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December Forecast Discussion


Wow

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This afternoon's Euro again producing a significant storm Days 8-10...Brandon made a good point last night, with the -NAO being solid something big may happen before the month ends.

It looked like it was really gearing up for something big to roll through the NE which could help with a pattern change? TN also looked to maybe get in on some action on the back side at the end of the run.

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It looked like it was really gearing up for something big to roll through the NE which could help with a pattern change? TN also looked to maybe get in on some action on the back side at the end of the run.

Am I seeing ULL's on the Euro? Looks like a few of them rolling on in from the west coast.

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Am I seeing ULL's on the Euro? Looks like a few of them rolling on in from the west coast.

Yep, quite a few of them I noticed, and more and more runs lately are showing them, so this is like a throwback in that aspect atleast, to last Winter. Last year definitely took the cake in ULL's , more than I have ever seen in my lifetime of following weather, they were everywhere in the northern hemisphere. This pattern coming up is odd with how the ridginess that stretches between northeast Canada to Scandinavia to Russia has a strong cold trough below it in the northern Atlantic, on the ECM it's quite strong, and will atleast get Europe out of the deep freeze soon (after pounding them once again initially though).

I still don't like how the Pacific goes right back to the Aleutian HIGH and western North American troughing, but atleast overall, the blockiness in northeast Canada/Greenland to Russia will help keep a supressed type of flow. Usually I like supressed flows for winter threats, but this one will take some time to bleed enough cold air in. Just look at the 850 temp anomalies and actual numbers.....they remain above normal mostly through 10 days and maybe even 15 days overall, but GFS does seem to work those numbers down to around average by 15 days. The Ensembles off GFS actually look good for snow and ice chances most likely roughly along and north of I-40 from Ark-TN-NC by that time frame, but I'm not trusting them now. Overall, the pattern isn't changing that much in NA yet, but other places the anomalies are moving around, so it's rather odd that we're stuck with the same old, same old, while the rest of the world sees some pretty wild swings from major cold to above normals...but Alaska stays cold, regardless and most of the continental US stays at to above normals for a while. The next big thing to watch will be the system on ECMWF 240 hours.

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Wish I shared the optimism I'm reading for the pattern -- I don't see how a big ULL that tracks from Arkansas to WV does us any good.

Looking at the Day 9/10 Euro, it's alarming to see how the cold air is all locked up on the other side of the pole -- Canada sees above normal temps. The Pacific is still awful.

Seems like finding positives requires a vivid imagination, but maybe I'm just suffering hangover from last winter.

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Wish I shared the optimism I'm reading for the pattern -- I don't see how a big ULL that tracks from Arkansas to WV does us any good.

Looking at the Day 9/10 Euro, it's alarming to see how the cold air is all locked up on the other side of the pole -- Canada sees above normal temps. The Pacific is still awful.

Seems like finding positives requires a vivid imagination, but maybe I'm just suffering hangover from last winter.

Agree with your points, not much to look at for the foreseeable future...not sure there's much optimism being spewed tho, unless it's about severe weather :gun_bandana:

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I noticed Blacksburg and Raleigh are adding precip back into the area Tuesday night...questionable how far west this gets.

We could use some cold rain. Doubt it backs far enough west and there to be freezing temps or anything...but cold/cloudy morning would be nice.

Fixed it for you. ;) We need the rain, but I don't care for cold rain (not the poster, naturally. He's cool).

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Fixed it for you. ;) We need the rain, but I don't care for cold rain (not the poster, naturally. He's cool).

Haha! Thanks man. :). I just checked and saw Wilkes wanted some cold rain, so I was going to oblige. Cold Rain says that if the cold takes a vacation to the other side of the pole, it's going to be a long time before we get into a sustained cold pattern...not to say we won't have a thread-the-needle threat or two, but feeling like winter? Fuggetuboutit. Think January....if we're lucky.

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AO touching a -4 handle. Quite amazing month for the AO.

ao.obs.gif

I am doing a study right now on the AO index and it's correlation with snow in the Southeast. And I have to say it's an eye opener as I didn't know there was quite as much relationship as I see. Almost every major snow or Winter storm here also had a strongly -AO, or we were just entering/leaving the -AO period. The bigger the number, the more significant it seems the storm was, just eyeballing some storms since the 1950s. I would guess this worked for many parts of the Southeast as well, but probably not all instances. Looks like not all strong -AO periods worked, but the vast majority did. -3 and below seemed to really be a threshold on some bigger ones (here).

Robert thinks we will get rain here wednesday. Told me about an hour ago

Yep. I'm not positive how far west the shield gets though, but the trends seem to be a little further west than todays ECMWF run...as yesterday it too looked almost identical to today's 00z, 12z, 18z GFS with a shield of rain from Southeast Al through most of GA (except nw) and all of SC and most of NC, except the mountains barely get grazed. We'll see if the trend holds up, or if its faster and flatter. Could be interesting around Boone early Wednesday with temps at 850 hovering near freezing. Plus, whoever gets the steady rain in central SC to central NC will have classic Winter damming with the high in a good spot. 18Z GFS had temps around 40 from RDU, GSO to Boone most of the day. I hope it rains here, my lawn is powder now.

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I am doing a study right now on the AO index and it's correlation with snow in the Southeast. And I have to say it's an eye opener as I didn't know there was quite as much relationship as I see. Almost every major snow or Winter storm here also had a strongly -AO, or we were just entering/leaving the -AO period. The bigger the number, the more significant it seems the storm was, just eyeballing some storms since the 1950s. I would guess this worked for many parts of the Southeast as well, but probably not all instances. Looks like not all strong -AO periods worked, but the vast majority did. -3 and below seemed to really be a threshold on some bigger ones (here).

Yep. I'm not positive how far west the shield gets though, but the trends seem to be a little further west than todays ECMWF run...as yesterday it too looked almost identical to today's 00z, 12z, 18z GFS with a shield of rain from Southeast Al through most of GA (except nw) and all of SC and most of NC, except the mountains barely get grazed. We'll see if the trend holds up, or if its faster and flatter. Could be interesting around Boone early Wednesday with temps at 850 hovering near freezing. Plus, whoever gets the steady rain in central SC to central NC will have classic Winter damming with the high in a good spot. 18Z GFS had temps around 40 from RDU, GSO to Boone most of the day. I hope it rains here, my lawn is powder now.

Powder? Last time I was there it was all weeds and they don't die!!!! LOL!

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It seems like I recall Don Sutherland doing some research 2 years ago on the longevity of a -AO when it spikes below a certain range. Not sure of the specifics, but the gist of it was the AO is prone to stay negative for a lengthy time when it tanks this time of year. Hopefully that will be the case and we can get some other indices to cooperate at the same time.

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Powder? Last time I was there it was all weeds and they don't die!!!! LOL!

Yeah, that clover stuff is back in some mulch beds but the lawn is weed free! I guess this is payback for 2 good wet Summers. The NAM shows a drying front as it crosses the mountains, so GA, SC, NC and most of VA won't get much from the frontal passage. I have been forecasting this though, so I'm not surprised. Hopefully the second round is what gives us rain on Wednesday. For GA and most of SC and eastern NC, I'm positive it will....just hope I'm not missed completely.

post-38-0-56290600-1355106395_thumb.gif

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I am doing a study right now on the AO index and it's correlation with snow in the Southeast. And I have to say it's an eye opener as I didn't know there was quite as much relationship as I see. Almost every major snow or Winter storm here also had a strongly -AO, or we were just entering/leaving the -AO period. The bigger the number, the more significant it seems the storm was, just eyeballing some storms since the 1950s. I would guess this worked for many parts of the Southeast as well, but probably not all instances. Looks like not all strong -AO periods worked, but the vast majority did. -3 and below seemed to really be a threshold on some bigger ones (here).

Yep. I'm not positive how far west the shield gets though, but the trends seem to be a little further west than todays ECMWF run...as yesterday it too looked almost identical to today's 00z, 12z, 18z GFS with a shield of rain from Southeast Al through most of GA (except nw) and all of SC and most of NC, except the mountains barely get grazed. We'll see if the trend holds up, or if its faster and flatter. Could be interesting around Boone early Wednesday with temps at 850 hovering near freezing. Plus, whoever gets the steady rain in central SC to central NC will have classic Winter damming with the high in a good spot. 18Z GFS had temps around 40 from RDU, GSO to Boone most of the day. I hope it rains here, my lawn is powder now.

Not that surprised after being able to see the 09/10 and 10/11 winters from a model perspective. Seeing that huge HP sitting up there over southern Greenland during those winters was just a different sight than what we saw from 05 to 09. Everything just slowed down over the CONUS and so many phasing opportunities then arose. I do believe this Dec -AO dip is a great sign for the winter in its entirety.

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Yeah, that clover stuff is back in some mulch beds but the lawn is weed free! I guess this is payback for 2 good wet Summers. The NAM shows a drying front as it crosses the mountains, so GA, SC, NC and most of VA won't get much from the frontal passage. I have been forecasting this though, so I'm not surprised. Hopefully the second round is what gives us rain on Wednesday. For GA and most of SC and eastern NC, I'm positive it will....just hope I'm not missed completely.

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I've been loving recent runs of the Gfs for rains, but after being down so long, it's hard to get up even for near Goofyland depictions. I'll feel a lot better about winter if I can catch some good gulf moisture from the storms showing this week and next. I love cold weather more than anything, unless I'm in a horrid drought...then I find I'm whistling a different tune. And that sw wind seems to be bringing in the sheep, so I'm all for it, even if I have to endure 70's for a while. T

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Here's a sketch, very rough of the years for snow and ice events that affected the Southeast in general. This is by no means a comprehensive list, but just highlights that when you have a running 3 month mean of -AO, then something is definitely up about 99% of the time. In other words, a 3 month mean in Winter months of -AO is a strong, Extremely strong sign of Winter Weather in the Southeast. Notice how almost every period of -AO was accompanied by significant events and some of these were major and multiple storms per month in some areas of the Southeast. Also a few happened in raging pos AO (Jan 2000). I'm hoping to finish this study during the boring warm period coming up later next week.

post-38-0-33844100-1355110480_thumb.gif

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And right on que gfs has snowstorm setup day 7 lol.

I saw that...ridiculous...GooFuS. The cold really digs into the SE all the way to FL, allowing that low to pop off just in time and SE NC with the bonus of ~4"...bring on the weenies.

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