2013 Fall Medium Range Discussion

[Ender]

so we are in good shape for PD3?

Not unless .3" is good enough to make it into the PD group.

This winter's behaving a lot like a first year nina. Which is kinda weird. Last year was definitely a nina, and this one should be at least neutral based on SST. Since it's behaving more nina-like, however, one would at least expect (hope) it'd act like a second year nina rather than a first. Second year ninas tend to be a little less arid than their first year predecessors. Oh well, there's still time for a miracle...

[Mike.Ventrice]

<blockquote class='ipsBlockquote'data-author="Ottawa Blizzard" data-cid="1975983" data-time="1357063824"><p>

Does anyone have access to the European weeklies? I've heard through the grapevine that JB is depressed about them as they essentially call for the end of winter for this year.</p></blockquote>

The CFS, which was harping on a very warm December as of early Nov, was somewhat insistent on a cold January. At least through its 12/25 forecasts. It's been emphatic about a cold, to even brutally cold, February for the last week and a half. Interestingly it was going for a cold/very cold Jan followed by a warm/very warm Feb until about 12/20 when it started to back down towards moderately cold for Jan and very cold for Feb.

I've only been following the CFS for the last 6 months or so. It seems that its "1 month lead forecast", which should be for weeks 4 - 8 from now, usually ends up being a "week 3/4 - week 6/7" forecast. With that caveate the "cold January" forecasted between Dec 1 and Dec 10 would be coming to an end here around Jan 6th. While the "warm Feb" from the same time range is about to start 1/6 and run until at least 1/20. After which the CFS's past week's forecasts of a "cold Feb" will start and run until 2/7 - 2/14.

 

This is something that drives me crazy about CFS v2. This model does a pretty good job representing convectively coupled equatorial waves and the MJO.  The model is also coupled with the ocean, and therefore can produce atmospheric-ocean feedbacks. However, in forecast mode, the model is way too slow propagating the MJO and other tropical waves.  It also overkills ENSO transitions states, which causes unrealistic MJO states and amplitudes. Kyle MacRitchie has wave diagnostics using CFS v2 and you can watch these model deficiencies in his time-longitude plots.

 

Since the model propagates tropical disturbances that impact extratropical circulation patterns in week 3 and 4 too slowly, as well as is too bullish on transitioning interannual states that impacts extratropical patterns at one to two month time scales, it doesn't surprise me this is the pattern you are observing. Happy new year to all.

[cbmclean]

Mike.Ventrice

I am intrigue by this statement found in your last post

"Since the model propagates tropical disturbances that impact extratropical circulation patterns in week 3 and 4 too slowly"

 

Although this might be a better topic for the MET 101 thread since t came up here hopefully people won't hold it against me.  I wonder if you or any other Met here might be willing to give a brief primer for interested laymen about how tropical disturbances broadly impact extratropical circulation.  In my opinion, this is a facet of of weather which is not often presented to non Met audiences.  We lay peeps have to look hard to even find hints of such things in the the most technical of weather predictions given to us.  Even then they are usually presented a bald assertions, with nothing in the way of explanation.  For example, I have been perplexed by statements made by mets about how the remnants of typhoons in the SE Asia basin could "join" up with the westerly flow and have impacts downstream in the US.  I would love to know more about how this works.

[Mike.Ventrice]

Mike.Ventrice

I am intrigue by this statement found in your last post

"Since the model propagates tropical disturbances that impact extratropical circulation patterns in week 3 and 4 too slowly"

 

Although this might be a better topic for the MET 101 thread since t came up here hopefully people won't hold it against me.  I wonder if you or any other Met here might be willing to give a brief primer for interested laymen about how tropical disturbances broadly impact extratropical circulation.  In my opinion, this is a facet of of weather which is not often presented to non Met audiences.  We lay peeps have to look hard to even find hints of such things in the the most technical of weather predictions given to us.  Even then they are usually presented a bald assertions, with nothing in the way of explanation.  For example, I have been perplexed by statements made by mets about how the remnants of typhoons in the SE Asia basin could "join" up with the westerly flow and have impacts downstream in the US.  I would love to know more about how this works.

 

The tropical-extratropical interface is currently one of the hotest topics in meteorology. I recommend going to AMS's journals and searching the Madden Julian Oscillation (MJO). You will find numerous topics of teleconnections, etc.

 

A recent paper I read with regards to boreal winter MJO event during an El Nino year impacting the 2009-2010 North East snow event: http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-11-00033.1

 

There are other indices that investigate the extratropical-tropical connection, such as Klaus Weikmann's and Ed Berry's Global Wind Oscillation: http://journals.ametsoc.org/doi/abs/10.1175/2008MWR2686.1?prevSearch=Global+Wind+Oscillation&searchHistoryKey=

 

Heather Archambault, an old friend and alumni from the University at Albany, did a lot of the 'pioneer' work on recurving West Pacific Typhoons and their potential impact on extratropical circulation. You can find her webpage and examples here: http://www.met.nps.edu/~hmarcham/

 

Most of the ground breaking research is still debatable in the meteorology community, and will not be released to the public for some time. For example, the MJO was discovered in 1972 by Madden and Julian, however we are only now starting to see hints of discussion of the MJO here and there. I recall during my stint for HS3 this past September, I watched the Weather Channel, for the first time, talk about the MJO and potential for tropical cyclogenesis over the Atlantic in week 3. Just in 2010, Dan K. (Accuweather's lead hurricane expert) came up to one of my posters at the AMS trop. conference and told me that people would laugh at me if I presented my poster (MJO + African easterly wave activity + tropical cyclogenesis over the MDR) if it were 5 years earlier. Another example is the recognition of convectively coupled Kelvin waves on tropical cyclogenesis. It took me 4 years of persuading and talks to get the National Hurricane Center to acknowledge these waves over the Atlantic (Tropical Storm Florence)... it all depends on if the mets who have been there for x amount of years approves, or better yet, believes in it. There are many more instances I've seen or experienced that toot the same type of tune... it's all part of the process of a growing science.

[wxmx]

Also, the MJO is unfavorable for the East now. I expect it to move toward more favorable phases in the last week of the month.

 

The GWO phase diagram is showing a low amplitude wave toward phase 4, which would favor a NE Pac ridge, which jointly with rising heights near the arctic, favor a full latitude ridge in that region, with a dipping EPO, that the models have been adamant with. Thus, my initial idea of a much colder CONUS for most of January, with the the possible exception near the east coast (which I expect to reverse by the end of the month) is looking good.

 

There's a high amplitude MJO wave right now which is forecasted by most models to orbit thru unfavorable phases for the next 2-3 weeks, which leads us to the final week of the month.

[Srain]

The trends via the 12Z GEFS and OP Euro suggest a very negative EPO regime and a stormy and cold pattern across the West and Plains as we near the mid January time frame.

[QVectorman]

The tropical-extratropical interface is currently one of the hotest topics in meteorology. I recommend going to AMS's journals and searching the Madden Julian Oscillation (MJO). You will find numerous topics of teleconnections, etc.

 

A recent paper I read with regards to boreal winter MJO event during an El Nino year impacting the 2009-2010 North East snow event: http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-11-00033.1

 

There are other indices that investigate the extratropical-tropical connection, such as Klaus Weikmann's and Ed Berry's Global Wind Oscillation: http://journals.ametsoc.org/doi/abs/10.1175/2008MWR2686.1?prevSearch=Global+Wind+Oscillation&searchHistoryKey=

 

Heather Archambault, an old friend and alumni from the University at Albany, did a lot of the 'pioneer' work on recurving West Pacific Typhoons and their potential impact on extratropical circulation. You can find her webpage and examples here: http://www.met.nps.edu/~hmarcham/

 

Most of the ground breaking research is still debatable in the meteorology community, and will not be released to the public for some time. For example, the MJO was discovered in 1972 by Madden and Julian, however we are only now starting to see hints of discussion of the MJO here and there. I recall during my stint for HS3 this past September, I watched the Weather Channel, for the first time, talk about the MJO and potential for tropical cyclogenesis over the Atlantic in week 3. Just in 2010, Dan K. (Accuweather's lead hurricane expert) came up to one of my posters at the AMS trop. conference and told me that people would laugh at me if I presented my poster (MJO + African easterly wave activity + tropical cyclogenesis over the MDR) if it were 5 years earlier. Another example is the recognition of convectively coupled Kelvin waves on tropical cyclogenesis. It took me 4 years of persuading and talks to get the National Hurricane Center to acknowledge these waves over the Atlantic (Tropical Storm Florence)... it all depends on if the mets who have been there for x amount of years approves, or better yet, believes in it. There are many more instances I've seen or experienced that toot the same type of tune... it's all part of the process of a growing science.

Mike I'm watching the CCKW maps and wondering since it is creating an area of enhanced vertical lift over phase region 6,7,8 etc and creating the same types of complex of storms that the MJO does. Have you noticed the CCKW producing the same teleconnection patterns that the MJO does on winter weather over North America that the MJO does such as an anomalous trough over the eastern US 7-10 days after phase 7/8/1 of the MJO that Moon, Wang, Ha talk about in there Feb. 2012 paper? Or is the convection too weak or too small of aerial coverage to impact broader large scale circulation? Because I'm seeing a weak CCKW going through the region of phase 6 right now and models are progging a weak trough over the eastern US for Jan 13-15 time frame which would correlate to a 10 day lag. Don't know if that is just coincidence or if there was a connection there.

[tacoman25]

The trends via the 12Z GEFS and OP Euro suggest a very negative EPO regime and a stormy and cold pattern across the West and Plains as we near the mid January time frame.

 

 

That is some impressive blocking on the 12z Euro.

[wxmx]

That is some impressive blocking on the 12z Euro.

 

Heh

 

[tacoman25]

When both the EPO and NAO go super negative, that usually leads to big-time cold for the CONUS.

[Mike.Ventrice]

Mike I'm watching the CCKW maps and wondering since it is creating an area of enhanced vertical lift over phase region 6,7,8 etc and creating the same types of complex of storms that the MJO does. Have you noticed the CCKW producing the same teleconnection patterns that the MJO does on winter weather over North America that the MJO does such as an anomalous trough over the eastern US 7-10 days after phase 7/8/1 of the MJO that Moon, Wang, Ha talk about in there Feb. 2012 paper? Or is the convection too weak or too small of aerial coverage to impact broader large scale circulation? Because I'm seeing a weak CCKW going through the region of phase 6 right now and models are progging a weak trough over the eastern US for Jan 13-15 time frame which would correlate to a 10 day lag. Don't know if that is just coincidence or if there was a connection there.

 

Yes, CCKWs can most definately impact the extratropical flow! On most occasions, CCKWs are often mistakened for an MJO. This is due to CCKWs commonly projecting onto the RMM PCs. If you composite a particular phase of the MJO (>1 simga) using Wheeler and Hendon's RMM indices, there is information of CCKWs already in there and are times when the RMM is showing a coherent MJO where in reality it is just a strong CCKW.

 

Something I use to do with my old office mates is have a medium range prediction log of severe weather over the US during spring time. The only predictor I used was CCKWs and was shockingly quite skillful giving a 2-4 week prediction of severe weather over the US by just predicting when a CCKW would be located over Africa.

 

The strongest and most coherent signature of a CCKW in the extratropics that I have seen is the equatorward progression of cold air down the lee of the Andes when a CCKW propagates from the East Pacific to over the Atlantic. It happens nearly every time! Now this equatorward propagating of cold air is due to an edge wave (or a Kelvin wave!) propagating down the lee of the Andes. Liebmann et al. 2010 talks a little about this problem... so does Kyle Griffin's masters dissertation. George Kiladis has a good deal of work with regards to CCKWs over the Pacific and extra-tropical Rossby wave trains in the southern hemisphere.

 

There is a tremendous amount of potential work to be done by a prospering young meteorologist with respect to CCKWs and extratropical circulation patterns. I know Paul Roundy's research group at UAlbany is tackeling this very same problem but with respect to equatorial Rossby waves and the MJO. I've done quite a bit of CCKW-extratropical circulation flow, but haven't made this research public.

 

There is a 1.5 standard deviation CCKW event over the West Pacific (I assume that is what you mean by phase 6?). I have been tracking this CCKW since November!! This CCKW has sparked, or preceded the initiation of the current MJO event. There has also been a couple of tropical cyclones forming after the passage of this CCKW over the Indian and West Pacific.

 

[Ender]

When both the EPO and NAO go super negative, that usually leads to big-time cold for the CONUS.

 

CONUS or NWUS? 

 

The -EPO, -NAO, oh and massive PV over Moscow, can occasionally lead to some pretty impressive winter weather events right down to sea level. In Washington. State. 

[cbmclean]

Mike.Ventrice

 

I appreciate you taking the time to post that information.  I know that it might be frustrating having us weenies asking you mets beginner-level questions.

 

I did not realize that the MJO was so cutting edge.  I had noticed that I was having troubled finding detailed layperson-accesible information about it via a standard Google search.  I have been particularly puzzled by that little MJO octant chart like the one on your profile picture.  Still tryign to figure out how to read it, but I am making progress.

 

It is kind of interesting how meteorological ideas filter down to the lay public.  Twenty years ago it seems like there was a rise in the general consciousness about El Nino and La Nino.  Beginning 5 - 10 years ago it seems like the general public started to learn about the AO, the NAO, and the PNA.  Now we have the MJO.  Some of us find it fascinating.  Others probably find it annoying because they want the weather to be simple so taht the weatherman/woman can tell them exactly when it will be hot, when it will be cold, when it will be dry, and when it will be wet.

[QVectorman]

Ya Mike that is the one I have been following too. Thanks for confirming my theory and all the great info. I just found your W&H diagram for the CCKW. Excellent! I noticed this the first time back on Dec. 15-16 time frame when there was another CCKW around Vietnam/Singapore longitude region and your W&H diagram confirms that (I can't go back that far on the map loop, haha). In fact it shows up nicely on the W&H Dec. 16-17 entering phase 6 then we had the snow storm across the GLKS on Dec. 26. Now we have CCKW entering 6 again Jan 5 with the 12z GFS and previous runs hinting at a decent strength shortwave for Jan 15-16 across the midwest. (or maybe I'm wrong and it's was more phase 7 or 8 since both CCKW's were/forecasted in phase 7...Dec. 19 and now Jan. 8...so 19+7=Dec 26 and 8+7=Jan 15.) Maybe you can clear that up whether phase 6 or 7 was the perpetrator lol. 

 

Also, you can help me with figuring this out...the Dec. 19-20 storm that dumped 18 inches on Madison WI appears to have been triggered by the MJO growing past 1SD into phase 1 on Dec. 13...5-7 days later Madison storm. I see and remember that same time frame the CCKW was over phase 3/4 region (so I would rule out the CCKW for triggering during THAT time frame). But the CCKW was weak but moving through phase 8/1 region on the 10-11 so that would give it a 8-9 day lag to the plains (which to me seems feasible). My gut assumption is that the MJO was more responsible for producing that wave than the CCKW. But maybe it was a mix of both signals?? Or which signal do you believe was the trigger?

 

[wxmx]

CONUS or NWUS? 

 

The -EPO, -NAO, oh and massive PV over Moscow, can occasionally lead to some pretty impressive winter weather events right down to sea level. In Washington. State. 

 

I'm pretty sure that if you look at analogs with an EPO and NAO indices <-1.5 SDs, you'll find that there are an overwhelming number of cold analogs for Washington, D.C....probably even higher than Washington state, though I'm not sure about that last one.

[Harry]

I'm pretty sure that if you look at analogs with an EPO and NAO indices >-1.5 SDs, you'll find that there are an overwhelming number of cold analogs for Washington, D.C....probably even higher than Washington state, though I'm not sure about that last one.

 

 

Yeah.. I am not sure where Ender is coming from with that?

[Met1985]

Guys great discussion on the MJO and the CCKW!

[blizzard1024]

The trends via the 12Z GEFS and OP Euro suggest a very negative EPO regime and a stormy and cold pattern across the West and Plains as we near the mid January time frame.

 

UGH...what an awful pattern for the east. enjoy it out west! 

[Ender]

Yeah.. I am not sure where Ender is coming from with that?

My thoughts were -NAO, -EPO, -PNA = great for PAC NW...not so phenomenal for NE & MA. In other words, possibly a great way to waste a -NAO.

[The_Global_Warmer]

Ummm?  What?

 

 

 

 

Of Course this is a nice gradient pattern for my region.  Possibly, but it seems like a quite NAO flip from the OP.

 

[Geos]

That NAO forecast by the GFS couldn't be any more different then the CPC's outlook!

 

That definitely suggests gradient pattern with a EPO like that.

 

[Ender]

Ummm? What?

Of Course this is a nice gradient pattern for my region. Possibly, but it seems like a quite NAO flip from the OP.

Doesn't look anything like yesterday's ECMWF 10-day NAO eiher. Of course it's probably not safe to look at one or two deterministic forecasts and say, "Well, there ya go...Biblical blocking is on it's way, impressive -NAO, -EPO and a possible disaster on the PNA front too..." Things don't look nearly as catastrophic (for the east) per the 0Z EC; though they don't look exciting for snow lovers. Not those north of the VA/NC state line.

[Mike.Ventrice]

Ya Mike that is the one I have been following too. Thanks for confirming my theory and all the great info. I just found your W&H diagram for the CCKW. Excellent! I noticed this the first time back on Dec. 15-16 time frame when there was another CCKW around Vietnam/Singapore longitude region and your W&H diagram confirms that (I can't go back that far on the map loop, haha). In fact it shows up nicely on the W&H Dec. 16-17 entering phase 6 then we had the snow storm across the GLKS on Dec. 26. Now we have CCKW entering 6 again Jan 5 with the 12z GFS and previous runs hinting at a decent strength shortwave for Jan 15-16 across the midwest. (or maybe I'm wrong and it's was more phase 7 or 8 since both CCKW's were/forecasted in phase 7...Dec. 19 and now Jan. 8...so 19+7=Dec 26 and 8+7=Jan 15.) Maybe you can clear that up whether phase 6 or 7 was the perpetrator lol. 

 

Also, you can help me with figuring this out...the Dec. 19-20 storm that dumped 18 inches on Madison WI appears to have been triggered by the MJO growing past 1SD into phase 1 on Dec. 13...5-7 days later Madison storm. I see and remember that same time frame the CCKW was over phase 3/4 region (so I would rule out the CCKW for triggering during THAT time frame). But the CCKW was weak but moving through phase 8/1 region on the 10-11 so that would give it a 8-9 day lag to the plains (which to me seems feasible). My gut assumption is that the MJO was more responsible for producing that wave than the CCKW. But maybe it was a mix of both signals?? Or which signal do you believe was the trigger?

mjo.jpg

 

The experimental CCKW-phase space diagram I have on my webpage has 8 phases like Wheeler and Hendon's RMM, but note that the phase locations are different than the phases in RMM. The first two EOFs for the CCKW-index shows a wave number two signature... meaning the index will be the highest amplitude when there are two CCKWs.  Therefore, for each phase, there are two locations that a CCKW could be, or is when there are two CCKWs. This index will still work with one strong CCKW, but it won't be overly strong... so there are some downfalls.

 

It is very difficult to attribute the genesis of one extratropical storm to the MJO or a CCKW.  Much research would be needed to investigate causality verses coincidence for that particular case. While the MJO and CCKWs can influence the extratropical circulation, not every event is the same!  So there will be differences in extratropical patterns for different MJOs or CCKWs. There is some current research that suggests there are extratropical circulation patterns that tend to occur during preferable phases or locations of MJO convection. The methodoly behind such research is commonly done by compositing Wheeler and Hendon's RMM phases when the index was greater one sigma.  But the relationships from this methodology does not necessarily mean the relationship will hold true for every MJO because it shows up in the composite.  Knowing when the relationship will breakdown or hold is key.

 

  

From a glance (don't hold me to this!), it appears that the Dec 19-20 snow storm over WI had no contribution from the MJO.  A time-longitude plot of 200 hPa merdional wind averaged over 30-60N shows that there was an extra-tropical Rossby wave train over the Northern Hemisphere that transversed over the US during the time of the snow storm.  In the tropics, a strong CCKW was passing over the East Pacific-Atlantic region, in phase with the extra-tropical Rossby wave train. There was no MJO event during this time, even though the RMM MJO signal came out of the inner-core. This "MJO" was just noise in the RMM PCs, and not active during this time.  If I had to point fingers, I'd begin investigating the CCKW for there has been considerable recent research that shows CCKWs usually have an associated extratropical Rossby wave train in the Winter Hemisphere. But that being said, CCKWs and extratropical circulation has not been established in our field and some of the top research meteorologists would look at you with 10 heads if you suggested to them your hypothesis! 

[OSUmetstud]

Doesn't look anything like yesterday's ECMWF 10-day NAO eiher. Of course it's probably not safe to look at one or two deterministic forecasts and say, "Well, there ya go...Biblical blocking is on it's way, impressive -NAO, -EPO and a possible disaster on the PNA front too..." Things don't look nearly as catastrophic (for the east) per the 0Z EC; though they don't look exciting for snow lovers. Not those north of the VA/NC state line.

 

It's plenty of exciting in the long range for the midwest and the northeast...I'm not sure what you're looking at.  If you look at ensemble progs around day 9/10 and beyond...there's a nice gradient pattern in there.  I would bet against epic cold...but that could change later in the month.

[OSUmetstud]

though I don't feel the say way about the mid-atlantic..might have to wait a bit longer, there.

 

 

[QVectorman]

The experimental CCKW-phase space diagram I have on my webpage has 8 phases like Wheeler and Hendon's RMM, but note that the phase locations are different than the phases in RMM. The first two EOFs for the CCKW-index shows a wave number two signature... meaning the index will be the highest amplitude when there are two CCKWs.  Therefore, for each phase, there are two locations that a CCKW could be, or is when there are two CCKWs. This index will still work with one strong CCKW, but it won't be overly strong... so there are some downfalls.

 

It is very difficult to attribute the genesis of one extratropical storm to the MJO or a CCKW.  Much research would be needed to investigate causality verses coincidence for that particular case. While the MJO and CCKWs can influence the extratropical circulation, not every event is the same!  So there will be differences in extratropical patterns for different MJOs or CCKWs. There is some current research that suggests there are extratropical circulation patterns that tend to occur during preferable phases or locations of MJO convection. The methodoly behind such research is commonly done by compositing Wheeler and Hendon's RMM phases when the index was greater one sigma.  But the relationships from this methodology does not necessarily mean the relationship will hold true for every MJO because it shows up in the composite.  Knowing when the relationship will breakdown or hold is key.

 

  

From a glance (don't hold me to this!), it appears that the Dec 19-20 snow storm over WI had no contribution from the MJO.  A time-longitude plot of 200 hPa merdional wind averaged over 30-60N shows that there was an extra-tropical Rossby wave train over the Northern Hemisphere that transversed over the US during the time of the snow storm.  In the tropics, a strong CCKW was passing over the East Pacific-Atlantic region, in phase with the extra-tropical Rossby wave train. There was no MJO event during this time, even though the RMM MJO signal came out of the inner-core. This "MJO" was just noise in the RMM PCs, and not active during this time.  If I had to point fingers, I'd begin investigating the CCKW for there has been considerable recent research that shows CCKWs usually have an associated extratropical Rossby wave train in the Winter Hemisphere. But that being said, CCKWs and extratropical circulation has not been established in our field and some of the top research meteorologists would look at you with 10 heads if you suggested to them your hypothesis! 

 

Thanks Mike that makes sense. Is there a place to look at a time-long plot for forecasted 200hPa merdional wind averages to catch x-t RW trains? Is this a x-t RW train that is inadvertently calculated on the CCKW map below circled in red since it's outside the tropics and show strong merdeonal wind vectors? As I recall I noticed the same signature back on Dec. 16 time frame traveling across above 30N too and it was a 30-40 longitude degrees east ahead of the less contoured CCKW below it in the tropics. Same set up as today's map.

 

Also: Which W&H diagram on your page do you recommend for the most pure MJO signal (VPM indices, VPM partial, space-time or 6 variable)..ie one that would indicate that there was no MJO event during Dec. 11-13 time frame. I notice several of your diagrams appear to have kept the MJO in the COD at that time or near it but obviously the signal was none existent and produced a chaotic pattern and the lines go all over I'm having a hard time deciphering the date stamps and which one was the best at indicating that. 

[Mike.Ventrice]

Thanks Mike that makes sense. Is there a place to look at a time-long plot for forecasted 200hPa merdional wind averages to catch x-t RW trains? Is this a x-t RW train that is inadvertently calculated on the CCKW map below circled in red since it's outside the tropics and show strong merdeonal wind vectors? As I recall I noticed the same signature back on Dec. 16 time frame traveling across above 30N too and it was a 30-40 longitude degrees east ahead of the less contoured CCKW below it in the tropics. Same set up as today's map.

 

Also: Which W&H diagram on your page do you recommend for the most pure MJO signal (VPM indices, VPM partial, space-time or 6 variable)..ie one that would indicate that there was no MJO event during Dec. 11-13 time frame. I notice several of your diagrams appear to have kept the MJO in the COD at that time or near it but obviously the signal was none existent and produced a chaotic pattern and the lines go all over I'm having a hard time deciphering the date stamps and which one was the best at indicating that. 

sun.jpg

 

I have x-t plots of 30 days with GFS 7-day forecast appended:

http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/v.200.anom.30.30N-60N.gif

 

 

 

Yes, extratropical waves that have simliar eastward phase speeds as Kelvin waves will project onto the Kelvin filter, and therefore will be contoured. So as you state, the contours outside of the tropics are identifying an extratropical Rossby wave, not a Kelvin wave. The Kelvin waves will be near the equator

[QVectorman]

I posted this in the NE forums yesterday but it applies for every where east of the Rockies....

The GWO analogs eluded to this second warm up all the way back on Dec. 14. It will be short lived with the warmest air being tempered by cooler/colder air arriving in the Jan 15-19 range moving into the Jan 20-25 range with much colder air. Based on GWO and strat. analogs I'm guessing the coldest core of the 850 temps behind the short waves for the Jan 15-19 time frame will remain warmer than -15C then be reinforced with a coldest core of -15 to -25C for Jan 21-25 with a core of cold in the -25 to -30C range possibly as cold as -36C at some point for Jan 25-30. With -33C sneaking over the northern plains or GLKS or NE. Of course the cores of the coldest air will probably remain north of the border but still one can extrapolate what kind of 850 temps would be making down to the central US with those types of 850 temps just north of border.  With shortwaves arriving with more cold air for Jan 24-27 and Jan 27-29 and Feb 1-5. Though it appears the last week of Jan into Feb again would be the coldest air. Of course as stated before the caveat to these is how strong is the southerly flow ahead of these shortwaves that will also produce a spike in temps a day or two before the wave. So a strong wave will have a strong flow and could really spike temps for a day or two before it's arrive too. 

 

 

Actually I made a mistake when forecasting back in Dec. and I hate to flip flop...a big pet peeve of mine but since part of this is in testing stage I had conflicting strat and GWO signals for the 10-13 time frame and I assumed that the strat signal for cold would over whelm the GWO signal for warmth and the cold air would dominate for that time frame. But the GFS seems to be hinting that the GWO will dominate instead for that time frame. Which would change it to warm from Jan 8-10 then a fall in 850 temps for 1 or 2 days after peak in 850 temps then a spike in 850 temps Jan 11-13 which would put us back on track to a fall in 850 temps 1 or 2 days after that which lines up with the Jan 15-19 time cold pocket that I have forecasted previously. I still stand by a shortwave tracking through the central/eastern US although it may be weak Jan 10-11 as I stated last month. Which again since this is still in testing and working out kinks...so the GWO signal that I used that shows up for Jan 8-10 and Jan 11-13 may be a teleconnection that produces pattern (HP cell over the SE) that forces a wave to track west of the Mississippi and into Canada putting the east in a region of strong southerly flow that ends up producing warmer 850 temps. Since both waves for those periods on the GFS appear to stay west of the MS and track northward. 

 

QVectorman, on 14 December 2012 - 04:54 PM, said:

With the newest GWO numbers today the latest analogs indicate a 15-20F warm up in sfc temps Jan 3-Jan 6 compared to prior days highs across Midwest or NE (the Dec. 31-Jan 3 cold episode) and analogs suggest a stair stepped 15-20F temperature fall behind the warm up 1-2 days after that, meaning another spell of colder air Jan 5-8.

I extended my outlook through Jan 8 on Dec. 14. I still feel comfortable with those dates and with the newest GWO analogs and latest 10 and 30 mb temp forecast it appears the time frame between Jan 8-10 will see a warm up over the east with a short wave moving through the east Jan 10-11 with cooler air dropping in behind it for Jan 10-13 across the MW/GLKS and then pockets of cooler air arriving Jan 15-19 time frame for the east followed by a second reinforcement of cooler air Jan 20-24.

[QVectorman]

I have x-t plots of 30 days with GFS 7-day forecast appended:

http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/v.200.anom.30.30N-60N.gif

 

 

Yes, extratropical waves that have simliar eastward phase speeds as Kelvin waves will project onto the Kelvin filter, and therefore will be contoured. So as you state, the contours outside of the tropics are identifying an extratropical Rossby wave, not a Kelvin wave. The Kelvin waves will be near the equator

 

Great! So we are in almost the same CCKW and xt RW train set up as back on Dec. 16! Looks like that xt RWT will be over midwest about +8 days from now making Jan 14 target date.

[donsutherland1]

Some morning thoughts...

 

1. A renewed period of blocking (AO-) appears increasingly likely. Blocking analogs cited in #6 and the larger pool in #25 indicated a high probability that the January AO would average < 0. The main winter blocking analogs I cited were 1966-67, 1981-82, 2002-03, 2009-10. There has been a stratospheric warming event. Sometimes those events reflect a bottom-up response to a blocking regime (one just ended) and sometimes they reflect a top-down situation that would lead to renewed blocking. The stratospheric warming has gone down to about 10 mb. Personally, I'd like to see it propagate further down beyond 30 mb as happened during the 2009-10 winter. The GFS ensembles are in good agreement about the AO's going negative, possibly even tanking down the road.

 

2. There is good consensus on the ensembles that the EPO will go negative.

 

3. We are now in the transition to a period of moderation. Temperatures will likely peak in the East on Sunday-Tuesday (1/13-15). As noted previously, this is a temporary period of warmth. It is not the end of winter so to speak. Around 1/20 +/- a few days, the changes in the AO and EPO should produce a colder pattern and that pattern is likely to be of longer duration and greater magnitude than the one that is ending. The Plains States will likely see the cold occur first and they could also experience the largest cold anomalies.