Winter 2014-2015 Pattern Discussion Thread I

[WidreMann]

The Euro weeklies pretty much have warmer than normal SE temp.'s for all four weeks though with anomalies diminishing. Could the Euro weeklies be way off, especially as we get toward mid Dec.? Well, if we base it on how Nov. was treated, the answer is that that is quite possible. I just reviewed the Euro weeklies' forecasts for November. (I save them for reviews like this.) What's interesting is that all of the weeklies from 10/16 through 10/30 had warmth in November! Yes, even the 10/30 one had a lot of warmth just ahead!! Then the 11/3 magically turned on a dime and correctly predicted cold to dominate. Subsequent weeklies had cold for Nov.

 

 So, what does this tell us? Could they be dead wrong again at least, say, for around mid month? After all it is only 11/27!

There's no value in looking at what the Euro did for November and trying to extrapolate that behavior to December. If the modelling has a consistent bias that can be measured and correlated with specific patterns, then we can take that into account when judging the forecasts. What you're doing here is assuming that because it predicted generically warm and we got cold in November it will do the same in December. But the model doesn't just predict warm or cold. It predicts patterns and areas of warmth and cold, among many other things. So whatever made it pick warm initially for November may not be at all the same thing that it's keying in on for warm December. So if it was wrong for November, it may only be wrong for a subset of reasons that aren't in play for December. We (as weenies) certainly don't know. There's also probably little skill in predicting what models will predict, which is second-order prediction and is just crazy. We do it all the time, though.

[LithiaWx]

image.jpg

You can't defeat his genius

Oh my god.... His comments on wxsouths FB page are equally as wtf. I Was wondering which Amex poster was bobbitt. Thank you for this info, tells me a lot.

[GaWx]

Widre,

 Good points. To be clear, I'm not saying it will do the same in December. I'm saying that it wouldn't be surprising if it were to do the same, and if so, especially toward midmonth as opposed to early month.

 Here were the 10/30 Euro weeklies at two meters. Note how much of the country is covered by warmth!

 

[superjames1992]

image.jpg

You can't defeat his genius

 

LOL at Asheville being in the foothills.  Holy ****.

[Snowless in Carrollton]

If December it above normal, do we cancel winter or just look forward to the two months when we normally get our winter storms, just like last year!?

well, December is our 2nd coldest month on average so it would definitely be concerning if we wasted all of December with warmth.

[LithiaWx]

well, December is our 2nd coldest month on average so it would definitely be concerning if we wasted all of December with warmth.

Snowfall averages are obviously more important to the vast majority of Amex posters.

[WxBlue]

LOL at Asheville being in the foothills.  Holy ****.

 

That's just pure gold! All you have to do is drive from Marion to Asheville on I-40 to realize that Asheville is not part of foothills, haha. That's 1,000 feet in 30 minutes

[RONALD B]

That's just pure gold! All you have to do is drive from Marion to Asheville on I-40 to realize that Asheville is not part of foothills, haha. That's 1,000 feet in 30 minutes

I was just messing with Brad we talk all the time.He know's i was joking with him . I was talking compared too the big mountains it  was not serious.

an a postive pna means a lot. the euro ensembels shows it happening . the euro weeklies has been  a joke so far. It's my point of view that only wennies use  the euro weeklies for there long range forcasting? .https://twitter.com/RaleighWx/status/537983409222864896/photo/1

[GaWx]

I guess that last post about the AO was deleted. Here is how I'll grade myself. If DJF averaged AO isn't sub -1, I'll consider my SAI/OPI based AO prediction a bust. If Dec. ends up with +AO, that wouldn't be good at all obviously though DJF could still average sub -1. Regardless, it would appear to likely average slightly negative in early Dec.

[Bob Chill]

One thing I've observed about the weeklies is that they are only as good as the d11-15 period of the ensemble run. Weeklies typically extend the progression of predicted height anomalies from d11-15. If the euro blows that period the weeklies are usually way off. And it happens sometimes just like Oct going into Nov.

Skill obviously decreases through time and d11-15 has not been doing well lately. However, the euro ens picked up the relaxation were facing next week really well so it's hard to say if the upcoming d11-15 is going to verify in some fashion. One thing that give me some confidence is that the model has been steadfast for days and not moving things forward in time.

Even though the gefs has a better look and picked up the transient ec trough first, both models torch Canada. I'm not very enthused for a quick flip to a good pattern. No alt block will keep things moving fast. We'll likely see some cold shots behind fronts. I doubt we'll see a stable warm spell at least.

I'm looking forward to seeing the progged pattern break down. Ho hum for now

[packbacker]

One thing I've observed about the weeklies is that they are only as good as the d11-15 period of the ensemble run. Weeklies typically extend the progression of predicted height anomalies from d11-15. If the euro blows that period the weeklies are usually way off. And it happens sometimes just like Oct going into Nov.

Skill obviously decreases through time and d11-15 has not been doing well lately. However, the euro ens picked up the relaxation were facing next week really well so it's hard to say if the upcoming d11-15 is going to verify in some fashion. One thing that give me some confidence is that the model has been steadfast for days and not moving things forward in time.

Even though the gefs has a better look and picked up the transient ec trough first, both models torch Canada. I'm not very enthused for a quick flip to a good pattern. No alt block will keep things moving fast. We'll likely see some cold shots behind fronts. I doubt we'll see a stable warm spell at least.

I'm looking forward to seeing the progged pattern break down. Ho hum for now

Thanks Bob. Looking more at Dec 02 and 03 there is some similarities to what the models are calling for the next 2-3 weeks. Those turned out to be snowy winters in Jan/Feb. Not the extreme cold everyone is calling for but cold enough and snowy.

[LithiaWx]

One thing I've observed about the weeklies is that they are only as good as the d11-15 period of the ensemble run. Weeklies typically extend the progression of predicted height anomalies from d11-15. If the euro blows that period the weeklies are usually way off. And it happens sometimes just like Oct going into Nov.

Skill obviously decreases through time and d11-15 has not been doing well lately. However, the euro ens picked up the relaxation were facing next week really well so it's hard to say if the upcoming d11-15 is going to verify in some fashion. One thing that give me some confidence is that the model has been steadfast for days and not moving things forward in time.

Even though the gefs has a better look and picked up the transient ec trough first, both models torch Canada. I'm not very enthused for a quick flip to a good pattern. No alt block will keep things moving fast. We'll likely see some cold shots behind fronts. I doubt we'll see a stable warm spell at least.

I'm looking forward to seeing the progged pattern break down. Ho hum for now

 

Please post more in our forum.  Your thoughts are appreciated.

[nchighcountrywx]

Good analysis by Joe Daleo at Weatherbell.

 

http://www.weatherbell.com/premium/joe-daleo/a-few-hints-at-the-models-will-soon-change-their-tune

 

A shift of just 10degrees in the teleconnections can bring a trough into the east and SE.

[LithiaWx]

On the PNA. I've found over the years that what we want to look at is th exact placement of ridges and trofs in the west. A -PNA usually screws us all of the time. It really does take a properly placed ridge in the west (+PNA) to help us out in the SE. A +PNA can dump cold out into the Plains or lock it up just a bit too far north if the ridge isn't placed right.

A +PNA beats the heck out of a - one but a +PNA doesn't guarantee us a good pattern.

[RONALD B]

On the PNA. I've found over the years that what we want to look at is th exact placement of ridges and trofs in the west. A -PNA usually screws us all of the time. It really does take a properly placed ridge in the west (+PNA) to help us out in the SE. A +PNA can dump cold out into the Plains or lock it up just a bit too far north if the ridge isn't placed right.

A +PNA beats the heck out of a - one but a +PNA doesn't guarantee us a good pattern.

If am not mistaken? the postive pna will also have a helper after the 8th of dec with the mjo moveing into phase 7 , if the models are right ?

[LithiaWx]

If am not mistaken? the postive pna will also have a helper after the 8th of dec with the mjo moveing into phase 7 , if the models are right ?

 

For anyone interested :

 

 

 

You don't want the MJO to take a dive into the "circle of death".  Also higher amplitude of the MJO on this chart is beneficial.  You should be able to make some conclusions based on these two charts.

[Snowless in Carrollton]

Thanks Bob. Looking more at Dec 02 and 03 there is some similarities to what the models are calling for the next 2-3 weeks. Those turned out to be snowy winters in Jan/Feb. Not the extreme cold everyone is calling for but cold enough and snowy.

maybe in nc it was snowy but I don't recall any snow in Jan/Feb 03. I would much rather see a repeat of Jan 02 than Jan 03.

[WidreMann]

maybe in nc it was snowy but I don't recall any snow in Jan/Feb 03. I would much rather see a repeat of Jan 02 than Jan 03.

Jan 02 had one storm at the very beginning of the month and then torch the rest of the month. You'd rather see that seriously?

[WidreMann]

CFS weeklies look positively awful, and they keep getting worse with each day. If they come even close to verifying, it may put December 2001 to shame.

Then again, the monthlies for November looked very torchy and we all know how that turned out.

[burgertime]

No mention of the LR GFS at 12z? It looked pretty damn good to me....a lot like what we experienced last winter big +PNA/-AO major artic air over the east. Also a CAD setup in a few days with a 1044 high? I'll take it. Of course it's one run but again based on last year I'm more likely to believe that then a torch...who knows though. 

[GaWx]

No mention of the LR GFS at 12z? It looked pretty damn good to me....a lot like what we experienced last winter big +PNA/-AO major artic air over the east. Also a CAD setup in 5 days with a 1044 high? I'll take it. Of course it's one run but again based on last year I'm more likely to believe that then a torch...who knows though. 

 

Go to the banter thread where I put a post about the very cold 12/10-14 period per the 12Z GFS. I figured it is still banter material since it is the 11-15 and the GFS has been inconsistent for that period as usual.

[BullCityWx]

Jan 02 had one storm at the very beginning of the month and then torch the rest of the month. You'd rather see that seriously?

 

I had the same reaction

[packbacker]

CFS weeklies look positively awful, and they keep getting worse with each day. If they come even close to verifying, it may put December 2001 to shame.

Then again, the monthlies for November looked very torchy and we all know how that turned out.

 

Yeah, Jan 02 was a lucky fluke in other while a torch winter.  I would happily take that exact winter again, assuming I get 12" snow event in early Jan :-)

 

Comparing Dec 02/03 doesn't look far off from what a blend of 11-15 day ensembles and week 4 of the Euro weeklies...

 

Edit:  Let's face it, the winters 02/03 and 03/04 should have the CLT folks salivating.  Those must be 2 of the top 5 winters of all time for CLT?

[pcbjr]

All of this is quite a change in the direction of discussion versus about three weeks ago. Wonder what we'll be talking about three weeks from now?

 

If fantasy is desired the very end of the 12Z GFS, way past truncation, is interesting ....

[Snowless in Carrollton]

This winter is starting to remind me of 98-99. Or at least December is anyway. We started that month very warm if I remember correctly. I hate to be negative but I'm beginning to think this December as a whole will be horrible.

[Snowless in Carrollton]

Jan 02 had one storm at the very beginning of the month and then torch the rest of the month. You'd rather see that seriously?

I would rather have a big snow and torch the rest of the month than have cold for an extended period with no snow. Winters of 02-03 and 03-04 were just awful in my part of GA. 04-05, 05-06, 06-07 were also awful in terms of snow. Basically 6 years where we saw a combined 1/2" of snow. After Jan 02, I don't recall any significant snow until the amazing winter of 07-08. 07-08 was a great winter here. 2 snows in one week in Jan 08 !!

[RONALD B]

No mention of the LR GFS at 12z? It looked pretty damn good to me....a lot like what we experienced last winter big +PNA/-AO major artic air over the east. Also a CAD setup in a few days with a 1044 high? I'll take it. Of course it's one run but again based on last year I'm more likely to believe that then a torch...who knows though. 

the new gfs has a poss CAD for next tue's ?

[GaWx]

I would rather have a big snow and torch the rest of the month than have cold for an extended period with no snow. Winters of 02-03 and 03-04 were just awful in my part of GA. 04-05, 05-06, 06-07 were also awful in terms of snow. Basically 6 years where we saw a combined 1/2" of snow. After Jan 02, I don't recall any significant snow until the amazing winter of 07-08. 07-08 was a great winter here. 2 snows in one week in Jan 08 !!

 

Agreed! That early Jan. 2002 snow was a big one for ATL and the then biggest since the 1993 blizzard...~5". 02-03 was a no show other than moderate ZR in early Dec. 03-04 had that quick late Feb. snow that gave me no more than ~1" on the northside of ATL.

[Eric]

Eric,

 Wow, thanks for posting this! Your posts of articles addressing historic SE wx events are always enjoyable. Based on looking at multiple sources, I have 1880-1 as high end neutral positive to low end weak Nino, a range which has often resulted in great SE winters like 1884-5 and 1935-6. These snow reports are consistent with the 6" on 12/29/1880 at ATL. Based on liquid equiv. of only 0.28", ATL apparently got a very dry, powdery snow with ~20:1 ratios! Looking back at 135 years of history, this appears to have been one of the, if not THE, highest ratio snowfall there of any significance.

 

 The 12/29/1880-1/1/1981 period would have made this forum go bonkers. There were back to back Miller A's. I looked at the daily wx maps and it showed the first Miller A that "formed in the Gulf south of N.O." late on 12/28 per the text and the maps. It took the classic route across the far N FL peninsula as is shown on the later maps. It was the typical weak Miller A Gulf low that has often in the past given the SE heavy snow. While in the Gulf, it was down to only ~1010 mb per the maps. It then got stronger as it turned the corner and headed up the coast offshore. This gave the snow your article references as well as the 6" at ATL.

 The second Miller A was a further south ~1015 mb low that crossed central FL, i.e, a bit too far south for ATL and nearby areas to get too much precip. However, it did give some rare ZR as well as very cold rain to places like SAV in the 12/31-1/1 timeframe and light snow to Pensacola and Mobile among other SE cities. Wilmington, NC also got snow. The maps suggest this second low was accompanied by very strong CAD 12/31-1/1 as the low crossed C FL.

 

A brief summary of the temperatures in Charlotte from late November through December in 1880.

 

11/19-11/28 - Cold/Record Cold

11/29-12/06 - Mild

12/07-12/11 - Cold

12/12-12/18 - Mild

12/19-12/31 - Cold/Record Cold/Record Snow

[franklin NCwx]

Pretty good call by wxbell for November even though they weren't cold enough.