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Pattern December Dud 👀

Mitch West said:
We just suck at dropping a trough properly.
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If you can strengthen that trough in the NE/SE Canada and get a stronger cold feed from that, then we could make that look work, all though it would still be messy. But wintry is wintry, and recent CAD events have done well in the upstate
 
I think what’s going to happen in general from now til early February, is we go from this strong Nino pattern to the classic nina look.

During the very slow transition process between these 2 regimes, especially in early to mid January or so, that’s when we will probably see the +TNH/-EPO pattern shine and will probably provide our best chances for snow/ice this winter.
 
Metwannabe said:
Yep made some noise when it cane through, temp down to 48. 14° drop in 30 mins, not bad
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Dare I say it. Even cleaned out most of those annoying bed sheet size brown oak leaves that litter up a mans yard in dribble fashion all winter.

Awesome pic John 1122. Best way to get rid of leaf litter, bury it under snow.
 
jeremyt said:
I thought that didn’t happen until the 21st, must be some new stuff I wasn’t aware of!
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Nope, the days are getting shorter till then overall but sunsets have begun getting later... its not new, you are just ill informed

www.timeanddate.com

Sunrise and sunset times in Raleigh

Calculations of sunrise and sunset in Raleigh – North Carolina – USA for December 2024. Generic astronomy calculator to calculate times for sunrise, sunset, moonrise, moonset for many cities, with daylight saving time and time zones taken in account.
www.timeanddate.com www.timeanddate.com
 
Here's how the ERA-5 Outgoing Longwave Radiation (OLR) MJO Index (OMI) shakes out for NC winter storms since 1940. Looked at (& had to dig up) any winter storm that produced measurable snow east of the mountains or a glaze of ice.

First table here are the daily probabilities of a winter storm, sorted according to ENSO phase. It's actually crazy to see a 20% daily chance of a winter storm during cool neutral ENSO & phase 1 OMI (Western Hemisphere convection).

Phases 4-5-6 of the OMI MJO index tend to be unfavorable overall, while 8-1-2 are generally conducive for wintry weather.

There's also some ENSO sensitivity to these favorable OMI MJO phases. Phase 1 (western hemisphere convection) is better in cold ENSO (like this year), while Phase 2 (Indian Ocean convection) is more favorable in El Niño.

Screenshot 2024-12-11 at 9.11.18 PM.png



This is what the differences look like compared to climatology.

Screenshot 2024-12-11 at 8.56.15 PM.png

Screenshot 2024-12-11 at 8.51.49 PM.png


Here are the total day counts by ENSO phase:

Screenshot 2024-12-11 at 8.56.24 PM.png


https://psl.noaa.gov/mjo/
 
Webberweather53 said:
Here's how the ERA-5 Outgoing Longwave Radiation (OLR) MJO Index (OMI) shakes out for NC winter storms since 1940. Looked at (& had to dig up) any winter storm that produced measurable snow east of the mountains or a glaze of ice.

First table here are the daily probabilities of a winter storm, sorted according to ENSO phase. It's actually crazy to see a 20% daily chance of a winter storm during cool neutral ENSO & phase 1 OMI (Western Hemisphere convection).

Phases 4-5-6 of the OMI MJO index tend to be unfavorable overall, while 8-1-2 are generally conducive for wintry weather.

There's also some ENSO sensitivity to these favorable OMI MJO phases. Phase 1 (western hemisphere convection) is better in cold ENSO (like this year), while Phase 2 (Indian Ocean convection) is more favorable in El Niño.

View attachment 155796



This is what the differences look like compared to climatology.

View attachment 155795

View attachment 155793


Here are the total day counts by ENSO phase:

View attachment 155794


https://psl.noaa.gov/mjo/
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Fantastic, Webb, I am sure this took a lot of time and effort. So it looks as if going into phases 1 and 8 give better odds versus the traditional thought that phase 7 was the big ticket item, with the exception of warm neutral?
 
Stormdoc said:
Fantastic, Webb, I am sure this took a lot of time and effort. So it looks as if going into phases 1 and 8 give better odds versus the traditional thought that phase 7 was the big ticket item, with the exception of warm neutral?
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Well the traditional more widely known RMM MJO index and this OLR MJO index are calculated differently. This OLR MJO index relies on filtered OLR anomalies, whereas RMM relies on that and zonal low-level + upper level winds. I’d be interested to see an extension of the RMM index using ERA-5.


In any case, here’s where the OMI index was as of December 9.

Ideally, in this situation we want to get it into phase 1 in January, as this would nearly double our odds (vs normal) of seeing a winter storm, but phase 8 is also good.

IMG_3939.png
 
Webberweather53 said:
Well the traditional more widely known RMM MJO index and this OLR MJO index are calculated differently. This OLR MJO index relies on filtered OLR anomalies, whereas RMM relies on that and zonal low-level + upper level winds. I’d be interested to see an extension of the RMM index using ERA-5.


In any case, here’s where the OMI index was as of December 9.

Ideally, in this situation we want to get it into phase 1 in January, as this would nearly double our odds (vs normal) of seeing a winter storm, but phase 8 is also good.

View attachment 155801
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So I know there's a lag time with response to things like the NAO turning negative, etc. I'm assuming there is a lag time for the MJO as well?
 
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