Incoming winter weather advisories tonight! Any ice warrants an advisory and multiple MTN counties are shaded and a sliver of the western foothills.
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Pattern December to Remember
- Thread starter SD
- Start date
Op gfs has a peanut shaped pv in the strat later in the run with a lobe over Hudson Bay and the second in Siberia with poleward ridges over Scandinavia and AK. Really a nice look if it can get reflected down
We've got some high end mega frost potential Thursday morning
Can we talk about how insane this looks for December standards, this is a May like/early June H5 pattern 
Looks like a La Niña with a hint of GW
And uncle Larry has chimed in this morning, but he has been saying for a long time it would be late December/early January before any sustained cold and storminess could get into the central and eastern US.
13m
First, the storm sequence. Then we talk about the east and south advance of Arctic air. Once the current modest shot of Arctic values across Canada, the Midwest and Northeast exits by this weekend, southwesterly flow will allow for a quick warm-up to the right of the Rocky Mountains. While there could be a brief intrusion of cold with an area of low pressure and frontal structure from the south central states to the Eastern Seaboard early next week, this is your basic demand-killer scenario for energy usage. Except in that part of North America west of the Continental Divide. I will warn you that there is potential for some astonishing amounts of rain and snow along the West Coast during the next ten days (graphics in the comment boxes below this post). Each successive storm will tend to push the colder air further inland, and by the week of Christmas and New Year's erode the heat ridge in the Gulf of Mexico and Florida Peninsula. But you will not see a wholesale collapse of the warmth in this progressive 500MB pattern. Instead, a strong positive height anomaly forming in the northern Pacific Basin will edge into Alaska and its Gulf waters. That ridge will push the trough complex to the center of the continent, with northerly flow aloft bringing the frigid air into the Great Plains, Mississippi Valley, and then the Eastern Seaboard. This process will take about 2-3 weeks, and will likely be accompanied by a significant storm of the Colorado/Trinidad "A" type that aims at the lower Great Lakes and St. Lawrence Valley. Again, the process takes time. And with a progressive pattern and an active La Nina, we are bound to see a profound warming in the January Thaw in the middle two weeks of next month. But with any luck, the CFS series scenario of an icebox period Jan 20 - Feb 15 will verify, and make snow and ice fans like me smile.
Larry Cosgrove
Chief Meteorologist,WEATHERAmerica13m
First, the storm sequence. Then we talk about the east and south advance of Arctic air. Once the current modest shot of Arctic values across Canada, the Midwest and Northeast exits by this weekend, southwesterly flow will allow for a quick warm-up to the right of the Rocky Mountains. While there could be a brief intrusion of cold with an area of low pressure and frontal structure from the south central states to the Eastern Seaboard early next week, this is your basic demand-killer scenario for energy usage. Except in that part of North America west of the Continental Divide. I will warn you that there is potential for some astonishing amounts of rain and snow along the West Coast during the next ten days (graphics in the comment boxes below this post). Each successive storm will tend to push the colder air further inland, and by the week of Christmas and New Year's erode the heat ridge in the Gulf of Mexico and Florida Peninsula. But you will not see a wholesale collapse of the warmth in this progressive 500MB pattern. Instead, a strong positive height anomaly forming in the northern Pacific Basin will edge into Alaska and its Gulf waters. That ridge will push the trough complex to the center of the continent, with northerly flow aloft bringing the frigid air into the Great Plains, Mississippi Valley, and then the Eastern Seaboard. This process will take about 2-3 weeks, and will likely be accompanied by a significant storm of the Colorado/Trinidad "A" type that aims at the lower Great Lakes and St. Lawrence Valley. Again, the process takes time. And with a progressive pattern and an active La Nina, we are bound to see a profound warming in the January Thaw in the middle two weeks of next month. But with any luck, the CFS series scenario of an icebox period Jan 20 - Feb 15 will verify, and make snow and ice fans like me smile.
We on the eastern side of the ridge probably meaning temps going below forecasted at night and temps going above forecast during the day, a 60-70 over 30-40 type setup
Nothing to crazy, except for perhaps loss on the ensembles 
tennessee storm
Member
Good luck with seeing that with a good Niña still effect late winter February ?And uncle Larry has chimed in this morning, but he has been saying for a long time it would be late December/early January before any sustained cold and storminess could get into the central and eastern US.
Larry Cosgrove
Chief Meteorologist,WEATHERAmerica
13m
First, the storm sequence. Then we talk about the east and south advance of Arctic air. Once the current modest shot of Arctic values across Canada, the Midwest and Northeast exits by this weekend, southwesterly flow will allow for a quick warm-up to the right of the Rocky Mountains. While there could be a brief intrusion of cold with an area of low pressure and frontal structure from the south central states to the Eastern Seaboard early next week, this is your basic demand-killer scenario for energy usage. Except in that part of North America west of the Continental Divide. I will warn you that there is potential for some astonishing amounts of rain and snow along the West Coast during the next ten days (graphics in the comment boxes below this post). Each successive storm will tend to push the colder air further inland, and by the week of Christmas and New Year's erode the heat ridge in the Gulf of Mexico and Florida Peninsula. But you will not see a wholesale collapse of the warmth in this progressive 500MB pattern. Instead, a strong positive height anomaly forming in the northern Pacific Basin will edge into Alaska and its Gulf waters. That ridge will push the trough complex to the center of the continent, with northerly flow aloft bringing the frigid air into the Great Plains, Mississippi Valley, and then the Eastern Seaboard. This process will take about 2-3 weeks, and will likely be accompanied by a significant storm of the Colorado/Trinidad "A" type that aims at the lower Great Lakes and St. Lawrence Valley. Again, the process takes time. And with a progressive pattern and an active La Nina, we are bound to see a profound warming in the January Thaw in the middle two weeks of next month. But with any luck, the CFS series scenario of an icebox period Jan 20 - Feb 15 will verify, and make snow and ice fans like me smile.
Hurts my ? to look at it. Gonna take some time to beat that red eyed monster down...
SnowNiner
Member
Really a bummer for a cold/snow lover like me. Just the worst honestly, but it is what it is. In a Nina I have very little expectations. However I'm keeping a close eye on the mjo. Maybe at the end of the month we can get into phase 8 and things will improve (looks like we've got a shot). Right now it just looks like the best we get is a cold dump out west. Suspect it's going to be there a while. We'll see.
NoSnowATL
Member
Webberweather53
Meteorologist
Doesn't get any better than phase 7 in January
Southern Track
Member
Something for everyone .. and hopefully that end cool trend continues through Christmas .. we can’t go through another 80 degree Christmas
Webberweather53
Meteorologist
Gonna be keeping an eye on the MJO the next few weeks. The bias-corrected ECMWF monthly forecast from yesterday is probably one of the more realistic ones overall, keeping the MJO milling around w/ amplitude between phase 6-7 for basically the rest of December, which signals warmth overall in the SE US and cold intruding into the N Rockies + upper Midwest (canonical NINA pattern)
The reason I say this is when you breakdown the daily probability (%) of seeing a winter storm in NC (east of the mtns) by MJO phase and month, what really stands out is MJO phase 7 in January w/ nearly a 16% chance of a winter storm per day, higher than any other phase in any month, phase 8 & null are a somewhat close seconds in January. This likely has a lot to do w/ the subtropical jet becoming more active & a -NAO tendency being favored when the MJO moves towards the west-central Pacific (phase 7). If the CFS and EPS + empirical wave propagation for a slow-moving La Nina MJO event (i.e. history) are generally to be believed, we could see this come to fruition in/around early January. I.e. the most favorable window for a winter storm may be in this time period
Chart is shown below: NC Winter Storm Probability by MJO phase & month since 1974.
Most favorable phase overall (red/bold, Jan Phase 7), most favorable phase per month (orange/bold), 2nd & 3rd most favorable (yellow/bold)
View attachment 96701
Data source:
Nov-Mar Daily Teleconnections and NC Winter Storms List (1948-2021)
Going to repost this as a friendly reminder, because I see some recent posts saying they'd rather see MJO phase 8 in the longer-term. Honestly, both phase 7 & 8 are excellent in January and you really can't do any better than January phase 7, which has a one in six chance of producing a winter storm in NC on any given day. Odds are, if we rumble through phase 7 or 8 for a week (or more) in January as the Euro monthly suggests, we'll probably see at least one minor (1"+ snow/sleet or Trace ZR) winter storm somewhere east of the mountains in NC.
Webberweather53
Meteorologist
Good news is w/ +EPO, the core of the warm anomalies will be to our north. Definitely well above average but not quite as far above normal as the northern tier of the US will likely experience at least through the next 10 days or so.
Webberweather53
Meteorologist
Certainly possible we do, didn't think we had a great chance of flipping the pattern before then though.
Pain
Webberweather53
Meteorologist
