Am I wrong to be skeptical of a -NAO? Last year we had it inside 10 days on the GEFS and EPS and it still failed to materialize. I'll believe it when it actaully dives negative and has staying power there.
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Pattern The Great December Dump
- Thread starter Rain Cold
- Start date
Yes. It is coming this year.
I agree. If there's ever been a year it's this year
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Jon
Member
Yep and the core of the cold isn’t until the 18th-23rd...We should end up near normal or BN, wouldn’t be surprised at all given current LR modeling.
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Webberweather53
Meteorologist
Golf7575
Member
Webber, do you agree with Dr. Paul Roundy's assessment on there is an active Mjo despite the RMM charts suggesting otherwise?
Philstorm91
Member
For amateurs like me, who don't know all meteorological references to weather systems, I had to do some research on the "50/50 low". What I found is that this is an area of low pressure that forms near 50 degrees North, 50 degrees West, so the name makes sense. It's near Newfoundland, Canada. It seems this weather system has bigger impacts on the east coast versus the Gulf coastal regions, so maybe that's why this is the first time I've encountered the term. Just thought I'd put it here to clear up terms in the discussion for anybody wondering.
Some thoughts about the 21st/22nd system. The GFS has been consistent showing a weather system around the 21st/22nd time window. Would it be a rain storm? Snow storm? Rain changing to snow scenario? It's still too early to determine that right now, however, I'm not going to write off that this system could possibly bring snow for the southeastern US.
First things first, I've been thinking about what track will the low take? This will depend on the evolution of a ridge to the west. Which, this ridge will depend on a trough up stream over the eastern Pacific Ocean. If this trough over the eastern Pacific ocean digs down deeper, this would result a stepper ridge down stream. If that were to occur, the track of low would be further south, pushed further down into the Gulf. So far what I'm seeing on both GEFS and EPS (at the time of this update) this storm system would most likely be a Miller-A due to the upper air pattern and a 50/50 low, which we'll take a look at that 50/50 low later on this post.
If you take a look at the image below, you can see the trough over the eastern Pacific Ocean, again, this trough will play a roll of the evolution of the ridge over the Rockies. You can also see a positive tilt trough over the Gulf coast/lower Mississippi River, that is of course the developing storm system that could possibly bring snow for the southeastern US during the 21st/22nd time period. I'm also liking the high latitude blocking (-NAO) which high latitude blocking would mean that this storm system would have amplification as the storm system gains latitude.
Another thing that has came to my mind, will it be cold enough to support snowfall acorss the southeastern US during the 21st/22nd time period? Right now, it's still too early to determine that, but lets take a look at the 500mb(vort) from the GEFS. The 50/50 low will play a factor on the cold air as well as the track of low. Of course, with a more northern track of low, warmer air would be at play. If a more southern track, this would allow colder air to progress further south and east. If a 50/50 low isn't going to be in place, deeper cold air probably won't make it further down into the southeastern US.
Overview: As of now, places acorss, KY/TN, the mountains and NC/WV/VA may get some snow out of this system. Of course, a much larger portion of the southeastern US could get snowfall out of this system as well if the things line up right of what I mentioned above. If that ridge becomes taller, this would push the development of low further down into the Gulf, and if that were to occur, colder air would be at play much further south. So, those are some of the things that I would be watching out for, the evolution of the trough over the eastern Pacific ocean, the ridge and the 50/50 low. We'll see how things evolve over the coming days. Of course, I will have further in depth updates.
First things first, I've been thinking about what track will the low take? This will depend on the evolution of a ridge to the west. Which, this ridge will depend on a trough up stream over the eastern Pacific Ocean. If this trough over the eastern Pacific ocean digs down deeper, this would result a stepper ridge down stream. If that were to occur, the track of low would be further south, pushed further down into the Gulf. So far what I'm seeing on both GEFS and EPS (at the time of this update) this storm system would most likely be a Miller-A due to the upper air pattern and a 50/50 low, which we'll take a look at that 50/50 low later on this post.
If you take a look at the image below, you can see the trough over the eastern Pacific Ocean, again, this trough will play a roll of the evolution of the ridge over the Rockies. You can also see a positive tilt trough over the Gulf coast/lower Mississippi River, that is of course the developing storm system that could possibly bring snow for the southeastern US during the 21st/22nd time period. I'm also liking the high latitude blocking (-NAO) which high latitude blocking would mean that this storm system would have amplification as the storm system gains latitude.
Another thing that has came to my mind, will it be cold enough to support snowfall acorss the southeastern US during the 21st/22nd time period? Right now, it's still too early to determine that, but lets take a look at the 500mb(vort) from the GEFS. The 50/50 low will play a factor on the cold air as well as the track of low. Of course, with a more northern track of low, warmer air would be at play. If a more southern track, this would allow colder air to progress further south and east. If a 50/50 low isn't going to be in place, deeper cold air probably won't make it further down into the southeastern US.
Overview: As of now, places acorss, KY/TN, the mountains and NC/WV/VA may get some snow out of this system. Of course, a much larger portion of the southeastern US could get snowfall out of this system as well if the things line up right of what I mentioned above. If that ridge becomes taller, this would push the development of low further down into the Gulf, and if that were to occur, colder air would be at play much further south. So, those are some of the things that I would be watching out for, the evolution of the trough over the eastern Pacific ocean, the ridge and the 50/50 low. We'll see how things evolve over the coming days. Of course, I will have further in depth updates.
GFS shows a storm with a miller B evolution, classic miller B pattern with a ridge axis extending into the GLs 
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GFS appeared to have a late phase just off the east coast ? kinda cool to look at
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The 00z GEFS has very little snow in the SE. Many huge NE blizzards though.
Right now it’s between the north US modeling or the Suppressed Euro.
Right now it’s between the north US modeling or the Suppressed Euro.
I wouldn't put much stock with the 500mb from the OP with the time frame being far out. Mean while, the 0z GEFS still looks good for a Miller-A storm that bombs out on the southeast coast.
We all should take a step back and realize this is 10 days away... nothing that has ever been modeled 10 days away has happened that way and usually is completely different. The signal is there for a storm and that’s all the info we can grab as of right now ... let’s wait until about 5 days out and then we can truly see from modeling how everything appears to be shaping up .. we won’t know until then
The 6z GFS says I’ll take track number 4, right up the Apps!