Melissa track shifting west?

Throughout the morning and early afternoon, Melissa has continued on a slow wobbly track west. At the 11am forecast, NHC shifted a lot west for the first 12 hours then less so later in the track. Here is the 5am ET forecast (cyan/purple) , the 11am forecast, and the position fixes as of 2pm ET:

A couple things to notice. First, how the actual position fixes don’t follow a straight line. It is important to realize that the hurricane eyewall isn’t some solid object rolling along – it is a dynamic line of intense thunderstorms that is constantly forming and reforming. And that’s not even considering eyewall replacement cycles (link to Wikipedia) or other phenomena. As noted previously, these position fixes (especially those at 2am, 8am, 2pm, and 8pm EDT, the “synoptic time” fixes) are vital for feeding to the computer track models.

While the overall “big picture” of who should or should not evacuate/take shelter isn’t influenced much by these wobbles, the damage, and especially the overall economic impact, is – a lot. The difference between the track last night, which took the eye wall over Spanish Town, and the 11am track, is enormous – the new track is “only” 6 or 7 Billion dollars, the one last night was nearly $16 billion! Here is a zoom view of the damage swath from the 11am forecast using my TAOS(tm)/Lachesis impact model that generates those estimates:

The more recent computer models shift the track a bit more, they may shift even more this evening, but the last few automated fixes might be showing the turn as of 3pm ET.

This said, don’t be deceived that these small shifts – if they hold up, and the storm doesn’t wobble back to the east, means Jamaica is going to be spared. This is maybe the difference between “unimaginable” and “utterly horrific.” It will take another further 60 or more miles of westward movement, and the turn staying about the same angle – before eastern Jamaica sees wind damage levels really tail off – and of course the rain is causing a disaster all on it’s own. However, any reduction of potential impacts over the extremely vulnerable Kingston area is welcome. Of course then we have to worry about the Cayman Islands, Central Cuba, and potentially the Central Bahamas in addition to the Eastern Cuba and the Southern Bahamas …

We’ll just have to watch and see what happens.

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Some of you asked what happened to the donation link, it’s still active on the about page, but I don’t link it on pages discussing major disasters – just doesn’t feel right. Others have asked who to donate to for post-storm relief, I’m doing some catching up to check on who is reliable at the moment (organizations change over time and it’s been a long time since I’ve worked in Jamaica).