High Wind in California, January 20, 2025

Area Forecast Discussion
National Weather Service Phoenix AZ
114 PM MST Mon Jan 20 2025

.SYNOPSIS...
Near or below normal temperatures will be common over the next few
days ahead of warming trend for latter portion of the week. Breezy
to windy conditions are expected to develop across much of the
region this afternoon and evening, persisting for some areas into
the early hours on Tuesday. Overnight lows the next few nights will
fall close to or below freezing for many lower desert locations.

&&

.DISCUSSION...
Current upper-atmospheric analysis reveals long-wave troughing
stretched out across most of the the CONUS with an amplified ridge
centered just off the Pacific Coast. Closer to home, negative height
anomalies will result in slightly cooler than normal temperatures
for the region this afternoon, with highs for lower desert areas
ranging in the lower to middle 60s. A shortwave, currently digging
across the Great Basin, embedded in the broader flow pattern will
help generate breezy to windy conditions across portions of our
forecast area this afternoon and evening. Wind Advisories have been
posted for the Lower Colorado River Valley up through Joshua Tree
NP, where gusts are anticipated to reach upwards of 40-50 mph. These
enhanced winds will create hazardous travel conditions along I-8 and
I-10 with strong crosswinds and areas of reduced visibilities due to
blowing dust being the main hazards. Strong winds will will not be
confined to just this area however, with strong gusts developing
across south-central Arizona this evening as well, but the strongest
gusts will be relegated to high terrain areas so no Wind
Advisories are in effect for this region.

The long-wave troughing feature will shift further east heading into
Tuesday allowing for positive height anomalies associated with the
eastern Pacific Ridge. However, with cool northwesterly flow
projected for the region, Tuesday looks to be the coolest day over
the next week with lower desert high only reaching the upper 50s to
lower 60s, a good 5-10 degrees below normal for this time of year.
The flow pattern will also allow for much drier air to enter the
region, with forecasted PWAT values falling to 10% of normal. This
setup will be conducive for cold overnight low temperatures the next
few nights. A Freeze Warning has been posted for much of La Paz
County and the Aguila Valley for tonight/Tuesday morning, where
temperatures could dip into the upper 20s. One factor that could
keep nighttime temps above the freezing threshold will be any
lingering overnight breeziness. Nonetheless, there is high enough
confidence that freezing to sub-freezing temperatures will be
achieved tonight within the areas mentioned above. The coldest
night out of the next several will be Tuesday night into Wednesday
morning when conditions will be more favorable for widespread
freezing temperatures across the lower deserts as winds will not
be as strong. As a result, Freeze Watches are in effect for
portions of south-central, southwestern Arizona, and the Imperial
Valley.

Models are in excellent agreement regarding the further building of
heights aloft over the Desert Southwest during the middle and latter
portions of the week. This will allow for a rebound in temperatures
across the region, with afternoon highs reaching slightly above
normal for some areas by Thursday. Near to above normal
temperatures will continue through the beginning of the weekend
with lower desert readings in the upper 60s to lower 70s. However,
this period of warmer temperatures will be relatively short lived
as models indicate another troughing feature riding atop the
eastern Pacific ridge and diving across the Great Basin by next
weekend providing another push of cooler air into the region.

&&

.PREVIOUS DISCUSSION...
Ensembles are now in much better agreement in regards to the
evolution of this Arctic trough late this week. While previous
forecasts ranged from troughing dislodging the ridging along the
West Coast to even the ridge not weakening across western CONUS,
ensemble clusters now show a much more definitive trend towards the
troughing feature deepening across the Great Basin going into and
through this upcoming weekend. The discrepancies at this point is
how anomalous and deep this feature will become as it migrates
southward, although all clusters show some form of troughing across
the Desert Southwest over the weekend. Whatever version of troughing
comes to fruition will impact the potential and timing of
potentially unsettled weather. Regardless of these differences,
there has been a definitive shift that would be more favorable for
precipitation chances across some portion of the region over the
weekend. Thus, 20-40% PoP's does not seem like an overly
unreasonable outlook at this point starting as early as Saturday,
although admittedly the coverage of these PoP's remains broad
brushed due to the current spread amongst the ensembles for this
weekend.

&&

.AVIATION...Updated at 1750Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The primary aviation concerns this forecast period will be the
arrival of gusty NE winds by late this afternoon and into the
evening, as well as LLWS conditions developing late tonight.

Within the next couple of hrs, winds are expected to shift out of
the NW across the metro terminals, then continue to veer around to
the NE by the early this evening. During this transition, there
will be a northerly cross-runway wind component at KPHX and KDVT,
although speeds should remain below 10 kts. Winds will increase
out of the NE after sunset with gusts around 25-30 kts becoming
common at all terminals. There may be a brief period of even
higher gusts up to 35 kts at KDVT and KSDL which has now been
introduced into the latest TAF. Winds should begin to diminish
late tonight, mainly after midnight at which time LLWS conditions
are expected to develop as winds just above the sfc remain stout
(40-50 kts at 2000 ft). The most likely timeframe for LLWS will
be from 08Z-12Z. Skies should remain clear through the period.

Southeast California/Southwest Arizona including KIPL and KBLH:
The primary aviation concerns over the next 24 hours will be gusty
northerly winds developing by late this morning and strengthening
during the afternoon as a cold front progresses through the region.

Winds are expected to ramp up, especially after 20Z, becoming
gusty at KIPL and KBLH. Gusts between 35-40 kt at KBLH and
between 25-30 kt at KIPL will be common through this evening.
These strong winds will be capable of producing localized blowing
dust which could temporarily reduce surface visibilities to MVFR
levels and cause more prolonged slantwise visibility concerns
from lofted dust/haze. Winds will subside quickly after sunset at
KIPL, however will remain elevated and gusty at KBLH through late
tonight. Skies will remain clear through the period.

&&

.FIRE WEATHER...
Temperatures should hover close to the seasonal normal through the
middle of this week with expansive dry air in place resulting in no
chance of wetting rainfall. Minimum afternoon humidity levels
will generally be in the 5-15% range this week as drier air
persists. Overnight recoveries will remain poor of only 15-30%
through this week. While some gusty north winds resulting in a
period of elevated fire danger will exist today and tonight for
the western districts and some higher terrain areas of the eastern
districts, light winds will become more common over the remainder
of the region for the rest of the week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Wind Advisory until 11 PM MST this evening for AZZ530-532.

     Freeze Watch from Tuesday evening through Wednesday morning for
     AZZ530-531-535>540-542>544-546-548-550>555-559.

     Freeze Warning from 10 PM this evening to 9 AM MST Tuesday for
     AZZ533-534.

CA...Wind Advisory until 10 PM PST this evening for CAZ560-564-565-
     568>570.

     Freeze Watch from Tuesday evening through Wednesday morning for
     CAZ567-569.

&&

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