Friday, August 24, 2012

What next for Isaac?

UPDATE: As of LATE Friday morning, Isaac is a little stronger but remains disheveled. Even though there is plenty of rain with this system, most of it is to the south over the Caribbean Sea. Wind speeds have picked up somewhat, but the northern end of Isaac is being interrupted by the high terrain of Hispaniola. How much more strengthening Isaac will undergo remains to be seen.



Overnight recon detected a center that was being stretched out. Imagine if you will the core of a paper-towel roll, stand it up right, and that would be the center of a well organized storm. Good inflow at the bottom, and just like an exhaust, good outflow at the top.  In this case however, tilt the roll almost at a 45 degree angle and this is Isaac's center. It is elongated, stretched out, and with little organization.

About the only thing in its favor is the available fuel from the warm waters of the Caribbean Sea. Even with that NHC says it does not expect for Isaac to get that much stronger in the short term.

For the next day or two, it will aim for Haiti, Jamaica, and Cuba, and then.... this is where it gets interesting. Most models point it towards the Keys, but any slight deviation or change in forward speed, and those models could change. As a matter of fact, if the system keeps slowing down, it could give it a chance to grow stronger and nudge more in our direction.  DON'T LET DOWN YOUR GUARD.

From NHC earlier:

  • THE LONG TERM INITIAL MOTION ESTIMATE IS A HIGHLY UNCERTAIN AS THE INITIAL POSITION ESTIMATE IS BASED ON A BLEND OF RECENT FIXES AND CONTINUITY. 
  • THE TRACK MODEL GUIDANCE CONTINUES TO BE IN GENERALLY GOOD AGREEMENT ON THE RESUMPTION OF A WEST-NORTHWESTWARD AND THEN NORTHWESTWARD MOTION IN THE NEXT 24 HOURS AS THE SUBTROPICAL RIDGE NORTH OF ISAAC WEAKENS. 
  • THIS GENERAL MOTION SHOULD CONTINUE THROUGH DAY 4...WHEN A TURN MORE TOWARD THE NORTH IS SHOWN AS A SHORTWAVE TROUGH AMPLIFIES OVER THE MISSISSIPPI VALLEY. 
  • LATE IN THE PERIOD THE TRACK MODEL GUIDANCE IS IN BETTER AGREEMENT ON THIS SCENARIO...AS THE ECMWF HAS TRENDED EASTWARD TOWARD THE REST OF THE MODELS THIS CYCLE. 
  • THE NEW NHC FORECAST HAS BEEN ADJUSTED ABOUT A DEGREE SOUTHWARD IN THE FIRST 12 HOURS DUE TO THE INITIAL POSITION AND MOTION...AND IS THEN BLENDED BACK TOWARD THE PREVIOUS TRACK BY 48 HOURS. AFTER THAT TIME...THE NHC FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS ONE...AND IS BETWEEN THE ECMWF ON THE LEFT AND THE GFS AND TVCA CONSENSUS ON THE RIGHT. 


IT IS IMPORTANT NOT TO FOCUS ON THE EXACT TRACK DUE TO UNCERTAINTIES IN THE INITIAL LOCATION AND THE TRACK FORECAST...AND THE FACT THAT ISAAC HAS A LARGE AREA OF TROPICAL STORM FORCE WINDS ASSOCIATED WITH IT. 





Keep monitoring.

2 comments:

  1. OK YOU SAY IN YOUR BULLET POINT MOTION SHOULD CONTINUE UNTIL DAY 4, WHAT IS THE START SAY AND WHAT ARE YOUR PERSONAL THOUGHTS ON THE DIRECTION AND MOST OF ALL THANK YOU FOR WHAT YOU DO

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  2. Thanks anon. It should begin turning NW by Saturday. Once it leaves Cuba it depends where it will leave the island. To the east: more of an impact here. To the west, more for the West coast. NHC is favoring the west coast scenario, but anything is possible as it moves over Cuba's high terrain. It could act as a pinball in a pinball machine getting kicked around. Hope this helps.

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