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March 2018 Model Discussion


WeatherFeen2000

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11 minutes ago, RU848789 said:

Certainly looks like it based on NAO projections going from fairly negative to just about positive as the storm approaches and according to the abstract that's the only regime transitino associated with more frequent NE storms.  FYI, here's the abstract from her paper, which I just looked up, as I was curious...

This observational study investigates statistical and synoptic–dynamic relationships between regime transitions, defined as a North Atlantic Oscillation (NAO) or Pacific–North American pattern (PNA) index change from at least a 1 standard deviation anomaly to at least a 1 standard deviation anomaly of opposite sign within 7 days, and cool-season (November–April) northeastern U.S. (NE) precipitation. A statistical analysis is performed of daily cool-season NE precipitation during all NAO and PNA transitions for 1948–2003, and a composite analysis and case study of a major cool-season NE precipitation event occurring during a positive-to-negative NAO transition are conducted. Datasets used are the 0.25° NCEP Unified Precipitation Dataset, the 2.5° NCEP–NCAR reanalysis, and the 1.125° 40-yr ECMWF Re-Analysis (ERA-40).

Results of the statistical analysis suggest that cool-season NE precipitation tends to be enhanced during positive-to-negative NAO and negative-to-positive PNA transitions, and suppressed during negative-to-positive NAO and positive-to-negative PNA transitions. Of the four types of regime transitions, only the positive-to-negative NAO transition is associated with substantially more frequent major cool-season NE precipitation events compared to climatology. Results of the composite analysis and case study indicate that a surface cyclone and cyclonic wave breaking associated with the major NE precipitation event can help produce a high-latitude blocking pattern over the North Atlantic characteristic of a negative NAO pattern via thermal advection, potential vorticity transport, and diabatic processes.

https://journals.ametsoc.org/doi/abs/10.1175/2010MWR3362.1

GFS North Atlantic Oscillation Outlooks

Am I reading this wrong?  You mentioned at the top negative to positive NAO transition as most associated with storms, but the abstract says positive to negative transition.  In the abstract, it says negative to positive NAO associates with suppression. 

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1 minute ago, White Gorilla said:

Am I reading this wrong?  You highlighted negative to positive NAO transition as most associated with precip, but the abstract says positive to negative transition. 

No, I read it wrong. Which would mean this would not be an Archambault Event, according to the abstract.  Good catch - will edit it...

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3 minutes ago, RU848789 said:

No, I read it wrong. Which would mean this would not be an Archambault Event, according to the abstract.  Good catch - will edit it...

The weenie in me was hoping you were right and the abstract was wrong, lol, since next week is projecting negative to positive NAO and negative PNA, which the abstract says favors suppression. 

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It's the storm total to that point in both maps, i.e., through 12Z Weds in map 1 and through 12Z Thurs in map 2.  This is a model projection, not anyone's forecast, especially since the 2-low scenario is definitely an oddball one (although not unprecedented).  I posted them to show the potential not to say this is going to happen.  
understood. I just wanted to make sure I was interpreting them correctly.

Sent from my SAMSUNG-SM-G930A using Tapatalk

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1 hour ago, RU848789 said:

And the Euro is much weaker (generally 1.2" max LE) and suppressed south of Baltimore - not sure what to make of that...

Perfect spot. Climo says trend it north over the weeken.

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