March 7th 2018 Coastal Storm thread (not obs)

[donsutherland1]

8 minutes ago, strgazr27 said:

Which is why they’re wrong sometimes. I see nothing wrong with dons post or his call. He’s one of the VERY FEW on here worth listening to. Personally I think 8” for NYC or any place on LI may be wishful thinking. Call it bad forecasting if you want but model runs, trends, local climatology and yes, history all play into my call. FWIW

@DRZ1111 makes a fair point, IMO.

I use climatology as a reference in weighing uncertainty when there is a large spread in the guidance. It reminds me to go back to look at the maps for various outcomes e.g., the 1960 case, which are available on NCEP's re-analysis page back to the late 19th century, hence my reference about the 1941 and 1960 storm's having colder air masses. I don't literally use climatology in the short-term, but just to go back to look at various outcomes.

[NJwx85]

1 minute ago, weatherlogix said:

Ironically and in typical GFS fashion at 30, with the temp 33 and the rest of the column cold it says best guess: RAIN

I just want to reiterate that I never said I bought the GFS thermals. 

[Zelocita Weather]

GFS looking better, as is the RGEM. Nice slight eastward tweak with the 18z suite so far, but really just noise. 

Also looks like the initial overrunning is more significant than thought. By 7-8am from just pure over running 2-3" could already be on the ground. 

[Drz1111]

7 minutes ago, Blizzard-on-GFS said:

People say that but experience proves otherwise. 

"People" don't say that.   Ask any of the folks on here who professionally develop models.   It's been more than a decade since I was taught this, but my understanding is that folks have tried to prove the existence of trends and have failed.  Your 'experience' is a function of bias - when models random walk in an obvious way, it doesn't stick in your head, but a 'trend' does.  The human mind overfits patterns.

[Stormlover74]

1 minute ago, TriPol said:

UGLY RGEM run/RGEM hasn't changed, GFS is East and Colder/GFS is West and Warmer

How is it possible for people to look at the same picture, yet have completely different interpretations??

Listen, it's March and you're most likely going to get more than 6" unless you live on the South Shore and East End of LI. Be happy.

People live in different places. Rgem cut back on the southern edge 

[NJwx85]

Not sure about precip types yet but 18z RGEM has roughly 45-50 mm of precip on the metrogram for NYC with more to the N & W.

[ILoveWinter]

Honestly the chaos with each model run is very expected, it wouldn’t be a weenie forum without it!

[NJwx85]

3 minutes ago, TriPol said:

UGLY RGEM run/RGEM hasn't changed, GFS is East and Colder/GFS is West and Warmer

How is it possible for people to look at the same picture, yet have completely different interpretations??

Listen, it's March and you're most likely going to get more than 6" unless you live on the South Shore and East End of LI. Be happy.

Depends on location, 18z increased my totals by 3-5”.

[Ericjcrash]

Got the shops closed tomorrow text so it's totally going to rain. GFS ticking easy is encouraging. 

Hi res RGEM less amped thru 17

[tamarack]

8 minutes ago, donsutherland1 said:

@DRZ1111 makes a fair point, IMO.

I use climatology as a reference in weighing uncertainty when there is a large spread in the guidance. It reminds me to go back to look at the maps for various outcomes e.g., the 1960 case, which are available on NCEP's re-analysis page back to the late 19th century, hence my reference about the 1941 and 1960 storm's having colder air masses. I don't literally use climatology in the short-term, but just to go back to look at various outcomes.

Sort of an understatement.  The current rotting little HP means p-type issues all the way into Maine.  March 1960 was the first major snowstorm of my experience where the temps remained under 20° (in NNJ - Jersey Highlands.)  Of course we did it again that December, and even colder for the JFK inaugural storm.  While shoveling the Feb blizzard the air felt almost warm - upper 20s instead of low teens - despite the howling wind.

[Syrmax]

8 minutes ago, donsutherland1 said:

@DRZ1111 makes a fair point, IMO.

I use climatology as a reference in weighing uncertainty when there is a large spread in the guidance. It reminds me to go back to look at the maps for various outcomes e.g., the 1960 case, which are available on NCEP's re-analysis page back to the late 19th century, hence my reference about the 1941 and 1960 storm's having colder air masses. I don't literally use climatology in the short-term, but just to go back to look at various outcomes.

Don is one of the best non-pro forecasters around and frankly better than many of the Redtaggers. We see his verification scores routinely near or at the top in the ne.wx storm contests.  He doesn't let emotion cloud his thinking or engage in wishcasting

[Wetbulbs88]

Did anyone post the 3k NAM for 18z? Or is it only a two-run model? 

[hooralph]

NYC has to be ****ting bricks deciding whether to close schools tomorrow. 1-2"/hr during afternoon commute from schools could be nightmarish, but the bust risk of having the parents of a million kids at home for some sloppy drizzle seems high here.

[weatherpruf]

15 minutes ago, donsutherland1 said:

@DRZ1111 makes a fair point, IMO.

I use climatology as a reference in weighing uncertainty when there is a large spread in the guidance. It reminds me to go back to look at the maps for various outcomes e.g., the 1960 case, which are available on NCEP's re-analysis page back to the late 19th century, hence my reference about the 1941 and 1960 storm's having colder air masses. I don't literally use climatology in the short-term, but just to go back to look at various outcomes.

I thought you did pretty well. I think you provide a valuable amount of input here. Speaking as a social scientist, I don't know why your conclusion would be without merit, but then I am not a "hard" science kinda guy.

[Drz1111]

6 minutes ago, Syrmax said:

Don is one of the best non-pro forecasters around and frankly better than many of the Redtaggers. We see his verification scores routinely near or at the top in the ne.wx storm contests.  He doesn't let emotion cloud his thinking or engage in wishcasting

I’m not saying he was letting emotion alter his forecast.  Rather, I’m saying it’s logically incorrect to adjust the forecast for climatology for an event that’s progged to being in 12 hours.

[Nibor]

HRDPS looks good for mostly snow in NYC. 

[Syrmax]

1 minute ago, Drz1111 said:

I’m not saying he was letting emotion alter his forecast.  Rather, I’m saying it’s logically incorrect to adjust the forecast for climatology for an event that’s progged to being in 12 hours.

I believe you said something like its beneath him to post what he did. A bit harsh. And frankly, not considering climo as a forecast consideration is throwing out a useful tool. That ought to be obvious.

[NycStormChaser]

[bluewave]

29 minutes ago, Drz1111 said:

"People" don't say that.   Ask any of the folks on here who professionally develop models.   It's been more than a decade since I was taught this, but my understanding is that folks have tried to prove the existence of trends and have failed.  Your 'experience' is a function of bias - when models random walk in an obvious way, it doesn't stick in your head, but a 'trend' does.  The human mind overfits patterns.

The WPC keeps track of both model trends and biases. Sometimes people use the terms interchangeably to express predictable or repeating patterns of model error.

http://www.wpc.ncep.noaa.gov/html/model2.shtml

NAM and GFS Model Trend Graphics

These graphics supplement the Model Diagnostic Discussion by comparing 500-mb geopotential height and sea level pressure every 6-h from F00-F84 from the most recent 00Z or 12Z NAM and GFS model runs to output from the model initialized 12 hours and 24 hours earlier. Difference fields between the current and older runs can also be displayed. 

[Drz1111]

2 minutes ago, Syrmax said:

I believe you said something like its beneath him to post what he did. A bit harsh. And frankly, not considering climo as a forecast consideration is throwing out a useful tool. That ought to be obvious.

It’s not obvious that’s climo is a useful tool at this lead time.  You guys don’t understand how forecasting works.  The amount you regress to climo is proportionate to the uncertainty in the forecast which is proportionate to the lead time.

 

think of it this way:  how much snow NYC gets is almost entirely a function of the path of the 850mb low.  What is the climatological path of the 850mb low.  I’ll hang up and listen.

[SnowGoose69]

We need RhodieRick back on the forum right about now 

[Drz1111]

Just now, bluewave said:

The WPC keeps track of both model trends and biases. Sometimes people use the terms interchangeably to express predictable patterns of model error.

http://www.wpc.ncep.noaa.gov/html/model2.shtml

Yes - of course model biases are very real and they need to be understood and incorporated.  No disagreement there. 

[jm1220]

I could see a 2/13/14 situation developing where places just inland from the beaches stay snow as the heavy rates and east-turning low prevent further warm air from coming in. That's one way NYC could bust high. It would be really, really crappy for me but that comes with living on a barrier island. It happened then to me and I'm sure someday it will again. The hi-res RGEM seems to be showing something like this where warm air surges to the south shore and stops advancing. 

[MJO812]

18z Hi Res RGEM has near a foot for NYC

[USCG RS]

I could see a 2/13/14 situation developing where places just inland from the beaches stay snow as the heavy rates and east-turning low prevent further warm air from coming in. That's one way NYC could bust high. It would be really, really crappy for me but that comes with living on a barrier island. It happened then to me and I'm sure someday it will again. The hi-res RGEM seems to be showing something like this where warm air surges to the south shore and stops advancing. 

I've actually been thinking that about this storm in regards to 13 Feb 2014

Sent from my SM-N950U using Tapatalk

[Syrmax]

4 minutes ago, Drz1111 said:

It’s not obvious that’s climo is a useful tool at this lead time.  You guys don’t understand how forecasting works.  The amount you regress to climo is proportionate to the uncertainty in the forecast which is proportionate to the lead time.

 

think of it this way:  how much snow NYC gets is almost entirely a function of the path of the 850mb low.  What is the climatological path of the 850mb low.  I’ll hang up and listen.

Well, Put your forecasts up in the ne.wx snowstorm contests, get statistically scored and we'll see how good you are.

[LongBeachSurfFreak]

I had a feeling upton would go with an advisory for the SS. I could see this being a total fail there. The biggest opportunity would be late in the storm with the ccb. 

Where I am at 120th and Broadway  I think I do very well. This area isn’t just enough NW to do well in marginal events. I had 10” last march

[MJO812]

Wow HRDPS still shows 12 + for the metro area

[hudsonvalley21]

24 minutes ago, Wetbulbs88 said:

Did anyone post the 3k NAM for 18z? Or is it only a two-run model? 

 

[Franklin0529]

What's everyone thoughts on northern coastal Monmouth County?  Any accumulating snow?  Or just mostly a mix.  I been reading an getting mixed thoughts