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NYC/PHL Jan 25-28 Potential Threat Part 2


am19psu

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The purpose of the block is to enforce the cold airmass and now allow the high pressure to escape. It keeps the whole upper air pattern more favorable in our area. The lack of the block is fine with the 50/50, but guess what? The 50/50 isn't staying in the 50/50 location without the block. So as soon as it moves northeast (which it does it's a transient feature), the high pressure slips east and the amplification aloft develops a return flow of warm air into the system.

Could things change? Of course..the system is still plenty far out into the medium range. But we need some pretty big upper air changes to avoid this bringing in some good amounts of warmer air.

It isn't necessarily about the block though, you can just have a weak storm with a northern stream trough as the 18z/0z GFS shows....

Also, there is a strong North Atlantic ridge so I think people are grumbling too much about the lack of NAO.

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The purpose of the block is to enforce the cold airmass and now allow the high pressure to escape. It keeps the whole upper air pattern more favorable in our area. The lack of the block is fine with the 50/50, but guess what? The 50/50 isn't staying in the 50/50 location without the block. So as soon as it moves northeast (which it does it's a transient feature), the high pressure slips east and the amplification aloft develops a return flow of warm air into the system.

Could things change? Of course..the system is still plenty far out into the medium range. But we need some pretty big upper air changes to avoid this bringing in some good amounts of warmer air.

correctly timed, emphasis on corectly, the feedback between the strong 50/50 and the east based NAO can be enough to keep the HP anchored in. Its all about timing, but it can work as is if the SW ejects fast or does what the gfs does and keeps it almost all northern stream.

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The boxing day event featured historic positive anomalies from Greenland stretching back west into Central Canada...this event is going to be much more about timing and luck. The big ridge out west argues for amplification...so if the 50/50 isn't timed well this is going to end up rather amplified I think.

Feb. 2006 ftw? :whistle:

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correctly timed, emphasis on corectly, the feedback between the strong 50/50 and the east based NAO can be enough to keep the HP anchored in. Its all about timing, but it can work as is if the SW ejects fast or does what the gfs does and keeps it almost all northern stream.

Threading the needle can be done, as we saw in Feb 2006.

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The boxing day event featured historic positive anomalies from Greenland stretching back west into Central Canada...this event is going to be much more about timing and luck. The big ridge out west argues for amplification...so if the 50/50 isn't timed well this is going to end up rather amplified I think.

Right.

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Lol, I was thinking the exact thing and showed restraint and refrained from posting this but it is a valid comparison imo.

You know, dbc, February 2006 had just perfect timing, pretty rare to see that again, but then again, I might be wrong.

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what about previous panels of uk? does it completely miss all east, or does it go over bm and then slide east

It's weak...but scrapes the MA. Being weak is the only way this went east, with no blocking.

The issues are, IMO, the configuarion of the vorticity package that is being portrayed by the GFS vs. the NAM....very unconsolidated with the GFS, and it did this a couple storms ago also.

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correctly timed, emphasis on corectly, the feedback between the strong 50/50 and the east based NAO can be enough to keep the HP anchored in. Its all about timing, but it can work as is if the SW ejects fast or does what the gfs does and keeps it almost all northern stream.

Has he argued otherwise?

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The purpose of the block is to enforce the cold airmass and now allow the high pressure to escape. It keeps the whole upper air pattern more favorable in our area. The lack of the block is fine with the 50/50, but guess what? The 50/50 isn't staying in the 50/50 location without the block. So as soon as it moves northeast (which it does it's a transient feature), the high pressure slips east and the amplification aloft develops a return flow of warm air into the system.

Could things change? Of course..the system is still plenty far out into the medium range. But we need some pretty big upper air changes to avoid this bringing in some good amounts of warmer air.

I absolutely agree. A +NAO in a Nina of especially this strength is just asking for trouble, when the high is able to escape out to sea the way it has been in most model progs for this timeframe.

A long fetch SE flow into the storm is majorly bad outside of the inland, elevated areas that can escape it. There is a lot of preceding cold air, which may be the one saving grace for a lot of people.

We need the storm to develop faster and catch us when the high is still in place.

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