AL14 (Future Michael), Earthquakes, and other stuff

Several big events over the last two weeks, especially the earthquake/tsunami in Indonesia and the earthquake in Haiti yesterday evening.  And more Pacific tropical stuff.  Have been swamped with research stuff and will try to catch up over the next day or two, but getting lots of queries about the storm off of Belize so will say a few words about that first.  Here’s the noon Sunday satellite view …

Other than gusty winds, for the Caribbean threat is mostly to the west end of Cuba as the storm makes its way out into the Gulf over the next day or so.  The 11am NHC Advisory package for Tropical Depression 14, which will likely reach tropical storm status and be named Michael this evening, has landfall on the Gulf coast of Florida sometime Wednesday.  For those of you who just can’t live without your daily dose of pasta, here’s a look at some of the major forecast model track guidance guidance NHC was taking in to account in creating this forecast.  Some show landfall as far west as Mobile Alabama, some as far east as the “Big Bend” area of Florida, near Steinhatchee.  The big dynamic models bring the storm in as a Hurricane, so if you are on the Gulf Coast pay attention. The overall impacts depend a lot on the track – one of those “duh” things meteorologists like to say.  The further west, the more likely effects will be confined to the coast near landfall, and the storm will degenerate over land.  Further east, especially for a “back door” type storm that makes landfall on the Gulf Coast, exits or skirts the coast of GA/SC/NC, it’s a more widespread problem. 

Just a brief rant (again, sigh) about showing track models maps, especially those sites who show all of the individual tracks as the haze of lines.  Lets look at that brown line on the map above in more detail. Here is JUST the GFS Ensemble model and the members of that ensemble.  So in simple terms the way this works is that the model is run a number of times (in this case 20) using “perturbed” (different) initial conditions based on the uncertainty in the storm position and characteristics, with an averaging program run to get the average track.  The individual runs are interesting for understanding the uncertainty of the forecast, but treating them as “equal probability” outcomes is misleading – and it’s just plain wrong to go ZOMG THE AP20 RUN SHOWS A DIRECT HIT ON SAVANNAH as if that is a stand alone forecast equal to something like HMON or especially the consensus track models (much less the human-assisted official NHC track).  So I’ll say it again: be sure your pasta is cooked by a real chief and chew well before swallowing it 😛

NHC is more or less splitting the difference (as does the consensus model blend) and takes the storm over Panama City.   Fortunately we’re not looking at a Florence/Harvey kind of “move just lnland and stall” scenarios, this looks to be the typical “landfall and move on” 24hr kind of event.  Here’s the impact swath based on the official NHC track forecast (which, as I often rant, is the only thing you should really worry about) …

Notice how broad the wind field gets after landfall, and the big swath of 40mph+ winds that are offshore.  This is typical for a storm that accelerates rapidly after landfall.  For those in Georgia and SC, don’t freak out over maps like this that show the storm as a tropical storm well inland.  First, as you can see here, the strongest storms will likely be well away form the center, and mostly confined right on the coast.  Second, NHC tends to overestimate the inland winds from an impact standpoint.  (said in a different way, while it is true there might be a small patch of winds of tropical storm force 24 hours after landfall, it isn’t likely to be as widespread as models and graphics based on their forecast show).  That’s fine for planning purposes, but don’t get too upset over it just yet.  Again, small changes in this track can produce big changes in impacts, so watch for the official watches and warnings.  A direct hit on the Panama City area by a Category 1 hurricane could be messy – current impact estimates are around $4.5 Billion, but it’s so early that number isn’t very reliable.

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