Tropical Storm Isaac continues moving west-northwest into the open waters of the eastern Gulf of Mexico this morning. The pressure has decreased and winds are at 65 mph, and it’s signature on satellite has been improving:
The storm should become a hurricane by later today. Overnight hurricane track model guidance (all model images shown below are powered by Weatherbell Analytics, http://www.weatherbell.com/) has nearly overwhelmingly clustered on the southeast coast of Louisiana:
What’s even more concerning, is that most models have the storm slowing down and even stalling as it approaches the coast. Here’s the European from last night showing the storm moving very little over a 24 hour period from early morning Wednesday through early morning Thursday:
Wednesday, 3 am local time:
Thursday, 3 am local time:
Some models even take this to a category 4 (145 mph) as it approaches the coast, as shown by the latest HRWF:
While this is surely overdone, a category 2 or even category 3 storm is a possibility. Take this and combine it with the slow down in forward speed as it approaches the coast, and it’s a recipe for disaster in New Orleans, which is below sea level. This is different from Katrina, because although it may be weaker overall, it will likely be strengthening as it approaches the coast (Katrina was weakening), and it’s coming in from the southeast, increasing the threat of storm surge up the mouth of the Mississippi (Katrina was from the south).
The bottom line – although a major hurricane is a possibility, even if this storm comes ashore as a weaker category 2, a prolonged storm surge and copious amounts of rain could be just as bad as Katrina for New Orleans.
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