Major Nor'easter snow storm (possible top 20) Noon Wednesday-Noon Thursday Dec 16-17, 2020

[nesussxwx]

4 minutes ago, wizard021 said:

That model is crazy. How is Coastal Maine getting 20 to 30 inches.

 You only see it that way because you are wish casting I can tell based on your posts in the NE forum. It is a real possibility depending on how much the mid-levels amplify, could be a last minute trend.

 

[wizard021]

3 minutes ago, nesussxwx said:

 You only see it that way because you are wish casting I can tell based on your posts in the NE forum. It is a real possibility depending on how much the mid-levels amplify, could be a last minute trend.

 

The model cmc/ rgem are moving the low too far north and not moving it ene as expected,

[Dark Star]

29 minutes ago, weatherpruf said:

Hmmm....all these storms come to nowcast it seems; kind of makes following a forecast somewhat redundant....but we do it anyway. Gluttons for punishment.

I always say that the forecast should be determined no later than within 24 hours of the onset of precipitation.  Otherwise, it really isn't a forecast.  As Jeff Beradelli has taught me, the devil is in the details.  In other words, the pieces of the puzzle are there in the forecasting tools, it's up to the forecaster to know which ones to use and which ones to discard.

[bluewave]

This will be our first storm to test out the new dynamic ratio.

https://www.weathernerds.org/models/field_definitions/Snowfall.pdf

 

[SnowGoose69]

I expect the GFS will cave either this run or next at 00z

[wizard021]

Gfs is east

[Sn0waddict]

3 minutes ago, SnowGoose69 said:

I expect the GFS will cave either this run or next at 00z

Cave to what? There still doesn’t seem to be uniform agreement across the board. 

[F5TornadoF5]

[F5TornadoF5]

[SnowGoose69]

The fact the GFS tracks the 700 low west and doesn't show sleet anywhere is just baffling

[weatherlogix]

23 minutes ago, romba said:

RGEM Kuchera. Does Kuchera take sleet into account or treats it as 10:1?

 

based on the individual skew-t's even the south shore of Nassau Cty is REALLY close to all snow.

[Sn0waddict]

Practically identical at the surface at Hr 36 to 12z. Next panel is the most important one though. 

[nycsnow]

Solid trends for us on the mix line! 00z are huge 

[jm1220]

4 minutes ago, wizard021 said:

Gfs is east

Over Dover, DE at hr 36 is east?

[Sn0waddict]

Just now, Sn0waddict said:

Practically identical at the surface at Hr 36 to 12z. Next panel is the most important one though. 

1 mb stronger and a hair East. Looks pretty identical to 12z.

[weatherpruf]

12 minutes ago, Dark Star said:

I always say that the forecast should be determined no later than within 24 hours of the onset of precipitation.  Otherwise, it really isn't a forecast.  As Jeff Beradelli has taught me, the devil is in the details.  In other words, the pieces of the puzzle are there in the forecasting tools, it's up to the forecaster to know which ones to use and which ones to discard.

This is true in most things. Your doctor doesn't prescribe the same BP medicine to every patient.

[F5TornadoF5]

[jm1220]

3 minutes ago, SnowGoose69 said:

The fact the GFS tracks the 700 low west and doesn't show sleet anywhere is just baffling

To me looked like the 700 low tracked from NW of Philly to about over NYC? 

I guess call it a win that this doesn't look it came any further NW from 12z. 

[psv88]

Just now, jm1220 said:

To me looked like the 700 low tracked from NW of Philly to about over NYC? 

I guess call it a win that this doesn't look it came any further NW from 12z. 

GFS buries us. 16-18"

[Gravity Wave]

That banding close to the surface low after the front end comes through (and the upper air temps associated with it) are going to determine what kind of storm this is for the area, because i don't think the decaying CCB on the back side is going to give us more than an inch or two.

If it's strong like on the GFS we're on track for over a foot, if not I'm thinking 8 inches is the target.

[SnowGoose69]

The GFS is basically operating like a model in 1985 or 1990.  Its not seeing the mid-level warmth that would happen despite the mid level low tracks.  Normally the GFS nowadays compensates by showing rain but its likely being confused by the strong surface high to the north.

[HeadInTheClouds]

10 minutes ago, SnowGoose69 said:

I expect the GFS will cave either this run or next at 00z

It already did. it went from the 2 inches it was giving me for 5 days to 18, lol

[jm1220]

1 minute ago, psv88 said:

GFS buries us. 16-18"

Has a crazy enhanced precip area at around 9z come through that I guess would be snow as the low starts departing. The NAM had something similar but less intense. That would be the CCB I'm guessing. Lot of haves/have nots from banding inland it seems, lots of enhanced and shaft zones. 

[psv88]

2 minutes ago, jm1220 said:

Has a crazy enhanced precip area at around 9z come through that I guess would be snow as the low starts departing. The NAM had something similar but less intense. That would be the CCB I'm guessing. Lot of haves/have nots from banding inland it seems, lots of enhanced and shaft zones. 

 

You see our winter storm watch? 3-10"...wtf is that

[romba]

1 minute ago, psv88 said:

 

You see our winter storm watch? 3-10"...wtf is that

a CYA forecast special 

[Nibor]

Just now, psv88 said:

 

You see our winter storm watch? 3-10"...wtf is that

I think that's pretty accurate. Without a correction south and east by 50-100 miles I don't see how the island doesn't mix or dry slot.

[NJwx85]

5 minutes ago, SnowGoose69 said:

The GFS is basically operating like a model in 1985 or 1990.  Its not seeing the mid-level warmth that would happen despite the mid level low tracks.  Normally the GFS nowadays compensates by showing rain but its likely being confused by the strong surface high to the north.

Not sure I completely agree. The position of the 700mb low on the 12z vs 18z run valid 12z Thursday is nearly identical, and one mb deeper.

[Allsnow]

[jm1220]

3 minutes ago, SnowGoose69 said:

The GFS is basically operating like a model in 1985 or 1990.  Its not seeing the mid-level warmth that would happen despite the mid level low tracks.  Normally the GFS nowadays compensates by showing rain but its likely being confused by the strong surface high to the north.

I will say for whatever it's worth the GFS doesn't show the same warm nose the NAM has at 36hr on the soundings. Strange with a fairly strong southerly wind at 700-750mb. The 700 low does take a slightly better track on the gfs than the NAM. 

[bluewave]

9 minutes ago, SnowGoose69 said:

The GFS is basically operating like a model in 1985 or 1990.  Its not seeing the mid-level warmth that would happen despite the mid level low tracks.  Normally the GFS nowadays compensates by showing rain but its likely being confused by the strong surface high to the north.

They already know about the cold bias on the v15. So it probably isn’t the forecast tool to use in this situation. They appear to have fixed the cold bias on the V16 which is scheduled to go operational later in the winter.

https://www.wired.com/story/the-governments-new-weather-model-faces-a-storm-of-protest/