Rod's Weather Headlines

Let me begin by saying near normal temperatures with below normal rainfall  is in the forecast for Portland and Salem through the first 15 days of February.  The normal climate high for the period in the mid to north Willamette Valley is low 50s, meaning near normal is pretty comfortable.  Also, normal to below normal rainfall will seem quite dry when compared to the 18.16" of total precipitation that fell in Portland from December 1st through the month of January. Total precipitation the last two months is 7.36" above normal or nearly 170% of normal, making for an extra 6 weeks of rainfall.

Before warm weather lovers get overly excited, there are signs the back half of March will turn cooler and wet.  If true, the timing of the colder than normal air would be chilly and likely not the bitter cold we saw with the January Arctic air mass when Portland experienced three days of high temperatures in the 20s. Record cold high temperatures in mid- March for the Rose City are generally in the 40s. 

A timeline of warming climate numbers as spring approaches shows Portland's normal high temperature currently at 50 degrees, warming to 54 March 1st and to 57 degrees the first day of Spring.  By April 1st, Portland's normal daily high temperature is 59 degrees.  The average final spring freeze in Portland is around April 1st, while parts of the valley can see freezing numbers into early May. 

The current El Nino cycle, connected to our mild December and recent heavy rains in California is expected to weaken into Enso-Neutral conditions during the month of April.  NOAA is projecting a return to La Nina conditions this summer and into the fall season. 

Meteorologist Rod Hill 

Today's sunny break will quickly end as another winter storm arrives Tuesday.  The main concern tomorrow afternoon and into the night will be freezing rain and ice accumulation on roadways and surfaces.  The National Weather Service has issued a Winter Storm Watch Tuesday and Tuesday night for the freezing rain threat (shown in blue on the map).  Notice the watch area does not include immediate coastal areas where rain is expected, but does extend northward into Cowlitz county and through the west gorge into Hood River.  Areas east of Hood River are expected to see snow. 

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.

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.

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:

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