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Pattern February Discussion Part II

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pcbjr said:
JB tweeted this: Rare high amplitude phase 8 MJO for Feb being forecasted only 3 times last 40 years.. 1999,1988,1978

Went back and did composites for Feb of each of those three years; 1999 was warm (the month before - Jan - was also very warm, if not a "torch"), 1998 was cool (preceding Jan was very cool), 1978 was cold (as was the preceding Jan) (won't hog up a page showing all those maps LOL). Point being that even a strong Ph8 MJO doesn't always have the right mojo
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Thanks, Phil. I bolded what I think is an excellent point you made that can be applied to any single index. These indices are tools that work best when other tools (other indices) are used at the same time.

Further to what JB mentioned about high amp Feb phase 8, I'm going to repost some of the KATL temperature anomalies for these and other long stringed very high amp Feb phase 8 but I'll this time order them by strength instead of chronologically . 1988 was the strongest long stringed Feb high amp phase 8 followed by 1999, 2006, 1978 (there were actually two strings but the strongest one was the 4th strongest on record), and 2010:

1. 1988: 2/21-29. ATL averaged 1.4 colder than normal. No wintry precip.

2. 1999: 2/16-21. ATL averaged 0.8 warmer than normal. No wintry precip. Note that the MJO dropped to just outside the circle still in phase 8 just after this and got much colder with 0.4" of snow.

3. 2006: 2/4-9. ATL averaged 6.0 colder than normal & got a trace of snow.
Similarly to 1999, it then dropped to just outside the circle in phase 8 and got even colder with two days having a trace of snow.

4. 1978 two strings: 2/7-10 & 2/23-28. ATL quite cold with an average 8.7 colder than norm for the two strings combined. (Caveat: most of that winter was cold wherever was the MJO). They got two days with traces of snow.

5. 2010: 2/7-13. ATL was very cold with an average of 11.0 colder than normal along with a major snow (3.6") as well as a trace on another day! (Caveat: this was a very cold winter throughout regardless of where was the MJO thanks largely to historic levels of -AO/-NAO blocking.)
 
GaWx said:
Thanks, Phil. I bolded what I think is an excellent point you made that can be applied to any single index. These indices are tools that work best when other tools (other indices) are used at the same time.

Further to what JB mentioned about high amp Feb phase 8, I'm going to repost some of the KATL temperature anomalies for these and other long stringed very high amp Feb phase 8 but I'll this time order them by strength instead of chronologically . 1988 was the strongest long stringed Feb high amp phase 8 followed by 1999, 2006, 1978 (there were actually two strings but the strongest one was the 3rd strongest on record), and 2010:

1. 1988: 2/21-29. ATL averaged 1.4 colder than normal. No wintry precip.

2. 1999: 2/16-21. ATL averaged 0.8 warmer than normal. No wintry precip. Note that the MJO dropped to just outside the circle still in phase 8 just after this and got much colder with 0.4" of snow.

3. 2006: 2/4-9. ATL averaged 6.0 colder than normal & got a trace of snow.
Similarly to 1999, it then dropped to just outside the circle in phase 8 and got even colder with two days having a trace of snow.

4. 1978 two strings: 2/7-10 & 2/23-28. ATL quite cold with an average 8.7 colder than norm for the two strings combined. (Caveat: most of that winter was cold wherever was the MJO). They got two days with traces of snow.

5. 2010: 2/7-13. ATL was very cold with an average of 11.0 colder than normal along with a major snow (3.6") as well as a trace on another day! (Caveat: this was a very cold winter throughout regardless of where was the MJO thanks largely to historic levels of -AO/-NAO blocking.)
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Thanks!
Some folks can get too hung up on one index and not pay attention to or recognize the bigger picture (i.e., the entire set of dynamics, or as I said somewhere else here today - the grit in the gearbox).
But then ... I have some learnin' still to do, myself ... IMHO - and you're a good teacher - seriously!
 
ForsythSnow said:
Fortunately, it doesn't look as strong as the last event. Hopefully it doesn't go the way of severe weather again.
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For the moment and largely out of uncertainty @ this range, yes, but even a very subtle change in the placement, juxtaposition, and intensity of these waves will make all the difference... Given the general background in place & the eery similarities to late January's setup, it may become probable that someone in the southern tier, from Texas, Oklahoma, & Texas all the way to the Carolinas, VA & FL experiences severe wx in some way, shape, or form out of this ~ February 18-22.
 
Webberweather53 said:
For the moment and largely out of uncertainty @ this range, yes, but even a very subtle change in the placement, juxtaposition, and intensity of these waves will make all the difference... Given the general background in place & the eery similarities to late January's setup, it may become probable that someone in the southern tier, from Texas, Oklahoma, & Texas all the way to the Carolinas, VA & FL experiences severe wx in some way, shape, or form out of this ~ February 18-22.
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Does the cold and snowy pattern come after this!?
 
Despite the blocking that is perceived to be there, the 16/17 storm is trying to cut and at best is going to be an Apps Runner-Miller Bish like storm.
 
ForsythSnow said:
Well the NAO changed course happened suddenly.
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more head scratchin'
nao_mrf.gif

nao_sprd2.gif

4indices.png

up or down?
 
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Honestly the nao only helps the ne. -NAO, + PNA, + EPO is a recipe for cutters


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bouncycorn said:
Honestly the nao only helps the ne. -NAO, + PNA, + EPO is a recipe for cutters


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Click to expand...
2009/2010 seemed to help the South, the -NAO and blocking
 
I have heard arguments from both sides on what is the more important driver... Atlantic or Pacific? In my experience here in NC, high latitude blocking will trump a bad Pacific. However, that is mostly due to the CAD that's associated with blocking.
 
I'll have to look at some ensemble modeling, 500 heights to get some idea's up and keep an eye on the teleconnections.

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pcbjr said:
Thanks!
Some folks can get too hung up on one index and not pay attention to or recognize the bigger picture (i.e., the entire set of dynamics, or as I said somewhere else here today - the grit in the gearbox).
But then ... I have some learnin' still to do, myself ... IMHO - and you're a good teacher - seriously!
Click to expand...

You're welcome. You've inspired me to do a compilation of the peaks of 4 important indices, PNA, EPO (from your link), NAO, and AO (not necessarily in order of significance) during each string to go with the 5 highest amp long-stringed Feb phase 8 MJO episodes and the Atlanta temperature anomalies starting with the strongest phase 8 MJO and going less strong:

1. 1988: 2/21-29. ATL -1. Highest PNA: +1.5; Lowest EPO: -147; Lowest NAO: -0.2; Lowest AO: -2.3

2. 1999: 2/16-21. ATL +1. Highest PNA: +0.8; Lowest EPO: -7; Lowest NAO: +0.3; Lowest AO: +0.3

3. 2006: 2/4-9. ATL -6. Highest PNA: +1.4; Lowest EPO: -53; Lowest NAO: -0.5; Lowest AO: -2.5

4. 1978: 2/7-10,23-28. ATL -9. Highest PNA: +1.4; Lowest EPO: -234; Lowest NAO: -1.5; Lowest AO: -4.5

5. 2010: 2/7-13. ATL -11. Highest PNA: +1.2; Lowest EPO: +15; Lowest NAO: -1.3; Lowest AO: -5.0

My analysis of the above: Highest correlations of these 4 indices to cold during these very high amp Feb phase 8 strings in ATL fwiw appear to be -NAO and then the -AO close behind. I still maintain that the +PNA has one of, if not the, strongest correlation to SE US cold (I hope to post on this later when I get time), but here it isn't as clearcut partially due to a relatively low range. The lowest PNA (+0.8) was the warmest (1999), which is intuitive, but the coldest (2010) had the 2nd lowest lowest PNA (+1.2) although that is still a pretty high PNA. The -EPO is even less intuitive as the highest lowest EPO (+15) was the coldest (2010) and the 2nd lowest lowest (-147) was during the 2nd warmest (1988). But the EPO was intuitive with the other 3 cases.

Another thing to keep in mind is that these 5 very strong Feb phase 8 strings tended to be colder when that high strength wasn't as extreme. Is that due to MJO, itself, or is it due to the four other indices I listed? Who knows? One can drive themselves crazy trying to figure out the atmospheric puzzle!
 
gefs is entertaining with the cutoff days 7-10. you can see the blocking on the members as the cutoff hits a wall and heads due east
 
GaWx said:
You're welcome. You've inspired me to do a compilation of the peaks of 4 important indices, PNA, EPO (from your link), NAO, and AO (not necessarily in order of significance) during each string to go with the 5 highest amp long-stringed Feb phase 8 MJO episodes and the Atlanta temperature anomalies starting with the strongest phase 8 MJO and going less strong:

1. 1988: 2/21-29. ATL -1. Highest PNA: +1.5; Lowest EPO: -147; Lowest NAO: -0.2; Lowest AO: -2.3

2. 1999: 2/16-21. ATL +1. Highest PNA: +0.8; Lowest EPO: -7; Lowest NAO: +0.3; Lowest AO: +0.3

3. 2006: 2/4-9. ATL -6. Highest PNA: +1.4; Lowest EPO: -53; Lowest NAO: -0.5; Lowest AO: -2.5

4. 1978: 2/7-10,23-28. ATL -9. Highest PNA: +1.4; Lowest EPO: -234; Lowest NAO: -1.5; Lowest AO: -4.5

5. 2010: 2/7-13. ATL -11. Highest PNA: +1.2; Lowest EPO: +15; Lowest NAO: -1.3; Lowest AO: -5.0

My analysis of the above: Highest correlations of these 4 indices to cold during these very high amp Feb phase 8 strings in ATL fwiw appear to be -NAO and then the -AO close behind. I still maintain that the +PNA has one of, if not the, strongest correlation to SE US cold (I hope to post on this later when I get time), but here it isn't as clearcut partially due to a relatively low range. The lowest PNA (+0.8) was the warmest (1999), which is intuitive, but the coldest (2010) had the 2nd lowest lowest PNA (+1.2) although that is still a pretty high PNA. The -EPO is even less intuitive as the highest lowest EPO (+15) was the coldest (2010) and the 2nd lowest lowest (-147) was during the 2nd warmest (1988). But the EPO was intuitive with the other 3 cases.

Another thing to keep in mind is that these 5 very strong Feb phase 8 strings tended to be colder when that high strength wasn't as extreme. Is that due to MJO, itself, or is it due to the four other indices I listed? Who knows? One can drive themselves crazy trying to figure out the atmospheric puzzle!
Click to expand...
Drive themselves crazy or take a break from being in a courtroom!? I'll go for the sanity of weather, however unpredictable, after the unpredictable but enjoyable, and yes immediate, rush from the other (no models there - it's all now-casting without a window in sight ... LOL)
 
looking at the CVSv2 - yummy for cooking steaks ... something new, radical or not public that is a departure from those?
 
I can't wait to take a look at those weeklies

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