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Pattern The Great December Dump

SD said:
You know this ends up meeting in the middle. Decaying arctic air mass with the parent high going ots means a few people start as a few sleet pellets or snow flakes and go to rain quickly. That initial band of iso precip locks in the wedge, the tmb gets stuck east of 95 and most of nc is locked in at 34-40 with 850s of +10 so we get an elevated band of storms rolling through with areas SE of RDU making a last second push to 55-60

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You just said the last storm basically, lol
 
WxWatch said:
I understand that you disagree, everyone has their different views. But considering the polar and STJ convergence, there's no doubt that something wintry is bound to happen. It could be minimal, but a quick shot at some heavy snow on the back side of the moisture is possible. Or it could be something significant, a wide coverage of a long duration of heavy snowfall. I do think that strong storm signal around the 15th or so may come up on the tail end of the boundary. We'll see how things shape up, still to early to "iron" out anything.

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Yes there's always a chance, but to say there's a chance of a big storm this early is just not a smart call. Patterns can be watched, but STJ convergences alone won't do well. Check the 500 mb vort signature. Very weak and not even a good tilt. There won't be much moisture with this one.
 
WxWatch said:
The 18z GFS would have shown snow at the surface during the 10th/11th, but I think it's having a convection issue. Looking at the modeled IR, you can see cold cloud tops which this indicates convection. The modeled IR also depicts on where the STJ is streaming from. I have no doubt in my mind there would be snow falling from lower/mid Mississippi, AL, GA and and up through the Carolina's late next Tuesday into Wednesday. View attachment 26919
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No strong moisture flow and no neutral tilt = no moisture.
gfs_z500_vort_us_32.png
 
WxWatch said:
The 18z GFS would have shown snow at the surface during the 10th/11th, but I think it's having a convection issue. Looking at the modeled IR, you can see cold cloud tops which this indicates convection. The modeled IR also depicts on where the STJ is streaming from. I have no doubt in my mind there would be snow falling from lower/mid Mississippi through AL, GA and and up through the Carolina's late next Tuesday into Wednesday. View attachment 26919
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I hope for your sake this really does happen ?
 
ForsythSnow said:
No strong moisture flow and no neutral tilt = no moisture.
gfs_z500_vort_us_32.png
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You need 1 of 2 things here to really get something going. 1. The energy in Texas needs to be stronger with a weaker push from the trough in the lakes. That would allow the southern wave to amplify a bit and possibly kick off overrunning behind the lead front. 2. You need the main trough over the lakes to be deep but west. You could in theory kick the front through with the lead wave then maybe get something to fire up along the old front as the trailing trough approaches.

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ForsythSnow said:
No strong moisture flow and no neutral tilt = no moisture.
gfs_z500_vort_us_32.png
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I use a blend of models, and right now I'm using the CMC for the 500mb vort. with combination of the GFS. The trough in the southern stream is slightly positive, may become negative as it progresses east over night, 10th into the 11th. So yeah, with a blend of the latest GFS and CMC, I'd say there is a good chance for a wide swath of snow late next Tuesday into Wednesday.

gem_z500_vort_us_31.png


Even the 12z ICON has a slight positive tilt trough in the southern stream that could also go negative.


icon_z500_vort_us_61.png
 
Looks like we have the tale of two models, with the GFS looking wintry, while the Euro says no. Would be something if the GFS leads the way and the Euro falls in line. I mean, the GFS has to actually get better sometime, right?
 
altho I wouldn’t bet on wintry precip now, and I don’t find it as likely, the gefs says the first system isn’t out the window yet, some still show wintry precip in the SE with the first system, like I said it’s unlikely for now 1A104731-E4E9-4CDD-87B4-7573F10B9C35.jpeg
 
Something to keep a eye on. But I don’t see any snow chances at this point. Don’t mean it can’t trend that way though for Dec 10-12th


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Myfrotho704_ said:
altho I wouldn’t bet on wintry precip now, and I don’t find it as likely, the gefs says the first system isn’t out the window yet, some still show wintry precip in the SE with the first system, like I said it’s unlikely for now View attachment 26923
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Thank you for posting that! Now can people agree with me? When something has my attention, I mean it. :D
 
WxWatch said:
I use a blend of models, and right now I'm using the CMC for the 500mb vort. with combination of the GFS. The trough in the southern stream is slightly positive, may become negative as it progresses east over night, 10th into the 11th. So yeah, with a blend of the latest GFS and CMC, I'd say there is a good chance for a wide swath of snow late next Tuesday into Wednesday.

View attachment 26921


Even the 12z ICON has a slight positive tilt trough in the southern stream that could also go negative.


View attachment 26922
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Man, I don't know if you can pick and choose which features you like best on the different models and then put them all together. But that said, I don't disagree that it's a period worth watching and that you really can't rule anything out 100% at this point.
 
Rain Cold said:
Man, I don't know if you can pick and choose which features you like best on the different models and then put them all together. But that said, I don't disagree that it's a period worth watching and that you really can't rule anything out 100% at this point.
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Sounds like he’s all in on it. He should get to start the thread if it has legs.


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WxWatch said:
I use a blend of models, and right now I'm using the CMC for the 500mb vort. with combination of the GFS. The trough in the southern stream is slightly positive, may become negative as it progresses east over night, 10th into the 11th. So yeah, with a blend of the latest GFS and CMC, I'd say there is a good chance for a wide swath of snow late next Tuesday into Wednesday.

View attachment 26921


Even the 12z ICON has a slight positive tilt trough in the southern stream that could also go negative.


View attachment 26922
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Gotta slow down the southern wave by a good bit to see anything here, like the Euro was doing Sunday. Not impossible at this point though.
 
Rain Cold said:
Man, I don't know if you can pick and choose which features you like best on the different models and then put them all together. But that said, I don't disagree that it's a period worth watching and that you really can't rule anything out 100% at this point.
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I agree on a nice pattern, but cherry-picking it and saying there is a good chance of a large swath of snow, IMO is wishcasting. Heck, I'll get enthused if there is just on op with something.
 
Rain Cold said:
Man, I don't know if you can pick and choose which features you like best on the different models and then put them all together. But that said, I don't disagree that it's a period worth watching and that you really can't rule anything out 100% at this point.
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Who's to say JB doesn't pick and choose a blend of models? If so we all know how that turns out. Lol


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Ollie Williams said:
I agree on a nice pattern, but analyzing it and saying there is a good chance of a large swath of snow, IMO is wishcasting.
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It’s definitely a good pattern of systems every 3-5 days but the issue I see is that it isn’t cold enough for snow. Cold rain sure but below 32. Nope. Not yet . Looks like the cold stays in the mid west. Brent might get lucky.


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WxWatch said:
I use a blend of models, and right now I'm using the CMC for the 500mb vort. with combination of the GFS. The trough in the southern stream is slightly positive, may become negative as it progresses east over night, 10th into the 11th. So yeah, with a blend of the latest GFS and CMC, I'd say there is a good chance for a wide swath of snow late next Tuesday into Wednesday.

View attachment 26921


Even the 12z ICON has a slight positive tilt trough in the southern stream that could also go negative.


View attachment 26922
Click to expand...
Relying on the cmc for vort is like hoping your 1982 ford fiesta with 287k miles in need of major repairs to get you from New York to Dallas in one trip. The icon isn't too much better and seems to be all over the place most of the time but consistent, not in a good way.
 
ForsythSnow said:
Relying on the cmc for vort is like hoping your 1982 ford fiesta with 287k miles in need of major repairs to get you from New York to Dallas in one trip. The icon isn't too much better and seems to be all over the place most of the time but consistent, not in a good way.
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Bottom line is if the Euro doesn’t haven’t then it most likely won’t happen. The king is king for a reason, we don’t see too many winter storm that the Euro passes on. Is it . No but it’s the starting point for me.


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WxWatch said:
I use a blend of models, and right now I'm using the CMC for the 500mb vort. with combination of the GFS. The trough in the southern stream is slightly positive, may become negative as it progresses east over night, 10th into the 11th. So yeah, with a blend of the latest GFS and CMC, I'd say there is a good chance for a wide swath of snow late next Tuesday into Wednesday.


Even the 12z ICON has a slight positive tilt trough in the southern stream that could also go negative.
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What area do you think this "wide swath of snow" will fall? Not saying it won't happen.... just having a little doubt that it will all materialize as you described. There are too many variables at this range. However, I got to hand it to you..... you haven't backed down.
 
ForsythSnow said:
Relying on the cmc for vort is like hoping your 1982 ford fiesta with 287k miles in need of major repairs to get you from New York to Dallas in one trip. The icon isn't too much better and seems to be all over the place most of the time but consistent, not in a good way.
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Lol
I get it though seriously; I'm not trying to cause a ruckus between which model is better. They're all models that calculate all possible outcomes.

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Rain Cold said:
Man, I don't know if you can pick and choose which features you like best on the different models and then put them all together. But that said, I don't disagree that it's a period worth watching and that you really can't rule anything out 100% at this point.
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I'm going to be honest; I do "cherry" pick from the main models of the best realistic possible outcome. If other models agree with that best realistic possible outcome, then it has a good chance of the scenario occurring. My rule of thumb when it comes to these models, don't let the models do all the work for you. Instead, input your skills/experience alongside the model data. They simply need human input.

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Cad Wedge NC said:
What area do you think this "wide swath of snow" will fall? Not saying it won't happen.... just having a little doubt that it will all materialize as you described. There are too many variables at this range. However, I got to hand it to you..... you haven't backed down.
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IMO he’s been way too alarming for something far out. Does he not know it’s always a safer call to say it’s not gonna snow much outside the mtns? Some solid posts but I don’t listen to alarmists for winter weather it never pans out 9 times out of 10.
 
Here is a map I created on where I think the snow will be. Be advised, the snow-zone may need some adjustments as time goes on.

SnowPredictionMap.jpg


At the surface, it would be cold, but not dry. RH levels at surface are high as 80% across portions of AL, GA and upstate SC. Even some 90% RH levels across western NC.

SurfaceRH.png

Looking up at the surface, 500mb, the RH is also high due to the STJ conveying warm/moist air in the upper level.

500mbRH.png

With the trends I have been seeing, the convergence of the polar jet and sub-tropical jet, deep cold air plunging southward, surface temps and upper air temps would be dropping rapidly, these big factors are coming together, which these factors are indicating a possible heavy wet snow event.

Edit: I forgot to add the 300mb layer, RH levels are high as well over some area's. Sub-tropical jet at work! Valid at midnight next Wednesday.

300mbRH.png
 
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WxWatch said:
Here is a map I created on where I think the snow will be. Be advised, the snow-zone may need some adjustments as time goes on.

View attachment 26926


At the surface, it would be cold, but not dry. RH levels at surface are high as 80% across portions of AL, GA and upstate SC. Even some 90% RH levels across western NC.

View attachment 26927

Looking up at the surface, 500mb, the RH is also high due to the STJ conveying warm/moist air in the upper level.

View attachment 26928

With the trends I have been seeing, the convergence of the polar jet and sub-tropical jet, deep cold air plunging southward, surface temps and upper air temps would be dropping rapidly, these big factors are coming together, which these factors are indicating a possible heavy wet snow event.

Edit: I forgot to add the 300mb layer, RH levels are high as well over some area's. Sub-tropical jet at work! Valid at midnight next Wednesday.

View attachment 26929
Click to expand...
Man, you got me so pumped up for something. It's almost like were expecting a winterstorm next week lol. You got my hopes very high, I really hope something happens and if it does I'll send you something special for Christmas lol. Storm or not, I love your stuff.
 
WxWatch said:
Here is a map I created on where I think the snow will be. Be advised, the snow-zone may need some adjustments as time goes on.

View attachment 26926


At the surface, it would be cold, but not dry. RH levels at surface are high as 80% across portions of AL, GA and upstate SC. Even some 90% RH levels across western NC.

View attachment 26927

Looking up at the surface, 500mb, the RH is also high due to the STJ conveying warm/moist air in the upper level.

View attachment 26928

With the trends I have been seeing, the convergence of the polar jet and sub-tropical jet, deep cold air plunging southward, surface temps and upper air temps would be dropping rapidly, these big factors are coming together, which these factors are indicating a possible heavy wet snow event.

Edit: I forgot to add the 300mb layer, RH levels are high as well over some area's. Sub-tropical jet at work! Valid at midnight next Wednesday.

View attachment 26929
Click to expand...

Gotta look at the layer from 850mb to 500mb though. Massive dry layer there. No chance at any precip, other than perhaps some low level drizzle. Gotta get that 700mb flow out of the SW instead of the west to west north west.
 
To much of a SER on the ICON with 580dm + making it into the eastern SE, we need less of a SER for this to work, would appear to possibly be a severe setup on the warm sector area on the ICON
 
WxWatch said:
Here is a map I created on where I think the snow will be. Be advised, the snow-zone may need some adjustments as time goes on.

View attachment 26926


At the surface, it would be cold, but not dry. RH levels at surface are high as 80% across portions of AL, GA and upstate SC. Even some 90% RH levels across western NC.

View attachment 26927

Looking up at the surface, 500mb, the RH is also high due to the STJ conveying warm/moist air in the upper level.

View attachment 26928

With the trends I have been seeing, the convergence of the polar jet and sub-tropical jet, deep cold air plunging southward, surface temps and upper air temps would be dropping rapidly, these big factors are coming together, which these factors are indicating a possible heavy wet snow event.

Edit: I forgot to add the 300mb layer, RH levels are high as well over some area's. Sub-tropical jet at work! Valid at midnight next Wednesday.

View attachment 26929
Click to expand...
I like your stuff. If you pull this one off your going to be the goat on here. Lol
 
I maybe wrong, but I believe the ICON has terrible predicted temp. profiles. The placement of moisture is ideal though, it's in the snow-zone that I drew on my map that I posted up earlier. If it was cold on that run, that would be a lot of snow on tonight's ICON run. The main front passes through, moisture builds back in as the STJ kicks in gear starting at 06z Tuesday.
 
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