Feb. 17th-18th, 2018 Bowling Snow

[NJwx85]

This is precisely the negative swing of the windshield wiper effect that I spoke of yesterday. Rather than living or dying by each model run or cycle, use averages. That's why my call for 2-4" yesterday may have looked conservative for some, and today that might look overly optimistic. I still stand by my snow map from yesterday with just some minor tweaking which I will post below.

Updated call:

Inside Green - Coating to 1"

Inside Light Blue - 1-3"

Inside dark blue - 2-4"

Inside purple - 3-5" (Locally 6")

 

[NEG NAO]

1 minute ago, NJwx85 said:

This is precisely the negative swing of the windshield wiper effect that I spoke of yesterday. Rather than living or dying by each model run or cycle, use averages. That's why my call for 2-4" yesterday may have looked conservative for some, and today that might look overly optimistic. I still stand by my snow map from yesterday with just some minor tweaking which I will post below.

Updated call:

Inside Green - Coating to 1"

Inside Light Blue - 1-3"

Inside dark blue - 2-4"

Inside purple - 3-5" (Locally 6")

 

which models are backing up this idea that the heavier precip and snowfall totals are going to be north ? Both the 12Z NAM and the 12Z ICON are showing just the opposite

[SnowGoose69]

41 minutes ago, NEG NAO said:

this just supports the idea most of NYC metro will be mostly snow with no mix of rain or change to rain as some unnamed METS ( save that for the vendor thread ) are advertising this morning.

The numerical numbers have really come down on high temps tomorrow as well.  Some were showing 44-48 degrees at points 24-36 hours ago.  We now have the NAM at 37 and the GFS at 39 for LGA with dewpoints near 15-20.  The SE flow is simply too light and as another Met here pointed out doesn’t have a deep enough trajectory to really matter 

[allgame830]

3 minutes ago, NEG NAO said:

which models are backing up this idea that the heavier precip and snowfall totals are going to be north ? Both the 12Z NAM and the 12Z ICON are showing just the opposite

Yea I am not understanding his line of thinking with keeping pretty much ALL of Westchester in the 1-3 range doesn't seem likely to me, but we will see.  NAM and EURO seem to disagree.  

[NJwx85]

2 minutes ago, NEG NAO said:

which models are backing up this idea that the heavier precip and snowfall totals are going to be north ? Both the 12Z NAM and the 12Z ICON are showing just the opposite

If I adjusted the map based on every model cycle or run I would need to put out an updated forecast every six hours. It's better to make small adjustments. I also feel as though things will trend back in the other direction the next 24 hours. 

The 12z RGEM for example shows all rain for the coast and southern 2/3rds of NJ, giving the heaviest totals snow wise to the interior.

[NJwx85]

2 minutes ago, allgame830 said:

Yea I am not understanding his line of thinking with keeping pretty much ALL of Westchester in the 1-3 range doesn't seem likely to me, but we will see.  NAM and EURO seem to disagree.  

Because forecasting is about more than just looking at the latest model outputs. 

[NEG NAO]

2 minutes ago, NJwx85 said:

Because forecasting is about more than just looking at the latest model outputs. 

or using the RGEM which has the warmer solution and ignoring the NAM and ICON - they are not ignoring the models they are favoring one over another

[allgame830]

2 minutes ago, NJwx85 said:

Because forecasting is about more than just looking at the latest model outputs. 

I am all about forecasting not just based on model outputs so do not put words in my mouth.  that forecast snowfall is just not right.  but its your opinion and everyone is entitled to theirs.

[NJwx85]

Just now, NEG NAO said:

or using the RGEM which has the warmer solution and ignoring the NAM and ICON

If I had based my map off the RGEM then I wouldn't have put the city in the 1-3" range because the RGEM gives them nothing. 

I use something called a brain to make forecasts. 

[allgame830]

1 minute ago, NJwx85 said:

If I had based my map off the RGEM then I wouldn't have put the city in the 1-3" range because the RGEM gives them nothing. 

I use something called a brain to make forecasts. 

haha, someone woke up on the wrong side of the bed this morning.  cut the attitude dude.  so then your current line of thinking is totally going against the NWS... just asking??? also your saying places north of 287 and south of 84 in Westchester county will only 1-3/2-4... come on!! 

[NJwx85]

4 minutes ago, allgame830 said:

I am all about forecasting not just based on model outputs so do not put words in my mouth.  that forecast snowfall is just not right.  but its your opinion and everyone is entitled to theirs.

Because the crappy NAM and German models say so? You mean the same models that were showing 8"+ areawide yesterday? That's why they are useless. The Euro and GFS on the other hand have been fairly consistent with showing a wide area of 2-4".

And I am not sure who said the Euro was South when it clearly showed an area of 4"+ over the interior.

[BxEngine]

Lets try one more time. Discuss the WEATHER. 

[NJwx85]

1 minute ago, allgame830 said:

haha, someone woke up on the wrong side of the bed this morning.  cut the attitude dude.  so then your current line of thinking is totally going against the NWS... just asking??? also your saying places north of 287 and south of 84 in Westchester county will only 1-3/2-4... come on!! 

Look at where the watches are cutoff? If you notice it's pretty much South of 84 in NY.

[Stormlover74]

2 minutes ago, allgame830 said:

haha, someone woke up on the wrong side of the bed this morning.  cut the attitude dude.  so then your current line of thinking is totally going against the NWS... just asking??? also your saying places north of 287 and south of 84 in Westchester county will only 1-3/2-4... come on!! 

I don't think that's unreasonable. Nam is South and gfs has been consistently showing 2 to 3 areawide

[jm1220]

The RGEM is showing rain for the city and coast because of the southerly flow ahead of the storm and the warm air that brings, and light rates for the most part not overcoming the crap boundary layer. I think we really need a NAM like solution here to overcome the warm boundary layer to really have a shot at accumulating here. Away from the coast, this looks like an easier 3-5” call since the southerly flow won’t warm inland areas as much. A better 850mb temp and better track aren’t enough on their own this time. 

[NJwx85]

Just now, Stormlover74 said:

I don't think that's unreasonable. Nam is South and gfs has been consistently showing 2 to 3 areawide

Apparently it's difficult for some to understand averages/consensus.

I did lower my amounts from yesterday which called for 4-6" in the dark blue area where I am now saying 2-4". I really didn't think that was unreasonable. 

[allgame830]

Just now, NJwx85 said:

Look at where the watches are cutoff? If you notice it's pretty much South of 84 in NY.

Yes I 100% agree on the fact with places well further north wont be the best out of this.  They will most likely get an advisory.  But places N&W of 1-95 will see at least 3-6 inches out of this.... perfect timing with all falling after nightfall. dewpoints will be low so wetbulb will come into play.  

[NJwx85]

1 minute ago, jm1220 said:

The RGEM is showing rain for the city and coast because of the southerly flow ahead of the storm and the warm air that brings, and light rates for the most part not overcoming the crap boundary layer. I think we really need a NAM like solution here to overcome the warm boundary layer to really have a shot at accumulating here. Away from the coast, this looks like an easier 3-5” call since the southerly flow won’t warm inland areas as much. A better 850mb temp and better track aren’t enough on their own this time. 

That's why I went with such a sharp cutoff across the LHV, and if you look at where the watches are, NWS agrees.

[jm1220]

I think right now Upton went too high for the city. It’s in the 50s right now and the warm ground will limit accums even if somehow it’s all snow. I think it needs to really come down like the NAM has for it to accumulate much. It can, but there’s too many other outcomes out there for me to be comfortable saying so at this stage. 

[NJwx85]

1 minute ago, allgame830 said:

Yes I 100% agree on the fact with places well further north wont be the best out of this.  They will most likely get an advisory.  But places N&W of 1-95 will see at least 3-6 inches out of this.... perfect timing with all falling after nightfall. dewpoints will be low so wetbulb will come into play.  

That's your call, and I would encourage you to put out your own forecast/map. I am guessing it would look something like this?

Inside Light Blue - 1-3"

Inside Dark Blue - 3-6"

[allgame830]

1 minute ago, NJwx85 said:

That's why I went with such a sharp cutoff across the LHV, and if you look at where the watches are, NWS agrees.

Nobody is disagreeing with that.  Your "potential" totals is what I am disagreeing with.  but whatev doesn't matter at this point since we are roughly 36 hours out.  4-7 from NWS and 1-3 according to your map... we'll see. 

[MJO812]

CMC is further north and looks good

This is becoming a 1-3/2-4 inch event for the coast

[NJwx85]

Just now, allgame830 said:

Nobody is disagreeing with that.  Your "potential" totals is what I am disagreeing with.  but whatev doesn't matter at this point since we are roughly 36 hours out.  4-7 from NWS and 1-3 according to your map... we'll see. 

I have 1-3" for NYC. I wouldn't be shocked if they got 4" nor would I be shocked if they got nothing.

[SnowGoose69]

I’m trusting the GFS AND NAM numerical numbers at this range over the RGEM thermals and they basically average out to 36/26 at 00Z tomorrow night.  I can’t see how that’s not a snow event when all layers are below 0C and you don’t have a deep east or southeast flow.  Notice that the flow veers more NE by late evening tomorrow anyway once precip arrives.  At least on the models other than the GFS 

[snywx]

4 minutes ago, Snow88 said:

CMC is further north and looks good

This is becoming a 1-3/2-4 inch event for the coast

If I had to take a guess I would say 1-3" for the immediate coast. Areas just NW of the city like Bergen, Rockland, Westchester into CT look good with 3-5" amounts. I expect Upton to go with WWA for everyone. 

[NJwx85]

6 minutes ago, Snow88 said:

CMC is further north and looks good

This is becoming a 1-3/2-4 inch event for the coast

That pretty much agrees with my thinking. Just because the NWS issued a watch for 4-7" doesn't mean that's what's going to fall. That's why they issue watches and don't jump straight to warnings when possible. 

[NJwx85]

2 minutes ago, SnowGoose69 said:

I’m trusting the GFS AND NAM numerical numbers at this range over the RGEM thermals and they basically average out to 36/26 at 00Z tomorrow night.  I can’t see how that’s not a snow event when all layers are below 0C and you don’t have a deep east or southeast flow.  Notice that the flow veers more NE by late evening tomorrow anyway once precip arrives.  At least on the models other than the GFS 

I agree that the RGEM is probably showing rain where wet snow will be falling, but the fact that we're in the 50's today and that it's been warm lately doesn't help. This isn't like early January when the ground and ponds/lakes/rivers were all frozen solid.

[SnowGoose69]

1 minute ago, NJwx85 said:

I agree that the RGEM is probably showing rain where wet snow will be falling, but the fact that we're in the 50's today and that it's been warm lately doesn't help. This isn't like early January when the ground and ponds/lakes/rivers were all frozen solid.

If you look at its 2M temps on the meteogram you can see what the issue is. It doesn’t show any evaporative cooling at all.  It basically has temps 33/20 and it just goes to 33/33 for the entire event 

[SnowGoose69]

2 minutes ago, NJwx85 said:

I agree that the RGEM is probably showing rain where wet snow will be falling, but the fact that we're in the 50's today and that it's been warm lately doesn't help. This isn't like early January when the ground and ponds/lakes/rivers were all frozen solid.

It’s probably going to be an event where NYC gets 4-5 but 1/2 mile away it’s slush and LGA and JFK report 1 inch but someone in Flushing or Woodmere in their backyards get 5

[NJwx85]