Rod's Winter Outlook 2023-2024
By Rod Hill on 2023-11-06
This winter's outlook is centered on the high confidence projection from NOAA that El Nino conditions will continue through March of 2024. The recent El Nino in 2015-2016, brought the wettest month on record for Portland, leading to flooding and one of the strongest tornadoes on record in Washington.
Before we go any further, here is a recap of my winter outlook from last year. The most significant call was the projection that any big snow storms would take place during the final two weeks of February. The one snowstorm for the season dumped 11" February 22nd.
As mentioned, an EL Nino winter is likely. The typical El Nino flow pattern leads to an active, wet southern jet stream flow, bringing heavy rains to California and much of the southeastern United States. The northern Jet Stream tends to bring dry and mild ridging over the Pacific Northwest, while ushering cold Canadian air across the Great Lakes and Northeast.
A combination or spaghetti chart of weather models show equatorial water temperatures that define the
El Nino cycle projected at 1.0 to 1.4 degrees Celsius above normal, defining a moderate event.
Here are my conclusions for the upcoming winter, leaning heavily on the comparison winters of 2002-2003, 2009-2010 and 2015-2016. Notice the winter or rainy season months of November - March show 13 of 15 months having above normal mean temperatures. A mild winter is my highest confidence projection for this winter.
My second forecast conclusion shows little Portland snow or zero to 3" of total valley floor snowfall. It is interesting to note that my research shows a better chance of freezing rain this winter than snow. Could we be in for an ice-storm?
Bulletin point three is my conclusion that data from past comparative El Nino years does not support the ability to project precipitation totals. Meaning I cannot make a call for dry, wet or a normal winter. While El Nino winters statistically favor below normal precipitation seasons, there have been several soaking wet months in the data set, such as December of 2015. Therefore, no confidence is given.
Finally, a fourth point shows an elevated chance for several south wind events with gusty winds in the valley
reaching 50-60 mph. Nothing unusual here, simply expecting 1-3 south wind alert days.
Although I mentioned a no-confidence call to project total precipitation, El Nino winter's are historically more dry
than wet in terms of total statistics. There is always concern of an alarmingly dry season. Notice four of the five
driest water years on record since 1950 are El Nino seasons.
Here is my Winter Outlook for 2023-2024:
A mild winter with December being the warmest month in terms of positive anomaly to climate average. A warm December would likely lead to higher than normal snow levels in the Cascades and bring a new zero chance of low level snow to the valley floor.
As mentioned, no confidence to predict precipitation totals, but little to snow is expected. Data does support a decent chance to see a freezing rain or sleet event. Warm air aloft may flow over cold air blowing out of the gorge, producing an ice event.
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Mt. Hood Snow Outlook:
Mt. Hood snowpack is typically below normal in El Nino winters. Snow levels can reach above 5,000 to 6,000 feet
more often than a so-called typical winter. Meaning more high elevation rain than better ski seasons would experience.
Mt. Hood snowpack projection for this coming season is 74% of average. There is concern that ski season could get off to a slow start with less than ideal snowfall through the holiday season. Keep in mind the timing and quality of snow are often better indicators of a good recreation year than the amount measured in the snowpack come May 1st when the season ends.
I want to be clear that El Nino winters do not favor a bonus snowpack season, but past history also does not favor an historically poor season. Notice the poorest snowpack seasons since 2000 have been Neutral years, not El Nino. Here is hoping for at least 70% of normal snowpack this winter!
Happy winter everyone, this concludes my Winter Outlook for 2023-2024. The headline for Portland is a mild winter with little to no sticking snow. Remember there is a heightened ice storm chance.
A special thank you to my wife Gracen for putting together the graphic presentation and showing great patience during the many hours of this research project.
Rod Hill
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