Gabe's 2023-24 Official Winter Outlook: Oregon's Impact Of The First El Niño Since 2018

2018-2020 was spent working 8-10 hours per season with 40-50% accuracy, although that has increased to more than 36 hours since 2021. That sure paid off last year, 2022 came in clutch with 61.54% accuracy, my most precise winter prediction yet! What did I do well?

Temperatures were a big strong suit! Although I didn't expect October to be the warmest, I made the point that the month had a chance to be mild. Portland was 5.8 degrees above normal, while La Grande was 4.5 above - which was still good enough to fulfill my prediction of the first snowflake in the Grande Ronde Valley! I received a dusting on my doorstep in Summerville on October 24th, while the official Union station did so on the 25th. November's precipitation prediction of near to slightly above normal was also good. La Grande's data is missing many days that month, but the nearby Union station shows 1.28" above normal with Portland having a deficit of 0.28". Although Portland didn't receive its first dusting of snow until December 1st, Eugene did so on November 6th, fulfilling my prediction for the first snowflake in the Willamette Valley! Despite the lack of moisture east of the cascades, December's prediction of 1-2" above normal precipitation was very accurate for Portland, the station recorded 1.99" above! "January begins with slightly above average temperatures and precipitation, dropping near to slightly below into February." - Me, 12 months ago. That's exactly what happened! Portland was 3.9 degrees and 0.15" above normal through the first half of the month, dropping to 0.9 degrees and 1.84" below normal for the back half, bringing a deficit of 1.19" for February as temperatures remained 2.9 degrees below. La Grande was 5.1 degrees above normal and 0.25" below normal through the first half of the month, dropping to 4.1 degrees and 0.61" below normal for the back half, bringing a deficit of 0.42" for February as temperatures remained 2.7 degrees below. During the months of January and March, our third consecutive La Niña finally transitioned to ENSO-Neutral, which I supported with my set of analog years! Despite my prediction of 0.5-1.5 degrees below normal for March, it ended up being the coldest month on average as I anticipated. Portland was 3.1 degrees below normal, helping to fulfill my prediction for the final snowflake in the Willamette Valley, bringing a dusting to Portland on March 25th. La Grande finished the month with 6.3 degrees below normal! That really helped to increase our snowpack, which fulfilled my prediction of near to above normal snowfall across the Grande Ronde Valley, bringing the final snowflake in April as I expected - Union picked up a dusting on the 20th. Missing data continues to be the story at La Grande, but the nearby Cove station reported 70.3" of total snow last season with 60.1" for Wallowa, within 10" of my mean prediction! So what did I do wrong?

Overall, precipitation was my weakest point. Although the Willamette Valley had an accurate rain estimate for December, the Grande Ronde Valley did not... La Grande reported 1.88" below normal. And even despite that, the headline was incorrect. December did not end up being the warmest and wettest. In fact, the month was 2.6 degrees below normal for Portland and 1.5 below for La Grande. October's temperatures were the greatest above normal throughout the entire season, clocking in at 4.5 degrees above for La Grande and 5.8 above for Portland! The highest precipitation took place in April for the westside with 2.19" above normal in Portland, while out east it was in March, reporting 1.04" above for Cove as missing data continued for La Grande. "But with the lack of precipitation, that could negatively impact fire conditions next summer as temperatures warm. Definitely not a slam dunk, but something to think about as much of the precipitation will end earlier than last year." - Me, 12 months ago. Despite my prediction of a dry October that ended up near normal, January was the driest with a deficit of 1.69" in Portland and 1.33" for La Grande, although it didn't last that long. It was the second wet spring in a row. As you can imagine, that threw off my near to below normal snow prediction west of the cascades. Instead of 1-6" of total snowfall for the season, 11" was measured at Portland! Monthly rainfall continued through June 19th in Portland and June 28th in La Grande. I got fooled again! Portland received 1.21" for the month, even La Grande picked up 0.90". This is the one part of my outlook where I continue to celebrate the inaccuracy, this fire season was significantly below the 10 year average! Surely, this won't be the third consecutive year where I state otherwise, right??? Well, old habits die hard... But wait, wasn't there more to the outlook?

This is the section where I had a strong prediction mixed with a weak one. "January begins with slightly above average temperatures and precipitation, dropping near to slightly below into February. During that transition period, the snowiest part of the season should take place." - Me, 12 months ago. February 22nd into the 23rd was the snowiest part of the entire season for the Willamette Valley, blanketing most of the area with at least a little snow, bringing a surprise snowstorm of generally 5-15" to the east side of the Portland metro! Although not the same story in the Grande Ronde Valley, only 7.1" of snow was measured that month in Cove. It wasn't until March that the region received its highest amount, Cove measured 25.2" that month with 13.2" of that between the 14th and the 15th! And although my prediction of a near to below normal March and April continued to be accurate for temperatures, precipitation did not have that luxury. In conclusion, last year's outlook fulfilled 8/13 points, significantly better than the half or less seen in every other outlook I've produced! Now onto this winter...

El Niño has returned! It formed during the months of April and June and is expected to continue through winter, a greater than 95% chance according to NOAA with a 71% chance that it peaks as strong (≥1.5 degrees Celsius). What does that mean? Above normal sea-surface temperatures in the equatorial Pacific, which tends to push the main jet stream into southern California for the winter months. The stereotype is a drier and warmer winter for the Pacific Northwest, but that's not always true, especially in the rainfall department where several years have brought above normal precipitation. Although this year in particular, I do expect more of the stereotype. Why? I went back to 1950 to find years similar to the season we just came out of and that have the potential to be on track with seasonal forecasts from NOAA and ECMWF, CFS, CANSIPS modeling. Known as an analog year, 1976-77 stuck out to me as the only El Niño that came after a third consecutive La Niña, bringing the worst drought in Pacific Northwest history, according to Western Regional Climate Center. Even though it was a weak El Niño, I included it with the benefit of the rare triple dip La Niña we just came out of. That year produced a dusting of snow for Portland with 11.73" of total precipitation from October through April, bringing 15" of snow for La Grande with 5.69" of total precipitation from October through April. Why stop there? I decided to expand remaining analog years to a mix of locations across each valley, providing a more accurate result than just one data set, which also excludes the stations with missing data. 1972-73 did a better job representing this season's transition timing and strength from La Niña to Neutral to El Niño, supporting NOAA's potential peak of strong this winter, despite the previous La Niña's only being two in a row. That year produced 6.5" of snow for Portland with 22.85" of total precipitation from October through April, bringing 27.1" of snow for Cove with 8.55" of total precipitation from October through April. The remaining two are moderate El Niño's, which my data set averages to be strength for this winter, although that's based on the previous two consecutive La Niña's - not three. Meaning, strong is absolutely a possibility, but moderate is a slam dunk. Snow and rainfall accumulations leading up to the 2009-10 season seem to be the most comparable for the Grande Ronde Valley, bringing 6" of snow for Union with 8.51" of total precipitation from October through April. The same season brought 0" of snow to Corvallis, although 38.13" of total precipitation from October through April. Snow and rainfall accumulations leading up to the 1951-52 season seem to be the most comparable for the Willamette Valley, as well as being the most consecutive years with measurable snow at Portland of 7 in a row, other than last season totaling 8. That year produced 5.8" of snow for Hillsboro with 31.79" of total precipitation from October through April, bringing 35.3" of snow to Union with 8" of total precipitation from October through April. But don't let that fool you! According to the U.S. Forest Service, "...the 1952 fire season weather was of near normal severity for the season as a whole, but was much above normal in the fall in western portions of Oregon and Washington." That raises concerns for the potential for a tough wildfire season next year, especially in the fall, although now I have data to support this claim. With the 4 analog years averaged together, that gives a mean of 3.1" of snow with 26.1" of total precipitation for the Willamette Valley from October through April, 5.68" less than usual. I'll place my range between 0-5" for snow since only 1/4 years gave widespread snow across the valley and the odds of a 9th consecutive year of measurable snow at Portland is slim. For the Grande Ronde Valley, that gives a mean of 20.9" of snow with 7.7" of total precipitation from October through April, 3.91" less than usual. I'll place my range between 10-30" for snow to factor in Cove's typical snow bias with Union's warm bias as La Grande remains somewhere in between. Let's take this month by month...

Reference time: 00z 24 Sep 2023. Analog years average 0.37" below normal precipitation for October with ECMWF Seasonal near normal, while CANSIPS predicts 1-3" above normal and CFS ranges 1" above to 1" below. It's clear that October won't be that dry, odds favor near to slightly above normal, which should average higher than the remainder of the season. Other than the outlier of the analog years that show 1 degree below normal, ECMWF Seasonal predicts 0-1 degrees above normal with CANSIPS showing 1-2 above and CFS ranging 0-3 above. That makes me pretty confident that we'll see near to above normal temperatures for October. Analog years average 0.6 degrees above normal for November, while ECMWF Seasonal remains near normal with CANSIPS showing 0-1 degrees above and CFS ranging 1 above to 2 below. Other than the outlier of CFS, temperatures look to remain slightly above normal for November. As for precipitation, analog years average 0.83" below normal with ECMWF Seasonal showing 0-1" below and CFS ranging 1-5" below, while CANSIPS predicts 0-1" above. It's clear November won't be wet, odds favor slightly below normal. Could the east side of the cascades get a late start with no snow in October? Not a slam dunk, although definitely possible. Analog years average the first dusting of snow in the Grande Ronde Valley on November 2nd, waiting until December 18th for the Willamette Valley. December brings the best shot for snow west of the cascades and the highest amount out east throughout the entire season, along with the potential for the coldest temperatures region wide. Analog years average 3.1 degrees below normal, although ECMWF Seasonal predicts 0-1 degrees above with CANSIPS near normal and CFS ranging 1 below to 3 above. It's a wild card, but I feel as odds favor near to slightly below normal. 2/4 of the December analog years brought negative digits to the Grande Ronde Valley and single digits to the Willamette Valley, 1972 and 2009 both brought that setup between the 8th and 13th of the month. 1.5/4 of the analog years brought widespread snow with hefty amounts for some, 1972 brought that setup for the Willamette and Grande Ronde Valley between the 5th and 11th of the month. Additionally, the Grande Ronde Valley saw a repeat in 1951, between the 18th and 26th of the month, but the Willamette Valley did not. 1/4 of the analog years brought a widespread wind event, 1951 brought that to the Pacific Northwest on December 4th (my birthday), bringing 50-80 mph gusts. Although that is only one data set, it is something that needs to be watched as our last windstorm hasn’t occurred since December 2014. Going forward, months will be grouped due to more uncertainty further out. Between the months of January and February, the driest of the season should take place. Analog years average 0.98" below normal, while the CFS ranges 1" above to 5" below with ECMWF Seasonal predicting 0-2" below and CANSIPS showing 1-3" below. Analog temperatures average 0.8 degrees below normal, while CFS ranges 3 below to 4 above with CANSIPS showing 0-2 above and ECMWF Seasonal predicting 1-2 above. Between the months of February and April, the warmest of the season should take place. Analog years average 0.93 degrees above normal, excluding March's 1.3 degrees below normal, something to watch as CFS ranges 2 below to 5 above. Although, ECMWF Seasonal and CANSIPS remain 1-4 degrees above normal, so I still expect the temperatures to get to their highest point, regardless if temperatures briefly cool down. If temperatures drop, analog years average the final snowflake threat across the Willamette Valley on April 2nd with the 15th for the Grande Ronde Valley, otherwise February into March seems like a much better bet to me. Overall, this setup would lead to 3-7" less than the precipitation that we received this past October through April, roughly 50-75% less than the snow we received last year! I can only imagine how the summer progresses...

That's my sixth annual outlook, enjoy this fall and early winter before it's too late!

- Gabe Curtis, Creator of G-Weather

Gabe's Official 2022-23 Winter Outlook

It's been a while since I've posted a blog. After getting hired as the weather forecaster for EOA.TV in December 2020, I featured my winter outlook on their platform the following year. But I didn't give myself enough time to share it across G-Weather, even though I had predictions for both the east and west side. Since then, I have begun releasing extended forecasts for them five times a week - rather than just one. I was able to earn my high school diploma early, so I've had much more time for all things weather this past year! Before I get to my fifth annual outlook, I want to go over my accuracy from last winter.

The main takeaway through the months of November and March were correct, the weak La Niña brought slightly higher snowfall amounts than usual with temperatures near normal. Portland was 0.78 degrees above normal on average, while La Grande was 0.39 degrees below. Although, I didn't think we would see as much rainfall. There were 24.36 inches reported in Portland between November and March - over 5 inches of my mean prediction. Not as significant in La Grande with 10.3 inches, but still roughly 1 inch above the mean that I came up with. You can't forget that cool and wet spring, which I should've extended the outlook into because April brought rare snow to Portland bringing the season total to 6.3 inches - roughly 2 inches above average. It also increased the snowpack, bringing La Grande's season total to 56.9 inches through May - roughly 10 inches above average. Trying to predict timing was a mixed bag. I correctly predicted the first dusting of snow in La Grande being in October, in fact it happened on the 13th - nearly two weeks after I released the outlook. Although Portland didn't see a dusting until December 8th, when I thought it was going to happen in November. But that possibility diminished when November had temperatures 3.3 degrees above average in Portland. In fact, it was also 3 degrees above in La Grande - which delayed my projection for the first widespread snow from November to December. November became the warmest and rainiest month region wide, unlike my prediction of January in Portland and February in La Grande. Things quickly changed the second half of December as I anticipated, arctic air spilled in from Canada between Christmas and New Year's. That allowed for the first widespread snow of 1 to 6 inches throughout Portland with highs generally in the 30's and lows in the 20's. 10 to 20 inches of snow reported through La Grande with highs generally in the 20's with lows in the 10's, although New Year's Day brought the morning low down to 22 below zero. That was the coldest and snowiest part of the season region wide, which became the most accurate projection of my outlook. Although we got more spotty snow accumulations in February, nothing widespread due to the lack of precipitation - opposite of what I thought. Despite that, we still managed to receive slightly above average precipitation in the entirety of the season. Good thing it wasn't as dry as I projected, the rain helped set up a better wildfire season! Now onto this winter....

We're going into a triple La Niña, which has only been recorded twice in the past 72 years - 1975 through 1976 and 2000 through 2001. Both years have produced only dustings of snow in Portland, although the previous year that they came out of are not comparable to this past season - other than being a double La Niña. Different story in La Grande, 1974 through 1975 is very similar to what we just came out of and that brings 51.5 inches of snow the following season with 15.2 inches of precipitation between October and April. I'm very confident in using those as a mean this season, bringing the snow range from 36 to 67 inches across the Grande Ronde Valley. Why such a big range? Keep in mind, Union and Wallowa are polar opposites. Union is usually the warmest area, while Wallowa is the coldest and La Grande is somewhere in between. In fact, the mean snow year brings 67.1 inches to Wallowa and 36.4 inches to Union - how perfect is that? As for Portland, there is not one particular year that is close enough to represent the mean. I had to combine 1971 through 1972, 1972 through 1973, 2017 through 2018 and 2018 through 2019 just to get bits and pieces of this past season. The year that follows those seasons brings anywhere from a dusting to 7 inches of snow, bringing the mean to 3.5 inches of snow with 27.6 inches of precipitation between October and April. Those are the best numbers that I can come up with, especially knowing that triple La Niña years haven't produced much snow. Although I shortened the range between 1 and 6 inches across the Willamette Valley since there wasn't enough data to support the possibility of no measurable snow. That would bring near to below average snowfall west of the cascades and near to above average snowfall east of the cascades, which would be slightly less than last season. The highest temperatures and precipitation should average out during the first half of the season, before the lowest settle in the second half. That would bring slightly lower temperatures and precipitation than last season in Portland, although slightly more in La Grande. Now onto specifics....

October looks to bring less precipitation than normal, according to shorter range models that I use on a day-to-day basis. Long range models believe that it could even be the one month the remainder of the calendar year that brings below average precipitation. In fact, the set of years that I chose from that month received rainfall from 2.55 inches below average to 0.79 inches above average. ECMWF Seasonal forecast model projects rainfall this October from 1 inch below average to 0.25 inches above average. It's clear that October won't be wet, the mean from all the data sets brings 0.62 inches below average. I'll place my rainfall range between 0.5 inches and 1.5 inches below average. Using the same data, October will feature the first snowflake in La Grande - but will wait to reach Portland until November as La Grande receives the most amount of snow this calendar year. Both months will feature near to slightly above normal temperatures, but precipitation will be higher in November with averages near to slightly above normal. December looks the warmest and rainiest. Record data received rainfall that month from 1.38 inches below average to 4.16 inches above average, while temperatures ranged from 1.4 degrees above average to 4.0 degrees above average. ECMWF projects rainfall this December from 0.25 inches above average to 2 inches above average, while temperatures range from 1 degree above normal to 2.5 degrees above normal. The rainfall mean from all the data sets gives 1.26 inches above average, so I'll place the rainfall range between 1 and 2 inches above average. The temperature mean is roughly 2.23 degrees above average, so I'll place the range between 2 and 3 degrees above average. January begins with slightly above average temperatures and precipitation, dropping near to slightly below into February. During that transition period, the snowiest part of the season should take place. March will feature the coldest month. Record data from that month ranged temperatures from 3.5 degrees below average to 0.4 degrees below average, while ECMWF projects between 0.25 degrees below average to 1 degree above average. The mean is roughly 0.79 degrees below average, so I'll place the range between 0.5 to 1.5 degrees below average. Data suggests the last snowflake will be in March for Portland and in April for La Grande. There isn't much else to point out, April will be near to slightly below normal in precipitation and temperatures. The Climate Prediction Center shows the chance of La Niña downgrading to 54 percent during the period of January and March. 2001 transitioned from La Niña to ENSO-Neutral during the period of February and April, while 1976 did so during the period of April and June. Based on that, there is reason to believe that we could see a transition to ENSO-Neutral late this winter and into spring as conditions are turning drier and colder. But with the lack of precipitation, that could negatively impact fire conditions next summer as temperatures warm. Definitely not a slam dunk, but something to think about as much of the precipitation will end earlier than last year.

Weeks of work later and that's what I came up with! Are you hoping for cold and snow? As Rob Grimes from PDX WX Analysis would say, "C'MON!!!!" - Gabe Curtis, EOA.TV's Official Forecaster and Creator of G-Weather

Winter Weather: Final Thoughts

We're coming up on the final hours before the "eye candy" starts! National Weather Service has issued winter weather alerts for most of our area.

Amounts will vary by region. But the most excessive will be in the cascades, through the gorge and the lowlands of Washington that look to measure 1 to 2 feet of snow through Saturday.

What do I expect for the valleys? Well, forecast models are still in disagreement. But after looking at weather maps for 12 hours straight, I'm giving it my gut feeling.

On the west side of the cascades, the best chance for accumulating snow will remain north of Wilsonville this evening. It'll take slower for temperatures to cool down there. By the time it does, the upper atmosphere will be too warm to accumulate much snow to the surface. Definitely can't rule out a dusting of snow in the southern part of the Portland metro area, but odds favor that it will mostly be a mix of freezing rain and sleet. It looks to be all rain as you progress further south into the Willamette Valley.

Tomorrow has the best chance for something more significant. I'm projecting all snow into the lowlands of Washington, spots could be nearing a foot by the end of the day. As for Portland, the north and east side could see several inches as there won't be much ice. Different story on the west and south side, ice looks to be too widespread to accumulate any more than an inch or two of snow. The worst of the ice will be from Woodburn to Albany, don't be out on the road then. Very little ice may may it as far south as Eugene, but not expecting any issues as the south wind will overcome all chances very quickly.

Saturday could see a decent band of wintry precipitation move through in the morning hours for the northern part of the valley, but not expecting as much as tomorrow. Tracking the final chance for some snow and ice developing Sunday and into early Monday, but that's far less certain how that will play out. Regardless, it looks like the lowlands will be done with winter weather heading into next week as temperatures warm up.

Once you head east of the cascades, precipitation is lighter. Not seeing any more than a few inches of snow through through this evening.

Snow is even lighter tomorrow, as the cold air will make conditions drier.

On the bright side, no freezing rain is expected on the east side of the state!

Snow picks up a bit heading into late Friday and early Saturday, but higher amounts remain to the west.

It's very fascinating that part of the western valleys will see more snow than the eastern valleys, but that's what happens when the low pressure center doesn't push further inland.

Enjoy this winter event while it's still around, we may not experience something like this again for a while. That's all from me, thank you for reading!

- Gabe Curtis, EOAliveTV's Official Forecaster and Creator of G-Weather