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Winter Forecast


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Going to make this brief and easy to read.

 

While El Niño winters are typically the easiest to forecast, sample size issues are a concern once again, given complicating factors in the analog suite. Given these complications, I've essentially gone back and done a fractal analysis, taking bits and pieces of relevant analogs and stitching them together to depict what I believe will occur this winter.

 

This winter, the dominating low-frequency forcings are a powerful El Niño and potentially record-breaking +QBO wind-field in the tropical stratosphere. While there are several semi-viable analogs in terms of these two variables alone, nearly all of them feature contaminating forcings and/or variables that reduce their usefulness, including volcanic activity and high solar activity. That said, these analogs can still be useful on both seasonal and sub-seasonal scales.

 

The analogs I'm using this year will not be used to make sub-seasonal predictions (considering they are all unique and feature major all-around differences). The analogs are 1957-58, 1982-83, 1987-88, 1997-98, and 2006-07. These are what I consider the best overall analogs to the upcoming winter, mostly taking ENSO and the stratosphere into account, but also looking at factors such as solar activity and intraseasonal tropical forcing.

 

Prediction: Despite the aforementioned, my forecast is fairly straightforward and bland. I'm forecasting a classic backloaded El Niño winter over the U.S. with a stratwarm event/wave 2 between January 1-15, and a flip to a -NAM between January 10-25, under the anticipation of a more favorable strat/HT this winter vs the other big Niños. I also suspect the mid/late winter blocking will be NAO-based, as opposed to EPO-based, considering the anticipated nature of the NPAC wave train.

 

November: Overall -PNA/+EPO/+NAM. Warm overall across U.S. That said, intraseasonal IO forcing w/ Ewd progression in VPs favors an Arctic blast mid-late month over the central and/or eastern portion of the country, should this play out.

 

December: Overall +PNA/+EPO/+NAM month. Warm month overall across U.S. that probably grows warmer with time. Any shots of cold following spasms in the NPAC vortex will be limited to the eastern seaboard. Cool anomalies in the far S/SE, average to above average elsewhere.

 

January: Transition month, overall a +PNA/+EPO/+NAM month with a flip from a -NAM later on. Still warm over most of the U.S. in the means, colder than normal in the S/SE 1/3 of the US. Classic El Niño stratwarm initiates between January 1-15 with a series of wave breaking events that will crash the NAM. This should be more of a -NAO type response (starting between January 10-25) as opposed to a -EPO type response, though the nature of these phenomenon is difficult to predict.

 

February: Overall +PNA/neutral EPO/-NAM month, with blocking based in the NAO domain. Should be a flip to colder weather across the eastern half of the nation, warmer/drier out west versus December/January.

 

March: Overall +PNA/-EPO/-NAM, should be cold over much of U.S. That said, this is a low-confidence forecast and will depend on the exact nature of the late-winter stratospheric progression.

 

Below are aggregated 500mb anomaly maps using the analogs I listed earlier. This should not be taken verbatim, rather this should be used as a guide to the overall seasonal progression.

 

December: Note the +NAM, and strong, poleward-biased NPAC vortex.

 

500mb heights

 

image.png

 

 

850mb temps

 

image.png

 

 

January: Note the overall SW retrogression of the Aleutian low, accompanied by a signal for large scale wave breaking over the polar domain in the Western Hemisphere:

 

500mb heights:

 

image.png

 

 

850mb temps

 

image.png

 

 

February: Notice the -NAM (NAO based, typical of Niños) and further SW retrogression of the Aleutian low:

 

500mb heights

 

image.png

 

 

850mb temps:

 

image.png

 

This is about all I have to offer. Looking forward to all suggestions and/or general feedback.

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There is some hope for cold somewhere along the line in the PNW based on those analogs. 2006-07 had some good stuff here and Jan 1998 had a decent Arctic outbreak. Some people may not be aware of how close the NW came to being smacked in late Jan / early Feb 1988 also. At one point the NWS was calling for a huge snowstorm and bitter cold. I'll never forget how disappointed I was when it fell through. At any rate the opportunity was there, and that's beside some reasonable cold in Dec 1987.

Death To Warm Anomalies!

 

Winter 2023-24 stats

 

Total Snowfall = 1.0"

Day with 1" or more snow depth = 1

Total Hail = 0.0

Total Ice = 0.2

Coldest Low = 13

Lows 32 or below = 45

Highs 32 or below = 3

Lows 20 or below = 3

Highs 40 or below = 9

 

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I would be curious about any specific thoughts you have for my area Phil. Clearly above average temps with low arctic chances, but how about precipitation or snowfall?

Winter 23-24: Total Snow (3.2")    Total Ice (0.2")     Coldest Low: 1F     Coldest High: 5F

Snow Events: 0.1" Jan 5th, 0.2" Jan 9th, 1.6" Jan 14, 0.2" (ice) Jan 22, 1.3" Feb 12

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There is some hope for cold somewhere along the line in the PNW based on those analogs. 2006-07 had some good stuff here and Jan 1998 had a decent Arctic outbreak. Some people may not be aware of how close the NW came to being smacked in late Jan / early Feb 1988 also. At one point the NWS was calling for a huge snowstorm and bitter cold. I'll never forget how disappointed I was when it fell through. At any rate the opportunity was there, and that's beside some reasonable cold in Dec 1987.

I personally think November holds the most potential for you guys, with January holding some potential if a major stratwarm/wave2 were to occur, and do so earlier than I currently anticipate.

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I would be curious about any specific thoughts you have for my area Phil. Clearly above average temps with low arctic chances, but how about precipitation or snowfall?

I'm not too familiar with climo/topography out there, but I'd bet on a wetter than normal winter in the region, with the most prolific storminess occurring January and March. Don't know enough about snow climo to say much, but if you can educate me a bit on that, I can probably make a prediction.

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I'm not too familiar with climo/topography out there, but I'd bet on a wetter than normal winter in the region, with the most prolific storminess occurring January and March. Don't know enough about snow climo to say much, but if you can educate me a bit on that, I can probably make a prediction.

Well we average 55" at the airport, I'm at 4500 feet, and there is a large mountain range to my east with scattered mountains and valleys to the west but the mountains are lower. Any other info you need? We typically see snow with 500-1000 thickness of the low 540s.

Winter 23-24: Total Snow (3.2")    Total Ice (0.2")     Coldest Low: 1F     Coldest High: 5F

Snow Events: 0.1" Jan 5th, 0.2" Jan 9th, 1.6" Jan 14, 0.2" (ice) Jan 22, 1.3" Feb 12

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Well we average 55" at the airport, I'm at 4500 feet, and there is a large mountain range to my east with scattered mountains and valleys to the west but the mountains are lower. Any other info you need? We typically see snow with 500-1000 thickness of the low 540s.

Thank you.

 

In that case, I'd expect a snowier than average winter at your elevation, barring a complete and utter Pacific firehose. This is a strong Niño, but it's no 1997-98 in terms of forcing strength and longitude.

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That's sticking your neck out there. Thanks for putting the work into it.

No problem, it's a hobby of mine. I just wish more people would do it.

 

I remember Flatiron, Jim, and Tim used to make long range forecasts frequenty, often with great accuracy. Not sure why they stopped.

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No problem, it's a hobby of mine. I just wish more people would do it.

 

I remember Flatiron, Jim, and Tim used to make long range forecasts frequenty, often with great accuracy. Not sure why they stopped.

I have some ideas that I want to put together when I have some time.

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Winter 23-24: Total Snow (3.2")    Total Ice (0.2")     Coldest Low: 1F     Coldest High: 5F

Snow Events: 0.1" Jan 5th, 0.2" Jan 9th, 1.6" Jan 14, 0.2" (ice) Jan 22, 1.3" Feb 12

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I have some ideas that I want to put together when I have some time.

Awesome. I very much look forward to hearing your thoughts, especially regarding the progression in January.

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If I hear or read the term "modoki" again, I'm going to scream. I wish that word was banned.

 

Also seeing a lot of horrible stratosphere analysis lately. Point of note, several forecasts using ENSO alone as a proxy for NAM progression w/o accounting for changes in low-freq antecedent stratospheric conditions, solar, and long term Hadley/Walker ratios.

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I'm amazed by how on point Phil's Winter forecast has been thus far... Here comes the well advertised (& what will likely be brief, but couldn't be timed better wrt Thanksgiving Holiday) shot of cold east of the Rockies with a classic northeast Pacific ACWB in concert with a significant AAM crash...

 

http://weatheradvance.com/home/weather/weatheradvance.com/wp-content/uploads/2015/11/gfs1.png

 

http://weatheradvance.com/home/weather/weatheradvance.com/wp-content/uploads/2015/11/ecm_z500a_5d_noram_11-1024x768.png

 

 

The strong-Super NINO composites are nothing to sneeze at either. October's temperature distribution using 11 strong El Ninos I derived from merging ONI rankings from 12 SST datasets was captured very nicely & if this shot is as strong as advertised, with major erosion of the +anoms east of the Rockies (esp. in the plains) November looks like it will also perform well & December is pretty self-explanatory...

 

http://weatheradvance.com/home/weather/weatheradvance.com/wp-content/uploads/2015/11/FotorCreated-1024x448.jpg

 

http://weatheradvance.com/home/weather/weatheradvance.com/wp-content/uploads/2015/11/November-US-Temps-Strong-Super-El-Ninos.jpg

 

 

 

http://weatheradvance.com/home/weather/weatheradvance.com/wp-content/uploads/2015/11/cd152.7.224.5.312.6.42.43.prcp_.jpg

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