A low pressure system moving in the Gulf of Alaska tapped into deep subtropical moisture to produce heavy precipitation along the coast in Western Prince William Sound. Strong forcing and low-level instability combined with ample moisture to push precipitation inland toward Turnagain Pass.
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 AFC wrote it up.
A low pressure system moving in the Gulf of Alaska tapped into deep subtropical moisture to produce heavy precipitation along the coast in Western Prince William Sound. Strong forcing and low-level instability combined with ample moisture to push precipitation inland toward Turnagain Pass. Snowfall rates exceeded one inch per hour as the low's front pushed inland on November 29, leading to new snowfall accumulations in excess of one foot.
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 Anchorage, AK wrote its last area forecast discussion before the first event at Nov 28, 5:02 PM AKST, 9 hours 58 minutes earlier.
Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 502 PM AKST Tue Nov 28 2023 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/This afternoon through Friday afternoon)... Few major changes to the forecast as things remain largely on track. Wet and windy conditions were felt today across much of the region as a compact low moved through Southwest Alaska. With the low continuing to move north, winds have already begun to weaken across Kodiak Island. In other parts of Southcentral Alaska, winds should be at or nearing their peak. Winds today have remained largely as forecast, gusting to about 30-40 mph in Matanuska Valley and as high as 45-55 mph along the Anchorage Hillside. Expect these winds to gradually diminish from late tonight through early tomorrow morning as flow backs from southeast to northeast ahead of an incoming storm system. Overall, not too much has changed with the deepening low and its front, which will move into the Gulf of Alaska late tonight and linger through Wednesday. There remain some model differences with the track of this low, but confidence has increased enough for a Winter Weather Advisory to be issued for Turnagain Pass for snow and, potentially, blowing snow. Eastern Kenai Peninsula will likely see precipitation for much of the day Wednesday with this front, with the heaviest precipitation rates expected from Wednesday afternoon through evening as the front moves inland. Snowfall rates could reach or exceed 1 inch per hour in Turnagain Pass during this time period. While warmer temperatures will likely keep this as a wetter and heavier snow, there may still be visibility reductions due to heavy snow and/or gusty winds. No matter what happens, confidence is high that Wednesday will be a wet day along the north Gulf coast; satellite imagery shows precipitable water values of 0.5 to 1 inch with this system, which is quite moist for this time of year. Areas away from the coast may see a bit of precipitation, but most of it should be limited to Eastern/Southern Kenai Peninsula and Prince William Sound. -KC && .SHORT TERM FORECAST SOUTHWEST ALASKA AND BERING SEA/ALEUTIANS (Days 1 through 3)... A compact low is currently moving north through the Lower Kuskokwim Valley, bringing a mixture of rain, snow and wind to much of interior Southwest. An additional one to two inches of snow is expected this evening for interior areas before the system departs to the north. Behind the low, weather will become quieter with a return to more seasonal temperatures as colder air moves in from the Bering. A few weak shortwaves and instability aloft on Wednesday will generate coastal snow showers for the Kusko Delta and Alaska Peninsula, otherwise broken skies and decreasing temperatures will prevail for southwest through the early part of the weekend. Weather over the Bering will get increasingly active as a front extending off of a low currently south of Kamchatka reaches the western Aleutians tomorrow morning. Models are then indicating one or more additional lows developing along the front as it extends east towards the eastern Aleutians late Wednesday night. Depending on the location of these lows, isolated areas with storm force gusts are expected, but honing in on their location is challenging at the moment due to a large model spread. Broadly speaking, most of the Chain will receive high end gales through Friday, with pockets of storm force winds likely on the backside of the mesolows. -CJ && .LONG TERM FORECAST (Days 4 through 7)... The long-term forecast period begins Saturday morning with fair model agreement depicting a broad upper-level trough stretched across the Bering Sea into the Gulf of Alaska, creating several surface low pressure centers in the southeastern Bering and northern Gulf. These lows will draw westerly gales across the Aleutian Chain and easterly gales across the northern Gulf coast into Prince William Sound. Generally a showery, wet pattern will be in place across all of Southern Alaska, with areas such as the lower Kuskokwim Valley, and Copper River Basin seeing the driest conditions. Looking into Sunday model uncertainty remains fair, with most solutions sinking the low in the Southern Bering across the Aleutian Chain, into the northern-most Pacific, south of Adak. By Monday morning, model disagreements become severe with some solutions keeping a low in the Southern Gulf of Alaska while keeping coastal Southcentral in a light rain and breezy pattern. While other solutions take the low southeast, pushing into Juneau's region before advancing northward towards Southcentral. By Monday afternoon, models seem to converge on a solution bringing a strong low pressure system towards the Southcentral coastline. Heavy rains and strong winds appear to move in, however timing the system's arrival is still debated. At latest, Tuesday afternoon will likely be rainy and windy in the Prince William Sound region. Overall, a wet pattern for the Aleutians and Southcentral regions, looking colder and drier from mid to late week for Southwest Alaska, and cooler and wetter for Southcentral. CL && .AVIATION... PANC...Gusty southeasterly winds will continue through tonight. Winds diminish and transition to northerly early Wednesday morning. Flow aloft may hold on to southeast winds longer after surface winds have shifted, which may lead to some wind shear beginning around 12Z Wednesday. &&
1 winter weather. Local standard time, as filed.
The Summit Lake SNOTEL measured 14 new inches of snow on November 29. The heaviest snow occurred from late morning through the evening hours, with snowfall rates in excess of one inch per hour.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2023Every state in 2023This day in weather historyWarnings in Alaska, November 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 2026-10-01. Each event’s entry at NCEI: 1143757.