Hopefully, you got a good night's sleep. Now is the time to put your hurricane checklist into effect.
The bottom line is that I believe a major hurricane (categories 3, 4, 5) will strike the northern Gulf coast sometime Tuesday night or Wednesday morning.
A hurricane watch (purple) has been issued for part of the area but I do not believe it extends far enough west. So, I have added my area of concern to the map.
Let me hasten to add that the odds are roughly the same in the entire blue interval. It is too soon to know whether the eye will cross the coast at Appalachicola or New Orleans or somewhere in between.
There is dangerously warm water in the Gulf, especially over the middle and western thirds of the projected corridor I expect the eye to travel. Note that the light blue shading is the path of the eye, not the distribution of the winds. I'll have more on the wind distribution via the graphics below. A special thanks to Dr. Ryan Maue for his excellent depiction of the models' output.
A tornado risk will develop in the northern Gulf region coast on Tuesday: If you don't have a weather radio or other source of tornado warnings -- even if the power is out -- now would be a good time to purchase one.
Here are several scenarios. Unfortunately, none are good.
The model consensus is that storm intensity will be from category 2 to borderline 4. Why do I allow for the possibility of an even stronger storm? It is because there is extremely warm water under Isaac if it takes the more western path and we know from experience the models are far from perfect when forecasting intensity. So, given the very warm water, an even stronger storm is possible.
If you are on a vacation or business trip to the area: Get out. Now. If you are flying, here is my Airline Crisis Survival Guide. Do not be passive. If you are in, say, Gulfport and the flights are full, ask the airline if they can give you a confirmed reservation out of Mobile. Or, drive inland to Jackson or New Orleans. Just get out.
For residents of the hurricane watch...
If you are in one of the coastal counties in the hurricane watch or area of concern, it is time to make preparations for evacuating, if an evacuation is ordered.
If you are within 50 miles of the coast, now is the time to be thinking about that generator you've always thought about purchasing or -- at minimum -- a power inverter. The latter will keep your laptop and cell phone charged. It can also be used to keep, for example, a small refrigerator on from time to time (keep the door closed!) to keep essential medicine chilled.
Less than 15 days' on your prescription medicine? Get it refilled immediately. In an evacuation, you, your doctor, and your pharmacist will all be in different places. Go ahead and spend the money, you'll use the medicine eventually. This is even more true if you have an Rx for a controlled substance. It will be extremely difficult to get that refilled if on the road.
Get the car filled with gas. You'll need it to run the inverter and/or evacuate.
There are numerous hurricane watch/warning checklists. Get one from the web and then start accomplishing the items that pertain to you.
Good luck. Be patient.