Absolute Vorticity

the snow had started here in Pa right around 11 am today. so far its been light with just a dusting down. the forecast is for 1-3" total by Saterday morning

airwolf76 wrote: ↑Fri Dec 20, 2024 1:15 pm the snow had started here in Pa right around 11 am today. so far its been light with just a dusting down. the forecast is for 1-3" total by Saterday morning

Good luck Charles! Let us know how you do tomorrow.

These were 3pm temps

I don’t know, I think the models that called for more of the “or less “ were more correct(better temp forecast) than the widespread 1” to 2” for a chunk of the region some models showed. A few very isolated inch amounts .

QPF was 0.14" at CVG. Canadian was a little high. GFS did very well imo with that. What the Canadian did do well at was showing where the mod to hvy band would fall as the low moved over, and pivoted thru the region.

Going to put down a 1/4 to 1/2" for most, with 1"+ amounts N of I-70 as an end result for our area.

Will update snowfall stats in the contest thread once CVG updates at 5pm. Next chance for snow if the wind is right is a fetch of snow showers off of Lake Michigan Sat afternoon and evening. Could be interesting in South Bend perhaps for the Notre Dame game tonight? We'll see! For us locally it is a tomorrow thing for SW counties. Somewhere between LOU and Cincinnati along that I-71 corridor will see a light dusting of snow showers thanks to Lake Effect. Cold and dry everywhere else.

Next week we warm up and have a daily chance for light rain, nothing heavy. End of month gets more active and wet then cold / and or stormy Days 10-20? Stay tuned friends. While the first Met 1/3 of winter did not provide a thread worthy system, Jan 2025 IMO should. We'll see.

I am on vacation until 1/2/25 so let's talk weather eh? When you can of course. This is friends and family time too and with no active big ticket systems, I get it.

BG Tweeted this not long ago.


https://x.com/BGoodeWAVE3/status/187021 ... 07/photo/1

Tonight at 4:21 am is the winter solstice! It will feel like it lol 0.8" at CVG today putting our season total at 4.9" Well ahead of last year and above normal. Despite the warm break coming, the way Decembers have been lately, you can't complain. With how January is looking much to be excited about I think. No complaining, yet.

Dayton checks in with a Trace. Right at normal with 3.6" season total. For Columbus, a Trace and only 0.7" which is well below normal. At Columbus they are now running 3.4" below normal. We need an Eastern Apps runner for our friends there!

tron777 wrote: ↑Fri Dec 20, 2024 4:53 pm BG Tweeted this not long ago.


https://x.com/BGoodeWAVE3/status/187021 ... 07/photo/1

Les, I wonder if that look will mean a main storm track coming out of the Pacific NW and diving to the southern plains and then the southern Gulf states and then out to sea?

winterstormjoe wrote: ↑Fri Dec 20, 2024 5:20 pm

tron777 wrote: ↑Fri Dec 20, 2024 4:53 pm BG Tweeted this not long ago.


https://x.com/BGoodeWAVE3/status/187021 ... 07/photo/1

Les, I wonder if that look will mean a main storm track coming out of the Pacific NW and diving to the southern plains and then the southern Gulf states and then out to sea?

I think that will depend on when (and if) the SE ridge comes into play or not. You want a weak one centered off the SE coast to get it to cut at the right time for us. PNA ridge centered along the West Coast is an ideal spot for the trough to amplify down stream for us. These are the pieces needed with a well timed short wave to get the job done. You know how it goes Joe the pattern can be favorable but still have bad luck. I think we'll see a bit of an STJ with short waves coming into S California and then they re-develop across Texas. Do we see Panhandle Hookers or something more SE for us to get a piece of?

Here’s the WPC discussion on that week 3-4 forecast with some precautionary aspects that have been discussed for a while here at AV



With the apparent weak La Niña forcing on the mid-latitude teleconnection, this allows subseasonal tropical convection variability in the form of the Madden-Julian Oscillation (MJO) to play a more important role. Currently, the MJO is entering the Western Pacific and is forecast by the ECMWF and GEFS to propagate eastward over the next week into the Western Hemisphere. This propagation is most apparent when examining maps of velocity potential, which show negative anomalies strengthening over the Americas as we progress into Week 2. Historically, this evolution of the MJO tilts the odds in favor of a warm Week 2 across much of the contiguous U.S. (CONUS) that transitions to broad, colder than normal conditions during Weeks 3-4.

Other physical drivers considered for this outlook include the Northern Hemisphere cryosphere, the Arctic Oscillation (AO), the North Atlantic Oscillation (NAO), and the Pacific North American (PNA) pattern. Northern Hemisphere sea ice and North America snow cover are currently below normal. This suggests cold air intrusions into CONUS during Weeks 3-4 could modify toward warmer values. The NAO/AO is forecast by the dynamical models to be negative at the onset of Week 3 but trend toward neutral conditions by the end of Week 4. The GEFS forecast is notably more negative than the ECMWF, which implies colder conditions across CONUS. The PNA is also forecast to be neutral by Week 3. Currently it is positive, with a ridge axis just inland of the western coast of North America. This axis is forecast to retrograde westward over time to the North Pacific, more in quadrature with the canonical PNA pattern.

Taken in their entirety, the aforementioned physical drivers suggest a significant pattern change from Week 2 to Weeks 3-4 in CONUS from much above normal temperatures to below normal temperatures, particularly east of the Rockies. This transition is well-supported by the 500-hPa ensemble mean anomalies as forecast by the ECMWF, GEFS, CFS, JMA, and Canadian dynamical models. The agreement between the physical drivers and the dynamical models provides a medium- to high-degree of confidence in the outlook, which is evident in the elevated forecast probabilities for temperature and precipitation. Furthermore, the most anomalous troughing is forecast during the middle of the Weeks 3-4 period, which helps alleviate timing concerns, especially given how transient the pattern has been thus far this meteorological winter. One caveat to note is that if the current lack of North America snow cover continues, then the impact of any cold air outbreaks may be tempered.

still snowing here in Pa. it looks like about 3" so far. going by the radar it should be ending soon as we are on the back edge of the accumulating snows. I would expect some flurries into the morning and a cold northwest breeze.

No changes from models overnight from yesterday’s talking points heading into the new year with temps gradually getting closer to normal. Tropical forcing continues to be the biggest driver of the pattern with other telleconnections filling in the details. A few maps of what might be expected for the next 7 days and beyond. Notice the continued lack of snow in the plains

Good Morning and yes this December has been different than many in the past decade or so and why. One reason is the PV has been weak much of the past 45 days or so and this has allowed colder air to head into the lower latitudes and some of that has been directed at the eastern 1/3 of the USA. The PV is getting stronger at the moment but the cold is really not that cold for the arctic region. Usually by this time we see many readings in the -50 - -60 range and maybe a day or two in Siberia but at the moment the coldest is -38 in Siberia and -37 in northwest Canada. What does this mean for the remainder of winter and not sure but if the PV splits and one piece in south central Canada or southeast Canada then expect some cold weather for January. Sometimes we talk about to much of a good thing and yes that can happen sometimes with the PV moving to far south and we get cold and dry. Maybe since the temps in the polar regions are running above normal for them which is still cold will this help if the PV arrives next month and yes we get cold but maybe not the cold and dry you sometimes see. So far this season the cold has been directed towards the eastern 1/3 of the USA and if the models are correct its showing that again but maybe a tad further west at times. No doubt we need this further west and we need the STJ to start getting its act together. I believe that will happen and one reason is the milder temps and flow from the pacific will allow this to happen and the cold we have had will not suppress the STJ.

We are about 2/3rds of the way through December and temp wise about 2 degrees below normal and precip a tad above normal including snowfall barely above normal. By the end of the month it looks like with the surge of milder air we may end up a degree or so above normal and in my book anything from 1 degree below to 1 degree above is average. Rainfall looks to be above normal but not sure how much and snowfall will end up lower than normal. I know many mets and forecasters called for a really cold December and reasons being the late tropical season and the La Nina that was forecast to be around. Sure the La Nina is in gear I guess with the cold waters in the central pacific but it has been a struggle.

January should be fun and getting the correct amount of cold and precip in January can really be exciting. I love this mild spell coming up and usually we need that ahead of a decent cold shot as Mother Nature works her magic.

Good morning all! A chilly, but normal December morning in the 20s. Should see some flurries this afternoon and evening thanks to Lake Michigan but otherwise a cold weekend on tap. 40s and then 50s greet us for next week. Rain chances still look to be on the lighter side until we get towards next weekend. A stronger front then comes in.

By then we'll be in the new January thread but the turn to colder is there. How we get there is the question. One front or two? Strong storms if the timing is right? The southern stream when we are cold still looks active to me so if we can time one of those while we are cold, fun and games await.

I still see a favorable 500 MB pattern. The blocking is up top from AK thru Eastern Canada, maybe into S Greenland. It's more of a -PNA and neutral NAO pattern to me. We do have a nice negative EPO and AO driving the colder air south. It isn't arctic cold since it'll be modified but air in the 20s and 30s is all you need for snow so that's all anyone cares about anyway.

An interesting stat from Scotty D:

Latest MJO . Clearly see a phase 5/6 combo currently.

You can clearly see the t-storms over the Martine Continent. Classic signal for a warm pattern in the East which we know is coming. EDITED to add map. Per the Aussies, that's exactly where we are at.

Phase 5 living up to its warmth outcome next week. Getting Canada 20-30+ degrees Above normal with a healthy snow cover is no easy task, but that what we’ll see

Bgoney wrote: ↑Sat Dec 21, 2024 10:06 am Phase 5 living up to its warmth outcome next week. Getting Canada 20-30+ degrees Above normal with a healthy snow cover is no easy task, but that what we’ll see

No doubt and parts of south central Canada could see temps above 32f and like you mentioned not easy with a decent snow cover. My hope is between the 27th and 31st of December we start to ramp up some storms and yes cutters so we can lay another foundation of snow so the cold has a nice easy ride into the USA. Still want to see more snow in the plains in early January and you get a bare ground in the central plains and if the pattern continues that the coldest air is in the eastern 1/3 of the USA then we will be fighting the warmer weather in the southern an central plains and sure clippers are nice but really want to see some systems from the STJ. My call this winter has been we are on the border between some colder air to the east and milder air to the southwest and yes at times it plays in our favor and yes having bare ground in January not as bad as say February but some snow to our southwest is key in us keeping the cold around longer.

We're ready for Christmas Eve celebrations here when my Brother and the kids come.

tron777 wrote: ↑Sat Dec 21, 2024 10:51 am We're ready for Christmas Eve celebrations here when my Brother and the kids come.


17347962531255200984353040961901.jpg

Perfect

Nice!!! The little lights aren’t twinkling Clark.