The large, sprawling Tropical Disturbance we've all been following these past few days now appears much better organized and is quickly consolidating into a Tropical Depression.
Although certainly large and impressive looking (for a disturbance), 94L hasn't been particularly organized quite yet, nor has the convection been especially deep, being seemingly confined, thus far, to a linear banding feature stretching in an east / west line south of what appears to have been several competing low level circulation centers.
Well, all that has certainly changed today, with the disturbance taking on a much more symmetrical appearance, and a dramatic increase in convective organization, especially in the SE quadrant, as clearly portrayed in this animated visible satellite imagery.
You can easily see the massive flare-up of thunderstorms in the SE quadrant, as well as a general increase in shower bands forming in all quadrants, with thunderstorms also beginning to pop in curved cumulus streets in the NW quadrant.
Also of note in this animated imagery is a pretty decent outflow channel developing in the southern semicircle, quickly whisking away the cirrus debris from the underlying convection and shunting it off to the SW.
Interestingly, deep convection near and over the tight spiral of the currently exposed low level circulation have been paltry, at best, with only a few, transient, moderate storms intermittently flaring up.
But especially apparent is the Overall Increase in Organization of the Disturbance and the Rapidly Developing Symmetry of the system in general, as shown from the beginning of the loop to it's last frame, late in the day (local time), which also accentuates the blowup of thunderstorms to the SE, and their sharply increasing curvature during the time frame depicted.
All in all, I'd have to say that, after loosely languishing for a few days, 94L is quickly "getting it's act together", and is looking more and more impressive by the hour.
And, now that the nascent cyclone is entering the overnight convective maximum cycle, when thunderstorms usually attain their greatest proportions and coldest cloud tops, I'd expect to see a massive flare-up of "bursting" convection, with cloud tops of -70 to -80 degrees and colder, building closer and closer to the LLCC.
And when THAT happens, it imparts a MASSIVE quantity of energy to the developing cyclone, as enormous amounts of heat is released into the atmosphere (the release of latent heat of condensation), which, in turn, causes the gradual development of a true warm core, lowering surface pressures, stiffening the low level winds by several notches, causing even more surrounding warm air of very high CAPE (convective available potential energy) to continue to spiral in towards the center, initiating a positive feedback mechanism that continually escalates the entire process, and Viola !! Cyclogenesis.
Like many of you, I've got 'a feeling in my bones' that this just might be a storm we'll all remember for some time to come. Time will tell, but with each model run, and the track shifting progressively further west before a turn to the north, this looks to be a storm the US needs to very much keep appraised of.
One last thing: I find the name "Isaac" to be very telling. Can anyone guess WHY ?? (Hint: Something that happened well over a century ago.)
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