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Pattern Dazzling December

18z GEFS Mean AO gets down to -4.6

6BLmTTH.png
I did some checking and the -AO during the historic arctic outbreak in 1985 was around -6 on 1/19/85. Two days later many places in the south were below zero and set several records. One would have to think with our recent low AO numbers that it could up the snow chances in places that haven't seen snow in a while. I for one hope the whole board can cash in and take advantage of this rare occurrence.

Per NWS on the historic January 1985 cold.
https://www.weather.gov/ilm/January1985cold

Arctic air was pushed southward into the northern Plains and Great Lakes on January 18th by a building ridge of high pressure over northern Canada. The upper level high became unusually strong over Canada, diverting the jet stream on a looping path southward across the United States. The polar vortex dropped into the Great Lakes region on January 19th; this helped accelerate the movement of intensely cold air southward. The arctic cold front reached the Carolinas during the morning of January 20th and by that evening had pushed through all of Florida and into Cuba. Across North and South Carolina the coldest morning of the event was January 21, 1985, a date which shows up in most city's record books for the lowest temperatures ever observed.
 
The wave after the day 10 system on the EPS looks really interesting. I don't have much hope for snow with the Arctic front, because it's really a cold-chasing moisture setup. However, it may end up working for the Northeast or Mid-Atlantic people. After that, the wave dives into Atlantic Canada, and an s/w digs behind it due to the +PNA. There are many similarities between the EPS and the composite for NC's Major & Historic snowstorms.

ezgif-3-f0b0d68b6f.gifecmwf-ensemble-avg-namer-z500_anom-1671019200-1671796800-1672056000-40-2.gif
 

Sweet, I got one right! Boom!

That looks really good. I might be wrong on this, but for SE snowstorms, I seem to remember an old post that Allan made one time that showed that it is ideal to have the negative anomaly center over TN. Regardless, the image above looks quite chilly!
 
I did some checking and the -AO during the historic arctic outbreak in 1985 was around -6 on 1/19/85. Two days later many places in the south were below zero and set several records. One would have to think with our recent low AO numbers that it could up the snow chances in places that haven't seen snow in a while. I for one hope the whole board can cash in and take advantage of this rare occurrence.

Per NWS on the historic January 1985 cold.
https://www.weather.gov/ilm/January1985cold

Arctic air was pushed southward into the northern Plains and Great Lakes on January 18th by a building ridge of high pressure over northern Canada. The upper level high became unusually strong over Canada, diverting the jet stream on a looping path southward across the United States. The polar vortex dropped into the Great Lakes region on January 19th; this helped accelerate the movement of intensely cold air southward. The arctic cold front reached the Carolinas during the morning of January 20th and by that evening had pushed through all of Florida and into Cuba. Across North and South Carolina the coldest morning of the event was January 21, 1985, a date which shows up in most city's record books for the lowest temperatures ever observed.

It was extremely cold but also extremely dry East of the mountains.
We had flurries when artic front came through.
The low at GSP was -6.
 
I did some checking and the -AO during the historic arctic outbreak in 1985 was around -6 on 1/19/85. Two days later many places in the south were below zero and set several records. One would have to think with our recent low AO numbers that it could up the snow chances in places that haven't seen snow in a while. I for one hope the whole board can cash in and take advantage of this rare occurrence.

Per NWS on the historic January 1985 cold.
https://www.weather.gov/ilm/January1985cold

Arctic air was pushed southward into the northern Plains and Great Lakes on January 18th by a building ridge of high pressure over northern Canada. The upper level high became unusually strong over Canada, diverting the jet stream on a looping path southward across the United States. The polar vortex dropped into the Great Lakes region on January 19th; this helped accelerate the movement of intensely cold air southward. The arctic cold front reached the Carolinas during the morning of January 20th and by that evening had pushed through all of Florida and into Cuba. Across North and South Carolina the coldest morning of the event was January 21, 1985, a date which shows up in most city's record books for the lowest temperatures ever observed.
Remember it well. That was the ultimate pipe buster. My dad took the dog for a walk after his morning shower and his hair froze! ?
 
I did some checking and the -AO during the historic arctic outbreak in 1985 was around -6 on 1/19/85. Two days later many places in the south were below zero and set several records. One would have to think with our recent low AO numbers that it could up the snow chances in places that haven't seen snow in a while. I for one hope the whole board can cash in and take advantage of this rare occurrence.

Per NWS on the historic January 1985 cold.
https://www.weather.gov/ilm/January1985cold

Arctic air was pushed southward into the northern Plains and Great Lakes on January 18th by a building ridge of high pressure over northern Canada. The upper level high became unusually strong over Canada, diverting the jet stream on a looping path southward across the United States. The polar vortex dropped into the Great Lakes region on January 19th; this helped accelerate the movement of intensely cold air southward. The arctic cold front reached the Carolinas during the morning of January 20th and by that evening had pushed through all of Florida and into Cuba. Across North and South Carolina the coldest morning of the event was January 21, 1985, a date which shows up in most city's record books for the lowest temperatures ever observed.
There was actually a period of light snow that accompanied that cold front as it came through. It was a Sunday morning. It only added up to around an inch but it was a very dry snow that really didn’t really didn’t stick to the roads because it was so dry that it would just blow around. I remember my Dad driving us home from church in it… when we went into church that morning temperatures were still around 30… when we left a couple hours later it had dropped to 11 in Charlotte and it was in the single digits most of the afternoon.
 
The supressed moisture moving by underneath a sagging 0 line in Ga on the Gfs around the 18th has had me intrigued for days. Some runs the moisture is up into Ga and others it retreats, but in my life time I've see this scenario play out like the Doc has it now, with a band on top of the moisture shield, of what's probably sleet, and right over me. I think this idea of the doc's has legs. I hope it has legs, I've seen it happen before like that. The cold drops futher south, and the rain shield moves further north the closer it gets. The system is weak so the precip is sleet instead of rain. Here's hoping, lol.
 
The 18Z NAM took a step back for the 18th. The 18Z ICON however has trended better the past three runs and is now very close to some light wintry precip for portions on N. Ala and N. Ga. One more tick west with the vortex over the Great Lakes should do it.

Still not there, but I'm interested anyway.
icon_mslp_pcpn_frzn_us_22.png

icon_z500_vort_us_24.png

EDIT: The 18Z RGEM is trying too.
rgem_mslp_pcpn_frzn_us_68.png
 
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The 18Z NAM took a step back for the 18th. The 18Z ICON however has trended better the past three runs and is now very close to some light wintry precip for portions on N. Ala and N. Ga. One more tick west with the vortex over the Great Lakes should do it.

Still not there, but I'm interested anyway.
icon_mslp_pcpn_frzn_us_22.png

icon_z500_vort_us_24.png

EDIT: The 18Z RGEM is trying too.
rgem_mslp_pcpn_frzn_us_68.png
Seems like most of the times we start seeing those weird streamers in these setups they end up being more robust than modeled.
 
Seems like most of the times we start seeing those weird streamers in these setups they end up being more robust than modeled.
Yep.

I do wish we had some agreement from the GFS though. I couldn't find even one member glancing at the 12Z suite.

At this point, all we have is a virga and stray flake watch.
 
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