| typhoon_tip |
| (Meteorologist) |
| Fri Aug 31 2007 09:44 PM |
Re: Tropical Depression #6 Forms East of Caribbean
|
Quote:
been reading that too with Obs. from Barbados.. was wondering with the NICE CDO we have now with TD6, could it be a TS now? or was the winds a thing of TD and strong westerlies coming together, to give some good winds to the island?... Some of the 00Z runs are coming out... nice little shift showing up?One thing i have noticed, seems to me that this time the center of the high will be forming off the New England area, instead of more to the south where the last one was with Dean? Anyone else seeing this... I KNOW its way down the road, but looking at the globals... seems like this may be a little different setup then Dean? On time will tell, but with the shift showing up in a 00z runs... (ones i have seen so far)... this might be something we need to watch closely.... **I know the models will jump around a lot until we they get a good handle on the system and the surrounding enviroment***
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