A strong late season winter storm moved across the Desert Southwest during the afternoon and evening on the 1st, lasting through the early morning hours on the 2nd. Strong winds were observed out ahead of an associated cold front with gusts in excess of 40 mph observed.
Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS PSR wrote it up.
A strong late season winter storm moved across the Desert Southwest during the afternoon and evening on the 1st, lasting through the early morning hours on the 2nd. Strong winds were observed out ahead of an associated cold front with gusts in excess of 40 mph observed. Moderate to locally heavy rains associated with the cold front were also observed with most areas in and around the Phoenix metro observing between 0.5 to 1. This rainfall was enough to result in some elevated flows across northern Maricopa County near the Carefree and Cave Creek areas. Behind the cold front, a very cold air mass was pulled down into the region changing the rain to snow across areas mainly above 2000 feet during the overnight hours of the 1st into the 2nd, resulting in measurable snowfall accumulations.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Phoenix, AZ wrote its last area forecast discussion before the first event at Mar 1, 5:07 PM MST, 23 minutes earlier.
Area Forecast Discussion
National Weather Service Phoenix AZ
507 PM MST Wed Mar 1 2023
.UPDATE...Updated 00z Aviation Discussion.
&&
.SYNOPSIS...
A potent weather system will affect the region through
early Thursday, delivering strong winds, possible blowing dust,
lower desert showers and embedded isolated thunderstorms, and
higher terrain snow. More tranquil weather will then return and
prevail through at least early next week. A gradual warming trend
is expected by the upcoming weekend, which will push temperatures
back to near normal by the latter half of the weekend through
early next week.
&&
.DISCUSSION...
An active weather day today continues across the region as a potent
winter storm continues to progress through the southwestern CONUS.
The latest water vapor imagery and objective analysis shows the low
center of this strong system situated over southern California this
afternoon. Meanwhile, the associated cold front is now seen pushing
through southeastern California where very strong winds are being
observed. Observations across southeast California early this
afternoon showed winds gusting upwards of 40-50 mph, particularly
across parts of Imperial County as well as the Blythe area. Strong
winds gusting upwards of 55 mph (few gusts in excess of 60 mph
possible in western Imperial County) will continue across
southeast California through the afternoon as the cold front
pushes through before weakening this evening in the wake of the
frontal passage. A High Wind Warning remains in effect for the
western half of Imperial County, including El Centro, while Wind
Advisories are in effect elsewhere across southeast California.
Further east getting into south-central Arizona, winds gusting
upwards of 20-30 mph have developed this afternoon despite the thick
cloud cover over the region. Winds across the central and southwest
lower deserts will ramp up through the afternoon and early evening
with the frontal passage, with peak gusts generally upwards of 40-50
mph. Across the Phoenix area, winds will peak early this evening
during rush hour. Given the strong winds expected, blowing dust
will be possible across the lower deserts, especially in dust
prone areas, which can quickly reduce visibilities and make for
dangerous driving conditions. Wind Advisories are in effect for
our entire Arizona forecast area through the evening.
Radar this afternoon showed increasing coverage of light to moderate
showers particularly across the western CWA ahead of the front
with a few lightning strikes noted north of Blythe. Additional
showers will develop as the cold front progresses eastward through
our area through the rest of the afternoon and into the evening.
Sufficient moisture will be in place with IVT values upwards of
300-400 kg/m/s along the cold front, which according to the NAEFS
Climatology is above the 99th percentile. Thus, as indicated by
the majority of the Hi-Res model guidance, an organized line of
moderate to heavy showers will likely sweep through the area from
northwest to southeast along the cold front across Arizona this
afternoon through this evening. NBM PoPs indicate rain chances
around 90-100% across south-central early this evening. The latest
HREF and forecast soundings indicate at least some instability
will be in place as the front passes through the area, with MUCAPE
values around 100 J/kg. Thus, there will at least be a low chance
(<15%) of a few embedded thunderstorms and perhaps some small
hail. The latest WPC QPF show rainfall totals up to 0.30-0.50"
across much of the south-central Arizona lower deserts. Further
west, along and to the west of Lower Colorado River Valley,
rainfall totals are forecast to be under 0.10" as rain-shadowing
effects will tend to limit the overall rainfall coverage and
intensity. Across the higher terrain, liquid equivalent totals due
to orographic lift will be higher in excess of 0.75". Most of the
precipitation, however, will fall in the form of snow as snow
levels will rapidly plummet behind the cold front this evening. A
Winter Weather Advisory is in effect for areas above 3000 feet,
where between 1-4" of snow are expected and a Winter Storm Warning
is in effect for areas above 4000 feet, where between 2-11" of
snow are expected. As the cold core of the low passes overhead
early Thursday morning, snow levels are likely to plummet to as
low as 1500 feet and there could be enough moisture in place for a
few snow flakes around or just outside of the Phoenix Metro area.
As the low pressure departs towards the east and moves into New
Mexico going through the morning Thursday, the precipitation will
come to an end across south-central Arizona with clearing skies.
High temperatures, however, are expected to be very chilly with
highs only expected to top out only in the middle to upper 50s
across the lower deserts of south-central Arizona. This will be a
good 15 degrees below normal for this time of the year. Low
temperatures in a few lower desert locales may flirt with the
freezing mark over the next couple of mornings, primarily in the
colder locations, such as the Casa Grande area. Slightly warmer
temperatures in the lower to middle 60s are expected across the
western deserts. Across portions of southwest Arizona into
southeast California, there will be enough of a pressure gradient
on the back side of the system to result in some gusty northerly
winds between 20-30 mph through the morning hours before weakening
going through the afternoon.
Beginning on Friday and continuing into the weekend through early
next week, the overall synoptic pattern will be characterized by
overall troughing in the Pacific northwest with ridging over the
Gulf Coast states. This overall pattern configuration will put most
of the Desert Southwest under southwesterly flow aloft. Ensembles
are in general agreement that the troughing over the Pacific
Northwest will be far enough away to not have an influence on the
overall weather conditions locally. Thus, an overall warming trend
is expected through the weekend with below normal readings giving
way to near normal readings into the lower 70s beginning on Sunday
and continuing through at least the first half of next week.
&&
.AVIATION...Updated at 0010Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Showers currently over the western portions of the metro will
become more scattered for the next hour or so. The main line of
showers is expected to move across all terminals between 01-03z
this evening. This period will be marked with prevailing MVFR
conditions with VIS (3-5 SM) and CIG (015-030 kft) along with
gusty SW winds 35-40 kts. There is a 10% chance for embedded
lightning/thunder and small hail with the frontal band of rain.
Lifting CIGs, improving VIS, and dissipating SW flow will quickly
occur after 03z, but CIGs will remain in the 030-050 kft range for
all terminals. Another round of VCSH and lower CIGs expected
09-16z period as the main surface low center traverses eastward
across the metro. MVFR CIGs likely by 08-09Z and even IFR CIGs
possible (30-40% chance) Thursday morning. Chances for LIFR CIGs
are around 10%. There's a chance (10-20%) for additional light
rain/snow showers Thursday morning. After this period, calmer SSE-
SSW winds and lifting CIGs will commence late tomorrow morning and
into the early afternoon.
Southeast California/Southwest Arizona including KIPL and KBLH:
Gusty winds are already beginning to dissipate late this
afternoon, with this trend continuing into this evening.
Prevailing winds out of the W will become more NW going through
tonight at both terminals. Clouds will mostly clear out of the
region by later evening.
&&
.FIRE WEATHER...
A storm system will move through the area today. This will bring
strong wind gusts in excess of 40 mph across many areas as well as
wetting rains, mainly across south-central Arizona. Calmer
conditions are expected on Thursday as the system departs to the
east, although some gusty winds between 20-30 mph will linger
across portions of southeast California into southwest Arizona.
With moisture increasing with the approaching system, MinRH values
will be elevated today, but then drop significantly afterwards
through the next several days with values expected to range mostly
in the 15-40% range with good overnight recovery. Temperatures
will remain below normal through Saturday, before warming back to
near normal by Sunday through early next week.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Wind Advisory until 8 PM MST this evening for AZZ530>533-535-536.
Wind Advisory until midnight MST tonight for AZZ545-547-552-
556>558-560>563.
Winter Storm Warning until 11 AM MST Thursday for AZZ557-558-563.
Winter Weather Advisory until 11 AM MST Thursday for AZZ545-557-
558-562-563.
Wind Advisory until 9 PM MST this evening for AZZ534-537>544-546-
548>551-553>555-559.
CA...Wind Advisory until 7 PM PST this evening for CAZ564-565-569-570.
Wind Advisory until 4 AM PST Thursday for CAZ560-561-568.
High Wind Warning until 7 PM PST this evening for CAZ562-563-566-
567.
&&
DISCUSSION...Smith/Lojero
AVIATION...Young/Frieders
FIRE WEATHER...LojeroThe national radar mosaic for the moment the first event began.
2 strong wind, 2 heavy snow, 2 flood. Local standard time, as filed.
An overhead sign was blown down by strong winds in the northbound lanes of South Rural Road near US-60 in Tempe. No injuries were reported.
A four-inch diameter tree limb snapped in the area of 50th street and Chandler Boulevard in Ahwatukee. No injuries were reported.
Snowfall of 7 inches was reported in the area of Sunflower, AZ.
Trained spotter reported 5 inches about 11 miles south-southeast of Globe.
Nineteenth Avenue from Desert Hills Drive to Irvine Road along Skunk Creek in Carefree was closed due to flooding. No damages or injuries were reported.
North Old Stage Road at the Cave Creek River crossing was closed due to flooding. No damages or injuries were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2023Every state in 2023This day in weather historyWarnings in Arizona, March 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1085304, 1085306, 1085309, 1085311, 1085312, 1085318.