Absolute Vorticity

tpweather wrote: ↑Thu Dec 15, 2022 2:24 pm Les I love the map and you hit the nail on the head and we need that pna spike. It has been trying to head towards neutral and slightly positive but if we can get that spike at the correct time the chances go up for a bigger storm.

Exactly! That is my whole point. Get the PNA to be near +1 Standard Deviation above normal and we're in! Tough to do in a La Nina so the big dog solution has a low chance, but not zero! Like you said before... brief rain quickly changing to a wind driven snow with an inch or two possible is really a nice idea at this point. Could be less, could be more depending on the look upstream. That's about it lol

tron777 wrote: ↑Thu Dec 15, 2022 1:17 pm

mainevilleweather wrote: ↑Thu Dec 15, 2022 1:03 pm Can someone remind me what times the models run?
Euro 1pm
GFS 10:30am
CMC 11am
NAM 9am

Responses are in red and they will be for the 12Z runs. Time is EST of course.

Much appreciated!

mainevilleweather wrote: ↑Thu Dec 15, 2022 2:37 pm Much appreciated!

No problem! There are more... SREF, HRRR, UKMET, all of the ensembles. etc etc but you get the idea.

12Z EPS has a decent look but it shifted east a tad with the best snowfall. So again it's because what we've already talked about. A little less digging then the last run so the phasing is a bit later so the heavier snows will be further to the east. Verbatim, we would absolutely have a White Christmas with an inch or two (more SE of I-71). Still looking like a storm evolution where a low tries to work its way into the OV with an energy transfer to an East Coast low. A storm evolution such as this is highly likely thanks to the blocking pattern we're in.

In summation, we need to answer these questions.

1 - Amplitude of the PNA Ridge and position.
2 - Digging of the trough and it's angle
3 - How strong does our low get?
4 - How quickly does it transfer to the East Coast low?

#1 is the most important since it will answer questions 2, 3, and 4

Great Post Les and even without a storm these arctic fronts can no doubt raise the ratio from a normal 10-1 to probably 20-1 or higher. Plus if we get snow on the ground it will be there for several days with the cold coming in behind the front. So many questions to ask that we need answers for plus looking at the earlier gfs I should head down to Greenville has they get hammered on this run which would be nice for my son and his family to get a hint at what is heading his way once he moves to Wisconsin lol

I'd be fine with getting a decent snow here for Christmas and then getting a thumping in DC when we head there the week of the 26th with the follow up storm!

tpweather wrote: ↑Thu Dec 15, 2022 3:09 pm Great Post Les and even without a storm these arctic fronts can no doubt raise the ratio from a normal 10-1 to probably 20-1 or higher. Plus if we get snow on the ground it will be there for several days with the cold coming in behind the front. So many questions to ask that we need answers for plus looking at the earlier gfs I should head down to Greenville has they get hammered on this run which would be nice for my son and his family to get a hint at what is heading his way once he moves to Wisconsin lol

If it's a Miller A you would easily see more snow then us, unless the phase occurs too late of course then you'd get shafted even down there. Lots to like going forward though without a doubt. The cold pattern will be around for a while so we will have more chances even after next week. With regards to snow ratios for later next week, I like what BG said in one of his videos from the other day. Starting at 7 or 8:1 but quickly rising to 15:1 and even 20:1 before ending. That is a very reasonable.

mainevilleweather wrote: ↑Thu Dec 15, 2022 3:20 pm I'd be fine with getting a decent snow here for Christmas and then getting a thumping in DC when we head there the week of the 26th with the follow up storm!

They could see back to back big ones if the full snow weenie potential with this pattern is realized. Hopefully, we can do the same around here locally with a couple inches here, a couple more there. I'm okay with that. With the cold air around, the snow won't be going anywhere once it's down and we can keep building on to our snow pack with each smaller system that passes thru. Obviously, the snow weenie in me will always look for the big dog but the realist in me also says that we typically see the smaller snows around here versus the bigger ones.

Enjoy the evening and my guess many changes over the next 3-4 days as the new pattern sets up and more info is put into those wonderful models. The pattern is good for getting snow over the next 2 weeks and just need a little luck to come this way. I am sure other forums there are folks who live and die by each model run. All we can do is point out what the model shows and then decide if that makes sense going forward. Sometimes its a little bit of this model and a little bit of another model and you end up with what you believe will happen.

tpweather wrote: ↑Thu Dec 15, 2022 3:54 pm Enjoy the evening and my guess many changes over the next 3-4 days as the new pattern sets up and more info is put into those wonderful models. The pattern is good for getting snow over the next 2 weeks and just need a little luck to come this way. I am sure other forums there are folks who live and die by each model run. All we can do is point out what the model shows and then decide if that makes sense going forward. Sometimes its a little bit of this model and a little bit of another model and you end up with what you believe will happen.

I agree Tim! Using a model blend is a good idea and it's typically what a lot of good Mets do. We try and do that some here as well in my opinion. It'll be really fun next week when we get within the NAM's range. I await that classic "You've been NAM'ed" run. We haven't had one yet for the 2022-2023 winter. I bet we see one next week though.

tpweather wrote: ↑Thu Dec 15, 2022 5:49 am

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.

Hi Tim, I wish your son and his family the very best on their transition and this in this next chapter of their lives. I've heard of Wausau but hadn't re Stevens Point until now.

Great to hear from you, too, bro. My mom and I have some health issues but God is always good and He's got it!

https://absolutevorticity.com/viewtopic ... 0&start=50

Merry Christmas and a Happy Healthy New Year to you all, too.

My gauge picked up .46"

Currently 39 here in G'ville and progged for around 29 on Fri morning.

I just stepped outside and can definitely feel the temps dropping along with breezy SW winds. Down to about 41 here, wind chill of 37. Just think, today maybe the warmest day of what's left of 2022. Cold and snow lovers, it is now our turn so let's see what happens. Good luck to all and may you all have good health now and in 2023!

Good evening all! My high today was 55 at 1:30 this morning. Currently at 42. Finished picking up yard debris from past winds and blew off the patio and driveway and this snow weenie is ready to receive whatever comes our way as our new pattern begins to take shape.

We begin with some snow shower activity for tonight. Surface map shows a large 1036 MB High over Washington State and a large upper trough / associated surface low of 992 MB over Southern MN. It has run into the blocking over Canada so it is beginning to occlude. The energy transfer has begun to an East Coast low that is currently developing at 1004 MB over the Eastern VA / NC boarder along the Coast. The low will move north towards NJ tonight and slowly move NE along the Coast towards Maine by Saturday then stalling in the Gulf of Maine thanks to the -NAO and 50 / 50 Low in place and finally pulling out by Sunday.


For us in cyclonic flow, scattered snow showers will be possible later on tonight, Friday and Saturday as well. Not all folks will see it but if you do then expect reduced visibility at times and a grassy accum / car topper possible in isolated cases. Roads should be mainly fine, esp well traveled roads due to warm ground and the cold pattern that is only just beginning! I suppose an isolated slick spot is possible at night or in the morning.

Next system moves in by Tuesday via separated Northern / Southern Stream waves that never do phase. The GFS continues to ever so slowly try and get it together but it never does so a weakening system is the end result. Suppose a rain or snow shower is possible with this feature on Tuesday but not a big deal really at all at this point.

Now we get to Thursday and Friday of next week. We have a powerful trough / arctic front diving in from the Siberia/ North Pole region. I mean this thing is of arctic origin. Not something off of the Pacific Ocean where you get Pacific modified air. This is the arctic jet diving in bringing in the energy and cold air! Question is... does the PNA ridge spike at the same time so we can get proper trough amplification downstream to slow this cho-cho train down just enough to interact with a southern stream wave over the Southern / Gulf Coast States? Timing is everything in big Ohio Valley events and they are almost always thread the needle situations. The 18Z GFS this evening was a nice run and a step in the right direction for a plowable event. The entire key to this is how the trough enters the country. What you want is the 0Z Euro / 18Z GFS runs from today. See how the trough enters the country at a sharp angle? Look at that beautiful PNA ridge and where it's positioned. Look at how tall it is! That is called amplification folks and not some whimpy flat pos.

I've highlighted some items of interest here on the 18Z GFS run valid at 138 hours. Wednesday morning of next week. Note the position of the -EPO and -NAO blocks. The Aleutian Low pumping up the PNA Ridge much further to the West and nice and tall, all the way up into Alaska. Note the timing of the Northern and Southern stream shortwaves and the angle that the Northern trough is diving in! This is the look you want to see on future model runs to have a shot at a moderate to heavy event.


Now I'm not going to draw the features anymore on the rest of these maps, but watch the progression from Wednesday thru Sat morning (Christmas Eve).


The upper low doesn't close off over us like that like what the 0Z Euro run did and that's why it's not a crippling blizzard. But still a damn nice event if it worked out as modeled here. Going to be fun to watch this unfold guys in my opinion. Let's see if that look in the Pacific holds going forward. Sorry for beating the Pacific / PNA in the ground but it has to be right or we don't score. Simple as that.

Finally... early thoughts from the boys:

There is quite a bit of model variability as we head toward the
end of the week. Digging mid level energy dropping down across
the central US will help carve out a deepening upper level
trough/low that will shift across the eastern US through the end
of the week. This will usher in an even colder airmass with
daytime highs only in the mid 20s to lower 30s Wednesday and
Thursday and overnight lows in the teens. A lot of uncertainty
remains on how this will interact with southern stream moisture
being pulled up into the system and how fast it will all
translate eastward. We will be cold enough for pcpn to remain
all snow. Given the uncertainty, will keep pops in the high
chance to likely category for Thursday with the potential for at
least some light snow accumulations through the day.

NEW This Week in Weather from DT honking about this storm, mainly for the East Coast but good info at times in the video none the less.

Good morning all! Low to mid 30s across the area and even a few spots in the upper 20s. Most folks should stay in the 30s for highs today minus a few 40s possible in KY. Cooler this weekend mainly in the lower 30s with 20s at night. The ongoing forecast of isolated snow showers looks good for today and tomorrow. Moving on...

Still looking like that weak wave on Tues dissipates before getting here. We'll see some clouds from it but that's probably it. If we see a sprinkle or a snow flake that's worst case scenario based on the data I am seeing.

All eyes continue to be focused on Thurs and Fri with the arctic front and any storm that can develop along it as it moves through. Models have really diverged overnight due to their differences in the Pacific. GFS is more flatter again with the PNA ridge so the trough doesn't dig quite as much. No big East Coast storm either as this thing remains off shore. For us we still get light snow out of the deal with a broad surface reflection over the Apps then develops the low too far offshore for New England. The CMC and Euro are back to a front coming thru with a low cutting thru Iowa, ILL and into Michigan with it then weakening over Lake Erie as it gives way to the East Coast low. Then that low bombs out over interior New England (PA and Upstate NY). CMC is not as robust as the Euro is with this idea but has a similar look. GEFS Members continue to show various solution with a couple of big dog members still present. Snowfall mean is about 2" for the area which isn't horrible this far out. The EPS to me looks more supportive of the GFS where you had that weak primary low (a surface reflection really) over the Apps then it transfers to the EC Low. The Mean shows 1-3" from South to North across the area which again isn't bad from an avg of 51 members. So we'll see. We have a long way to go with this one. I am confident in seeing some snow Thurs into Friday it's just a question of what form does this storm take that determines how much we get.

Midway through Dec. Here's how we match up so far(temps) going back to 2010

Bgoney wrote: ↑Fri Dec 16, 2022 8:40 am Midway through Dec. Here's how we match up so far(temps) going back to 2010


Screenshot_20221216-083806_Chrome.jpg

We'll be eating away at that positive departure quickly once we get towards the end of next week. CVG currently sitting at +4.5 degrees above avg. Also of note, on this day back in 1989, we picked up a daily snowfall record of 7" during the strong La Nina winter of 1989-1990.

Is this some kind of evil joke? Florida panhandle gets 5 inches and we get 0?

mainevilleweather wrote: ↑Fri Dec 16, 2022 9:03 am Is this some kind of evil joke? Florida panhandle gets 5 inches and we get 0?

We have seen southern locations over the past few winters get snow before us. I doubt it will be that far south to the FL Panhandle but the TN Valley and Northern tier of the Dixie States, Tim's Greenville hood... are certainly in the game. We are too!

tron777 wrote: ↑Fri Dec 16, 2022 9:06 am

mainevilleweather wrote: ↑Fri Dec 16, 2022 9:03 am Is this some kind of evil joke? Florida panhandle gets 5 inches and we get 0?

We have seen southern locations over the past few winters get snow before us. I doubt it will be that far south to the FL Panhandle but the TN Valley and Northern tier of the Dixie States, Tim's Greenville hood... are certainly in the game. We are too!

It's tough to look at that's for sure!

mainevilleweather wrote: ↑Fri Dec 16, 2022 9:12 am

tron777 wrote: ↑Fri Dec 16, 2022 9:06 am

mainevilleweather wrote: ↑Fri Dec 16, 2022 9:03 am Is this some kind of evil joke? Florida panhandle gets 5 inches and we get 0?

We have seen southern locations over the past few winters get snow before us. I doubt it will be that far south to the FL Panhandle but the TN Valley and Northern tier of the Dixie States, Tim's Greenville hood... are certainly in the game. We are too!

It's tough to look at that's for sure!

It is! I won't lie. But I also know that it's not the final outcome either.

Here's the last 4 GFS and Euro runs centered on Wednesday morning of next week. See how the PNA ridge keeps getting handled differently? Until we get some kind of agreement on that part of it, it's going to continue to be model mayhem for a little while longer.

tron777 wrote: ↑Fri Dec 16, 2022 9:14 am Here's the last 4 GFS and Euro runs centered on Wednesday morning of next week. See how the PNA ridge keeps getting handled differently? Until we get some kind of agreement on that part of it, it's going to continue to be model mayhem for a little while longer.


GFSTrends.gif


EuroTrends.gif

I like your optimism.

mainevilleweather wrote: ↑Fri Dec 16, 2022 9:31 am

tron777 wrote: ↑Fri Dec 16, 2022 9:14 am Here's the last 4 GFS and Euro runs centered on Wednesday morning of next week. See how the PNA ridge keeps getting handled differently? Until we get some kind of agreement on that part of it, it's going to continue to be model mayhem for a little while longer.


GFSTrends.gif


EuroTrends.gif

I like your optimism.

Thanks! We truly have a long way to go with this system. Realistically, the potential for a 1-2" event all the way up to a 4-6" event is absolutely on the table. A big dog event once again is LOW but not ZERO as of yet.