Absolute Vorticity

Until we can get more of an influence from either the STJ or some sort of SE ridging the weakening low scenario for the OV is going to keep dominating our systems.

Bgoney wrote: ↑Wed Nov 29, 2023 6:42 am Until we can get more of an influence from either the STJ or some sort of SE ridging the weakening low scenario for the OV is going to keep dominating our systems.

That is the problem with an El Nino around here as the STJ is moving fast and hard to build up a SE ridge and usually an area to the north away from the STJ that gets caught up between the STJ and Polar Jet. Will the STJ move further north especially out west and once I start seeing system coming in Southern California I will have more confidence of a more active pattern locally but atm STJ is coming up through Mexico and hits the lower Gulf states and head east/northeast. Sure we get a few systems in here which is good because any rain helps but I remember sometime early this month or last month where models were showing a big uptick in precip amounts around here and that has not even been close.

I am going with the idea now of a lot of back and forth for the first half of December. Cold for a couple of days, then we warm up, wash, rinse, and repeat. I still believe that positive changes for snow lovers are coming for the last 10 days of Dec and into January as well. I still like very much what the longer term guidance is showing. We just have 2-3 weeks to get thru first before we get there. Remember, we did forecast above normal temps for December but it won't be the historic warmth of last year whatsoever.

tron777 wrote: ↑Wed Nov 29, 2023 10:35 am I am going with the idea now of a lot of back and forth for the first half of December. Cold for a couple of days, then we warm up, wash, rinse, and repeat. I still believe that positive changes for snow lovers are coming for the last 10 days of Dec and into January as well. I still like very much what the longer term guidance is showing. We just have 2-3 weeks to get thru first before we get there. Remember, we did forecast above normal temps for December but it won't be the historic warmth of last year whatsoever.

Yea I see no reason to change thoughts on the first half of Dec. , to early for me just yet to go beyond in to much detail. But not seeing atm at least of major cold shot for the OV for week 3

Thurs night into Friday still looks to be the wettest period of the next 5-7 days. Then, I am still watching that clipper for Tues or Wed time frame next week for some rain and / or snow showers. Not much else to report. No big warm up's or big cool downs expected.

NEW This Week in Weather posted last night from DT:

Good morning all! Rain moves in Thurs night, after midnight thru Friday with the steadiest rains coming during the AM Commute. 1/2" or less for most folks. Then, do we get clipped on Sunday or remain dry with the next wave? After that, two clippers dive in from the NW and the tracks on these are still TBD. This is for the Mon - Wed period next week. Thinking light rain showers versus snow showers due to the lack of cold air. The only thing that would help is if they pass thru at night. Currently, I don't see the lows digging south of us which is what you would want for snow so that's another problem.

Looking longer term, around Dec 10-13th period, a more significant storm system looks to be in the cards. The GFS has a front stalling over the OV with a low riding along it producing rain, mixing with and changing to snow on the NW side of the precip shield. CMC and Euro if they went out further would show a cutter. I am inclined to go with the cutter solution at this time. Then we get a blast of cold air then warm up again for the mid month period as the jet goes zonal again and lifts to the north. Again as stated the other day, I am going with better conditions for snow lovers the last 10 days or so of December. Until then... up's and down's and slim chances for snow. Recall my original winter call, a mild December, a better January and a nice Feb with spring coming early in March. So far, the December call is looking good. Once again, let me stress that I do not see historic warmth. 50s and 60s is not historic warmth. The 70s like we saw last year is.

December History during the 2000s at CVG


Normal mean temp is 35.6
Normal snowfall is 4.1”

A big problem to overcome at some point is the complete lack of snow to our NW cold source region all the way to at least mid December, from the Canadian prairies through the plains/midwest . What little snow there is now in a few locations will erode by mid month

Great images Bgoney! Thanks for posting all of that. You can truly see how bad Decembers have been over the last decade or so.

LOL @ the 6Z GFS.

tron777 wrote: ↑Thu Nov 30, 2023 10:51 am LOL @ the 6Z GFS.

Lock it in.

Trevor wrote: ↑Thu Nov 30, 2023 11:12 am

tron777 wrote: ↑Thu Nov 30, 2023 10:51 am LOL @ the 6Z GFS.

Lock it in.

A CB special!!

The 12z GFS offers a solution that I find much more plausible. A cutter with rain ending as some backlash snow showers.

NWstern states will shrink there drought coverage in half over the next 7-10 days

Bgoney wrote: ↑Thu Nov 30, 2023 12:00 pm

Trevor wrote: ↑Thu Nov 30, 2023 11:12 am

tron777 wrote: ↑Thu Nov 30, 2023 10:51 am LOL @ the 6Z GFS.

Lock it in.

A CB special!!

Absolutely! Great post!

Trevor wrote: ↑Thu Nov 30, 2023 2:59 pm The 12z GFS offers a solution that I find much more plausible. A cutter with rain ending as some backlash snow showers.

The 18Z GFS concurs.

Rain is increasing to our SW this evening and will over spread the area after midnight. A wet AM commute still is on tap. Most of the steadier rains will be ending by lunch time and the PM commute from a rain standpoint won't be too bad. This will be the most significant system for a bit as Sunday won't be too much with us just getting clipped by that system thanks to no phasing. Then with the clipper or two coming in next week, these won't have much moisture to work with and I still do not think they will dig far enough south to cause us any issues with rain or snow. A few flakes or light rain showers perhaps but really, I just don't see this as being a big deal or anything. The next significant system should be the cutter (rain to maybe back end snow showers) around the Dec 10-12th period.

Good Evening and made it back from Chicago. Had a wonderful time at the concert though this old man does not stay out late like the old days lol.

Have not looked at much but the one thing imo that stands out is the PV. I keep hearing about a strong PV but I disagree and there is more than just satellite images. Real data is more important and its just not getting that cold in the polar regions this season plus we keep seeing spokes of the PV able to move rather far south. Eastern Europe and the eastern part of the USA have seen this in recent weeks and eastern Canada is covered with snow which is much earlier than normal for them. From early indications this is going to be a season where the PV is weak and easy to head south. The biggest problem is may not quite get as cold when you see a stronger PV. I want to see over the next few weeks when I expect a milder period for much of the USA do we see the PV get strong at this time or does it stay in a weaken state. At the moment lowest temp in Siberia is -17 which I never remember seeing in late November. Most years are at least -30 - -40 and many times much colder. There has been some cold in north central Canada but pretty normal for this time of year with temps in the -20 - -30 range and that air has been able to come southeast and of course we had a piece of that earlier this week but the main surge was east and I keep seeing this as a trend. Will study more this weekend but will see if I can find some info from met's that may be seeing the same thing or is just me

Glad you had a good time Tim and have made it back home safely!

I'm still expecting the PV to be weakening later in December. I've been posting some of the EPS PV data and here is another interesting tweet showing the Ensemble Gudiance in the 8-14 day range putting the "squeeze play" on the PV.





If correct, we should see an SSW occur in late December. It might pay dividends in January as long as the cold air doesn't wind up in Siberia or Europe lol

Hey Les and I guess my biggest point is we are not getting that cold in the arctic areas like we normally see and the coldest if located in northern Canada which ships cold air to eastern Canada and USA plus cold in the Sweden,Finland and eastern Russia and that is putting some cold air pretty far south in eastern Europe. So with the NAO and AO being mainly negative in the past several weeks the cold is not building up where it normally builds up this time of year. Do we even need a SSW if the PV is weak because when its in a weaken state it can push cold like spokes across the lower latitudes. Maybe I have a hard time explaining what I am seeing and hopefully I can find more info on this. Even Alaska has only had a few episodes of cold this season. We started off in Oct with less snowfall in the arctic regions and did that improve in November and I will need to look at that though one thing I have noticed in recent years is heavier snows further north towards the poles as we have more water vapor but that also makes it warmer as the polar regions get very little snow but what they get is one the ground for several months.

Coldest of the cold has been in Siberia and stays there into mid month

Tim / Bgoney... I understand where you both are coming in and you are both right. We need the -EPO back to promote cross polar flow to get the cold from Siberia into Canada and then eventually down into the Lower 48. We don't need brutal cold, just air cold enough for snow. I think that is possible the second half of Dec with the brutally cold air holding off until January.

Meanwhile, a wet morning in progress as we expected.

Early totals:

CVG - 0.05"
Me - 0.07"
Boone Co mesonet - 0.09"

The heaviest of the rain is moving thru now and will taper off late morning / midday. NW of Cincy appears to have the best chance at getting to the half inch mark. South of Cincy 0.25" or less.