…CENTER OF ISAAC NEARING THE COAST OF SOUTHEAST LOUISIANA…STORM
SURGE FLOODING ALREADY OCCURRING…
SUMMARY OF 600 PM CDT…2300 UTC…INFORMATION
ABOUT 15 MI…25 KM SSW OF THE MOUTH OF THE MISSISSIPPI RIVER
ABOUT 95 MI…150 KM SE OF NEW ORLEANS LOUISIANA
MAXIMUM SUSTAINED WINDS…80 MPH…130 KM/H
PRESENT MOVEMENT…NW OR 315 DEGREES AT 8 MPH…13 KM/H
MINIMUM CENTRAL PRESSURE…970 MB…28.64 INCHES
The Gulf of Mexico is loaded with oil rigs. Some have weather observing gear in use even while the rigs are unmanned. A few hours ago one in the Mississippi Canyon area reported a wind gust of 92 knots (106 mph).
The anemometer on this rig is up around 260 feet above the water line. Surface speeds though brutal are surely less.
Wind damage is caused by gusts, but hurricanes are ranked by their sustained wind. I have found no hurricane force sustained winds onshore or off. No big surprise. This is common.
There are probably some winds near NHC’s 80 mph reading for Isaac, now officially a hurricane. As is nearly always the case the official number will be higher than what nearly anyone gets¹.
In spite of Rush Limbaugh’s, “It’s the Democrats’ wet dream that this thing hit New Orleans,” no one wanted destruction like Katrina.
A little oceanography before we move on. There are three factors that build waves and move water: wind, time and fetch. A weaker storm can bring more water if it’s allowed to sit for a long time. Hurricane Isaac has slowed, so that’s now a concern, but again probably well below Katrina.
$15 billion has been spent shoring up New Orleans’ defenses. They’re still susceptible. Not as much.
This storm has turned into weather porn for The Weather Channel and to a lesser extent the cable news nets. If your reporter is literally on-the-beach don’t tell me how bad it is. If it was that bad he/she wouldn’t be on the beach.
I don’t expect Isaac to live up to its hype.
This is not to say evacuations aren’t necessary is some areas. They are and lives will be saved. There will be damage. There will be flooding. There will be post-Isaac news porn with visible destruction on TV.
It’s likely Isaac will parallel the Mississippi Delta’s western edge and not make landfall until sometime Wednesday. Last night I tweeted a Tuesday afternoon landfall. Guilty as charged. Not every forecast is right.
The Gulf of Mexico is beautiful. It is an idyllic location, but no one lives there without understanding the potential downside.
¹ – A notable exception was Hurricane Andrew.