December 2023 Weather Discussion

[tpweather]

Good Morning and no changes to the forecast. Rain still likely on Christmas and will keep totals between 0.25 - 0.75 for most folks locally. After that we start to get cold and maybe can get some snow showers in here by the end of the week. No major snow storms on the models but that can change when the two jets play ball. Still wish there was more snow cover to the north and west but never a perfect setup for us locally.

Once the cold gets here how long will it stay and part of that will be how much snow can fall on the lower 48. Getting a nice snow cover especially in January can be of help in keeping the colder air around longer. Polar Vortex and how will that play out next month. Still believe the east coast is in the best spot for bigger storms with the STJ located along the gulf coast and then heads northeast.

[tron777]

Good Morning and no changes to the forecast. Rain still likely on Christmas and will keep totals between 0.25 - 0.75 for most folks locally. After that we start to get cold and maybe can get some snow showers in here by the end of the week. No major snow storms on the models but that can change when the two jets play ball. Still wish there was more snow cover to the north and west but never a perfect setup for us locally.

Once the cold gets here how long will it stay and part of that will be how much snow can fall on the lower 48. Getting a nice snow cover especially in January can be of help in keeping the colder air around longer. Polar Vortex and how will that play out next month. Still believe the east coast is in the best spot for bigger storms with the STJ located along the gulf coast and then heads northeast.

Good morning Tim! This is most likely going to be correct. We've seen a lot of coastal lows and late phasing systems already. For us, the upper low will bring in the snow. Remember the East Coast Blizz of January 1996? We weren't supposed to get much from the upper low but we ended up getting over a foot! Not saying that this will happen in January 2024 but my point is, the upper low that will help develop the East Coast low is where we can cash in around here locally. You get a strong enough upper low and have it slow moving, it can certainly tap the Gulf for moisture. These again are situations that will not be picked up on by modeling early, if at all so I certainly expect some surprises down the road.

[tpweather]

Good Morning Les and already on my second cup of coffee. I agree about surprises and will be watching the energy coming into southern California but also energy that rides over the ridge in Alaska and western Canada as those pieces should no doubt be near us quite often the next two months. AO is tanking and heading towards neutral and yes negative. The NAO is a little slower but is heading towards neutral and believe that will head towards negative as well once we get the Greenland block which can take a little longer to establish.

Watch the CMC for later this week as it did the best with the previous snows in our area and I believe Trevor mentioned how he tends to follow that model for energy coming out of Canada. My guess I will see some snow while in Wisconsin but nothing where I am not able to travel and though it will be getting cold there but still above normal for them.

[tron777]

I just poured my second cup as well, Tim. The GEFS Mean thru the 1st week of January for snowfall is around 2" for Cincy with the GEPS (Canadian Ensemble) around 4". Remember, the ensemble mean is an avg all of members so we look at them for signals and trends. I like what I am seeing!

I like where things are headed Tim. I share the same optimism that Doug posted on last night. I just checked the AO forecast and it looks to drop into negative territory around NYE thru early January with the NAO neutral as you mentioned. The PV is weakening and will be on the move. Still not sure on a total wind reversal i.e. a major SSW but at any rate, things are changing for sure. We've talked about needing a -EPO as one of the most important ingredients that you want for cold and snow chances in the Eastern US. We look to be getting that here shortly as well. Our future is looking bright for us snow lovers Tim!

[tron777]

This was posted yesterday on X (Formally Twitter) by a respectable Met. I have followed Allan Huffman for many years!

EPS PV.png

[tpweather]

Les I agree about the PV and not sure if we get a total wind reversal but also if that happens and the way the pattern is shaping up it may pull to much cold air into the eastern half of the country and we get really cold but dry. Again as I have watched the season progress in Europe and Asia and the one item that continues to show up is huge snow storms on the southern edge of these cold outbreaks. That is a trend to watch over the next few weeks and if the PV does a wind reversal and the vortex heads to southern Canada that would not be here until later in January and if we have a decent snow pack then we are in business. Again the PV could decide to head towards Asia or Europe and way to early to say where it may end up if it happens.

[tpweather]

Les, Alan is a very good met and when he puts stuff out like this we should pay attention. The one thing this season is the PV is strong but not the coldest by any means and I believe part of that is because it has been able to throw those spokes of cold away from the poles like we have seen in Europe and Asia. You really get the cold with the PV when its strong and not moving for weeks without the spokes coming out. Sure -55 - -60 is cold but that is more average up there plus the coldest of air has shifted eastward towards eastern Siberia and another reason China has got record cold and snows in many areas. Once we get the ridging setup out west hopefully we get the cross polar connection and some of that heads this way.

[tron777]

Les I agree about the PV and not sure if we get a total wind reversal but also if that happens and the way the pattern is shaping up it may pull to much cold air into the eastern half of the country and we get really cold but dry. Again as I have watched the season progress in Europe and Asia and the one item that continues to show up is huge snow storms on the southern edge of these cold outbreaks. That is a trend to watch over the next few weeks and if the PV does a wind reversal and the vortex heads to southern Canada that would not be here until later in January and if we have a decent snow pack then we are in business. Again the PV could decide to head towards Asia or Europe and way to early to say where it may end up if it happens.

If we get a full wind reversal, we won't see the effects right away, there is always a lag. I'd look for those impacts to be later in January and also February. Look for a big storm on the leading edge of the arctic airmass or as it tries to retreat. One or the other, typically yields a big storm for somebody. Since we are in an El Nino, we are going to see shortwave after shortwave traversing across the southern US and we will also see shortwaves ejecting from the trough in the NE Pacific dropping in overtop of the ridge in AK / Western Canada by the 1st week of January. It will always boil down to timing but from this distance, my mouth is truly watering at the potential.

[tron777]

Les, Alan is a very good met and when he puts stuff out like this we should pay attention. The one thing this season is the PV is strong but not the coldest by any means and I believe part of that is because it has been able to throw those spokes of cold away from the poles like we have seen in Europe and Asia. You really get the cold with the PV when its strong and not moving for weeks without the spokes coming out. Sure -55 - -60 is cold but that is more average up there plus the coldest of air has shifted eastward towards eastern Siberia and another reason China has got record cold and snows in many areas. Once we get the ridging setup out west hopefully we get the cross polar connection and some of that heads this way.

I agree Tim and if you look at a hemispheric view of the Ensembles, you will notice by the Jan 4-6th time period that both Trev and I think looks very interesting for a winter storm... notice how the PV is stretched more North to South in the classic spot over Hudson's Bay. Truly textbook right there my friend.

[tpweather]

Les, Alan is a very good met and when he puts stuff out like this we should pay attention. The one thing this season is the PV is strong but not the coldest by any means and I believe part of that is because it has been able to throw those spokes of cold away from the poles like we have seen in Europe and Asia. You really get the cold with the PV when its strong and not moving for weeks without the spokes coming out. Sure -55 - -60 is cold but that is more average up there plus the coldest of air has shifted eastward towards eastern Siberia and another reason China has got record cold and snows in many areas. Once we get the ridging setup out west hopefully we get the cross polar connection and some of that heads this way.

I agree Tim and if you look at a hemispheric view of the Ensembles, you will notice by the Jan 4-6th time period that both Trev and I think looks very interesting for a winter storm... notice how the PV is stretched more North to South in the classic spot over Hudson's Bay. Truly textbook right there my friend.

100 p/c agree and this is one where the pattern is ripe for a big storm and the models will catch up in the next week or so. I sent out my neighborhood winter weather outlook maybe 10 days or so ago and mentioned rain for Christmas followed by us getting colder towards the New Year and then we should have a couple good months of winter weather before an earlier spring in March. My problem before this was just rushing the pattern by a week and had 12/21 as a pattern change but 12/28 will work just fine as well.

[tron777]

Les, Alan is a very good met and when he puts stuff out like this we should pay attention. The one thing this season is the PV is strong but not the coldest by any means and I believe part of that is because it has been able to throw those spokes of cold away from the poles like we have seen in Europe and Asia. You really get the cold with the PV when its strong and not moving for weeks without the spokes coming out. Sure -55 - -60 is cold but that is more average up there plus the coldest of air has shifted eastward towards eastern Siberia and another reason China has got record cold and snows in many areas. Once we get the ridging setup out west hopefully we get the cross polar connection and some of that heads this way.

I agree Tim and if you look at a hemispheric view of the Ensembles, you will notice by the Jan 4-6th time period that both Trev and I think looks very interesting for a winter storm... notice how the PV is stretched more North to South in the classic spot over Hudson's Bay. Truly textbook right there my friend.

100 p/c agree and this is one where the pattern is ripe for a big storm and the models will catch up in the next week or so. I sent out my neighborhood winter weather outlook maybe 10 days or so ago and mentioned rain for Christmas followed by us getting colder towards the New Year and then we should have a couple good months of winter weather before an earlier spring in March. My problem before this was just rushing the pattern by a week and had 12/21 as a pattern change but 12/28 will work just fine as well.

I rushed the change also by 7-10 days. Just glad to see it happening and the can kicking seems to be done now. This is a case where we are seeing things actually look better the closer we get instead of the other way around.

[tpweather]

Les that is so true and though December has been mild it has been nice in terms of sunshine and getting things done even outside. Last year we were in the ice box with snow on the ground and boom the pattern changed as the MJO stayed in phases 4-6 for an extended period.

[tron777]

Les that is so true and though December has been mild it has been nice in terms of sunshine and getting things done even outside. Last year we were in the ice box with snow on the ground and boom the pattern changed as the MJO stayed in phases 4-6 for an extended period.

Exactly Tim. This year is the opposite. MJO went thru the warm phases late Nov and thru the first 2/3's of December. Combined with a raging Pacific Jet and there you go. Now, we are seeing the MJO get into Phases 8 and eventually 1 and 2 over the next few weeks. Canadian ridging retrograding towards AK will also help to slow down the raging Pacific Jet so this new pattern could potentially have some staying power to be honest if things break the right way.

[Bgoney]

The MJO models are still showing a tour thru the colder phases 8-1-2 late this month and into early January. There is a lot to like folks in the next few weeks once we get past the Christmas time period. Hang in there!!!!

I hope this isn't Lucy pulling the football away just before the kick. I really don't think so though. This new pattern looks to be legit. We have seen model agreement for a very long time regarding this pattern change. And for once the pattern seems to be getting better the closer we get. I really like how the jet stream is being modeled as very active. I really do not believe we will be cold and dry with this upcoming pattern. I haven't been this optimistic for a very long time concerning winter weather threats. Januarys have been very mild lately compared to average. We talk about the warm Decembers we have had over the last decade. Januarys have been pretty mild, relative to average, over the last several years as well. February and March have been the only winter months we have had any consistency in below average temps. And they really haven't been all that much below normal. Probably just average, but with how mild the first half of our winters have been, those months have seemed colder because they have been closer to average. We are definitely far overdue for a below average temperature and above average snowfall January.

Great post, upcoming normalish temps for the last day or two of this year and to start Jan are going to be perceived differently. When Canada’s well above normal temps get pushed into the lower 48 by some form of a -EPO , it morphs into near normal temps for the US . Poor(southern )Canada has a long way still to see a cross polar flow to get them near normal, in the meantime we can still make good use of there scraps

[tron777]

The MJO models are still showing a tour thru the colder phases 8-1-2 late this month and into early January. There is a lot to like folks in the next few weeks once we get past the Christmas time period. Hang in there!!!!

I hope this isn't Lucy pulling the football away just before the kick. I really don't think so though. This new pattern looks to be legit. We have seen model agreement for a very long time regarding this pattern change. And for once the pattern seems to be getting better the closer we get. I really like how the jet stream is being modeled as very active. I really do not believe we will be cold and dry with this upcoming pattern. I haven't been this optimistic for a very long time concerning winter weather threats. Januarys have been very mild lately compared to average. We talk about the warm Decembers we have had over the last decade. Januarys have been pretty mild, relative to average, over the last several years as well. February and March have been the only winter months we have had any consistency in below average temps. And they really haven't been all that much below normal. Probably just average, but with how mild the first half of our winters have been, those months have seemed colder because they have been closer to average. We are definitely far overdue for a below average temperature and above average snowfall January.

Great post, upcoming normalish temps for the last day or two of this year and to start Jan are going to be perceived differently. When Canada’s well above normal temps get pushed into the lower 48 by some form of a -EPO , it morphs into near normal temps for the US . Poor(southern )Canada has a long way still to see a cross polar flow to get them near normal, in the meantime we can still make good use of there scraps

I agree... I don't see arctic air either as I have mentioned before. Seasonal temps, which are temps in the 30s for January will yield snow. This will be vastly different from the 40s and 50s (even an occasional 60) that we have been seeing for weeks now.

[tpweather]

The MJO models are still showing a tour thru the colder phases 8-1-2 late this month and into early January. There is a lot to like folks in the next few weeks once we get past the Christmas time period. Hang in there!!!!

I hope this isn't Lucy pulling the football away just before the kick. I really don't think so though. This new pattern looks to be legit. We have seen model agreement for a very long time regarding this pattern change. And for once the pattern seems to be getting better the closer we get. I really like how the jet stream is being modeled as very active. I really do not believe we will be cold and dry with this upcoming pattern. I haven't been this optimistic for a very long time concerning winter weather threats. Januarys have been very mild lately compared to average. We talk about the warm Decembers we have had over the last decade. Januarys have been pretty mild, relative to average, over the last several years as well. February and March have been the only winter months we have had any consistency in below average temps. And they really haven't been all that much below normal. Probably just average, but with how mild the first half of our winters have been, those months have seemed colder because they have been closer to average. We are definitely far overdue for a below average temperature and above average snowfall January.

Great post, upcoming normalish temps for the last day or two of this year and to start Jan are going to be perceived differently. When Canada’s well above normal temps get pushed into the lower 48 by some form of a -EPO , it morphs into near normal temps for the US . Poor(southern )Canada has a long way still to see a cross polar flow to get them near normal, in the meantime we can still make good use of there scraps

Good Morning Bgoney and you are correct but the good thing is eastern Canada has been cold and we can grab some of that air later this week into next weekend. Northern Canada has been cold of course but near normal or slightly above but -30 is still cold. Heading to Wisconsin where my son lives and it has been so mild up there with the biggest snow on Halloween. Many days in December with temps 20 degrees above normal. Still trying to figure the migration of the birds and wish I knew somebody that is an expert because I saw less in the way of birds heading south and the ones that were heading that way were probably 3 weeks later than normal. Does this have anything to do with the milder temps in southern Canada and the northern plains and not sure

[tron777]

I will gladly take seasonal temps. You risk suppression if it is too cold and the TN Valley or Atlanta gets snow while we are cold and dry. Air cold enough for snow is all we really need to make it work and that is what I am expecting from an airmass standpoint.

[tron777]

12Z GFS after the Christmas rains tomorrow, bring in the main upper low Wed night into Thurs next week with mixed rain / snow showers then a secondary upper low Thurs night. This is much faster then the Friday date I have set for some light snow. Then another shortwave dropping thru the flow centered a bit NE of Cincy on 1/1/24 to kick off the New Year.

12Z CMC is not as widespread with the snow showier activity on Fri the 29th but the timing to past runs is similar.

[tpweather]

Good Afternoon. So far only a few things are somewhat different on the models and that is the system for Christmas is a little stronger but also a little further west and the piece of energy for later in the week is still there and the gfs is even showing it at this time. In the extended don't get caught up if you don't see a storm for an extended period. The STJ is busy but also rather fast and many times models will not be able to pick these up plus my guess the models are not quite there with the blocking that should start happening after the next year. Again models never pick up every piece of energy in the polar jet and with a quick moving STJ a bigger system will seem like its coming out of nowhere but it finally will see about 3-4 days ahead of the two jets getting closer to each other.

[tron777]

The GEFS members vary in timing and intensity with the upper lows for Thurs and Fri but I am going with rain / snow showers Thurs and all snow showers for Friday. Too early to pinpoint any accumulations but if the shortwave is strong enough on Friday, I could see up to 1" falling for sure.

For early January, the OP 12Z GFS continues to look interesting for a winter storm for the area around the 4th or so.

[tron777]

Wow... a pretty cold 12Z suite so far today. I'm wondering if the PV splitting and the stratosphere warming has anything to do with it? The end of the GFS run has a legit arctic airmass coming into the country and a storm on the leading edge of it. CMC has very cold air as well inside of 10 days.

[tpweather]

I agree Les and models have been hinting at the colder runs but looks like today is the day they all go in for the cold. Storm stronger on all 3 models for Christmas which is a change from earlier systems this fall but you are getting both jets involved and it makes a difference. Concerning the new year and we look to get very busy from what I can tell and may be a winter with a storm every 3-5 days for a period of time.

BTW northern Alaska getting in on some of the cold air from Siberia finally while the south part of the state is having tons of fun with rain,snow,wind and everything else you can think of.

[tpweather]

Another item to mention is the STJ. So far for the most part the STJ has come through Mexico up through the Gulf States and then up the east coast. The current storm came through California then the central plans and will head northeast from there. No big deal but it is because this allows the ridging in western Mexico and the southwest to happen next week and that ridge looks to head north towards western Canada and eastern Alaska. When the STJ was non-stop through Mexico ridging was unable to take hold but it looks like this time that will happen

[tron777]

Another item to mention is the STJ. So far for the most part the STJ has come through Mexico up through the Gulf States and then up the east coast. The current storm came through California then the central plans and will head northeast from there. No big deal but it is because this allows the ridging in western Mexico and the southwest to happen next week and that ridge looks to head north towards western Canada and eastern Alaska. When the STJ was non-stop through Mexico ridging was unable to take hold but it looks like this time that will happen

The STJ definitely is going to kick in once we get to 2024. The pattern change is already underway and the Christmas rainer is what kicks everything off in motion we have been tracking.

[tron777]

So in summation... while the Euro rolls in, my expectations are this: (Subject to change of course LOL)

Light rain today
A beautiful Christmas Eve
Rain on Christmas Day

Rain / snow showers for the 28th
Light snow on the 29th

Possible light snow for New Year's Day
Possible winter storm Jan 4-6th time period
More to come after that...