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Winter 2014-2015 Pattern Discussion Thread I

LithiaWx

By LithiaWx,
in Southeastern States

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GaWx

GaWx

Posted
Posted

I remember that too. I was very young but I remember it melted by noon. Maybe Larry can help us out on the year. I know parts of the south had snow around Christmas 1989, but not sure that was the year that we had snow .

 

I'll have to check later. I think that the def. of a white christmas per the NWS may be 1"+ on the ground. So, that one may not count officially. It can be confusing.

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BullCityWx

BullCityWx

Posted
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CHRISTMAS? Long time readers know there is very little skill in a specific weather forecast beyond seven days, but we can often gather ideas about trends in the 7 to 15 day period. Still no sign of the Arctic Oscillation (AO) or the North Atlantic Oscillation (NAO) flipping negative for now, and it looks like temperatures will be close to average values. Doesn’t bode well for those dreaming of a White Christmas. See the Weather Xtreme video for maps, graphics, and more details.

 

^ what he actually said

 

James Spann is a great severe weather guy. He has, undoubtedly, saved hundreds if not thousands of lives in Alabama. However, in my opinion, he struggles with the long range in winter.

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packbacker

packbacker

Posted
Posted

I read from HM and usedtobe this AM in the mid-atlantic thread that the AO and NAO aren't flipping that soon.  What Spann said is supported by others.

 

Thanks for sharing...with the likelihood that this Dec won't have a solid -AO I looked at relevant analogs that fell in the following criteria...

 

+ENSO (0.3 or higher)

+PDO

Dec AO warmer than -0.3

 

For Nov, we get a cold central US.

 

For Dec, we obviously get a +AO/+NAO, we get the low over AK/Aleutians and we get a warm central-US and Canada.

 

For Jan/Feb we get a textbook setup for the SE/East for winter/snow, the analogs for RDU average out to 11" of snow.  And if you toss the super nino torch of 1998 it's even better, but I left it in.

 

For me this is going as I had hoped, things start to evolve end of Dec and hopefully by mid-January we are in a solid cold/snowy pattern.  I still think end of Dec this area, probably western/elevation areas start getting snow chances.

post-2311-0-99212900-1418143896_thumb.pn

post-2311-0-90732100-1418143900_thumb.pn

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LithiaWx

LithiaWx

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Thanks for sharing...with the likelihood that this Dec won't have a solid -AO I looked at relevant analogs that fell in the following criteria...

 

+ENSO (0.3 or higher)

+PDO

Dec AO warmer than -0.3

 

For Nov, we get a cold central US.

 

For Dec, we obviously get a +AO/+NAO, we get the low over AK/Aleutians and we get a warm central-US and Canada.

 

For Jan/Feb we get a textbook setup for the SE/East for winter/snow, the analogs for RDU average out to 11" of snow.  And if you toss the super nino torch of 1998 it's even better, but I left it in.

 

For me this is going as I had hoped, things start to evolve end of Dec and hopefully by mid-January we are in a solid cold/snowy pattern.  I still think end of Dec this area, probably western/elevation areas start getting snow chances.

 

I think this looks great.  I've said since before winter started that patterns come and go and we just need to hope to have the good patterns land in prime climo.  It's looking more and more likely that this is exactly what may be happening.  Prime pattern in prime climo.

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Webberweather53

Webberweather53

Posted
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Wow, that's very cool!  Let's hope the models keep on improving with the warming. 

 

I'm sure you've heard about the super-massive stratospheric warming that took place in 1984-85 (which was followed by record breaking cold, below zero temps across much of central NC January 21, 1985, he just sent me this animation of the incredible event... He added in a few pressure levels as well (from top to bottom 5mb, 30mb, & 150mb) He also sent me the animation to the 2009-10 warming event...

I would definitely bookmark or save these, extremely valuable information...

 

1984-85 SSWE 

https://dl.dropboxusercontent.com/u/16376055/76665.mov

 

2009-10 SSWE

 

https://dl.dropboxusercontent.com/u/16376055/09.mov

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Jon

Jon

Posted
Posted

I read from HM and usedtobe this AM in the mid-atlantic thread that the AO and NAO aren't flipping that soon.  What Spann said is supported by others.

Nice quotes but they didn't really say anything jaw dropping. usedtobe said the AO will be "maybe neutral at best" which, I disagree at the "at best" part...-AO has been progged at models to go neutral in the LR, but it has also been progged to dive negative...If you're going to say the AO might go neutral you're at least on the fence here. Usedtobe also stated he tends to be consevative with pattern changes, so I take that as he's dampering his expectations and thus, his AO/NAO predictions. Usedtobe also says the pattern is improving towards Christmas.

 

HM only mentions the AO/NAO once in his post and it's not even a prediciton, he's saying he's just waiting for it to come around, which can be antyime from here until what, the end of winter? I assume he thinks it's possible for both to flip before Jan, or at least the AO.

 

usedtobe, on 09 Dec 2014 - 10:21 AM, said:

    Right now I'd still place the probability of getting snow xmas week pretty much at climo. I had been leaning a little above so I could still change my tune by Thursday's outlook but right now am not ready to pull the above normal for xmas lever.  The southern storm track is a big plus but the NAO and AO  are still likely to be positive or for the latter maybe neutral at best while the former is still gonna be positive.  We have to hope there is enough ridging over the west to sneak enough cold air into the area while also having the pressure stay high over the great lakes so any high pressure are doesn't get pushed off the coast.  That's always a worry with a positive nao.  Like you, I still think we have a good January and think the pattern looks to be improving some towards xmas but.....I tend to be conservative with pattern changes.

 

 

HM, on 09 Dec 2014 - 10:28 AM, said:

    Sounds good. Basically, the background PDO-ENSO state favors a climo progression, for a change. We've had a negative state for so long that usually there is no sign of a southern stream at this point or PNA. This background state allows each passing week to do what it is supposed to do in the Mid Atlantic and slowly increase probability of snow. That's really all you can ask for at this stage. As far as anything significant, until the NAO/AO comes around that will obviously be low chances. But a parade of southern stream lows is definitely a welcomed sight!

 

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LithiaWx

LithiaWx

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Nice quotes but they didn't really say anything jaw dropping. usedtobe said the AO will be "maybe neutral at best" which, I disagree at the "at best" part...-AO has been progged at models to go neutral in the LR, but it has also been progged to dive negative...If you're going to say the AO might go neutral you're at least on the fence here. Usedtobe also stated he tends to be consevative with pattern changes, so I take that as he's dampering his expectations and thus, his AO/NAO predictions. Usedtobe also says the pattern is improving towards Christmas.

 

HM only mentions the AO/NAO once in his post and it's not even a prediciton, he's saying he's just waiting for it to come around, which can be antyime from here until what, the end of winter? I assume he thinks it's possible for both to flip before Jan, or at least the AO.

 

I agree with everything you just said. It's pretty clear to me everything is still on track to a flip between the 20th of December and the 10th of January.  Hopefully by mid month we are in the clutches of an epic pattern that delivers for the SE.

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dsaur

dsaur

Posted
Posted

 Living in the Atlanta area and most of the nonmountainous SE doesn't bode well for a white Christmas, cold or not. Atlanta has had what..two white Christmases in 100+ years? So, ~2% chance per climo? I'll take the under at this point. ;).

 

 Now, mainly nonsticking flurries? That is a different ballgame. Better chance than 2% for that.

Lol, I was going to say many Atl weather folks have made a living saying it won't snow on Christmas...and for as long as I can remember.  And actually not just Xmas.  You can make a living saying it won't snow in Atl at all, and be right most of the time :)  YOu could predict in June it won't snow in Atl on Xmas and be right a huge number of times, lol.  I can count the times it has sleeted or flurried in my life time on Xmas on both hands, and maybe one foot. And we are talking minuscule amounts. 10 sleets or 100 flakes would count.

  Now to pull a CR and say it will snow on Xmas in Atl. is a cat with different stripes.  He broke the bank with that one. 

  By the way, I've had 3 periods of rain to total .1, and it looks like a week of temps coming where it could snow.   T

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Snowless in Carrollton

Snowless in Carrollton

Posted
Posted

Lol, I was going to say many Atl weather folks have made a living saying it won't snow on Christmas...and for as long as I can remember. And actually not just Xmas. You can make a living saying it won't snow in Atl at all, and be right most of the time :) YOu could predict in June it won't snow in Atl on Xmas and be right a huge number of times, lol. I can count the times it has sleeted or flurried in my life time on Xmas on both hands, and maybe one foot. And we are talking minuscule amounts. 10 sleets or 100 flakes would count.

Now to pull a CR and say it will snow on Xmas in Atl. is a cat with different stripes. He broke the bank with that one.

By the way, I've had 3 periods of rain to total .1, and it looks like a week of temps coming where it could snow. T

you've only had .1" this month ? I had 1" of rain last weekend and Birmingham had close to 2" of rain !
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dsaur

dsaur

Posted
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I'll have to check later. I think that the def. of a white christmas per the NWS may be 1"+ on the ground. So, that one may not count officially. It can be confusing.

While we are at it let's define a White Christmas as something falling from midnight to midnight and sticking :)  Not something from 3 days before.  And at the airport, not Buckhead or May'retta, or Cartersville, or Carrollton :)  T

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dsaur

dsaur

Posted
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you've only had .1" this month ? I had 1" of rain last weekend and Birmingham had close to 2" of rain !

Yeah, and it took 3 days to get it :)  It ain't the cold I'm worried about.  If the temps this week verify there will be 5 or 6 days cold enough for snow in my yard, but only 3 periods of rain this month, and I'm betting the end of the month will show a lot more cold than rain days.  Drought trumps torch almost every time, lol.  T

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buckeyefan1

buckeyefan1

Posted
Posted

I can actually see chances for some of us in the next few weeks.  There is 1 constant that is showing up and that is storms.  It will not be overwhelmingly cold, but it does look like the storms are going to keep rolling across.  

split flow ftw!     :lol:     Now I wait for some blocking   ;) 

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packbacker

packbacker

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It's starting to look like days 6-10 next week may be the peak of this craptastic pattern, after this we see the ridge in the west start to build and a trough in the east start to come together, which all the ensembles agree on, day 11+. 

 

Euro day 8 is plain ugly, trough on west coast, ridge in central part of country...but by day 10 you see west coast ridging trying to get going...

 

ecmwf_z500a_nhem_9.png

 

 

Day 10

 

ecmwf_z500a_nhem_11.png

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LithiaWx

LithiaWx

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It's starting to look like days 6-10 next week may be the peak of this craptastic pattern, after this we see the ridge in the west start to build and a trough in the east start to come together, which all the ensembles agree on, day 11+.

Euro day 8 is plain ugly, trough on west coast, ridge in central part of country...but by day 10 you see west coast ridging trying to get going...

ecmwf_z500a_nhem_9.png

Day 10

ecmwf_z500a_nhem_11.png

Makes you think there would have to be a decent storm rolling across the southern tier with that euro look.

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packbacker

packbacker

Posted
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Storm, not snowstorm lol

 

Yep, it will be unsettled, but nobody in the SE is getting snow the next 10 days, well I guess the mountains are getting snow today.  But, after that, based on the how the day 11+ ensembles look there will be chances the last week of Dec.  Probably for western/elevation areas.

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JoMo

JoMo

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It's still pretty crappy looking on the Day 10 Euro today and that probably isn't the ridging you're looking for, yet.... The thing to watch and the thing the Ensembles from last night say is going to happen is the next system out by the Aleutians (the one marked by the "501" area in the chain) is going to dig a bit farther south, and then sit there or even retrograde to the west a bit. This is going to enable that ridge to it's south to pull E or NE eventually into the west coast/GOA area which will develop troughing downstream over the SE. This will all probably happen after the 20th, as it looks right now. Have to see if the 12z ensembles look similar to that in about an hour.

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