Winter Pattern Discussion 2014-2015 (December/January)

[Met1985]

0z Euro at day 10 is hinting at a western ridge, eastern trough.  Normally, I could care less about the day 10 Euro.  However, the 0z GFS and 6z GFS are showing a similar pattern to some extent.  I would take the details w/ a grain of salt.  However, I think the models are hinting at a gradual pattern change around December 20th.  That would seem to mesh w/ the weeklies that were discussed yesterday.  Overall, cold returns to N America and the lower 48(according to today's models) around Christmas.  I would look for a lag due to lack of cold.  It will take some time to rebuild the supply.  So, around Christmas day(give or take 2-3 days) the cold returns...

 

And Mr. Bob, I remember reading those weekly posts you referenced where no one wanted to believe them.  After that winter, I was a believer.  If every model was pointing the other direction, but the weeklies said, "Warm...."  I am going w/ the weeklies.  Last winter, they also did a great job w/ the depth and duration of the cold in January. 

 

edit:  Just checked CPC's NAO, PNA, and AO ensembles.  All hint at blocking in the east by mid-late December.  The NAO is finally making a turn downward.  Another thing to watch, as we all know, is when the NAO takes a dip...often a storm accompanies it.

Good post Carver. I really think that the key date is around the 20th for a pattern stepping down. This will be a process. I do not think though we really torch from know until the 20th though. Maybe no snow threats but no outright heat waves for this time of the year either. The Teleconnections do look a bit better in the later stages.

[John1122]

I agree.  I lived in Knoxville during that time frame and can say those numbers are wrong - too low.  Now, we had a lot of ice then when areas just outside of Knoxville were hammered w/ snow.  But still, more than 5.9".  Look-up how many days Knoxville schools had to make-up due to the snow - was a crazy amount.  However, I can't say this strongly enough, somebody has tampered w/ the climatological data at TRI.  No doubt about it.  I confronted MRX on FB several months(March) ago when I noticed the snowfall records had been changed...long standing records were changed.  I took screenshots of my FB conversation w/ them to save just in case.  But I am 100% certain data was "lost" or removed.  Consequently, it has made the 90s(terrible snow years minus some memorable storms) look far worse than they actually were.  Removing the 95-96 data is like removing the 93 blizzard...very big snow year.  And I ask, why would someone want the climatological data at KTRI to appear less snowy than it really was?  The response I received from KTRI is that the data is lost or missing....even though I found it on the web!!!!  Here is a graph from SRH.NOAA.  In the age of computers and the fact that during the 90s we kept double records(hard drives and paper), that data is not lost.  I work for the government, the data is redundant - no doubt about it.  Things don't get "lost" unless someone wants it lost.  That is about all I will say unless we want to begin a new thread about the missing data.  But clearly, there is much data missing. Thank you for bringing up the point.  I know your family has kept its own records, which might be helpful in this matter.

 

seasonalsnowfalltotals.JPG

 

If you all want to see the actual conversation, I will be glad to PM you since the screenshot has my FB name and don't want to post them on the net.  In March, they were actually trying to lower the yearly record from 51 in to 29 in.  I called them on it, and they left it alone or changed it back.  Still, the seasonal record is around 33, and I feel certain that should be much, much higher.  Interestingly, I can pull Kingsport's records for the 95-96' time frame and they show the big storm.  Now, sometimes there can be a descrepancy between the two cities(JC/KPT)...but this is a 12" descrepancy between Kingsport and the airport. 

 

I have no idea how or why there are such data errors. I was reminded again of this when David Aldridge did his winter forecast and said he was ignoring the current 20 year average because of all the missing data, all of which involved missing several large snow events. I know for sure that at least 15 inches of snow fell in Knoxville that season, I have the Knox News Sentinel for at least two of those storms where 7 and 8 inches were recorded at the airport. I believe that data entirely ignores at least one other 5+ inch event in Knoxville. I had around 40 inches that season and it was the most snow of my life until 2009-2010. 

[tnweathernut]

Looks like we are headed toward a "pop" goes the -EPO, with a trough developing in the east. I wonder if we can hold on to some warmer weather through Christmas or if we change more quickly than that.

[Coach B]

The site from MRX above shows why the vastly lower snow average for 1990-2010 happened. Tons of missing data from some very snowy years. That site shows .8 inches of new snow for February 2nd 1996 but a snow depth that goes from 0 to 8 inches from the 1st to the second. I'd guess close to 20 inches fell in the winter of 1995-1996 in Knoxville but it lists a total of 5.9 inches of new snow in January and February of that year with only 0.9 listed for all of February.

OHX's NOWData page is missing a bunch of snowfall data from 95-05 as well. Wonder why????

[jaxjagman]

After the barrage of seemingly endless computer model runs that indicated a long spell of mild temperatures across the continent, quite a few people who review or forecast weather threw out their winter forecasts. Out went the mostly "cold and snowy" descriptions, in came the terms of "blowtorch" and "balmy" for the DJF period 2014-2015. As I have often cautioned in releasing my predictions, outcomes shown by the numerical depictions are often short-term deviations from what eventually occurs.

So it should come as little surprise that beginning with the Friday 12z December 5 model runs, signs of high-latitude ridging, southern branch storminess and a slow decline in temperature were seen in the 11 - 15 day time frame. These shifts continued through Saturday, and affirms my belief that we are indeed headed into a "rough patch' covering the last week of December, and most of January, February into the first half of March. I have not changed my winter outlook one iota, for the reason that I thought there would be an extensive mild phase in this month that ultimately gave way to Arctic air and cases for more widespread snow.

The reason why the current "El Nino" type configuration (split flow with mild ImP and mT air mass dominance) will shift to a highly amplified set-up featuring +PNA, -AO, and -NAO elements has to do with the active southern branch flow. What the models, and the analog formula, are saying is that a stronger disturbance will take shape in Texas, swing through the Deep South, and then move up along and off of the Eastern Seaboard. I am uncertain as to which particular storm will be the change mechanism, but the analog sample (20 members) points toward a new shortwave moving out of northern Mexico on December 17, translating to a colder, stronger low pressure center near Cape Hatteras NC on the 21st. Perhaps it is the same feature shown by the ECMWF model family over Texas in ten days. But I call your attention to the fact that when you compare ALL of the numerical versions to the analog-derived forecast, you see how very similar the maps are. Most notable: besides the storm threat, check out the extensive high-latitude ridge display. Yes, +PNA, -AO, -NAO coming up on tap!

I am not predicting a rapid change to a colder scenario in the U.S., but insist that the southern branch storm system will be the catalyst. This impulse may become an entrenched cA vortex over QC and ON at some point in the last week of December, after bringing copious amounts of rain with some inland snows. The snowpack should start to increase in coverage over the Midwest, Great Lakes and Appalachia during the 11 - 15 day time frame, leading of course to colder temperature forecasts east of the Rocky Mountains. I suspect we are going to be dealing with a mild West vs. cold Central and East set-up by Christmas Day.

All I want for Christmas is 498dcm cAk 500MB vortex over Lake Michigan....and a moderate Modoki El Nino with a persistent moisture fetch from the Caribbean Sea to the Grand Banks.

You can figure it out.

Prepared by Meteorologist LARRY COSGROVE

[Carvers Gap]

After the barrage of seemingly endless computer model runs that indicated a long spell of mild temperatures across the continent, quite a few people who review or forecast weather threw out their winter forecasts. Out went the mostly "cold and snowy" descriptions, in came the terms of "blowtorch" and "balmy" for the DJF period 2014-2015. As I have often cautioned in releasing my predictions, outcomes shown by the numerical depictions are often short-term deviations from what eventually occurs.

So it should come as little surprise that beginning with the Friday 12z December 5 model runs, signs of high-latitude ridging, southern branch storminess and a slow decline in temperature were seen in the 11 - 15 day time frame. These shifts continued through Saturday, and affirms my belief that we are indeed headed into a "rough patch' covering the last week of December, and most of January, February into the first half of March. I have not changed my winter outlook one iota, for the reason that I thought there would be an extensive mild phase in this month that ultimately gave way to Arctic air and cases for more widespread snow.

The reason why the current "El Nino" type configuration (split flow with mild ImP and mT air mass dominance) will shift to a highly amplified set-up featuring +PNA, -AO, and -NAO elements has to do with the active southern branch flow. What the models, and the analog formula, are saying is that a stronger disturbance will take shape in Texas, swing through the Deep South, and then move up along and off of the Eastern Seaboard. I am uncertain as to which particular storm will be the change mechanism, but the analog sample (20 members) points toward a new shortwave moving out of northern Mexico on December 17, translating to a colder, stronger low pressure center near Cape Hatteras NC on the 21st. Perhaps it is the same feature shown by the ECMWF model family over Texas in ten days. But I call your attention to the fact that when you compare ALL of the numerical versions to the analog-derived forecast, you see how very similar the maps are. Most notable: besides the storm threat, check out the extensive high-latitude ridge display. Yes, +PNA, -AO, -NAO coming up on tap!

I am not predicting a rapid change to a colder scenario in the U.S., but insist that the southern branch storm system will be the catalyst. This impulse may become an entrenched cA vortex over QC and ON at some point in the last week of December, after bringing copious amounts of rain with some inland snows. The snowpack should start to increase in coverage over the Midwest, Great Lakes and Appalachia during the 11 - 15 day time frame, leading of course to colder temperature forecasts east of the Rocky Mountains. I suspect we are going to be dealing with a mild West vs. cold Central and East set-up by Christmas Day.

All I want for Christmas is 498dcm cAk 500MB vortex over Lake Michigan....and a moderate Modoki El Nino with a persistent moisture fetch from the Caribbean Sea to the Grand Banks.

You can figure it out.

Prepared by Meteorologist LARRY COSGROVE

And for the record, my comments this AM were written before reading these this evening from LC. Where I differ is that I think Feb and Dec will be warm - making the winter warmer than normal for temps. Again, snowfall should be normal as it can snow even in a warmish pattern. I think we get a solid six weeks of winter from Christmas to Feb 1. After that, I think Spring is early with maybe a snowstorm thrown in for good measure. Just a hunch...nothing more than that.

[jaxjagman]

And for the record, my comments this AM were written before reading these this evening from LC. Where I differ is that I think Feb and Dec will be warm - making the winter warmer than normal for temps. Again, snowfall should be normal as it can snow even in a warmish pattern. I think we get a solid six weeks of winter from Christmas to Feb 1. After that, I think Spring is early with maybe a snowstorm thrown in for good measure. Just a hunch...nothing more than that.

Wild card should be the PV though,when will we have the SSW?If of course we have one.If it doesn't happen until say Mid Jan his forecast would probably weigh out i'd think

[Carvers Gap]

Wild card should be the PV though,when will we have the SSW?If of course we have one.If it doesn't happen until say Mid Jan his forecast would probably weigh out i'd think

Cohen mentioned the strat warming maybe in early Jan. Depending on how long that takes to propagate and if it is strong enough and if it translates to our side of the hemisphere...true. I think we just have a good, normal winter - nothing extreme. And I will take it...even the messed-up snow average.

[jaxjagman]

 

Cool look at the PV, isosurface.Saw this on another board

[metwannabe]

After the barrage of seemingly endless computer model runs that indicated a long spell of mild temperatures across the continent, quite a few people who review or forecast weather threw out their winter forecasts. Out went the mostly "cold and snowy" descriptions, in came the terms of "blowtorch" and "balmy" for the DJF period 2014-2015. As I have often cautioned in releasing my predictions, outcomes shown by the numerical depictions are often short-term deviations from what eventually occurs.

So it should come as little surprise that beginning with the Friday 12z December 5 model runs, signs of high-latitude ridging, southern branch storminess and a slow decline in temperature were seen in the 11 - 15 day time frame. These shifts continued through Saturday, and affirms my belief that we are indeed headed into a "rough patch' covering the last week of December, and most of January, February into the first half of March. I have not changed my winter outlook one iota, for the reason that I thought there would be an extensive mild phase in this month that ultimately gave way to Arctic air and cases for more widespread snow.

The reason why the current "El Nino" type configuration (split flow with mild ImP and mT air mass dominance) will shift to a highly amplified set-up featuring +PNA, -AO, and -NAO elements has to do with the active southern branch flow. What the models, and the analog formula, are saying is that a stronger disturbance will take shape in Texas, swing through the Deep South, and then move up along and off of the Eastern Seaboard. I am uncertain as to which particular storm will be the change mechanism, but the analog sample (20 members) points toward a new shortwave moving out of northern Mexico on December 17, translating to a colder, stronger low pressure center near Cape Hatteras NC on the 21st. Perhaps it is the same feature shown by the ECMWF model family over Texas in ten days. But I call your attention to the fact that when you compare ALL of the numerical versions to the analog-derived forecast, you see how very similar the maps are. Most notable: besides the storm threat, check out the extensive high-latitude ridge display. Yes, +PNA, -AO, -NAO coming up on tap!

I am not predicting a rapid change to a colder scenario in the U.S., but insist that the southern branch storm system will be the catalyst. This impulse may become an entrenched cA vortex over QC and ON at some point in the last week of December, after bringing copious amounts of rain with some inland snows. The snowpack should start to increase in coverage over the Midwest, Great Lakes and Appalachia during the 11 - 15 day time frame, leading of course to colder temperature forecasts east of the Rocky Mountains. I suspect we are going to be dealing with a mild West vs. cold Central and East set-up by Christmas Day.

All I want for Christmas is 498dcm cAk 500MB vortex over Lake Michigan....and a moderate Modoki El Nino with a persistent moisture fetch from the Caribbean Sea to the Grand Banks.

You can figure it out.

Prepared by Meteorologist LARRY COSGROVE

Where do you find these. Does larry have a blog?

[jaxjagman]

 

Cosgrove

[1234snow]

Last night's Euro was one of the weirdest and craziest runs I've seen. It takes the cutoff that forms in the Northeast in a couple days and moves it due south. It first cuts it off over New England and it stalls it for a few days. But then the cutoff moves due south across Virginia and into North/South Carolina.

The 0z line stays over us for most of the run after the cutoff forms. If the Euro is right with its extreme solution then colder anomalies could take the place of warmer anomalies that was supposed to happen.

[Carvers Gap]

Last night's Euro was one of the weirdest and craziest runs I've seen. It takes the cutoff that forms in the Northeast in a couple days and moves it due south. It first cuts it off over New England and it stalls it for a few days. But then the cutoff moves due south across Virginia and into North/South Carolina.

The 0z line stays over us for most of the run after the cutoff forms. If the Euro is right with its extreme solution then colder anomalies could take the place of warmer anomalies that was supposed to happen.

Was literally about to write the same thing. I bet the 12z sobers up. Can't say I can rmember getting a storm rotating from Philly before. No good words. LOL.

[1234snow]

Was literally about to write the same thing. I bet the 12z sobers up. Can't say I can rmember getting a storm rotating from Philly before. No good words. LOL.

Lol, it sobered up only slightly. 12z Euro still moved the cutoff back to the south but it only got to around VA this time. Then it moves out to sea.

Heck toward the end of the run the Euro has 3 cutoffs across the county! Talk about wackiness.

[Carvers Gap]

Lol, it sobered up only slightly. 12z Euro still moved the cutoff back to the south but it only got to around VA this time. Then it moves out to sea.

Heck toward the end of the run the Euro has 3 cutoffs across the county! Talk about wackiness.

ImageUploadedByTapatalk1417990866.578228.jpg

Looks like "Day After Tomorrow." LOL. You think the steering currents are a bit weak?

[dwagner88]

Lol, it sobered up only slightly. 12z Euro still moved the cutoff back to the south but it only got to around VA this time. Then it moves out to sea.

Heck toward the end of the run the Euro has 3 cutoffs across the county! Talk about wackiness.

ImageUploadedByTapatalk1417990866.578228.jpg

That is possibly the craziest thing I've ever seen on any model run.

[tnweathernut]

I like where we are headed wrt ensembles, just don't know if we can get there to provide a legit snow opportunity before the end of the month.  

 

I think that is unlikely, but let's see how things progress over the next 3-5 days.

[1234snow]

Looks like "Day After Tomorrow." LOL. You think the steering currents are a bit weak?

That is possibly the craziest thing I've ever seen on any model run.

The 12z Euro today still has 2 cutoffs in the medium to long range. A broad trough moves into the west and breaks off into 2 cutoff lows. One of the lows treks across the Southeast and the other up near the Canadian Border and Minnesota. Even with the very amplified solutions we still don't have a chance of snow with the current teleconnections. The northern cutoff low really hurts the chances of snow. It cuts off the flow of colder air that could get drawn into the southern storm. Also there is obviously no cold air source before the system gets here.

12z Euro Hour 192:

Carvers, I just think there is tons off energy floating around in this active El Niño and all of the energy is turning negative tilt and cutting off. I am confused as to why the Northeast cutoff in a few days stalls and then moves southeast without a -NAO?

Like tnweathernut I don't think we will see good snow chances until the end of the month and that is okay with me. I am encouraged that we have a very active southern stream this winter with a lot of energy around creating a good number of storms. We are just waiting on a -AO/-NAO pattern to develop.

-AO/-NAO + active southern stream = BOOM!

I think January and February will have above average snowfall and below normal temps. It probably won't be wall to wall cold or wall to wall snowy (no winter ever is) but I think we will have a few bigger storms to boost snowfall totals.

[Stovepipe]

-AO/-NAO + active southern stream = BOOM!

 

I like the way you talk!

 

As an added bonus, if we flip the pattern at the end of the month or a little later, my (and Bob's) garlic will have that much more time to establish a good root system.  I got mine in a hair too late and it's just now starting to pop.  Can we squeeze another moderate week or two out of this month please?  After that, bring it!

 

More on topic I suppose, my GFS meteogram is trying it's hardest to give me a dusting tomorrow.  Might end up with a few flakes in the air before the day is done in Knoxville if the last two runs have anything to say about it. 

 

[Mr Bob]

I have a bunch of shoots up! Exciting, I know....

 

00Z Euro ens have some more stable ridging ont he west coast in the outlying period....Not an ideal winter pattern but some progress!

[tnweathernut]

There is quite a bit of ensemble guidance showing a return to a colder pattern later this month.  It might be tough to get to a pattern that fully supports snow/ice by Christmas, but if the ensemble guidance is correct, there will likely be a chance for someone in the mid-south or other part of the southeast to see something before the New Year comes crashing in.  

 

If the ensemble guidance is correct in the 11-15, it will be interesting to see if the trough on the east coast and the ridge on the west coast will be a stable pattern (vs. transient) and also if we can FINALLY (after 3 years) find an elusive -NAO.

[tnweathernut]

What a great write-up by Joe D at weatherbell. If you have access, check it out.  Very thorough and a great outlook..... if you like colder weather and possible snow opportunities down the line.

[1234snow]

Um, Hello 12z Euro!

[tnweathernut]

Um, Hello 12z Euro!

I will be in Nashville, looks about right. LOL

[John1122]

The Euro and Canadian have both been hinting around at a Miller A or B system rolling through around this time frame. The Canadian had a huge ice storm for most of Tennessee yesterday. 

 

Lots of storms rolling through the southern stream, just have to hope we can find some cold air to throw into the mix.

[tnweathernut]

[jaxjagman]

http://www.wsi.com/blog/energy/medium-range-why-colder-changes-will-continue-to-dominate-se/

[jaxjagman]

https://www.aer.com/science-research/climate-weather/arctic-oscillation

 

aer update today

[Carvers Gap]

https://www.aer.com/science-research/climate-weather/arctic-oscillation

 

aer update today

 

To sum up...No  SSW for two weeks.  Add ten days due to lag.  According to the article, still looking at three weeks(at the earliest) until a real shot at a pattern that supports consistent Arctic air getting dislodged off the pole.  Gradual cooling will take place over NA over the coming weeks.   The pattern over NW Asia is delaying the start of winter for the lower 48 it appears.  That snow graph for NA is not appetizing.  Still suspects winter to get cold and stay that way for several weeks - but delayed at this point due aformentioned feature in Asia.  Looks like patience will be the key...  

 

I suspected the pattern would change around Christmas.  I am wondering after reading this article if that is too quick...If I was just to base my thinking from information in that article, I would move the sustained cold to early or mid-January at the earliest.  The 0z GFS shows very little in the way of winter for the upper South, mostly cold chasing rain.  It still is depicting some cold late in the 14-16 day time frame.  The CFS2 still paints the eastern winter as mostly normal to above the rest of the winter.  By no means is winter over...it has yet to begin.  I am now beginning to think(but am not completely sold) that winter is going to be a contracted period of three to four weeks of winter wx (sometimes sever) beginning in early January and ending in early February.  What does that tall us?  Climatology is going to win the day.  We get winter in January more often than not.

 

(edited a couple of times w/in ten minutes of posting)

[jaxjagman]

The latest Euro is showing 6 inches for western Tn 3"for middle Tn,the set up is prime for us for a change