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Wintry Winter Discussion 2023/24

griteater said:
I'm gonna hang in there for wintry prospects until they lay me in the coffin

This is loop of Oct/Nov/Dec/Jan runs of Euro Seasonal for February. Somewhat interesting seeing the trend of lower latitude Aleutian Low for February on Euro Seasonal....i.e. could facilitate a low latitude storm track (Cali/Baja into TX). +PNA/-EPO

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Alternate single image for Feb:

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So will I grit, but I'll self loath while I do it.

Aren't the weeklies though just programing in standard Nino meteorology and we're seeing that output? I'm not sure they're seeing the complex pacific forcing that causes eventually the jet to either retract or extend, avoid our needed sweet spot, and go to a western trough. I feel like all these extended products want to show what should happen.....but in time always shows the inevitable western trough.
 
SnowNiner said:
So will I grit, but I'll self loath while I do it.

Aren't the weeklies though just programing in standard Nino meteorology and we're seeing that output? I'm not sure they're seeing the complex pacific forcing that causes eventually the jet to either retract or extend, avoid our needed sweet spot, and go to a western trough. I feel like all these extended products want to show what should happen.....but in time always shows the inevitable western trough.
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Fair point, and it could be dead wrong, but the model should be picking up on what is going on over the past couple months with the stratosphere and the El Nino structure and should be able to add those as inputs to make a better guess....and just trying to pick up ideas from how the model is trending as we get closer.
 
griteater said:
Fair point, and it could be dead wrong, but the model should be picking up on what is going on over the past couple months with the stratosphere and the El Nino structure and should be able to add those as inputs to make a better guess....and just trying to pick up ideas from how the model is trending as we get closer.
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Just out of curiosity do you have the verification scores on the Euro Weeklies. I’m curious as to how accurate they are and how far out the accuracy goes.
 
Chazwin said:
Just out of curiosity do you have the verification scores on the Euro Weeklies. I’m curious as to how accurate they are and how far out the accuracy goes.
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I do not. Never really seen the accuracy scores for it. I'd say it has been more stable this year though with the strong nino. Not bouncing around out at range as much as normal
 
griteater said:
I do not. Never really seen the accuracy scores for it. I'd say it has been more stable this year though with the strong nino. Not bouncing around out at range as much as normal
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Correct me if I'm wrong, but isn't the mini SSW event trumping the warm phases of mjo with the ridge Bridge effect and subsequent pv split into the US? I know it will warm up, but hopefully not for long after cold spell
 
Looking ahead:

1) Short wintry window if/when the arctic blast kicks east (0-6 day window depending on how the models trend going forward): mid to just past mid-Jan

2) Atmospheric river into the west coast as the AK block retrogrades into Siberia / Brief thaw for us from our heavy hitting winter

3) Fairly quick flip to climo El Nino for late Jan into Feb as MJO will be on the move and rising AAM. Aleutian Low w/ some split flow. ?? will be whether the Pac Jet gets too over-extended. If yes, there will be too much waviness running into W Canada and it'll be tough to get it cold enough for wintry. If it is tame, should set us up for a few chances

Euro Wk MJO Product shows MJO -VP uplift signal already past the dateline here by 1/25

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Best daily panel on today's Euro Weeklies is on Feb 6

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Itryatgolf said:
Correct me if I'm wrong, but isn't the mini SSW event trumping the warm phases of mjo with the ridge Bridge effect and subsequent pv split into the US? I know it will warm up, but hopefully not for long after cold spell
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I would say that the MJO being in the E Hemisphere (warm phases) and the fall in AAM is at least helping somewhat with the propensity for this Arctic air to drop down into the W U.S.
 
griteater said:
I would say that the MJO being in the E Hemisphere (warm phases) and the fall in AAM is at least helping somewhat with the propensity for this Arctic air to drop down into the W U.S.
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Do you think the euro and euro eps is incorrect with it depiction of the cold being further south and east?
 
griteater said:
Falling zonal wind trend shown for Jan 16-17 on last 4 00z runs of the GEFS, with large drop in the most recent run

In addition, the 06z GFS Operational run shows an official SSW on January 16th

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Would it be wrong to say the split is already in motion and is already propagating down to at least 100 hpa? I don't have access to data other than 10 MB (too cheap, lol).
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Wild Weather Monger said:
Would it be wrong to say the split is already in motion and is already propagating down to at least 100 hpa? I don't have access to data other than 10 MB (too cheap, lol).
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Although there is a split in the contours here, an actual hardcore split would be when the entire Strat PV splits into completely separate 'daughter' low anomalies. So, this is showing an SPV that is stretched and pushed off the NPole a bit, which is how a SSW Displacement would be. But either way, the SPV is highly disturbed right now. The NASA GEOS MERRA forecast shows the lower stratosphere dropping to record / near record lows in mid-Jan (100mb)

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This image is from the 06z GFS run. This covers the full stratosphere and troposphere (1mb down to 1000mb). The blue coloring shows how the zonal winds are weaker than normal thru the stratosphere with some downwelling occurring in the forecast. Source: http://weatheriscool.com/

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You can get some good Strat images for free here with the NASA GMAO GEOS forecasts. Note that images can be slow to load when you click on them on that site (i.e. Animate button), but otherwise the loops work well once loaded. Source: https://fluid.nccs.nasa.gov/wxmaps//

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You analysis is intriguing but I'm always wondering what exactly it means. I would assume it leads to arctic outbreaks, etc.
 
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