5 inches led to washout of Forest Service road near Hope, Idaho.
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The episode as NWS OTX wrote it up.
Snowmelt and rain amounts near 2.5 inches led to washout of Forest Service road near Hope, Idaho.
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 Dec 6, 2:49 PM PST, 5 hours 11 minutes earlier.
Area Forecast Discussion National Weather Service Spokane WA 249 PM PST Wed Dec 6 2023 .SYNOPSIS... Rain will continue today however the air mass will begin cooling with snow slowly returning to the mountains from west to east. More seasonal temperatures return Thursday into the weekend. Snow showers return Thursday night and Friday for some areas then widespread snow arrives this weekend with another atmospheric river. Next week looks seasonal and drier than normal. && .DISCUSSION... Tonight through Friday night: The long-lived plume of moisture aimed at the Pacific Northwest will finally shift eastward through Thursday. Precipitable water anomalies of 250+ percent of normal will promptly exit to the east with the arrival of a cold front, which will also work to cool down our boundary layer temperatures. Surface temperatures this afternoon across the Inland Northwest climbing to the upper 40s and even some 50-54F readings being seen (some 10-13F degrees above normal, especially for Lewiston). The next round of precipitation is moving in right now, albeit we saw little to no break for some locations today. This plume of rain showers will blossom and continue to push northeast to east overnight with more of a south to north orientation. The cold front timing will work to bring down snow levels from the 6000 ft range to 2500 ft range or so by Thursday morning. Timing the precipitation, snow accumulation in the Idaho Panhandle mountains, more specifically Shoshone County and I-90 from east of 4th of July Pass to Lookout Pass and into Montana, will become more persistent in the early hours Thursday morning through late morning and perk up again Thursday afternoon through overnight Friday morning. Both impacting the commute times, with accumulations of around one quarter to one half inch per hour at times (20-30% chance). Precipitation across the region Thursday will largely be confined to southerly facing favorable locations in Ferry, Stevens, Pend Orielle counties with amounts around one tenth of an inch. Elsewhere, the focus will be on the higher elevations in the Idaho Panhandle. The pressure gradient will tighten with the cold front passage and influence breezy to gusty southwest winds across the southern Basin and the Palouse with winds of 15-20 mph and gusts up to 30 mph through the day Thursday. Temperatures will continue to cool as we move into the weekend. /Dewey Saturday through Sunday night: The weekend will be highlighted by a potent system moving through the Northwest in the wake of the colder air moving into the region late this week. A transient upper ridge will be in place on Saturday morning, but this ridge will move quickly eastward as a vigorous vort max moves ashore during the following 24 hours. Though moisture will be more limited with this system than those affecting the region early this week, the ambient near-surface cold air will provide a thermodynamic environment favorable for snow at all elevations to start the event. Snow will begin in the Cascades during the day, spreading eastward into the rest of the CWA during Saturday evening and night. Strong orographic lift in advance of the vort max will produce decent snow rates in the higher elevations of the Cascades, with ensembles showing potential for 6-12+ inches late Saturday afternoon through Saturday night. Low-level flow will also favor the Idaho Panhandle mountains, mainly Saturday night into Sunday morning (where 4-8+ inch amounts are projected). Meanwhile, in the lowlands, a decent bout of snow is expected Saturday evening, but given the strong warm/moist advection in advance of the vort max, the cooling effects of precipitation and lift are expected to be counteracted strongly. Most guidance indicates a slight warming trend during the overnight hours into Sunday. I suspect that models are probably a little too warm during this stage of the event, but given the marginal surface temperatures and potential warming trend as the event continues, I was hesitant to stray too much from consensus (generally 1-4 inches, with lesser amounts in the lower Columbia Basin). Notably, some guidance is depicting higher totals, with approximately 10-20 percent of ensemble members depicting 3+ inches in Spokane, for example. Of particular concern is portions of the Palouse and Camas Prairie, where GEFS and CMCE are showing totals of 3-6+ inches. The evolution of the system is favorable for upslope flow and heavier totals in this particular region, so this bears watching. Accumulations are expected to become more muted with time as temperatures warm slightly late Saturday night into Sunday, particularly for areas near and south of I-90 in Washington. There may even be a transition to rain or a wintry mix during this period, before precipitation shuts off quickly from west to east. More showery precipitation may linger in the higher terrain of the Cascades and the Idaho Panhandle Sunday night, as the system progresses quickly eastward and out of the region. Monday through Wednesday: A rather uncertain forecast develops next week, with ensembles depicting a pattern more dominated by ridging. However, the strength and location of the ridge axis are quite variable among the ensembles, and the Northwest may be far enough north and west to be on the fringe of faster flow by midweek. This may bring in another series of vorticity maxima and precipitation as early as Wednesday. Additionally, ensembles are depicting a weak perturbation moving through the Inland Northwest on Monday. With these trends in mind, kept mentionable precipitation in the higher terrain as well as most of the Idaho Panhandle and far eastern Washington through Monday, and included more PoPs for Wednesday. There should be a dry period in this three-day window, but confidence is lower than average on timing and duration of this dry period. The temperature forecast is higher confidence, with a period of near to slightly below average conditions expected. /CMS && .AVIATION... 18Z TAFs: Plume of moisture still streaming from southwest to northeast this morning and will gradually move eastward through the day with a cold front pushing east. Cascade slopes and valleys are maintaining the colder air while the Basin, Palouse, eastern WA and northern ID are in the warm sector ahead of the front. Temp-dew point spread and precip has kept ceilings and vis in MVFR/VFR status for Spokane, Felts, Colville, Pullman, Wenatchee. For other locations like Moses Lake, Coeur d'Alene, Sandpoint the wind has not been an influence such to lift flight categories and IFR/LIFR conditions are present for several hours today. Winds will increase out of the southwest with the front late tonight/overnight, seeing wind speeds 15-20 mph and brief gusts to 30 mph. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS: Confidence is moderate at KGEG/KSFF/KCOE that ceilings will remain above 3000 feet with the cold front arrival this afternoon/evening. Main uncertainty for these sites will be duration of rain throughout the day and influence of wind. Confidence is moderate/high for IFR/MVFR conditions along the East Slopes of the Cascades and northern mountain valleys given what has been occurring and lack of strong winds to mix out these lower cigs through 00z. After 00z, there could be enough mixing to scrub out the low clouds but thinking this will redevelop after 06z. Confidence is moderate/high for VFR conditions until the cold front arrives late in the afternoon/early evening at KPUW/KLWS. /Dewey ------------------ Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance For additional probabilistic information for NWS Spokane airports, please refer to the Aviation Dashboard on our webpage: https://www.weather.gov/otx/avndashboard && .PRELIMINARY POINT TEMPS/POPS... Spokane 36 41 28 37 24 35 / 100 50 50 10 0 50 Coeur d'Alene 36 39 28 35 23 34 / 100 80 60 30 0 40 Pullman 36 41 28 36 24 34 / 100 70 70 30 0 40 Lewiston 43 49 35 43 28 40 / 90 50 70 20 0 30 Colville 29 40 23 37 18 33 / 100 30 40 10 10 70 Sandpoint 36 39 29 36 23 34 / 100 70 70 50 20 60 Kellogg 36 38 31 34 25 34 / 100 90 90 70 20 40 Moses Lake 36 46 27 42 25 37 / 90 20 10 0 0 70 Wenatchee 36 42 31 40 28 33 / 80 20 10 0 0 80 Omak 33 41 28 39 26 34 / 90 10 20 0 0 80 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. &&
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Lightning Creek flooding led to washout of Forest Service Road 419 North of Clark Fork, Idaho.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2023Every state in 2023This day in weather historyWarnings in Idaho, December 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: 1154163.