A cold upper level trough brought continuous waves of moisture across the region for March 8 through 10. These waves generated wide spread snow shower activity.
Every event with a place to put it; 3 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 OTX wrote it up.
A cold upper level trough brought continuous waves of moisture across the region for March 8 through 10. These waves generated wide spread snow shower activity. Most areas received snow amounts of two to five inches. A few areas received six plus inches.
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 Mar 7, 9:39 PM PST, 31 minutes earlier.
Area Forecast Discussion National Weather Service Spokane WA 939 PM PST Tue Mar 7 2023 .SYNOPSIS... Cool and unsettled weather is expected to continue through the work week with hit or miss snow showers. Temperatures will moderate slowly by the end of the week with a more significant weather system expected to hit the region Thursday night into Friday. This system is expected to bring widespread precipitation to the Inland Northwest consisting of a mix of rain and snow in the valleys and snow over the mountains. && .DISCUSSION... Tonight through Thursday afternoon: We are still (yes, another day on repeat) under the influence of the unstable atmosphere with scattered terrain driven cumulus clouds on the periphery of the upper level Low. The upper level feature will slowly move through Oregon over the next 48 hours before we have a bigger change in the weather (more on that below). Today (Tuesday) we've had quite a bit of clear skies across the Basin, Palouse, and eastern WA which has allowed temperatures to warm into the low to mid 40s for many places, and the mid to upper 30s in the mountains. We are still quite unstable (lapse rates +8 C/km) and even have analyzed MUCAPE values of 100-200 J/kg. Easterly flow at the surface and 60-80% of normal precipitable water values. Can't rule out some pop-up showers this afternoon especially as we are gaining more daylight this time of year. Going into tonight, the best instability and potential for precipitation will reside in the eastern slopes of the Cascades in Chelan and Okanogan Counties, mainly in the mountainous terrain between Hwy 2 and Methow Valley. Wednesday and Thursday's weather have very similar setups though the frontal passage/wave overnight Wednesday into early Thursday looks more impactful especially for the Thursday AM commute. The latest models are more robust (higher amounts) with precipitation between midnight and 10 am Thursday. The feature has a good amount of lift as well as veering winds becoming south- southwesterly. Maintaining the moisture and the timing of the precipitation could play well to accumulate on area roads for the Thursday morning commute. The national blend of models gives Pullman, Spokane, Davenport, and Wilbur over 70% probability of accumulating snowfall through 11 am, but only a 25-35% probability of seeing 1" or more. The global ensemble guidance and deterministic versions are all hovering around 1-1.5". All that said, what could go wrong? The timing. We're looking closely at the timing because if this should slow down 6+ hours and begin snowing after 8 am then we will struggle with the daytime heating and warming road temperatures for poor snowfall accumulation. The eastern slopes of the Cascade mountains will see additional snow accumulation Wednesday and Thursday, and lowland snow accumulation for the late Wednesday night through Thursday morning will be impactful. However, I would argue the Friday into Saturday weather may be more impactful in the forecast period. /Dewey Thursday night through Monday: The Western US will be entering yet another active period of weather by the end of the work week into the weekend and into early next week. Two land falling atmospheric rivers directed into central California will allow for a warm and wet airmass to move northward into the Inland Northwest. While we won't see the significant impacts that are being forecasted for Californian communities, we will see our own variety of forecast challenges that will bring minor and moderate impacts across our region. Thursday night through Friday: Models are coming into much better agreement on the general idea of the next system forecasted to impact the majority of the west coast beginning Thursday night and persisting into the weekend. The upper level low that has brought several days of snow showers to the region will finally be kicked to the east, but will be quickly replaced by a deep upper level closed low sliding down the northwest coast as a strong atmospheric river takes aim into central California. While the Inland Northwest is not expected to receive the true brunt of the atmospheric river, the increasing southwest flow aloft will bring an influx of moisture into the region. Once the low begins to move onshore along the Washington/Oregon border Thursday night, the low level flow will shift to the east- southeast and further draw the warm, moist air into the region. The combination of strong warm air advection and low level flow directed into the east slopes of the Cascades will provide favorable conditions for areas around the Methow Valley, Omak, Chelan, and Wenatchee to see an impactful snow event. The latest model ensembles have begun to increase their storm total snow amounts, with our latest snow forecast for the east slopes of the Cascades also seeing a significant increase. The limiting factor for this forecast will be the timing of this system. Right now, models are in solid agreement on an overnight Thursday into Friday morning arrival, which would support an all snow event as overnight lows drop below freezing Thursday night. However, if this system were to slow down and arrive during the late morning or afternoon, a high March sun angle would significantly limit snow accumulations. Since models are in good agreement on the nighttime arrival as of now, I felt confident in the decision to increase the snow totals across the region. This snow will make for a rather messy Friday morning commute for most locations. For the 48 hour timeframe from 10PM Thursday to 10PM Saturday, we are forecasting the following probabilities for specific snow amounts: Valleys: >1", >2", >4", >6" -Spokane 80%, 60%, 5%, 0% -Omak 95%, 90%, 65%, 35% -Winthrop 100%, 95%. 80%, 55% -Sandpoint 100%, 100%, 95%, 70% -Moses Lake 35%, 10% 0%, 0% -E Wenatchee 100%, 100%, 75%, 45% Mountain Passes: >6", >8", >12", >18" -Stevens Pass 75%, 55%, 15%, 0% -Lookout Pass 100%, 100%, 75%, 0% -Sherman Pass 75%, 60%, 15%, 0% A cold front looks to move through the region Friday afternoon, which will bring an end to the moderate to heavy snow across the east slopes and allow for the best chances for additional snow to retreat to the mountains. There will be a slight uptick in winds with and behind the front, with gusts up to 25 to 35 mph. Saturday through Monday: Temperatures will begin to trend warmer through the weekend as weak upper level ridging keeps the region in a southwesterly flow aloft. There looks to be lingering showers across the region on Saturday, with the best chances over the mountains. There will be a brief lull on Sunday as a weak ridge builds over the Inland Northwest before the next system begins to enter the region sometime Sunday night into early next week. Ensembles are in solid agreement this far in advance that the lowland will see mostly rain with snow in the mountains. /vmt && .AVIATION... 06Z TAFS: A weather disturbances moving up from the south will track over the Cascades tonight producing scattered snow showers including Wenatchee, Chelan, and Winthrop. This combined with easterly flow banking up moisture against the Cascade crest will keep areas of MVFR conditions through at least 18z Wednesday. Elsewhere a lack of shower activity and easterly boundary layer winds should keep conditions VFR through Wednesday morning. Another weather disturbance coming up from the south Wednesday afternoon into the evening will bring an increasing chance for snow showers, with local MVFR conditions expected with the snow showers. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 22 42 26 41 29 38 / 10 10 50 50 40 80 Coeur d'Alene 21 42 23 41 26 38 / 0 10 40 40 30 90 Pullman 24 42 26 42 32 41 / 20 30 60 10 40 90 Lewiston 29 49 30 49 36 49 / 10 20 40 0 30 70 Colville 19 43 23 39 25 38 / 0 0 10 30 40 90 Sandpoint 23 38 22 36 26 35 / 0 10 20 30 30 90 Kellogg 21 39 23 39 28 37 / 10 20 30 40 30 90 Moses Lake 27 47 28 48 33 44 / 10 20 20 20 50 80 Wenatchee 29 40 28 39 31 40 / 20 20 30 30 80 80 Omak 26 41 28 39 29 35 / 10 20 50 40 60 80 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. &&
The national radar mosaic for the moment the first event began.
3 heavy snow. Local standard time, as filed.
Observer reported 6 inches of snow.
Observer reported 6 inches of snow near Loon Lake. Newport and Colville also had reports of 4 to 6 inches of snow.
Observer reported 6 inches of snow in the Mead area. Other reports in the Spokane area ranged from 2 to 5 inches.
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, 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: 1089522, 1089526, 1089529.