Mild temperatures and near half an inch of rain created some localized flooding and rock slides in the Cascades.
Every event with a place to put it. 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 OTX wrote it up.
Mild temperatures and near half an inch of rain created some localized flooding and rock slides in the Cascades.
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 Spokane, WA wrote its last area forecast discussion before the first event at Jan 6, 9:52 PM PST, 2 hours 8 minutes earlier.
Area Forecast Discussion
National Weather Service Spokane WA
952 PM PST Fri Jan 6 2023
.SYNOPSIS...
Persistent light precipitation is expected across north-central
Washington tonight through Saturday. Expect wet snow in the
valleys with winter travel at times over the mountain passes.
Seasonably mild temperatures will continue through the weekend
into next week with more rounds of light precipitation a wintry
mix of precipitation expected in the valleys and light snow in the
mountains.
&&
.DISCUSSION...
Evening update: Based on the incoming 00z model guidance and
current temperature trends, QPF has been increased further for
Central WA...decreased in Eastern WA and snow levels have been
lowered. This has resulted in higher snow amounts for tonight into
Saturday for some areas. Starting off with temperatures, models
are not doing well capturing the current cooler air still
lingering around Omak, Chelan, and Wenatchee. All locations remain
cold enough for snow and temperatures between 29-31F. As outlined
in the previous discussion, a front will become stalled over
Central WA tonight and into Saturday with disturbances tracking
along it bringing periods of light to moderate precipitation.
Several pieced of guidance continue to bring upwards of 0.50-0.90"
of liquid for some of the higher benches along and just west of
the Hwy 97 corridor but there are still some pieces of guidance
suggest as the ECMWF which displace this closer to the crest with
nearly half that amount. We have made some adjustments toward
these 00Z runs higher amounts and given the current temperature
profiles, snow amounts have increased for locations like Omak,
Conconully, Carlton, Manson, and Ardenvoir. NAM/GFS bufkit data
would even support 6+ inches of snow for Omak AP but this does not
carry any probabilistic support from the NBM 4.0/4.1, NAM3KM , or
HREF.
The wildcard with this event will also be the snow ratios. Nearly
all model guidance suggest snow ratios of 7:1 to 10:1 with a
majority siding closer to 7:1. It is tough to argue with this
notion given the lack of persistent omega slicing through the
dendritic layer and potential for valley temperatures to near 33F.
In these thermal profiles that hug the 0C isotherm and stalled
frontal boundary, there is always concern and modest uncertainty
and potential for some locations to bust but overall, did trend
snow amounts higher for this latest update. /sb
Previous discussion...
Tonight through Saturday night: Satellite
imagery shows a tightly wound low pressure system out at 45N/135W
in the eastern Pacific. An occluded front is moving into western
Washington this afternoon and this front is progged to move over
the Cascades this evening. Model guidance has trended toward this
front becoming hung up over north-central Washington tonight
through Saturday with an upper level shortwave disturbance pushing
across through the day on Saturday. The combination of dynamic
forcing along the front, supported by dynamics aloft with
favorable orographics with easterly flow at low levels will result
in a long during of light precipitation over this portion of the
region over the next 24 hours. Precipitation is primarily expected
to fall as snow with lower elevations below 1500-2000 feet seeing
a harder time for accumulating snow on roads, especially during
the daylight hours on Saturday. Winter weather advisories have
been issued for generally 2 to 6 inches of snow with mountains
seeing the potential of up to around 8 inches. Due to the lighter
intensity of snowfall, I expect travel along Highway 97 along the
Columbia River and along the Okanogan River in the Okanogan Valley
to mostly just be wet or see wet accumulating snow on the
shoulders. Main impacts of accumulating snow on roads will be on
the higher benches in the Wenatchee Area and in the Okanogan
Valley, as well as the colder pockets tucked into the east slopes
of the Cascades and the Okanogan Highlands; the colder pockets
referring mostly to Leavenworth, Plain, Stehekin, Methow Valley,
and Republic. Slippery travel is expected with the snow, but may
see roads becoming mostly wet Saturday afternoon where snowfall
intensities are lighter. Winter Weather Advisories may be able to
be lifted early Saturday afternoon for some forecast zones if that
is the case. Winter travel is expected over the mountain passes
in the Cascades and over Sherman Pass. There may also be some
pockets of freezing rain over the Moses Lake Area into portions of
the Upper Columbia Basin since skies will start out mostly clear
this evening and could see temperatures drop below freezing at the
surface with a weak warm nose aloft. Precipitation amounts look
to be light for these areas, which is why I decided to hold off on
an advisory for freezing rain, but that potential will need to be
monitored through this evening as well.
The frontal band won't shift much through the day Saturday, but
precipitation will dissipate as support aloft decreases into
Saturday evening. This will result in precipitation chances
decreasing through night on Saturday. With the mid level front
remaining mostly squared over central Washington, precipitation
chances and accumulations were decreased across extreme eastern
Washington into the Idaho Panhandle. /SVH
Sunday through Thursday: The Inland Northwest will remain in an
active pattern for the end of the weekend into the next work week.
Multiple rounds of shortwave troughs will push into the region from
the southwest with moisture support from the atmospheric rivers that
are impacting California over the next week. These systems will
arrive as mountain snow and predominately lowland rain, with the
exception of the Methow Valley tucked away in the North Cascades.
The first two systems for this period will occur Sunday into Monday
and Monday into Tuesday. These two events will be quite similar in
nature, with neither one sticking out as particularly strong.
However the back to back occurrences will result in modest 48 hour
precipitation totals across the region. Our current forecast from
Sunday morning through early Tuesday morning has widespread
precipitation amounts from around 0.25 inches to 0.50 inches. Lesser
amounts are expected for the L-C Valley, the Camas Prairie, and
around Bonners Ferry. This precipitation will result in rises in
small creeks and streams, with Paradise Creek at Moscow forecasted
to reach bankfull late Monday night. We currently aren't expecting
this to be similar to the flooding at Paradise Creek a week and a
half ago, but this will be something we are keeping an eye on over
the next couple of days.
A third system will Pacific Northwest Wednesday night into Thursday,
and models are beginning to indicate this system to be accompanied
by a stronger tap of moisture as the shortwave moves up the west
coast, but there is still many discrepancies on how close to the
Inland Northwest it will track. This will play a big role on how
much preciptiation we see. Recent cluster guidance is leaning toward
the drier solution with about 66% of ensembles keeping the heaviest
precipitation west of the Cascades. Because of this there is too
much uncertainty at this moment to message specific impacts, but
this will be another event we will continue to monitor.
Temperatures this week will remain pretty consistent through the
week with high temperatures in the low 30s to low 40s (about 5 to 10
degrees above average) and lows in the 20s and 30s (about 10 to 15
degrees above average). /vmt
&&
.AVIATION...
06Z TAFS: A frontal band will stall out over the Cascades into
Saturday. This will result in an extended period of light wintry
precipitation with snow at the Wenatchee Airport to airports in
the Methow Valley and over to Omak. A light wintry mix of
freezing rain/rain/snow is possible Saturday morning across the
Waterville Plateau and into Ephrata and Moses Lake airports, tho
confidence is low. IFR conditions is likely with the precipitation
under the frontal band in central WA with a better chance for VFR
conditions continuing over the Palouse (Pullman Airport) to the
Lewiston Airport. Rain or rain/snow mix will move into the Spokane
area aft 16Z with periods of MVFR conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 30 37 32 40 31 40 / 10 30 30 40 40 50
Coeur d'Alene 29 37 32 40 31 41 / 10 30 30 30 50 30
Pullman 32 39 34 40 31 42 / 10 20 20 30 40 50
Lewiston 34 45 35 46 34 47 / 10 10 10 20 30 30
Colville 30 36 32 40 31 40 / 20 70 60 40 50 30
Sandpoint 30 36 32 37 32 39 / 10 30 50 40 70 20
Kellogg 29 40 32 41 33 41 / 10 10 20 40 60 30
Moses Lake 30 38 32 40 30 42 / 40 70 40 50 20 70
Wenatchee 28 34 31 36 31 35 / 80 90 50 60 20 60
Omak 30 34 33 37 32 37 / 80 100 70 60 40 50
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Winter Weather Advisory from 9 PM this evening to 9 PM PST
Saturday for Central Chelan County-Okanogan Highlands-
Okanogan Valley-Waterville Plateau-Wenatchee Area-Western
Chelan County-Western Okanogan County.
&&The national radar mosaic for the moment the first event began.
2 debris flow. Local standard time, as filed.
Rock slide along the East shore closed US 97A near milepost 220.
Peter Dan road closed after hillside sloughed onto road half a mile from Highway 155.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2023Every state in 2023This day in weather historyWarnings in Washington, January 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: 1078332, 1078333.