Strong Wind in Arizona, March 13, 2025

Area Forecast Discussion
National Weather Service Phoenix AZ
135 PM MST Thu Mar 13 2025

.SYNOPSIS...
A strong weather system will quickly exit the region tonight, but
not before bringing widespread strong winds and showers, along with
high terrain snow. A weaker weather disturbance will sweep through
the area Friday afternoon through Saturday morning resulting in
scattered light rain showers across the lower deserts and higher
elevation light snow. Through the weekend and early next week, drier
and warmer conditions will take hold across the region with
temperature rebounding close to the seasonal normal.

&&

.DISCUSSION...
An intense negative PV anomaly was moving inland over the SW Conus
early this afternoon with modeling showing both the midtropospheric
height and wind fields towards the 99th percentile of climatology
for this time of year. In fact wind speeds through the H8 layer are
about as strong as it gets for any time of year peaking around 40-
45kt within the trough base. Moderate IVT with a favorable southwest
trajectory was importing ample moisture along and ahead of a cold
front while robust ascent aided by a negative tilt of the shortwave
orientation and strongly divergent jet level winds was support
widespread showers across the forecast area. The progressive nature
to the primary vorticity center and cold front will limit residence
time of precipitation, however orographic lift in the eastern CWA
should maintain rain/snow somewhat longer into the overnight before
ending as the entire trough axis shifts into New Mexico Friday
morning and temporary subsidence overspreads SE California and
Arizona.

Higher elevations east of Phoenix this evening will still experience
the cold front and cooling aloft rapidly propagating into the area
causing snow levels to crash below 5000ft, eventually reaching 3500-
4000ft late evening/overnight. Dry air at the H7 level surging east
overnight may quickly contaminate better saturation of the dendrite
layer, however robust IVT along the front juxtaposed with the
lowering snow levels should result in a period of higher snowfall
rates along with expansive blowing snow likely given the anomalous
strong low level wind fields. It still appears total snow
accumulations may only flirt with advisory criteria, but impacts may
still be significant given the blowing snow aspect, and even a brief
period of sub-advisory snow could affect areas down to the 3500-
4000ft level before coming to an end prior to sunrise Friday.

The primary vorticity center will quickly eject east into New Mexico
overnight, then into the plains during the day Friday creating an
even more intense midlatitude cyclone. However, a broad longwave
trough carved out by the initial system will allow a trailing,
sheared shortwave to descend from the Pacific NW into the four
corners Friday evening into Saturday morning. While the notable IVT
experienced today will be long eliminated by Friday afternoon,
lingering modest deep layer moisture combined with anomalously cold
tropospheric temperatures will more easily attain saturation than
otherwise would be expected. With H7 readings around -7C and H5
around -25C, forecast total column PWATs above 0.50" are
comparatively quite impressive, and favorable vorticity forced
ascent coincident with the left front quadrant of an upper jet
should readily support numerous showers through south-central
Arizona. Trends in model output have depicted much better response
for widespread showers through the eastern half of the CWA,
particularly in orographically favored locations. With snow levels
look to hovering around 4000-4500ft, a prolonged period of saturated
ascent through the dendrite layer now appears even more likely
Friday night into Saturday morning resulting in efficient snow
production at higher elevations. If these trends continue, another
separate snow advisory may be necessary in future forecast updates.

The entire ensemble suite remains in excellent agreement that
ridging will temporarily build into the region early next week with
H5 heights peaking around 580dm. This will result in warming
temperatures with readings slightly above the daily normal Monday -
quite a turnaround from Friday representing better than 20F
difference in high temperatures over 72 hours. The progressive
western hemisphere flow pattern will persist throughout next week
with another trough propagating across the western Conus Tuesday.
GEFS membership remains steadfast in projecting a lower amplitude,
drier solution while EPS output suggests a more amplified outcome
allowing some showers to materialize north of the cyclonic jet core
over higher terrain areas. Regardless, temperature will certainly
cool back near and/or slightly below normal with gusty winds in the
typical locations of SE California. Otherwise, the preponderance of
ensemble evidence still indicates some manner of flat ridging
returning to the region during the latter half of next week with dry
conditions and temperatures gradually warming slightly above normal.

&&

.AVIATION...Updated at 1800Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The main aviation concerns for today will be the strong winds, rain,
and potential for an isolated thunderstorm during the afternoon.
South southwest winds have increased with gusts upwards of 20-25 kts
so far. These strong southerly winds are likely to cause an extended
period with crosswind issues, especially this afternoon before the
arrival of a front. These gusty winds will also likely loft dust and
may cause slantwise visibility reductions by early afternoon, and
potentially cause some brief VIS restrictions at area terminals,
especially at KIWA.

A strong cold front is then expected to push across the area mid to
late afternoon bringing even stronger winds out of the west
southwest. The front is expected to pass around 23-00Z, with a few
concentrated lines of SHRA and isolated TSRA, and gusts likely in
excess of 35 kts. Chances for MVFR visibilities from rain and MVFR
CIGs will be maximized between 23-01Z, and the front will quickly
pass east of the terminals by early evening. Once the front passes
winds are expected to remain elevated through just after midnight,
but CIGs improve significantly. Just beyond the current TAF period,
low-level CIGs (050-060) are expected to return, with the potential
for VCSH/-SHRA and MVFR CIGs starting late Friday afternoon.

Southeast California/Southwest Arizona including KIPL and KBLH:
VFR CIGS are expected to prevail during the bulk of the TAF period.
A strong cold front has passed over the terminals this morning and
is currently evident as a fine line in reflectivity over SW AZ, with
lingering -SHRA behind the front and passing over the terminals for
the next couple hours. The potential for occasional MVFR
visibilities remains while the showers continue. Post-frontal W/SW
winds are likely to increase further with gusts to around 40 kts
this afternoon. These strong winds may also lead to areas of blowing
dust and restricted visibilities, especially at KIPL. Elevated
westerly winds with gusts to around 25 kts are likely for the rest
of the evening into the early overnight hours.

&&

.FIRE WEATHER...
A strong weather system will move through the region today bringing
widespread strong winds along with chances for showers and
thunderstorms and high terrain snow. Windy conditions will develop
areawide later this morning as a cold front with a line of showers
and isolated thunderstorms sweeps eastward through the area.
Widespread 35-45 mph gusts are expected by this afternoon with some
areas, particularly across southeast California, potentially seeing
some gusts in excess of 50 mph. Any thunderstorms today will have
the potential to produce localized stronger wind gusts near severe
limits. Another weather system will lead to additional precipitation
chances Friday. Humidities will remain elevated through the period
with MinRHs generally above 35%. Drier and warmer conditions are
then expected to prevail later this weekend into the start of next
week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Wind Advisory until 10 PM MST this evening for AZZ530-556>558-
     560>563.

     Blowing Dust Advisory until 5 PM MST this afternoon for AZZ553-
     554.

     Winter Weather Advisory from 5 PM this afternoon to 5 AM MST
     Friday for AZZ557-558-563.

     Wind Advisory until 8 PM MST this evening for AZZ531>555-559.

CA...Wind Advisory until 10 PM PDT this evening for CAZ560-561-
     563>570.

     Wind Advisory until 11 AM PDT Friday for CAZ562.

&&

DISCUSSION...18
AVIATION...Whittock/Kuhlman
FIRE WEATHER...Smith/Kuhlman