Absolute Vorticity

The first month of Met Winter starts on Sunday! The month looks to start off cold with highs in the 20s and 30s and lows in the teens and 20s for the area. Any snow remains to be seen with regards to clippers. Will it be a December to Remember? Discuss!

Good Morning and glad Les has started this topic. Overall I believe the month will end up colder than normal any going 1-2 degrees below normal and in regards to precip going with a normal month. Looks like the first 7-10 days will be below normal in terms of temps and should see at least 2 clippers in that period. Do expect a change to milder temps after the 1st 10 days or so and normally this will bring in a storm system to help with the change. Again to far out for models to pick this up but expect we start seeing that on the models next week. Will that bring a major snow for us and again just to far out in time for any specifics. Will the pattern we see for early December continue through the winter with some decent cold spells followed up by milder periods. No doubt this winter is different than last year and hopefully this brings us several systems over the winter to follow besides the clippers which I expect to be one of the main items this winter.

The first half of the month definitely is going to be colder then avg. Anything on the wintry side is TBD Cold and dry is certainly a risk but I'll take my chances with the 500 MB look every time. I also believe, along with Tim, that a clipper or two is likely with the upcoming pattern.

Thinking about what it took to get to the forecast for the first 10-14 days of below normal temps. A full trip from the MJO moving across the Pacific and touching all the winter holy grail phases of 8–1-2. Entering 8 way back around the first taking about 2 to three weeks for North America changes to start unfolding. A warm up is of course inevitable after this time period, how much , how long as always the MJO will have us guessing

I wonder with more of a La Nada and not full blown La Nina that the mjo responds in a way that it does circle that phases with brief stops in certain phases but overall keeps trucking along. Seems like we have either been in a La Nina or El Nino over the past several years and getting one that is neutral will this give us a more normal winter in the USA. Of course blocking is key as we know and tends to show up only a week or so before it happens. I hope once we get into a milder mid-Dec period this amps up the storms and we see extended snow cover showing up in the northern and central plains and upper mid-west. This would hopefully help in getting cold shots as we head to the heart of winter a better shot of pushing further south.

Bgoney wrote: ↑Tue Nov 26, 2024 6:38 am Thinking about what it took to get to the forecast for the first 10-14 days of below normal temps. A full trip from the MJO moving across the Pacific and touching all the winter holy grail phases of 8–1-2. Entering 8 way back around the first taking about 2 to three weeks for North America changes to start unfolding. A warm up is of course inevitable after this time period, how much , how long as always the MJO will have us guessing

I'm wondering also what the driving the pattern besides the MJO? With ENSO being neutral we know it isn't that. The PDO is still very negative but we know it's not driving the upcoming pattern either. I do believe that some of it is MJO induced but not all. Most of the modeling keeps the MJO weak when it goes thru the warmer phases, Hopefully, we'll get some answers going forward. How long the colder pattern lasts ought to give us additional clues. I am also expecting a warm up, but how much and when (as you mentioned) TBD.

tpweather wrote: ↑Tue Nov 26, 2024 6:53 am I wonder with more of a La Nada and not full blown La Nina that the mjo responds in a way that it does circle that phases with brief stops in certain phases but overall keeps trucking along. Seems like we have either been in a La Nina or El Nino over the past several years and getting one that is neutral will this give us a more normal winter in the USA. Of course blocking is key as we know and tends to show up only a week or so before it happens. I hope once we get into a milder mid-Dec period this amps up the storms and we see extended snow cover showing up in the northern and central plains and upper mid-west. This would hopefully help in getting cold shots as we head to the heart of winter a better shot of pushing further south.

Great post Tim. Your post ties in directly with what I just said lol It will really be interesting if the upcoming pattern is winter showing its hand. If it is, it should be a very fun winter for us to track for a change! Only time will tell of course.

tron777 wrote: ↑Tue Nov 26, 2024 6:56 am

Bgoney wrote: ↑Tue Nov 26, 2024 6:38 am Thinking about what it took to get to the forecast for the first 10-14 days of below normal temps. A full trip from the MJO moving across the Pacific and touching all the winter holy grail phases of 8–1-2. Entering 8 way back around the first taking about 2 to three weeks for North America changes to start unfolding. A warm up is of course inevitable after this time period, how much , how long as always the MJO will have us guessing

I'm wondering also what the driving the pattern besides the MJO? With ENSO being neutral we know it isn't that. The PDO is still very negative but we know it's not driving the upcoming pattern either. I do believe that some of it is MJO induced but not all. Most of the modeling keeps the MJO weak when it goes thru the warmer phases, Hopefully, we'll get some answers going forward. How long the colder pattern lasts ought to give us additional clues. I am also expecting a warm up, but how much and when (as you mentioned) TBD.

For me, There’s always the background tellie’s that determine the finer details of our weather , low pressure strength and path for instance but to get to that point and make those background influences matter , the most important factor is the air mass available and what a massive process that is to move and advance, ( especially deeper into the conus) and time and time again in the past , that process is instigated by a favorable MJO

My thoughts are cold for early December. Below avg temps first 7-10 days IMO. Question that most folks care about is snow chances and besides the little clipper we are covering Sat night in the Nov. thread... for this particular thread, I think comes sometime in the Dec 5-8th time frame. I think that the cold will try and ease but ahead of the next shot of cold air, a storm will form. Question will be degree of phasing and how much digging of the trough do we get? Depends on location and angle of PNA Ridging out West. The dates here being discussed are in flux but the general idea to me is the first bonified winter storm of the season for the Midwest, Lakes, and OV regions. Climo speaking, areas to our NW would be favored. However, we'll have had arctic air going in and another shot will be coming in on the way out, so we'll see where we sit as the storm will be in between these cold shots. Should be our first interesting period to watch for the winter season.

We will be doing separate storm threads this year if we see anything decent now that Met Winter is about to kick off! I don't see anything thread worthy as of yet. Oh and one more thing... if anyone sees an event as thread worthy, then by all means, start up a storm thread and I will pin it. Any potential event that gets within range of 24 hours to 5-7 days out is a good thread starting window I would think. So no 384 hour GFS BS. Save the digital snow for the main monthly thread here.

Time to start looking at the wind anomalies that affect the MJO response and wow, that’s a wide expand of easterlies in the Pacific. I would expect this to slow down/weaken the eastward movement of MJO in the coming days/weeks into the Pacific phases

Good Morning and love this kind of day with a cloudy sky and seeing that some winter weather is headed our way. I have put in the turkey or should I say the extra turkey I cook for my wife and I every year. Of course will make all the extras on Thursday which I enjoy so much and then I turn on the football game before I head to relatives around 330pm.

Enough of the turkey talk but time to get ready for December. First week is really set in stone in terms of cold and some decent cold as some arctic air heads this way. Do I believe this is record cold and no is the answer but could see a few days that stay below 32 and nights that may get near 10. If we had a decent snow cover then temps could drop more and though we have a few clippers around nothing heavy by any means. I know the models and met's are trying to figure out beyond week 1 and what happens. What does the mjo forecast look like and it looks to be moving into some warmer phases but not strong and the AO and NAO in the neutral zone but it does have the PNA a tad positive so a pattern that could get a little busier in terms of precip imo but also maybe some milder temps as well. When I say milder I am just talking 40's and nothing higher unless a big storm forms that can bring up some warmer air for a day or two but at this point no way to predict. I know Brian mentions that these patterns can be hard to break and I agree though if we had a nice snow cover over more of the northern and central plains I would feel a tad more confident so playing the neutral card at the moment and expect a more seasonal pattern in the 2nd week of the month which is temps in the low-mid 40's for highs and upper 20's or so for lows. Okay that covers week 1 and some thoughts on week 2 but again the second week is still up in the air imo whether we stay cold with clippers or become milder with chances of a stronger system or two. Btw starting Dec 1st we could see 3 clippers in one week which has something we have been lacking for the past several winters.

Last couple of Euro runs have shown a decent little clipper for Monday afternoon next week, The GFS has lost it. Waiting to see if the 12Z run brings it back or not.

Les I believe after we get the pattern carved out after Thanksgiving models may try and give us a better handle on the energy going up and over the ridge in the west. I understand they will go back and forth with intensity and path and also these are small pieces of energy so the window is much more narrow and many times it can be 24 hours before a system moves in to get that path narrowed down. I am happy we have something to follow next week.

tpweather wrote: ↑Wed Nov 27, 2024 11:52 am Les I believe after we get the pattern carved out after Thanksgiving models may try and give us a better handle on the energy going up and over the ridge in the west. I understand they will go back and forth with intensity and path and also these are small pieces of energy so the window is much more narrow and many times it can be 24 hours before a system moves in to get that path narrowed down. I am happy we have something to follow next week.

Agreed Tim. It'll be cold that is for sure. Any snow is the unknown at this point. I see small chances until the cold relaxes. Once that happens we'll see if a bigger system can develop ahead of the next shot of cold air.

MJO phase 4 for a neutral Enso in December. To me, this is not the worst look in the world. Blocking to or north. All that cold in Alaska and Western Canada could possibly try to bleed into the Midwest and Southeast with that look. It's not ideal, but for phase 4 it could be a lot worse.

dce wrote: ↑Wed Nov 27, 2024 12:56 pm MJO phase 4 for a neutral Enso in December. To me, this is not the worst look in the world. Blocking to or north. All that cold in Alaska and Western Canada could possibly try to bleed into the Midwest and Southeast with that look. It's not ideal, but for phase 4 it could be a lot worse.

Still looks seasonal for temps and storms would still have to slide underneath the block over Eastern Canada. I'm with you Doug... not a bad look at all. The MJO if it stays on the weak side (as a lot of models suggest), tells us that the colder pattern / NW Flow, may stick around for a bit. We'll just have to wait and see.

tron777 wrote: ↑Wed Nov 27, 2024 1:05 pm

dce wrote: ↑Wed Nov 27, 2024 12:56 pm MJO phase 4 for a neutral Enso in December. To me, this is not the worst look in the world. Blocking to or north. All that cold in Alaska and Western Canada could possibly try to bleed into the Midwest and Southeast with that look. It's not ideal, but for phase 4 it could be a lot worse.

Still looks seasonal for temps and storms would still have to slide underneath the block over Eastern Canada. I'm with you Doug... not a bad look at all. The MJO if it stays on the weak side (as a lot of models suggest), tells us that the colder pattern / NW Flow, may stick around for a bit. We'll just have to wait and see.

I agree about how it looks seasonal. My biggest concern in keeping colder air around longer is lack of snow cover in the northern and central plains. Yes we will get some in the northern plains over the next week but nothing major and the central plains may be missed all together and this would allow southerly winds to make an easier path late next week into the 2nd week of December.

It’s a textbook long wave pattern (imo) to start out December, been a long time since this has happened in this time frame. Expansive Aleutian Low/trough to an expansive western ridge to an expansive trough in the east. Those three cover a huge area of real estate . The trough in the east is so huge , the wimpy SE ridge is no where to be found, so no help with moisture from the GOM as noted by all , during this time period.

Bgoney wrote: ↑Wed Nov 27, 2024 6:16 pm It’s a textbook long wave pattern (imo) to start out December, been a long time since this has happened in this time frame. Expansive Aleutian Low/trough to an expansive western ridge to an expansive trough in the east. Those three cover a huge area of real estate . The trough in the east is so huge , the wimpy SE ridge is no where to be found, so no help with moisture from the GOM as noted by all , during this time period.

I agree and this is another reason we are seeing several chances for clippers. Moisture available along the area with the greatest temp difference and this weekend that may be near us and then again once temps try to climb back later next week we could see another decent chance of some snow but with limited moisture. Lucky we are getting cold and will not need to worry about whether its rain or snow for at least a week or so and ratios will be greater than 10-1 and many times 15-1. Sooner or later the pattern will break and that usually involves a bigger system but of course that also includes milder air getting involved but this far out nothing to even forecast.

Easterly’s still forecast to rule , so a slowdown and weaker MJO in its eastward movement should still be expected, imo , into the kryptonite phases

Good Morning and just listen to Brian's video and always happy when my thoughts are similar to his in regards to long term. Also listen to DT's video and again longer term is normally his strength and though I believe he may be a little to excited about the whole winter I do believe what he is seeing has a decent chance this winter.

This is not like the last few winters and especially since the La Nina has not developed and really a just a neutral ENSO is not a bad place to be imo. Yes its cold in Alaska but they have not had the 2 week stretch where they have the snow and then the brutal cold and it locks up so that is a plus. Getting plenty cold in northwest Canada and that is a good sign as pieces of cold work their way down here over the next week or so plus if we can get the ridging to move further north in western Canada and eastern Alaska this can lead to a cross polar flow. Again Siberia has not been cold for them but again -30 - -40 is still plenty cold. I still believe we need a period to reload the cold in the polar regions but trying to figure out the time period is almost impossible.

I am glad Brian mentioned the flurries on Friday as he believes that with this set up models tend to miss the leftover moisture around and clears us out way to soon and yes flurries but if you get the sun to pop up before the moisture leaves you get those snow showers.

The clipper looks locked in but placement still up in the air for later Saturday and then he is still concerned about the one later Monday and early Tuesday and will watch this and not sold yet as the cold may be really in place and any energy goes south and its weaker. Then later in the week we will see of the milder air flows in and at first an overrunning event but probably short in nature and then watch next weekend to see if we have any sort of system that forms. To early but the pattern is giving us some clues of what may happen.

Good Morning and you can feel the cold. Came home last night around 830 or so and had a little rain mix with a few ice pellets but caused no problems except for the glare on the roads. Today expect some snow flurries and yes still a chance for a snow shower as the atmosphere rings out the remaining moisture. The clipper for late Saturday and early Sunday. Still on track but exact placement and how much can we expect is still a tough forecast. When it heads into Missouri and southern Illinois on Saturday this system may get a tad stronger as some southwest winds add a little more moisture but as it heads towards us it will weaken. Going to be a very narrow path of the heaviest snowfall and when I say heavy 1 inch maybe 1 1/2 but that is in maybe a 25 mile wide area at best . So Saturday night at your house it may be snowing with a nice coating and 10 miles away a few flurries. This will reinforce the cold and the first cold warning in the lower 48 as northern North Dakota has one for today. Seeing some -40 in the northwest terr and russia still only around -30 so the coldest air is on this side of the planet.

Next week should become busier and trying to find that energy for late Monday or Tuesday but I have always had a hard time with this so not going to forecast anything at the moment. Then mid-week on we start to see more energy plus the gom is trying to open for business. Give a few days to see where everything set up after this weekend and see is there anything a tad stronger for us to track.

I See Some of the models are now adjusting more noticeably to the mentioned slowdown/weakening of the MJO eastward advance.

Major lake effect unfolding up here just north east of Cleveland. We will be mostly dry here in Cleveland till Sunday afternoon and overnight when that band will shift south