DECEMBER 16th 17th 2020 Snow Threat???

12Z RGEM. Did bump slightly NW but kept LI and NYC all snow. Nice stripe of 12+

nutleyblizzard wrote:

rb924119 wrote:

Frank_Wx wrote:In my opinion, the small shift S-SE on the NAM was not enough. The general idea is we get very heavy snow before dry slotting and/or changeover to mix. It's still a big difference compared to just 24 hours ago.

Agree, Frank. The surface depictions are wrong, I don’t know what else to say. You have mid-level closed lows passing to our west/overhead and then even northwest of us at H5, embedded in deep-layer southwesterly flow; you aren’t going to magically see those circulations stop dead and jump due east. Sorry. If anything, they will eventually arc, but not before they reach and/or exceed our latitude. And this is actually projected quite well on the QPF maps getting the banding well to our north and west with the dry slot showing up for us. People can say that it shifted east and colder, but dynamically speaking it didn’t at all. And, in these setups, warm air advancement aloft always outpaces modeling, so I would a quicker transition from snow to slop.

I have to disagree with you RB. We have a strong high along with a powerhouse 50/50 low. I can’t see a primary low plow right into that. The Nam showed some improvements with stronger confluence and a bit better H5 setup. I take it as a positive for us. Man I love this hobby. Onto the Gfs.

That’s fine, you can disagree, I won’t get upset so, the 50/50 low isn’t exactly 50/50; it’s more like 51-52N/50W, and although it’s blocked from heading further north, it has an escape route to the east beneath blocking as it feels the weakness created by the wave break ahead of it. As a result, the confluence has room to shift north as the warm advection raises heights ahead of our storm before being able to hold its ground. It’s this poleward and eastward flexion of the confluent zone “50/50” low that I have been arguing for days, and what allows the primaries to gain more latitude before the blocking gets a firm foothold. Also, this flexion allows the low-level high to begin slipping/building east over the northwestern Atlantic, which means you start drawing in a more modified airmass as opposed to if the high was pressing from the north or northwest, and also open a pathway further west.

Edit: “arguing” was a poor word choice for this forum, “debating” is much more applicable lol

aiannone wrote:

aiannone wrote:ICON mostly rain for NYC and LI. Mixing in NNJ and SCT otherwise jackpot is up towards 684

that still gives nyc tristate 6+ doesnt look mainly rain there.

aiannone wrote:12Z RGEM. Did bump slightly NW but kept LI and NYC all snow. Nice stripe of 12+

a NW shift is not what we wanna see on southern folks, but as that stands im in the jackpot, but trends seem to be in the wrong direction, im hoping in a perfect world GFS comes a bit north and the others hold serve, and the icon meh.

RGEM for the most part held serve from prior runs.

The RGEM would drop 3 feet of snow over NNJ with this type of H7 forcing

Early look at gfs, it's going to hold serve

Northern Extent of GFS here

GFS is very cold because it is the southern-most model with this storm. It did come north a bit, but not by as much as I would have thought. I can't tell if that's a red flag to the models that are a lot more tucked/NW, or its just a REALLY bad model.

GFS did score a coup with Juno, if I remember correctly

06z EURO vs 12z GFS

Canadian Initialized. 12z EURO wait is suspensful.

GFS defintely came north with the heavier snow.

I was at 5 inches last run and it put me at 10 this run.

Frank_Wx wrote:06z EURO vs 12z GFS

General agreement on the heaviest snow areas but big difference on the northern extent.

Frank_Wx wrote:The RGEM would drop 3 feet of snow over NNJ with this type of H7 forcing

that looks like it would also include Hudson Valley and lower Westchester no? Same dark shaded area over us too. Oh and a page back or so soul posted the ratio map that shows just that though not quite 30 8nches but close. Included this area too which would cripple yonkers. I def can't complain about too much snow cuz last year I complained we hardly saw any lol

I would not toss the GFS at this point. The goal posts IMO are set. Where the 500/700/850 lows eventually pass could very well be over Cape May or right over NYC. The closer to the latter the worse it is for the I95. At 2+ day out absolutely nothing is set in stone and the I95 could get a crushing snowfall out of this. A matter of 50 miles could make all the difference.

The only thing I'm somewhat confident in now is that SE Jersey is not in the game for big snows. Atlantic, Cape May, Southern Ocean.

It's always a nail biter with these big events, albeit the consistency of the modeling since Day 5 is very rare thing. Ensembles and Ops.

Early look at cmc, ticking SE

For the vast majority of people on here both the GFS and the Euro are a "win" just to different degrees depending on where you are on which model. I define a "win" in this storm as anyone who gets at least 6" of snow. I've always thought that reasonably speaking if you get a half-foot of snow from a storm, you should be happy. We all love blockbusters with two feet, but how often do most of us in the NJ/NYC region get those? 6-12" or more is a real storm with real impacts.
The NAM is what worries me now. And rb. I have night terrors during the daytime right now inspired by rb and the NAM. lol

heehaw453 wrote:I would not toss the GFS at this point.  The goal posts IMO are set.  Where the 500/700/850 lows eventually pass could very well be over Cape May or right over NYC.  The closer to the latter the worse it is for the I95.  At 2+ day out absolutely nothing is set in stone and the I95 could get a crushing snowfall out of this.  A matter of 50 miles could make all the difference.  

The only thing I'm somewhat confident in now is that SE Jersey is not in the game for big snows.  Atlantic, Cape May, Southern Ocean.

It's always a nail biter with these big events, albeit the consistency of the modeling since Day 5 is very rare thing.  Ensembles and Ops.

Agree. 12z GEFS did come NW a bit.

I think we're on the verge of seeing models come to a compromise. Meaning, the NAM is likely an outlier being too far NW, and the EURO probably going to adjust slightly SE of its 06z run and meet the GFS in the middle.

12z CMC calms the coasties nerves. Pushes the r/s line right to fire island but stops. sometimes you have to smell the rain to get the best snow!

Wherever the heaviest bands set up, do we see rates around 1-2"/hour?

dsix85 wrote:Wherever the heaviest bands set up, do we see rates around 1-2"/hour?

Almost certainly.

The CMC is extreme and absolutely crippling situation! Note how the 700/850/500 lows move ENE instead of due east. That kind of movement could crush NYC/LI.

If the track goes East by 50 miles, would that expand the precip shield west due to a stronger low, or would it just take the precip shield East with it?

Jan ‘16, Ocean County was told to expect a ton of mixing and we were forecast at 1-3” as of the night before. The storm ticked East a smidge, we thumped, then dry slotted, then thumped some more and finished at 16-17”. I see this set up (from a forecast/surface map standpoint) possibly setting up the same way.

And HeeHaw, I agree that LBI (how ironic!!) seems to be the cut off for this storm and most storms for Tri-state weather as opposed to more of the Delmarva weather. I’m about halfway down the state coastline and at the northern 1/3 marker of Ocean County, just 20 miles N of LBI. I basically live on the border of the two climates and usually have razor thin margins on storm track!

But 48 hrs, and I feel like Ocean Cty is right there in the game. Losing by a little bit, and time is starting to tick, but here we are nonetheless. Right in the game!!

aiannone wrote:12z CMC calms the coasties nerves. Pushes the r/s line right to fire island but stops. sometimes you have to smell the rain to get the best snow!

where do I sign? That's hot. Lol. Frank I agree almost always the models converge on some kind of compromise. Is it still possible to see a Godzilla or like rgem a frsnkzilla? I know probably but is there a chance as Jim Carrey would say lol