Absolute Vorticity

CVG reached 53, DAY 50 and CMH 48 on Sun.

Good morning all! A wet Monday and Wednesday are on tap this week. Tues will be our nicest day this week. Turning colder Thurs thru the weekend. Maybe some flurries on Fri with a northern passing clipper? Doesn't look to be a big deal at this point. Then, the GFS is dry but the CMC has rain on Christmas Eve and the Euro has light snow. That will be our next system to keep an eye on. Then, I think we turn warmer and wet between Christmas and New Year's. After that ??? That is my overview of the rest of the year.

Good Morning and Les has the forecast covered and not much to add lol. Rain could be heavy at times today and looks like a good .75-1.00 with the usual some may get a tad less and some a tad more but pretty uniform 30 miles either side of the river. Snow chances are still slim for Christmas but still have time to see if the upcoming cold can stay in place long enough before the moisture returns. Then milder air like Les mentioned between Christmas and the New Year. When does the cold return and again up in the air at this point though I still feel confident of a colder than normal January and hopefully we can get the overall trough that has been set up over the eastern 1/3 of the country in December to move somewhat further west but not to far because then the dreaded southeast ridge likes to poke its head out and have a dislike for southeast ridge lol

The Euro Weeklies continue to look cold and stormy for early to mid January. A nice -EPO block with a +PNA and -NAO is what is being shown. As usual, we shall see but I still have hope down the road. The MJO still needs to be watched and it would argue against what the Euro Weeklies are showing since I do not believe that we see Phase 8 unfortunately by early January. I think it'll be in Phase 7 or the COD.

I wouldn’t mind a SEridge at least a normal one. Not having one for our December cold spell has killed any chance of a decent wintery system, not just for us but anywhere in the central part of the US . With the cold fronts meeting no resistance, no baroclinic zone to help create a stronger system

Bgoney wrote: ↑Mon Dec 16, 2024 6:53 am I wouldn’t mind a SEridge at least a normal one. Not having one for our December cold spell has killed any chance of a decent wintery system, not just for us but anywhere in the central part of the US . With the cold fronts meeting no resistance, no baroclinic zone to help create a stronger system

Yes a normal one would be good and there are signs we are starting to see this in the longer range and this also allows the flow from the GOM to become more likely as well. The GOM still very warm especially the western portion and if we can get the trough situated in the central USA then the chances of bigger storms rise. Still not seeing a strong PV this season and we know sometimes its so strong that we are just left with a west to east flow and very seldom does that bode well for snow.

The MJO, indeed, took a dive in phase 5 toward the circle of death. It just doesn't want to make it to phase 6. Who knows what is going to happen? Much uncertainty, but cold seems to be the way to go in the medium and long term, regardless of what happens with the MJO. This could be a winter where the cold wins out for the Eastern US? Or maybe everything blows up? Hard to really forecast.

We are all taking stabs at the forecast which I love to see! We definitely could use some blocking to slow the flow down to get a bigger system. We're not seeing that as of yet. I think we'll need to wait until January for that to happen. I expect rain makers for the rest of the year except in that Dec 20-25th range. I still am watching for a shot of some light snow in that window. I have not given up on that. Too much uncertainty IMO for next week.

Hey Doug, yes I did not see this dive in phase 5 as it just sort stuck around deciding what to do. I had us mild for the second half of December but with the dive we see the cold snap later this week and lasting maybe 3-5 days. The mjo does show it heading back to phase 6 which is a warmer phase and I believe that is true. Once we get the milder temps again it could be many days of above normal temps and since we had this quick cold snap its just going to take somewhat longer to bring back the cold. Original thought was around the New Year but that must be pushed back several days. Not sure if that means the 3rd of January of the 10th or somewhere in between. If the PV gets stronger which at the moment no signs then I believe closer to the 3rd but if somehow the PV gets it act together and becomes strong then maybe the 10th or even later. The puzzle is never easy and its ever changing but that is where the challenge is and sometimes that is fun and other times not so much.

Yep , all the models are finally showing the low amplitude into 6 , GEFs has it climbing but I think that will adjust as its own data has it in 6 and weakening as it approaches 7 like the EU. Think that’s the way to go as far as the forecast for the MJO . That would definitely delay arctic invasion deeper into the US/OV for the new Year

Pac jet is raging coming off of Asia and will be extending north of Hawaii for a while, thanks to the MJO being stuck in 5.

tpweather wrote: ↑Mon Dec 16, 2024 7:06 am

Bgoney wrote: ↑Mon Dec 16, 2024 6:53 am I wouldn’t mind a SEridge at least a normal one. Not having one for our December cold spell has killed any chance of a decent wintery system, not just for us but anywhere in the central part of the US . With the cold fronts meeting no resistance, no baroclinic zone to help create a stronger system

Yes a normal one would be good and there are signs we are starting to see this in the longer range and this also allows the flow from the GOM to become more likely as well. The GOM still very warm especially the western portion and if we can get the trough situated in the central USA then the chances of bigger storms rise. Still not seeing a strong PV this season and we know sometimes its so strong that we are just left with a west to east flow and very seldom does that bode well for snow.

That's the big question for us isn't it? The SE ridge. Too strong and we torch. Too weak and we get the northwest flow, which occasionally can bring in a bigger storm but most of the time light snows on the order of a dusting to 1-4 inch your of events. We definitely have a real possibility of seeing the SE ridge going into to just the right position this winter. How long it would last, who knows? I like our chances though.

What I like is storms moving into the west coast. This should help in getting snow cover in the northern plains and upper mid-west that will stay awhile. Hopefully by early January we see this extended further south. The south central part of Canada has done well in the snow fall department and that should continue which is also a big help. Is the mjo going to be in a progressive move this year is key and will it make pit stops in certain phases like it has in phase 5. I believe without the PV getting strong a progressive mjo is likely. So many items to look at and what is controlling the weather is the question. Yes neutral Enso though the last week or so tend to head towards a La Nina. Funny thing about either a La Nina or El Nino and must have 3 straight months for it to be classified either or but that is a bad way of looking at the final outcome. Normally for us getting a weak event or neutral Enso is the best shot for a decent winter around here. So I like what I am seeing on that front but again more items than just that to figure out this puzzle. One item for sure and its not going to be like last winter which was the sunniest winter I ever remember in our area since we live in a valley clouds are part of winter

0.18" of new rainfall as of 10am at CVG. That brings us up to an event total of 0.76" 1-2" thru Wed was the original call so we certainly look to be right on track with that idea. Of course, most folks want to know about snowfall and while we don't have anything big on the horizon, we still need to keep an eye on the Fri / Sat period as well as Christmas Eve / Day. If the mild air comes in sooner then we could see more wet then white with that second system around Christmas. We'll wait and see as the smart thing to do is take one system at a time.

For Fri, we must see more southward digging of that trough otherwise the best snows miss to the north which is what the data currently shows. I will keep some flurries in the forecast for now. Can this change? Can we get a better dig? Perhaps. I won't rule it out this far away in time. We should know more on how Fri / Sat looks once we get towards Thurs as the colder air begins to move in.

I wish I had better short and medium range news, but it is what it is.

Brian;s video was short but sweet. I agree with what he mentioned and this last spell of cold is sort of delaying when a longer period of cold could arrive. If we did not have this 4 or 5 days of cold we would be mild for the last two weeks of the month and then hopefully the cold would arrive around the New Year. I believe we are all on the same page and just like usual going about it in different directions but if we all end up with similar outcomes then we are probably on to something in regards to January.

Oh wow! Just had a big clap of thunder here at the office. I wasn't expecting that lol

EDIT Seeing some pretty heavy rain too! Wow!

tron777 wrote: ↑Mon Dec 16, 2024 12:31 pm Oh wow! Just had a big clap of thunder here at the office. I wasn't expecting that lol

EDIT Seeing some pretty heavy rain too! Wow!

Same here Les though only one clap and then the heavy downpour a few minutes later that lasted about a few minutes. Again something we predicted could happen but was nothing that was going to be severe

Event total as of 2pm at CVG - 1.14"

1.21" now as of 4pm - CVG event total

5 day anomalies to finish the month from EU ensembles