back over the region
Sunday into early next week resulting in temperatures warming to
slightly above normal levels and a return to dry conditions.

&&

.DISCUSSION...
The main forecast concern over the next week will be the chances
for showers and isolated thunderstorms later today which could
bring localized gusty winds. An upper level trough has moved over
the Southwestern U.S. since yesterday with the weakening low that
was off the southern California coast now barely discernible
moving across southern Arizona. A stronger shortwave continues to
track slowly southward across the Great Basin with a trough axis
extending through western Arizona. Noticeably cooler air has
already moved into our region, but even more cooling is expected
today as negatively height anomalies continues to sag southward
into our region.

As the main shortwave enters northern Arizona this afternoon, a
cold front will also move southeastward reaching central Arizona
late this afternoon. Forcing associated with the advancing front
and the shortwave is expected to bring scattered showers and maybe
even a few isolated thunderstorms into south-central Arizona as
early as late afternoon, but more likely during the evening hours
today. The 00Z model guidance seems to be a little stronger and a
bit farther southwest with the shortwave with the center now
closer to central Arizona. As result, we are a little more
optimistic with rain chances later today (centered on this
evening) and PoPs are now in a 35-55% range for the Phoenix area
to upwards of 50-70% over the higher terrain. However, rainfall
amounts are still expected to be light ranging from a few
hundredths of an inch on average for Phoenix to 0.1-0.2" over
higher terrain areas. Dry air in the lower levels is expected to
bring a gusty wind threat with any shower and thunderstorm
activity with the 00Z HREF showing a 10-30% probability of 35+ mph
winds across Phoenix to a 30-40% probability over the northern
foothills of Phoenix. The bulk of the shower and isolated
thunderstorm activity should shift to the east of the Phoenix area
by around midnight with chances lingering through around sunrise
for the higher terrain east of Phoenix.

Increasing subsidence aloft and drier air is then expected to
spread across the region from the west on Saturday as the weather
system shifts out of Arizona. By Sunday, the weather pattern will
become very quiet with any weather systems mainly only impacting
the northern tier states for several days. For our region, this
should result in quasi-zonal westerly dry flow dominating over the
Desert Southwest through at least the middle of next week.
Temperatures are forecast to warm back into the normal range by
Sunday and maybe a couple degrees warmer for Monday through
Wednesday with highs in the upper 80s to the lower 90s. Ensembles
do try to introduce some broad troughing by late next week either
extending along and just off the West Coast or even into our
region. This uncertainty does start to introduce a good deal of
temperature spread by late next week into the following weekend
with temperatures anywhere from slightly below normal to slightly
above normal.

&&

.AVIATION...Updated at 1720Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Breezy to occasionally windy conditions along with periods of
rainfall will be the main aviation concerns during the TAF period.
W`rly winds will prevail through the afternoon and evening, with
occasional gusts to around 20 kts. By the early evening, a broken
line of showers is projected to move through the metro, which
could lead to brief periods of reduced visibilities and gusts
potentially reaching (50% chance) upwards of 30 kts. These showers
should quickly move out by early tonight while wind speeds relax
and switch to the E during much of the overnight. Even with shower
activity, VFR conditions are expected to prevail, with CIGs
remaining AOA 6k ft. However, brief moments of MVFR VIS cannot be
completely ruled out with heavier showers.

Southeast California/Southwest Arizona including KIPL and KBLH:
Breezy to occasionally windy conditions, especially at IPL will be
the main aviation concern over the next 24 hours. Winds are
expected to contain a W`rly component through most of the period,
with gusts at IPL reaching 25-30 kts this afternoon before speeds
relax tonight. At BLH, gusts closer to 20 kts will be common
during the afternoon. Other than a relatively brief window of
lower-clouds (bases 7-9k ft) moving through this afternoon and
evening, skies will be generally clear otherwise.

&&

.FIRE WEATHER...
A weather system will move through the region today into early
Saturday bringing more breezy to locally windy conditions and
chances for rain. Expect scattered showers and a few isolated
thunderstorms mainly this evening across south-central Arizona
with activity lingering through the overnight hours across the
eastern Arizona higher terrain. Increased moisture and below
normal temperatures will keep RHs elevated today with MinRHs
between 25-35% before falling back to around 10% by Sunday.
Lighter winds are anticipated starting Saturday while
temperatures gradually rise back to around normal on Sunday.
Tranquil weather conditions are expected for next week with
temperatures at or slightly above normal, seasonably dry
conditions, and relatively light winds.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 8 PM PDT this evening for CAZ562.

&&

$$


DISCUSSION...Kuhlman
AVIATION...RW
FIRE WEATHER...Kuhlman