Winter 2014-2015 Pattern Discussion Thread II

[SN_Lover]

Looked at some historical data. If the Oscillations trend unfavorably, like models imply, 60's to even 70's are possible for Charlotte. Highs of 2014 late November and early December might happen again. Hope i'm wrong, bit I think we will have some harder times before it gets colder.

[FallsLake]

The 6z GFS does not look horrible. The LR actually looks good with some kind of fantasy system at day 12; but as I stated before the LR is useless. Just looking out to day 7 we go below normal temp wise but eventually go back above as a system pushes up through the center of the country. We can hope that this will pull down some cold after it passes to the north. I would say this is what we need to focus on. It will be critical to possible setting the stage for something in the day 11/12 time period.  

[Webberweather53]

I'm always quite intrigued when I see potential for snow in the desert southwest, this pattern looks like it could deliver to Las Vegas of all places...

http://forecast.weather.gov/MapClick.php?textField1=36.17&textField2=-115.13#.VJ_9bp3AA

[Met1985]

Just looking at the two Euro runs from yesterday and then the overnight run just shows you how volatile the models are from run to run are right know. We go to death ridge to trough in the East. Also this has been going on for quite a while.

[Webberweather53]

I also posted this under GaWx's new MJO thread, a plot of RAH past events & the MJO by month, the Pacific phases (6-8) are generally more favorable than the Maritime Continent & Indian Ocean (phases 2-4 specifically) (which makes sense knowing that based on my previous posts which discussed that in order to see big winter storms in the southern tier you need to block up the pattern over the northeastern Pacific & this is exactly what happens in MJO phases 6-8 when the MJO's associated convection & upper level divergence causes Pacific Jet Extension that strengthens the Aleutian Low & raises the PNA index... MJO phase 7 (w/ amplitude) in January is quite popular.

 

 

I also came across this diagram showing NE US mid-latitude cyclones w/ pressures below 995mb & their relation in MJO phase space. The Pacific phases once again are favored, although there's notably more activity in MJO phase 1-2 in the NE US vs here in NC...

 

[South_MountainWX]

Heck i was looking at a model last night think it was the gfs was showing what looked like snow for most of southern California possibley even l.a of all places lol

[packbacker]

Day 9-12 look potentially interesting for something to occur on the EPS, tall ridge in a good spot on the west coast, PV over Hudson Bay, SE ridge is weakened...

 

 

[Met1985]

Day 9-12 look potentially interesting for something to occur on the EPS, tall ridge in a good spot on the west coast, PV over Hudson Bay, SE ridge is weakened...

not a bad look at all. Let's see what the models do with the SE ridge today. I still expect some wild swings though. Just fits the craziness we are going through.

[Cold Rain]

^ That is a monster block up there around AK!

[packbacker]

^ That is a monster block up there around AK!

 

Yeah, and that's a 10+ day ENS mean too.  It would be nice to someone in the east score something around then, because after that the models take the pattern into the abyss.  I assume this is the period SnowGoose was talking about, I thought the GGEM-ENS looked the best or the worst in this case...

[packbacker]

^ That is a monster block up there around AK!

 

HAH..Allan agrees...

 

Allan Huffman ‏@RaleighWx  Watching 1/8-1/11 time frame for wintry threat upper SE/lower MA. Vortex shifts to QB, suppresses SE ridge, with cold highs across Lakes/NE.

 

His 2nd tweet is interesting...

 

Allan Huffman ‏@RaleighWx Models turn pattern mild after that. At least 5-10 days for mid-month. Then do we see colder pattern for late Jan? Perhaps, but questionable

[packbacker]

A good post by blizzardof96, I follow him on twitter too, between him, Eric and HM there is usually lot of good discussions.

 

http://www.americanwx.com/bb/index.php/topic/45074-winter-2014-15-medlong-range-discussion-part-2/page-24#entry3216457

[Cold Rain]

That block might be harder to break down than the models are indicating, Pack. Not so sure we quickly go back warm....assimg we do go cold first and the strength and placement of that block is correct.

[packbacker]

I also posted this under GaWx's new MJO thread, a plot of RAH past events & the MJO by month, the Pacific phases (6-8) are generally more favorable than the Maritime Continent & Indian Ocean (phases 2-4 specifically) (which makes sense knowing that based on my previous posts which discussed that in order to see big winter storms in the southern tier you need to block up the pattern over the northeastern Pacific & this is exactly what happens in MJO phases 6-8 when the MJO's associated convection & upper level divergence causes Pacific Jet Extension that strengthens the Aleutian Low & raises the PNA index... MJO phase 7 (w/ amplitude) in January is quite popular.

 

 

I also came across this diagram showing NE US mid-latitude cyclones w/ pressures below 995mb & their relation in MJO phase space. The Pacific phases once again are favored, although there's notably more activity in MJO phase 1-2 in the NE US vs here in NC...

 

 

 

That's interesting the difference between Jan/Feb.  In Jan it's clear we need to be in 6-7-8 or COD but Feb there doesn't seem to be a winner but rather to avoid 1-2-3.

 

Edit:  Interesting the Euro has us getting to phase 6 after Jan 7-8th, about the time it shows a chance at something.

[packbacker]

That block might be harder to break down than the models are indicating, Pack. Not so sure we quickly go back warm....assimg we do go cold first and the strength and placement of that block is correct.

 

Franklin had a good post the other day, let's see the warmth get inside day 10, I think we do warm up though, we seem to always warm in mid-Jan for whatever reason.  Look at the analogs below, it seems to always come, even in the snowiest winters...

[Isopycnic]

My Davis Vantage Pro2 is at +0.2f for the year so far.

[FallsLake]

Just looking at the 850 temp map for the 12z NAM at hour 84, would get most people excited.

 

http://mag.ncep.noaa.gov/Image.php?fhr=084ℑ=data%2Fnam%2F12%2Fnam_namer_084_850_temp_ht.gif&model=nam&area=namer&param=850_temp_ht&group=Model+Guidance&preselected_formatted_cycle_date=20141228+12+UTC&imageSize=M&ps=model

[sparkync]

Just looking at the 850 temp map for the 12z NAM at hour 84, would get most people excited.

I'll take it. Now wait and see!!

http://mag.ncep.noaa.gov/Image.php?fhr=084ℑ=data%2Fnam%2F12%2Fnam_namer_084_850_temp_ht.gif&model=nam&area=namer&param=850_temp_ht&group=Model+Guidance&preselected_formatted_cycle_date=20141228+12+UTC&imageSize=M&ps=model

[GaWx]

^{I just realized this morning that a very strong SSW is imminent:}

 

^{http://www.americanwx.com/bb/index.php/topic/44807-winter-2014-2015-medium-term-discussion/?p=3216533}

[tnweathernut]

^{I just realized this morning that a very strong SSW is imminent:}

^{http://www.americanwx.com/bb/index.php/topic/44807-winter-2014-2015-medium-term-discussion/?p=3216533}

So why does DS think its weak? Data looks good to me.

[mackerel_sky]

It's still a unicorn type of desperation thing to me, the ssw. Larry did a write up I believe in early Dec, that stated all the colder / snowy winters that did NOT have a ssw, and they weren't necessary for a good winter!??

[GaWx]

So why does DS think its weak? Data looks good to me.

 

I haven't the faintest idea. I'm awaiting his response.

[GaWx]

It's still a unicorn type of desperation thing to me, the ssw. Larry did a write up I believe in early Dec, that stated all the colder / snowy winters that did NOT have a ssw, and they weren't necessary for a good winter!??

 

 Yes and I'm not at all backing away from what I said. Actually, what I said is that a SSW is not at all necessary to generate a very strongly -AO month as only ~1/2 of them had a nearby SSW.

 

 Regardless of its impacts or lack thereof, its occurrence, itself, would seemingly be an important met. event that should generate discussion.

[dsaur]

Goose,

 I assume you're not going back to the 1930's. However, if you were to do so, Dec. of 1931 also had only two 32 or lower: both at 31.

 

 I just found there were only two in 12/1923 with lowest of 29, in 12/1900 with lowest of 30, and in 1889 with lowest of 29.

Larry, I've had 8 nights below freezing here 40 miles south of Atl..down below the edge of the earth, that's the official reading...and my own sensors read 12 mights below. A third of the month when I could have had snow if I'd had rain.

  The Atlanta reading is only for what, a square mile?  At what point does the data seem less potent due to the fact the airport was much less built up in the 30's, and the city heat island around it much less built up?  If that one square mile of space  had remained static down through the years, wouldn't it be a stronger signal, even with the growth around it?  And with the largest sprawling settlement in human history growing year after year, all around the airport, how can any correlation with a reading in the same spot in the 30's be made? Why wouldn't it just be apples vs oranges?  Climo would use the airport to produce data, but that data would have little to do with actual conditions on the periphery of the settlement, north or south.  Certainly in 1900 you are talking about a temperature taken in the midst of fields and forests as far as the eye could see, though I don't know where the sensor was placed back in 1900, lol.  Buckhead was a tavern in the woods.  Even my old stomping grounds in midtown was a good days wagon ride to the area that would be the airport.  I just know it wasn't a concrete and steel jungle, denuded of a good portion of the trees, and the contours of the land forever altered....over and over.  Wouldn't all that change over time be a factor?  Wouldn't two freezing temps in 1900 be far more indicative of warmer conditions in the general area, than the same readings today as they relate to conditions just 20, or so miles south of the airport? Or in Buckhead, or May retta, Carrollton, or Conyers? All a part of what is now Atlanta.  Just curious. T

[mackerel_sky]

Yes and I'm not at all backing away from what I said. Actually, what I said is that a SSW is not at all necessary to generate a very strongly -AO month as only ~1/2 of them had a nearby SSW.

Regardless of its impacts or lack thereof, its occurrence, itself, would seemingly be an important met. event that should generate discussion.

I'm still holding you to the 2 major wintry events for the ATL ! I'm hoping to benefit as well!

[GaWx]

I'm still holding you to the 2 major wintry events for the ATL ! I'm hoping to benefit as well!

 

Mack,

 You should but here is what I actually predicted:

 

1. One major ATL wintry precip. event and a nontrivial chance for two (much higher chance for two vs that for  an average winter) possibly incl. ZR.

2. At least three measurable wintry precip. events possibly incl. ZR.

3. DJF averaging -3 or colder.

[GaWx]

Larry, I've had 8 nights below freezing here 40 miles south of Atl..down below the edge of the earth, that's the official reading...and my own sensors read 12 mights below. A third of the month when I could have had snow if I'd had rain.

  The Atlanta reading is only for what, a square mile?  At what point does the data seem less potent due to the fact the airport was much less built up in the 30's, and the city heat island around it much less built up?  If that one square mile of space  had remained static down through the years, wouldn't it be a stronger signal, even with the growth around it?  And with the largest sprawling settlement in human history growing year after year, all around the airport, how can any correlation with a reading in the same spot in the 30's be made? Why wouldn't it just be apples vs oranges?  Climo would use the airport to produce data, but that data would have little to do with actual conditions on the periphery of the settlement, north or south.  Certainly in 1900 you are talking about a temperature taken in the midst of fields and forests as far as the eye could see, though I don't know where the sensor was placed back in 1900, lol.  Buckhead was a tavern in the woods.  Even my old stomping grounds in midtown was a good days wagon ride to the area that would be the airport.  I just know it wasn't a concrete and steel jungle, denuded of a good portion of the trees, and the contours of the land forever altered....over and over.  Wouldn't all that change over time be a factor?  Wouldn't two freezing temps in 1900 be far more indicative of warmer conditions in the general area, than the same readings today as they relate to conditions just 20, or so miles south of the airport? Or in Buckhead, or May retta, Carrollton, or Conyers? All a part of what is now Atlanta.  Just curious. T

 

Tony,

 I agree with you 1,000%, especially what I highlighted.

[mackerel_sky]

Mack,

You should but here is what I actually predicted:

1. One major ATL wintry precip. event and a nontrivial chance for two (much higher chance for two vs that for an average winter) possibly incl. ZR.

2. At least three measurable wintry precip. events possibly incl. ZR.

3. DJF averaging -3 or colder.

Deal! I would take this in a skinny minute!

[GaWx]

Meanwhile, the 12Z GFS has a major winter storm for part of the SE US 1/9-10 fwiw...mainly entertainment.

 

This is the typical very weak Miller A that usually causes widespread SE winter storms. They are very rarely caused by strong lows.

[FallsLake]

Meanwhile, the 12Z GFS has a major winter storm for part of the SE US 1/9-10 fwiw...mainly entertainment.

 

This is the typical very weak Miller A that usually causes widespread SE winter storms.

The 6z also showed sufficient cold and a storm in the same period. This might be a time to look at for some type of storm (hopefully it's wintery). All we can hope for at this time is for the cold to establish itself at the day 7 period. This(cold) is something we can realistically track at this time. An actual storm(to track) will have to wait.