Got my chair set up!
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Wintry Winter Discussion 2023/24
- Thread starter Rain Cold
- Start date
Which is interesting because it seems like for a number of years the GFS has had a warm bias in the summer and cold bias the further we get into fall and winter.
Brent
Member
cyclogent
Member
lexxnchloe
Member
Miracle snow
If the teleconnections and ensembles are on to how the first 10 days of December play out, there might really be a lot of busted monthly forecasts. While it’s not showing anything extremely cold, the biggest takeaway when looking at them is that there is nothing to indicate an extended stretch of above to well above average temperatures.
Brick Tamland
Member
Not saying it will happen since it's two weeks out, but the models have been showing something off and on in the long range around this time for a while now.Miracle snow
jeremyt
Member
Got to love the 0z run of the GFS, harder to get snow in NC outside of the mountains than it is in Mexico 
Webberweather53
Meteorologist
Experimenting with something new tonight. Having one of those very late night coding sessions (usually when I do my best work).
This is what the historical tercile summaries look like for El Niño events since 1855, weighted more heavily towards analogous events that were accompanied by a positive Indian Ocean Dipole (+IOD), negative Pacific Decadal Oscillation (-PDO), early winter -NAO, and a positive Atlantic Multidecadal Oscillation (+AMO), or warm Atlantic.
In essence, this provides you with a true apples-to-apples comparison of Climate Prediction Center (CPC) probabilistic winter outlooks to what has historically occurred in El Niño winters like this over the last 150+ years or so.
The plots will look a little noisier than the ones I've shown previously because I'm looking at finer-scale details in the local probability distribution at each point.
(i.e. splitting the data into thirds/3 parts instead of 2 equal halves yields slightly noisier data).
Here I've only looked at February, but I'd be curious about what other months show.
I plan to take a look at ERA-5 reanalysis monthly snowfall data (which goes back to 1940) at some point tomorrow and perform the same analysis (or in this case I guess today because it's already past local midnight here).
This is what the historical tercile summaries look like for El Niño events since 1855, weighted more heavily towards analogous events that were accompanied by a positive Indian Ocean Dipole (+IOD), negative Pacific Decadal Oscillation (-PDO), early winter -NAO, and a positive Atlantic Multidecadal Oscillation (+AMO), or warm Atlantic.
In essence, this provides you with a true apples-to-apples comparison of Climate Prediction Center (CPC) probabilistic winter outlooks to what has historically occurred in El Niño winters like this over the last 150+ years or so.
The plots will look a little noisier than the ones I've shown previously because I'm looking at finer-scale details in the local probability distribution at each point.
(i.e. splitting the data into thirds/3 parts instead of 2 equal halves yields slightly noisier data).
Here I've only looked at February, but I'd be curious about what other months show.
I plan to take a look at ERA-5 reanalysis monthly snowfall data (which goes back to 1940) at some point tomorrow and perform the same analysis (or in this case I guess today because it's already past local midnight here).
Webberweather53
Meteorologist
Now the map that most everyone here has probably been waiting for:
Snowfall tercile summaries (CPC-like probabilities) across the CONUS for El Niño winters since 1940 using ERA-5 reanalysis:
Snowfall tercile summaries (CPC-like probabilities) across the CONUS for El Niño winters since 1940 using ERA-5 reanalysis:
Webberweather53
Meteorologist
Same analysis, but over the entire Northern Hemisphere. It tends to get quite snowy over much of Eurasia during El Niños, esp over the Tibetan Plateau of western China.
Brent
Member
Webberweather53
Meteorologist
Fwiw, these are the (weighted) analogs I came up w/ for this winter & posted about on twitter/"X" a few days ago. I weighed more intense El Niños, El Niños accompanied by a positive Indian Ocean Dipole (+IOD), negative Pacific Decadal Oscillation (-PDO), a neutral - negative NAO in December, and a warm Atlantic (+AMO) more heavily than other Ninos.
Even when you account for things like long-term climate change and changes in instrumentation/measurement & sampling techniques over the record, this subset of years paints a rather cool/stormy picture across the southern tier of the US.
Snow is obviously a whole different animal. While I didn't factor the background warming of the climate into the ERA-5 (CPC-like) probability composite shown below, you definitely get the idea that things are really leaning in our favor this year regardless.
Even when you account for things like long-term climate change and changes in instrumentation/measurement & sampling techniques over the record, this subset of years paints a rather cool/stormy picture across the southern tier of the US.
Snow is obviously a whole different animal. While I didn't factor the background warming of the climate into the ERA-5 (CPC-like) probability composite shown below, you definitely get the idea that things are really leaning in our favor this year regardless.
Webberweather53
Meteorologist
Here's what precipitation looks like in ERA-5 for all El Niños (top) and these analogs (bottom).
Not all that far off from the latest CPC and C3S Ensemble Mean Forecasts.
sigwx
Member
Thank you for your analysis and being on board with all of us!!!
Brent
Member
Topeka got more snow in 12 hours than the entire winter last year ? I mean how is that possible
I didnt realize it but it's been twenty years since the CLT airport has had a double digit season.