The 2022–2023 Winter Forecast
The 2022–2023 Winter will be the third consecutive winter with a La Nina in the Tropical Pacific. During a La Nina, the sea-surface-temperatures over the Eastern and Central Tropical Pacific are cooler than usual, and the trade winds are stronger than usual. And although La Nina (and its brother, El Nino) have the strongest and most predictable impacts on the weather of the Tropical Pacific, their impacts can extend into the mid-latitudes as well.
Historically, La Ninas have a slight tendency to be cooler and wetter than average in the Pacific Northwest, and the stronger the La Nina, the stronger this tendency is. This is because the stronger than average trade winds in the Tropical Pacific can, in turn, alter the location of the jet stream, causing it to approach the Pacific Northwest from a more northwesterly direction than usual. This pattern is extremely effective for bringing gobs of snow to the Cascades, and many of the Cascades’ snowiest winters and springs have occurred during La Nina years. Paradise Ranger Station set a world record for the most snowfall measured in a winter during the 1971–1972 La Nina year when 1,122 inches fell, but this was broken during the 1998–1999 La Nina winter when Mt. Baker ski resort 150 miles to the north saw an incredible 1,140 inches.
However, not every La Nina year is blessed with cool, wet weather and bountiful mountain snowfall. The La Nina winter of 2000–2001 was one of the driest Pacific Northwest winters on record, with much of the Pacific Northwest only receiving half of its typical winter precipitation. Seattle saw its driest combined spring/summer on record during 2021, and summer/autumn 2022 was one of the hottest and driest periods on record for the Pacific Northwest, with Seattle experiencing a record 12 days of 90+ degree temperatures and Portland experiencing a 67-day stretch of dry days. This past “Augtober” had very little precipitation, thick smoke, and extremely warm temperatures through the first 2/3rds of the month, including an incredible 88 degrees on Sunday, October 16, 16 degrees above the previous daily record. At the beginning of the summer, long-term forecasts called for near-average temperatures over due to La Nina conditions, but reality ended up being much different.
So what can we expect for the 2021–2022 winter? Being a La Nina winter, the 2021–2022 winter has a slightly greater than average chance of above-average precipitation and near or cooler than average temperatures. Unlike El Ninos, which are notorious for bringing very little snow to the lowlands, La Ninas usually give us a few brushes with lowland snow, so I expect we’ll see lowland snow at some point this winter. The highest confidence feature during La Nina winters is above average snowfall in the Cascades, particularly the northern Cascades, but as the 2000–2001 winter showed, even this isn’t a sure thing. Still, buying a seasons pass looks like a safe bet this year.
Our summer was wonderful, but I am ready for the rain to wash away the smoke. Stay warm, dry, and safe this winter.
Charlie Phillips is a Madrona native and lifelong weather geek who now works at Puget Sound Energy as an energy trader, making sure there is enough energy to keep the lights on! Check out his weather blog at weathertogether.net.