A Bora windstorm impacted Southcentral Thursday, March 9 through Friday night, March 10 as a shortwave trough dug southward across Southcentral Alaska, ushering Arctic air southward into the Gulf of Alaska. While areas around Southcentral experienced heightened winds, the windstorm primarily impacted the Valdez area and its vicinity, as the temperature differentiation increased and the…
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 Bora windstorm impacted Southcentral Thursday, March 9 through Friday night, March 10 as a shortwave trough dug southward across Southcentral Alaska, ushering Arctic air southward into the Gulf of Alaska. While areas around Southcentral experienced heightened winds, the windstorm primarily impacted the Valdez area and its vicinity, as the temperature differentiation increased and the subsequent pressure gradient differentiation heightened.
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 Mar 8, 4:40 PM AKST, 12 hours 20 minutes earlier.
Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 440 PM AKST Wed Mar 8 2023 .ANALYSIS AND UPPER LEVELS... In the upper levels the anomalous ridge is reorienting across the eastern half of Alaska with a shortwave moving across western Alaska in the Fairbanks area. This shortwave is beginning to reorient the ridge and shift it westward over the eastern Bering over the next 24 hours. Otherwise, light snow is occurring across the Kuskokwim Delta and valley areas associated with the shortwave, with high level clouds spilling over the ridge into Southcentral. A low pressure system south of the eastern Aleutians is pulling moisture northward across the eastern Aleutians and AKPen with areas of light rain, low ceilings and some fog as warm air is pumped into the area. Across Southcentral low level clouds are spreading across the northern Gulf and Prince William Sound. && .MODEL DISCUSSION... Model guidance is in good agreement with a pair of shortwaves moving across Southcentral Thursday and Friday bringing colder air and strong gap winds. The main forecast challenge will be the possibility of high winds across Valdez and Thompson Pass Thursday evening through Friday. Also, strong winds across the Matanuska Valley with gusty winds up to 50 knots possibly extending along the Glenn Highway from the Hay Flats to Chugiak and towards the JBER area as well as western Anchorage, with 35 to 40 knot gusts possible. These winds may also resuspend some of the snow reducing visibilities. && .AVIATION... PANC...VFR conditions and light winds will persist. There may be a brief lowering of the ceilings to 5,000 to 7,000 feet this evening and tonight but should remain VFR. && .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: This afternoon through Saturday afternoon)... Warm and quiet conditions today give way to colder temperatures and stronger winds by Thursday night. The ridge that has persisted over Southcentral Alaska for the past few days will weaken tonight as a shortwave moves over top of it. Little to no precipitation continues to be expected for much of Southcentral; most locations will see increased cloud cover tonight, but light snow will be limited to higher elevations in the Copper River Basin. A surface low develops in the Eastern Gulf Thursday as the shortwave exits into the Eastern Gulf. The north-south pressure gradient across the state tightens as a 1040 mb Bering ridge tilts into Northern Alaska. With another upper level shortwave descending south across the Eastern Chugach range on Friday and cold air filtering into Eastern Alaska, the stage is set for gusty outflow winds. A High Wind Watch is in effect for Valdez and Thompson Pass from late Thursday night into Friday, with max gusts of 80 mph possible as cold air channels out of the Copper River Basin. Further east, a Special Weather Statement is in effect for Matanuska Valley and Anchorage as cold outflow winds (weaker than those expected for Valdez and Thompson Pass) exit the Copper River Basin and move south along Knik Arm and Cook Inlet. Though melting and compaction from our recent warm weather has likely shored up the snowpack, there remains a potential for blowing snow with these stronger winds. Confidence is lower for max wind gusts through Matanuska Valley and Anchorage, so stay tuned as we continue to update the forecast. && .SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Tonight through Saturday)... A shortwave trough that has since tracked over the Kuskokwim Delta earlier this morning is now making its way across the Kuskokwim Valley bringing light snow showers to the area. Once the aforementioned shortwave tracks further east, an upper-level ridge will set up and bring widespread dry conditions back to Southwest. This will lead to the development of offshore flow and will bring cooler temperatures and drier conditions back to the region through the weekend. && .SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3: Tonight through Saturday)... An upper-level ridge of high pressure, originally located over the Gulf of Alaska, is swinging its way over to the Bering. This high pressure will expand across the Bering through the end of the week with continued benign conditions forecasted. Any moisture trapped beneath the aforementioned ridge will likely introduce persistent fog and low-level stratus for the Bering, Aleutians, and Pribilofs. A warm front weakening to an inverted trough is forecast to continue tracking across the Chain east to west and reach Atka and Adak by Thursday afternoon. A weak trough over the far western Aleutians may produce some widely scattered showers for Attu and Shemya through tomorrow morning. Leading into the weekend, the ridge of high pressure will dominant the region and lead to drier conditions and warmer temperatures across the Chain/Bering. && .LONG TERM FORECAST (Days 4 through 7: Sunday through Wednesday) The long term begins Saturday night with an upper-level ridge anchored over the eastern Aleutians and extending northeast across the interior of the state. This feature is bisecting two upper- level shortwave troughs. The first looks to be exiting the Gulf of Alaska to the south, with the resultant northerly flow between it and the ridge over interior Alaska keeping clear but cols across much of the Southern Mainland. The orientation of these feature will also likely maintain the gusty gap winds along the Southcentral coast; however, these winds should be well below their expected peak from previous days. The ridge then quickly retreats to south of the eastern Aleutians for Sunday as that second shortwave moves south and east from the Chukchi Sea to a position somewhere over the southern half of the state by Monday morning. While the position and strength vary between models, the result is generally the same: a resurgence of arctic air and temperatures falling well below normal, especially across Southcentral Alaska. This pattern looks to further amplify by Tuesday as yet another shortwave dives from eastern Russia toward southern Alaska as an upper-level ridge builds between the western Aleutians and the Kamchatka Peninsula. Areas of light snow, mainly at higher elevations, is possible with this systems as it drives a surface cold front from west to east across the state. The bigger story, though, will be a reinforcement of colder air with 850 mb (~4500 ft) temperatures potentially falling to -20 degrees Celsius or colder across the region. This would likely correspond to daytime highs across the region struggling to get out of the teens for most locations, especially across interior Southcentral and Southwest Alaska by Wednesday, temperatures more climatologically representative of mid-January than mid-March. Along with the cold temperatures, this pattern will likely keep the gusty gap winds along the coast persisting through mid-week next week. && .AFC WATCHES/WARNINGS/ADVISORIES... PUBLIC...High Wind Watch 131. MARINE...Gale Northern Gulf of AK Heavy Freezing Spray Bristol Bay, Kuskokwim Delta FIRE WEATHER...NONE. && SYNOPSIS AND MODEL DISCUSSION...RC SOUTHCENTRAL ALASKA...KC SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...NS LONG TERM...TM
SPECIAL WEATHER STATEMENT National Weather Service ANCHORAGE AK 456 AM AKST Thu Mar 9 2023 AKZ101-111-100300- Anchorage-Matanuska Valley- Including the cities of Anchorage, Eagle River, Indian, Eklutna, Palmer, Wasilla, Sutton, and Chickaloon 456 AM AKST Thu Mar 9 2023 ...GUSTY OUTFLOW WINDS EXPECTED FROM TONIGHT THROUGH FRIDAY EVENING... Strong north to northeasterly winds are expected across the Matanuska Valley and West Anchorage beginning late tonight around midnight and lasting through much of Friday. Peak winds are expected to develop from Friday morning through the early afternoon hours. Currently, peak gusts of up to 60 mph are forecast in the Matanuska Valley while gusts of up to 35 mph are forecast in West Anchorage. There remains a moderate amount of uncertainty regarding the strength of the highest wind gusts. Motorists are urged to use caution while traveling as gusty winds may affect the Friday morning and evening commute. Blowing snow may occur if winds resuspend fallen snow, though visibility reductions are not expected to be widespread. Be sure to secure loose objects and monitor the forecast for updates.
1 high wind. Local standard time, as filed.
The Thompson Pass DOT camp reported that their highest observed wind gust was 96 mph at camp. They also reported that the wind gusts were much stronger through the Thompson Pass gap. Meanwhile, the Valdez ASOS recorded a peak wind gust of 76 mph.
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, 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: 1105185.