eduggs

14 minutes ago, Prismshine Productions said:

*Extremely loud incorrect buzzer noises*

Systems are fluid and dynamic, the tiniest tenth of a degree in the midlayers at a random point (for example, 715-735) can throw off the ratio that actually accumulate. 10:1 can help guess upper-ene impacts under *ideal* conditions, but far from accurate conversion

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You and your dumb ass buzzer are confusing yourselves.

Whether a 10-1 ratio is correct is irrelevant to the point. When a snow map shows "total snowfall at 10:1", the primary model parameter in question is QPF, not accumulated snow. The secondary model parameter, which is often calculated by 3rd party algorithm, is ptype.

If a model correctly predicts QPF and ptype, a snowfall map that multiplies liquid equivalent by 10 and displays it as total snowfall at 10:1 would be absolutely correct. It just might not be an accurate prediction.

Some 3rd party maps do this task pretty well. StormVista does not.

11 minutes ago, weatherwiz said:

Incorrect x10000000000000

Obviously all snow maps are coarse approximations because many factors affect snow accumulation. But some algorithms are semi-accurate at identifying ptype under most conditions and then multiplying QPF by 10.

StormVista is different. It will show 4" of snow based on 2 tenths of liquid and a min temps of 37F. StormVista snow maps are garbage and distinctly worse than most other maps. This is a relatively simple and hopefully non-controversial point.

8 minutes ago, ORH_wxman said:

Hence why we call them clown maps and clown range. 

No.
Some snow accumulation maps accurately convert modeled liquid precipitation to snow at a 10:1 ratio. StormVistaWx does not. So it's in a different category altogether from other so called clown maps. Hopefully this is understood when people consider what they would take in terms of fantasy snowfall.

19 minutes ago, ORH_wxman said:

If someone offered us 8-10” of snow between now and 12/12, I think most of us would take it in SNE. There was prob a time I’d rather roll the dice, but not now. 
 

1. Most of the ens modeled snow comes in weenie range outside of NNE.

2. StormVista snow maps are inflated by approx. a factor of 2.

29 minutes ago, MJO812 said:

Clipper city on gfs. It has a clipper reforming off the coast next week.

It will be difficult to get more than a tenth of an inch liquid out of any of those. And the GFS still has ptype issues for the immediate coastal plain. But still an entertaining run.

The CMC has a less favorable trof angle with the ridge pushing further east giving us more of a NW flow instead of WNW on the GFS.

Subtlety in the evolution and progression of the shortwaves will determine if we can score an inch or two of snow over the next 7-10 days. There should be at least a few periods of snow showers, possibly even lake-effect streamers. It's nice to have some coldish weather. But no significant storms on the foreseeable horizon for now.

The 12z GEPS likes Dec 5-6 for a potential coastal storm - miller B style. GEFS and EPS have a weak signal there too, but nothing exciting.

Cold and dry after Thanksgiving until further notice but enough interest to keep checking model runs.

2 hours ago, Damage In Tolland said:

He didn’t do that well. He posted he had an inch or so . Just to his NW went Hammertime 

It was elevation dependent in that area. 6"+ in all direction from Walt D, including east and south, above 1100ft.

20 hours ago, eduggs said:

I'm thinking the towns on the NW side of the Hudson Highlands ridge do pretty well: Vernon, NJ, to Warwick, NY to Monroe, NY etc...

Based on the OKX PNS, it looks like those areas did pretty well, even below 800ft!! Good start to winter!

...Orange County...
Port Jervis                  12.8 in   0630 AM 11/22   COCORAHS
1 WNW Monroe                 8.2 in    0700 AM 11/22   Trained Spotter
Chester                      8.2 in    0815 AM 11/22   Trained Spotter
5 N Port Jervis              7.4 in    0530 AM 11/22   Public
Warwick                      7.2 in    0700 AM 11/22   COCORAHS
Warwick 3.9 W                7.0 in    0600 AM 11/22   COCORAHS
0.8 N Port Jervis            4.0 in    0700 AM 11/22   COOP

1 hour ago, snywx said:

Checked the board an hour ago and measured 4”. Elevation dependent is an understatement. I would say at 500’ you have a general 2-3” but above 1000’ there is 10+. I-84 from Middletown to port jervis is shut down. Greenville mtn is getting hammered. Buddy measured 12” up there at 1200’

Modeling was fairly accurate IMO and the weather gods delivered! Also good call by you if I remember correctly.

Overall I thought guidance performed very well for this storm. The complex synoptics were well modeled by midrange guidance and the thermals were fairly accurately depicted by mesos and even midrange with hi-res thermals.

Models correctly predicted the major snows in elevated parts of Sussex, the snow into lower Westchester, the approx. snow line at 700ft or so, and even flakes in the air for much of the region.

When the model output shows a snow event, IMO it's a good idea to believe it... especially when you have inter-model and multi-model support. I know in previous decades it was unpopular to practice so-called modelology, but weather models have come a long way. Medium and especially short-range models are pretty accurate. Despite this event being well-advertised, it still seemed to sneak up on some people.

Welcome to winter!

Driving around NE Morris County... couple observations:

Slushy accumulations began at about 600ft and rapidly increased above 1000ft.

No acc. at 500ft
Coating at 600ft
1" at 750ft
2" at 900ft
6" at 1100ft

On radar it looks like heaviest bands will be shifting towards the NJ-NY border area into SENY over the next few hours. The SLP is pretty far east.

At 8:30 in central Morris County near I-287 I observed first mixing with snow at about 500ft and 36F and first slight dusting at about 850ft and 34.5F.

On the east side of the terrain fall line, it seems like the intensity isn't sufficient to dynamically cool the column enough yet to fully switch elevations below 1000ft to accumulating snow. But it's getting closer.

Per radar reflectivity, it looks like snow is mixing in elevated Sussex and Warren and should be increasing over the next few hours.

The HRRR keeps printing out good (wintry) runs for Orange county. The elevated western parts of the county are obviously in a good spot, but even the Rt 94 corridor looks like it could pick up a few inches. Maybe plowable in some spots. Elevated Putnam, Rockland, and even Westchester has a shot at some accumulation too if the meso models are to be believed. Hopefully at least flakes in the air for many on Friday!

I'm thinking the towns on the NW side of the Hudson Highlands ridge do pretty well: Vernon, NJ, to Warwick, NY to Monroe, NY etc...

There's an upslope-downslope component visible on the meso models favoring the NW terrain for highest QPF and lowest temps.

This is one of those weird cases where mid elevations near places like New Milford, NJ or Chester, NY could get basically nothing or 6"... and it wouldn't be a surprise either way.

The HDRPS is printing out well over an inch of precipitation after the column can support snow for much of Sussex, northern Passaic, and Orange counties. Even Rockland and western Putnam get in on the action. I don't particularly trust this model, but it's not entirely alone.

Where does the banding set up tonight and does anything accumulate during the day on Friday under the ULL? My guess is Friday is mostly an elevation thing, but intense banding associated with a still deepening SLP tonight is the wild card. Satellite and radar look pretty good so far IMO.

1 hour ago, snywx said:

I was strictly referring to orange W of the walkill River. Areas like Otisville, Mount Hope, Port Jervis, Greenville Mtn area are mostly above 750’ and far enough W to benefit 

I think those places are in a great spot for this.

The caveat for me is that this looks like a localized event as opposed to a widespread snowfall. Mesoscale banding and terrain effects will likely play a role. I wouldn't be too confident anywhere until later tonight as the radar presentation evolves.

15 minutes ago, snywx said:

Areas aoa 750’ up here in Orange are def in for a nice surprise. 6”+ might not be out of the question. Above 1000’ I think might be a lock for those amounts 

Seems like a good call.

I worry a little about locking anything in these scenarios. The SLP and associated vorticity and precipitation shield is going to make a loop-de-loop of some sort with the radius of that loop dependent on how quickly the mid/ULL take on a negative tilt and cut off. Exactly where any stalled or retrograding banding sets up will determine who cashes in. My fear is that it pushes too far NW and then weakens by the time it rotates back in. Some ensemble members give almost nothing outside of PA and the Catskills. Others spread the wealth to Passaic, Putnam, Westchester etc...

1 hour ago, Allsnow said:

Nw jersey with elevation might get a surprise 

If it happens, it shouldn't be a surprise since even us amateurs have been talking about potential snow in that area for days. And multi-model guidance has been steadfastedly highlighting the potential. But it's been so long since we've had rain, much less snow, it will seem like a surprise no matter what.

Overnight runs looked impressive for Sussex. Even into northern Morris and Orange. ECM, RGEM, GFS, HRDPS...

Could be some surprised people up there if they wake up to saggy snow covered branches with some still leaf-covered trees. NWS Mt Holly is finally talking about the banding potential. If it sets up, someone is going to get pounded.

Pretty much all guidance shifted towards more of a SLP loop-de-loop scenario as opposed to more of a stall. NAM and ICON had been leaning in this direction with CMC on the other end. IF this is correct, accumulating snow looks confined primarily to NEPA and higher elevations of Catskills. 18z and 0z will help determine is this change is homing on the eventual outcome or just a blip. Ultimately it's probably a nowcast, but considering the pinwheeling packets or vorticity, I think it's probably real.

Best chance for flakes outside of hill towns would then probably be Fri or Fri night under the ULL with low thicknesses and steep lapse rates.

7 minutes ago, SnowGoose69 said:

HRRR/NAM both don't show nearly the QPF into NE NJ/NYC which is likely the higher res models seeing the downslope impact IMO.  I have been suspect given the WSW flow that we'd see that much moisture south of the low

Could be. But the NAM has also been shifting every run for 2 days. Other models - EC, CMC, GFS... even ICON have been steady.

Usually when the NAM is in the consensus and then suddenly diverges, then it's sometimes onto something. In this case I think it isn't properly reflecting the anomalous synoptics. But we will probably know by 12z or 18z. A few days ago I would have guessed the NAM evolution of shifting things north and then northwest of the area was likely correct. But all other guidance disagrees. I agree about downsloping and would definitely favor the NW side of any terrain.

The NAM is probably still adjusting. Although sometimes when it's on its own, it's right. But presumably that comes more in line with the GFS, ECM, and CMC. If so, the snow accumulation averages are going to increase in places like Sussex, NJ.

6 hours ago, Nibor said:

Actual snowfall accumulation is gonna be above 2k feet. Some early season flakes are definitely not out of the question though.

Most model sounding profiles look pretty cold Thurs night into Friday. If the thermals are right, that could be accumulating snow down to maybe 800ft or so in spots. Yes for big snows I'd want to be in NE PA, preferably above 1500ft.