Tropical Storm Isaac continues to move through the Florida Straits this morning with 65 MPH winds and a very slowly lowering central pressure. There are lots of watches and warnings in effect, and Isaac's effects will be felt in Florida through the day and evening today.
Here's the storm on satellite as of 8:45 AM EDT, with a pretty noticeable lack of defined organization:
Here's the forecast track from the NHC (as of 11AM) and stats on the storm (as of 8AM):
Here's a breakdown of the watches and warnings, which are in effect for both coastal AND inland areas...
-The red shading is a hurricane warning.
-The blue shading is a tropical storm warning.
-The salmon-y colored shading is a hurricane watch.
-The yellow shading is a tropical storm watch.
Here's Isaac as seen from the Key West, FL radar, with the center of circulation circled in red. The strongest winds (sustained 65+ MPH winds) are in the storms right around the center.
Rather than giving a long essay on why this is such a tough forecast and why there are so many unknowns, I'll do this instead...
- A hurricane will make landfall somewhere along the northern Gulf Coast on Tuesday night or Wednesday.
- Isaac isn't too terribly organized at the moment, but it is strengthening. If it's able to get an internal structure in order, the following bullet point is extra valid...
- Isaac has the potential to rapidly strengthen once it hits the highly favorable atmosphere and very warm waters of the Gulf.
- Isaac is a very large storm, so even if you're not in the path of the center, you could still feel all the impacts of a tropical system.
- The models are still in disagreement as to where Isaac will make landfall. In just 24 hours they shifted from Panama City to southern Louisiana, and everywhere in between.
- Those who live in evacuation zones from New Orleans to Panama City FL need to be prepared to take immediate action with little notice.
- Tornadoes are possible in parts of the southeast each day as Isaac approaches land. While they won't be huge, even a small EF-0 tornado could be deadly if it lobs debris at you.
- Anything can happen.
The 12z models are showing the potential for the storm to go a lot further west than was originally planned, by having it go into parts of southern Louisiana. Since the models keep changing so much, I expect this, too, to change.
Remember...a Gulf Coast landfall is still three days away. Lots can and will change between now and then.
I will continue updating this diary as a liveblog as needed throughout the day.
National Weather Service San Juan PR
National Weather Service Tampa FL
National Weather Service Key West FL
National Weather Service Miami/South FL
National Weather Service Melbourne FL
National Weather Service Tallahassee FL
National Weather Service Mobile AL
National Weather Service New Orleans LA
7:58 AM PT: The NHC has shifted the track west to a Gulfport/Biloxi, MS landfall, as of 11AM. Waiting on the updated forecast track image.
8:04 AM PT: Forecast track updated not two minutes ago. New Orleans metro is now included in the hurricane watch. The NHC is indicating extreme uncertainty right now in the forecast after tomorrow.
THE TRACK FORECAST BEYOND DAY 2 HAS BECOME PROBLEMATIC. DYNAMICAL MODELS DEPICT THE CYCLONE MOVING INTO A BREAK IN THE SUBTROPICAL RIDGE NORTH OF THE GULF COAST IN ABOUT 72 HOURS. HOWEVER THERE IS A LARGE SPREAD AMONG THE MORE RELIABLE TRACK MODELS. FOR EXAMPLE... THE ECMWF FORECAST IS ABOUT 300 N MI EAST OF THE GFS SOLUTION AT DAY 3. SINCE THE DYNAMICAL MODEL CONSENSUS HAS SHIFTED WESTWARD...THE OFFICIAL TRACK FORECAST IS MOVED A BIT TO THE WEST OF THE PREVIOUS ONE. THIS REQUIRES AN EXTENSION OF THE HURRICANE WATCH WESTWARD ALONG THE LOUISIANA COAST. IT SHOULD BE NOTED THAT THERE IS GREATER THAN USUAL UNCERTAINTY IN THE TRACK FORECAST.
THROUGHOUT THE PERIOD...IT IS IMPORTANT NOT TO FOCUS ON THE EXACT FORECAST TRACK SINCE SIGNIFICANT HAZARDS EXTEND WELL AWAY FROM THE CENTER.
Many are asking why this tropical system is so hard to forecast… the answer is that ALL of them are hard to forecast. In the Internet/social media world, you are just seeing the men “behind the curtain” and data as it comes in to us. It has always been this way.
10:27 AM PT: The center of Isaac is now very visible on radar imagery out of Key West, and it's starting to develop what appears to be a bit of an eyewall:
10:51 AM PT: The general consensus of this morning's model runs is that a slow-moving major hurricane will hit Louisiana. This could (and probably will) change, but it's concerning nonetheless.
"MANDATORY evacuation now in effect for Grand Isle, LA. Everyone must leave by 9AM Monday."