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Late Weekend Storm Threat


IsentropicLift

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If the high was stonger this run would have been much worse from an ice point of view. CAD only helps the lower levels stay cold.

The key here will be the s/w sampling in about 36 hours and what the AO does. AO forecasts are still pretty fickle right now for the next week, so these two features must be watched. Sidenote*: The EPO is also expected to go positive during this time frame.
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the east based blocking has definitely trended weaker over the past day for the mid-range...allows the PV to tick further north and lead to a warmer solution for us 

Again, what good would a stronger high pressure do in this case? If you want the mid-level warming to stop then you need the surface low to go way South until the transfer occurs.

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the east based blocking has definitely trended weaker over the past day for the mid-range...allows the PV to tick further north and lead to a warmer solution for us

That's the unfortunate part without a -NAO. It's tough getting a major snowstorm without it but it's not impossible. Luckily we live far enough north that we reap some benefits because south of us they are getting screwed big time.

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its not tough whatsoever to get a snowstorm without a -nao stop with these garbage posts i had 60 inches last year, 35 this year and got a 28 inch storm in 2013 all without a -nao

Not to mention, the nao is forecast to trend negative b398be71239c246de4e77f54c6dafb79.jpg
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its not tough whatsoever to get a snowstorm without a -nao stop with these garbage posts i had 60 inches last year, 35 this year and got a 28 inch storm in 2013 all without a -nao 

your 60 inches was more a result of the severly -EPO.   Last year was an exception.   Generally you want a -NAO especially from NYC south.   SNE can get away with it to some extent....this year has been a good example of that.   NYC has been on the edge of the good snows and south of there has sucked.  Philly and DC with 5 inches YTD while BDR and BOS have 30 and 55 respectively

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your 60 inches was more a result of the severly -EPO.   Last year was an exception.   Generally you want a -NAO especially from NYC south.   SNE can get away with it to some extent....this year has been a good example of that.   NYC has been on the edge of the good snows and south of there has sucked.  Philly and DC with 5 inches YTD while BDR and BOS have 30 and 55 respectively

ok so whats ur excuse for 35 inches already this year and a 28 inch HECZ in early febuary 2013? pls stop overrating the nao

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Look at the differences at H5

 

Yeah definitely is slower with the individual short waves and digs the northern stream wave more allowing for greater interaction and amplification like you said. Changes in the phase and amplitude of the western U.S. ridge (and upstream trough) will have pretty big implications.

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Again, what good would a stronger high pressure do in this case? If you want the mid-level warming to stop then you need the surface low to go way South until the transfer occurs.

 

...and what would make the surface low go further south?  Stronger high pressure is the result of more confluence over Quebec which results in more suppression.  With less confluence, everything is further north.  Look at the Euro maps you posted comparing 12z to 00z....much less confluence over Quebec.  A much better look would be a return of more confluence which in turn would also result in stronger high pressure 

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...and what would make the surface low go further south?  Stronger high pressure is the result of more confluence over Quebec which results in more suppression.  With less confluence, everything is further north.  Look at the Euro maps you posted comparing 12z to 00z....much less confluence over Quebec.  A much better look would be a return of more confluence which in turn would also result in stronger high pressure 

Right, I'm not disagreeing with you, but you don't have any blocking, just a well timed shortwave trying to run into arctic high pressure.

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its not tough whatsoever to get a snowstorm without a -nao stop with these garbage posts i had 60 inches last year, 35 this year and got a 28 inch storm in 2013 all without a -nao 

Important point. The state of the AO is more important than the state of the NAO when it comes to big snowstorms during the first half of February in New York City. Below are the statistics for the February 1-15, 1950-2014 timeframe:

 

AO:

6" or more: 76% AO-

10" or more: 73% AO-

 

NAO:

6" or more: 53% NAO-

10" or more: 45% NAO-

 

6" or greater snowstorms: 17

10" or greater snowstorms: 11

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925 is roughly 2500 feet

850 is roughly 4800 feet

H7- 10k

H5- 18k

Indeed, so the melting occurs at 850mb but then refreezes at the 925mb layer so you end up with sleet.

 

If 925mb temps hang around 0C, or -1C to +1C you will get a mix of IP and ZR, but it also depends on how warm 850's are to begin with. And for good snowgrowth you want cold 700mb temps.

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Not necessarily. The depth of the above freezing layer is more important in determining sleet vs. freezing rain. Supercooled droplets can fall a long way without freezing.

When I lived in Oklahoma we had an event once that was forecast to be FZRA and ended up as entirely sleet despite the fact the sub freezing layer was only 1000ft, the belief was the size of the droplets is what caused it coupled with the fact the temps were 12-18 degrees at the surface

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