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Quote: Actually, I am not really inclined to think it is all that different than Dean's set-up at this time; though like snowflakes, no two patterns are "identical" either. The -GLAAM (Global Atmospheric Angular Momentum) is very powerfully locked in an anomalous state at this time... Moreover, the graphical presentation of where the crux of that anomaly distribution is situated is along and beneath 30N, and N of 30S... What that means is, -GLAAMs are correlated with longitudinal biases in the field and therefore, there is less likelihood that a wayward opening in the ridge will suddenly emerge and draw this system up; the meridional incursion (or in other words, increased troughing) into sufficiently south latitudes becomes anticorrelary and thus doubtful, given to this background overwhelming signal to maintain a stronger subtropical ridge axis. That is far from absolute, of course! The GLAAM is a scalar value that is a calculation of integrated torque via several sources, throughout the atmosphere as a whole. It is not a prognostic tool, it is a measurement. That being said, until this deeply negative anomalous state starts to show a positive modality, it is just the lesser of likelihoods at this time that meridional avenues will open up. It is the best way to use this observable teleconnector "responsibly", as possible correction scheme for forecast models. In this case, however, the models are pretty clearly persistent with the ridge and therefore, we have little room to doubt their veracity -- even at this extended lead; highly unusual but this is probably directly the cause in why the Global models did so terrifyingly beautiful predicting the path of Dean. They were locked into a persistence pattern where subtropical ridging was anomalously strong along 30 to 35N. I was going over the 300mb, 500mb, and 700mb loops of the tropical Atlantic for the next week's worth of hours and across several runs of the GFS, there is indications of deep layer brick migrating W through the SW Atlantic Basin, across the Bahamas and west through the Gulf, in perfect tandem with "Felix's" probable forced S path. John |