Absolute Vorticity

Bgoney wrote: ↑Wed Dec 14, 2022 10:24 am Parts of Australia continue to get significant cold intrusions for what now is their summer, most impressive was the -5.4C (22.3F) set at Mt. Hotham, a reading which felled the State of Victoria’s lowest December (and summer) temperature ever recorded, the -5.2C (22.6F) from Dec 20, 1978 (solar minimum of cycle 20).

The Caribbean has also been unusually cold , coldest December start for some of the islands in 30 years. Martinique had their lowest temp ever recorded of 53 degrees

I love seeing info like this and The Caribbean makes since as the southeast ridge over that area was further west in the Yucatan area and this also kept the south central area of the USA very mild with cold shots having a hard time digging. The Australia one was a bigger shock to me and I wonder if this has anything to do with La Nina in its third year and maybe its dying off finally. Have no ideal and sure somebody is already on the case lol

No doubt we can say it will be cold on Christmas but will it be white. Still not a fan of the 1 inch on the ground at 7a to be considered a White Christmas. So if you get a foot of snow after 7am it will not go down in the books. How the arctic front moves next week is key in whether we get a decent storm or just a rain to snow which can cause problems because like I mentioned yesterday those kind of systems can cause the flash freeze and roads turn to ice and then you get an inch or two of snow on top. Watching the pna to see how the ridging goes on the west coast and also into Alaska early next week. This is such a broad area of cold the this may be a time where Alaska and the eastern half of the USA are both cold. At this point the coldest is pointed towards the mid-west and no problems but would love to see a little more dive into the southern plains as you may be able to tap the gom before it gets shut down for several days. With these arctic fronts we know they can be quite dry but at first you usually have some energy attached to the cold so most of time with this kind of outbreak you will get some snow. Still seeing a few places of -70 or so in Siberia so we have a good source of cold and sure it won't even come close to that kind of cold but its headed over Canada and the northern plains and upper mid-west which has plenty of snow and much of it just the past week or so. Still expect 2 storms before the New Year to bring 2 inches or more and still expecting to hit zero or below during this time as well. Hoping for more snow but again those are still rare in this part of the world.

Quite the rain shield

Bgoney wrote: ↑Wed Dec 14, 2022 5:53 pm Fairly large tornado on traffic cams in New Orleans

It's been a tough day in LA and MS, and esp for NOLA as you mentioned. SPC currently has 5 tornado reports and 4 wind damage reports as of this post.

https://www.spc.noaa.gov/climo/reports/last3hours.html

0.71" now for my event total as the next wave of heavy rain works in with that second low that is currently over West KY / SW IN tracking NW as the trough goes negative tilt. A wet night ahead.... the good news is that the front should clear us out rain wise I am hoping in time for the AM Commute.

I heard on the WHIO evening wx segment that the high temp a week from Fri could top out at just around 14 in DAY!

Currently 39 here in G'ville and progged to hold steady there to about 40 into Thurs morning.

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tpweather wrote: ↑Wed Dec 14, 2022 9:03 am Nice little snowstorm heading for north central Wisconsin later today and Thursday. Expecting 8-12 inches so I need to tell my son this is what you can expect in that area of the country. Plus once that snow pack is down up there it seldom goes away for weeks and sometimes months.

Hi Tim,

What city or town in WI is your son and his family relocating to?

I have a couple of retired high school teacher friends from my school days in Cincy who reside in Appleton not far from Green Bay.

MVWxObserver wrote: ↑Thu Dec 15, 2022 12:36 am

tpweather wrote: ↑Wed Dec 14, 2022 9:03 am Nice little snowstorm heading for north central Wisconsin later today and Thursday. Expecting 8-12 inches so I need to tell my son this is what you can expect in that area of the country. Plus once that snow pack is down up there it seldom goes away for weeks and sometimes months.

Hi Tim,

What city or town in WI is your son and his family relocating to?

I have a couple of retired high school teacher friends from my school days in Cincy who reside in Appleton not far from Green Bay.

Hey Eric, two towns near each other is most likely where he will live. Wausau and Stevens Point which is north central part of the state. Good hearing from you and hope your family is doing well. Merry Christmas and a Happy New Year to you and your family.

A balmy 49 when I left the house. Event total .75". Some scattered snow bursts later tonight and tomorrow . A cold slightly below normal next 7 days , before the well publicized true arctic front plows into the region late next week with snow along the front with possibly a low developing also . The winds with this system are going to be the trouble maker

Good morning all! 1.01" at CVG for the event total. 1.11" at the Boone co Mesonet site and 1.15" here! A much needed soaking for sure. The drought map being issued this morning won't have this event factored in so next Thurs will be the time to check it for more accuracy for our hoods.

Great post Bgoney in terms of our updated forecast for the coming 7 day period. All eyes are going to be focused on next Thurs and Fri for sure with a little snow shower action tomorrow and Sat as well. Should be some fun tracking ahead. I'd love to be in a clipper pattern for my Christmas Vacation this year! We'll see how it goes.

For Mon / Tues of next week... that weak wave is still there and models are trying a little bit to phase the energy together but it just doesn't happen so the precip dissipates before getting here. That has been the ongoing theme with that system so I will still go dry for the first half of next week.

For Thurs and Fri of next week... the arctic front is still coming in with a vengeance and the question remains... does a wave develop along this front to enhance our snowfall chances? I believe that it will. The speed of this system is an issue for those wanting big snows because the cold air is going to want to charge right in! The 0Z GFS and CMC models aren't too shabby for snow lovers and if either of those scenarios were to pan out, we would get that elusive White Christmas!

The 0Z Euro run was a big dog and it shows you one way how to solve the speed issue I just spoke of. What's happening on that model run is that you get a low coming out of the Gulf and then moving near or just off the SE Coast. The model develops this low further which causes the arctic front to slow down right over the Apps. Our wave along the front has no choice but to phase with the low near the East Coast. This draws moisture in from the Atlantic also! The whole 500 MB Low closes off and stalls over the Ohio Valley hammering us with snow! Why doesn't the GFS and CMC show this? They both have that low off the SE Coast but it's further away from the Coast then the Euro so less influence on the arctic front. Also, because of this, no phasing occurs with our wave along the front so it's a lighter snow event. The Euro's solution obviously has an extremely low chance of occurring, but it is one way to get the job done!

How about the Ensembles? GEFS Members range from a touch of snow, to the OP GFS and CMC solutions to even about 2 or 3 members trying to cook up a big dog like the Euro had. I cannot see the individual EPS members but the Mean looked really nice to see. Looks like a wave comes into the OV then gives it up to an EC Low. Precip looked decent for us though. Probably a brief rain to snow ordeal which is entirely possible. Usually ahead of an arctic front that is how it usually goes for us.

So in conclusion... confidence is rising on getting snow sometime in that Thurs / Fri window next week. Amounts and evolution of the system are low confidence. Very high confidence in a major temp drop with high ratio snows with any snow that is there behind the front. Also very high confidence on very strong winds as well reducing visibilities and potentially causing issues with blow snow as well. This is looking more and more like a thread starter to me since it's our first event of Met Winter plus it's got a nice chance at a White Christmas too! I think it is wise until we get to Day 5 before starting a thread which would be over the weekend or so. If things still look this good in a couple more days then it's time to create that thread in my opinion.

Good Morning Les and wonderful post as usual. Many options for later next week and we just watch as the new pattern forms. Ended up with 0.92 inches of rain the past two days which was in my range though the airport got 1.01 so missed it by that much. The cold we have this weekend is a nice Canadian brand so its cold but not bitter. We will not be able to say that in a week and will just watch to see how the new pattern pans out. One area that will get warm with this new pattern is eastern Canada and especially northeast Canada and you could see that area 30 degrees above normal in about a week or so.

Weekend thread sounds good Les.

Here's The trend on the EU the last couple days for around Xmas eve eve eve , with it developing or moving a ridge along the coast improving odds of wintry precip

I just got caught up reading all the posts concerning later next week white Christmas potential. I would like to see something between the Euro and GFS, not a big dog but something like 3-5 inches! Saw the 06 GFS for later next week and I want to throw that one out! LOL

Thanks guys! I appreciate it! Love that Euro trends GIF there and you can clearly see the nice improvements over the Pacific as Bgoney eluded to. Here's the 500 MB GIF of the storm's evolution with regards to that big dog run at 0Z. A low chance of occurrence but a thing of beauty all the same.

winterstormjoe wrote: ↑Thu Dec 15, 2022 8:55 am I just got caught up reading all the posts concerning later next week white Christmas potential. I would like to see something between the Euro and GFS, not a big dog but something like 3-5 inches! Saw the 06 GFS for later next week and I want to throw that one out! LOL

Good morning Joe! Always a chance that the 6Z GFS is right. About the same odds of the 0Z Euro being right. The 0Z GFS and CMC are really a good compromise in the middle of the two extremes.

Which model will handle the new pattern? No doubt the CMC was the leader showing this new pattern and seldom switched gears. Later next week the gfs and cmc are similar at the moment with the Euro somewhat in a different outcome. Which one is correct and again this is a pattern that we don't see every winter and the models will struggle lol but met's and forecasters as well . When you see a pattern that shows up every winter and it happens several times during each winter you get a good ideal of how it will play out but this one is more rare and the homework is piling up.

Concerning early next week and I understand where the models are coming from but I have seen this set up so many times and the models wait until the last minute and guess what you end up with an inch of snow. This was never a big system but one I believe needs watched.

Must say the Euro and a few other models blew it on rain totals this week and not sure what they saw and even made me question my forecast and I hate going against myself and though I never changed the forecast I thought to myself what the heck am I missing.

Hey Tim... I am still watching early next week too. I was just never impressed with the set up on that one. The flow to me just looks too fast early next week and the waves are still pretty far apart. If we had better wave spacing then you'd have a much better shot at that inch or at least a chance of snow. Who knows... maybe that changes in the next day or two once the current system winds down. It is possible that models can mishandle it. But for sure... that system never did have a lot going for it in terms of something decent.

Concerning later next week, it will be interesting to see which model handles this the best. I too think the Canadian has been the leader. Curious to see how the NAM does once it gets within range. For those wanting a 0Z Euro like solution, then look towards the Pacific. If the PNA spikes correctly timing wise and if the ridge is positioned along the West Coast where the Euro has it, then the incoming trough can dig quite a bit as the model shows and the big dog solution is actually reasonable. If we don't get the proper PNA spike then the snow will be much lighter. It's going to boil down to how the Pacific looks so we get the proper down stream impacts here locally.

Les since the new pattern will feature true polar air models are lets say working with less info as we are so its going to be tough and my guess we will see everything from getting no snow to a blizzard. The cold and wind is the easy part of the forecast and we just need to figure out if any snow is possible. Most likely solution would be rain quickly changing to snow with a flash freeze and snow totals of an inch or two. This is not a forecast and only if someone said your life depended on the forecast next week this is what I would throw out. An easy compromise and one we have at least seen with arctic fronts. The pacific is important on how the trough may look next week but don't forget the nao as this is a big player in these kind of situations especially trying to figure if it will slow down systems like this week has shown. So far models are showing a neutral nao and usually I love that but with an arctic outbreak a little more negative would be nice. The AO will continue to be negative and that is a given and then the pna and usually I like a slightly positive to neutral with this pattern but since the arctic outbreak is not in norm for weather conditions then like you mentioned how the trough shapes up over the central and eastern part of the country will determine if we can get a bigger storm or just some lighter snows but either way cold and bitter cold is on the way.

tpweather wrote: ↑Thu Dec 15, 2022 9:47 am Les since the new pattern will feature true polar air models are lets say working with less info as we are so its going to be tough and my guess we will see everything from getting no snow to a blizzard. The cold and wind is the easy part of the forecast and we just need to figure out if any snow is possible. Most likely solution would be rain quickly changing to snow with a flash freeze and snow totals of an inch or two. This is not a forecast and only if someone said your life depended on the forecast next week this is what I would throw out. An easy compromise and one we have at least seen with arctic fronts. The pacific is important on how the trough may look next week but don't forget the nao as this is a big player in these kind of situations especially trying to figure if it will slow down systems like this week has shown. So far models are showing a neutral nao and usually I love that but with an arctic outbreak a little more negative would be nice. The AO will continue to be negative and that is a given and then the pna and usually I like a slightly positive to neutral with this pattern but since the arctic outbreak is not in norm for weather conditions then like you mentioned how the trough shapes up over the central and eastern part of the country will determine if we can get a bigger storm or just some lighter snows but either way cold and bitter cold is on the way.

That idea Tim is very reasonable and it's one that we see all the time as you mentioned. However, with the extreme EPO Block and the -AO plunging in the cold air, something a little more interesting could be in the offing here. As we all know, a few more days are needed to monitor the trends but I really like what I have seen thus far from the overnight guidance.

More cold nuggets from Australia and Central America

The station of Valle Nuevo in the Dominican Republic recently sank to 1.9C (35.4F). This is the country’s lowest temperature ever recorded in the month of December, and the lowest in any month for almost 50 years.

Australia

Bgoney wrote: ↑Thu Dec 15, 2022 10:17 am More cold nuggets from Australia and Central America

The station of Valle Nuevo in the Dominican Republic recently sank to 1.9C (35.4F). This is the country’s lowest temperature ever recorded in the month of December, and the lowest in any month for almost 50 years.

Australia


Screenshot_20221215-101038_Chrome.jpg

Freaking incredible! I wish I had more knowledge of "Does the Southern Hemispheric cold in summer impact the Northern Hemispheric cold in winter?" I mean this in terms of the polar vortex in terms of it's strength and position. Are there any correlations? I wish I had time to research some of this stuff because it's truly fascinating!

Bgoney wrote: ↑Thu Dec 15, 2022 10:17 am More cold nuggets from Australia and Central America

The station of Valle Nuevo in the Dominican Republic recently sank to 1.9C (35.4F). This is the country’s lowest temperature ever recorded in the month of December, and the lowest in any month for almost 50 years.

Australia


Screenshot_20221215-101038_Chrome.jpg

Darn global warming or like they call it now climate change is freezing people to death. Just wonder what the folks in the Dominican Republic are dealing with as they have no heat for the homes or clothes for that kind of cold plus living there your blood is so thin and getting under 60 probably feels cold.