Above is a recent image from the radar site at Key West, FL. The center of Tropical Storm Isaac is located approximately at the tip of the white arrow. This is about 104 nautical miles to the East/Southeast of Key West. You can view this and other images, including animations, at our dedicated Isaac webpage.
As of the 7am CDT/8am EDT National Hurricane Center (NHC) advisory, maximum sustained winds were estimated at 65 mph, and the minimum central barometric pressure was 29.38 inches.
Isaac is moving toward the West/Northwest at about 20 mph. This general motion is forecast to continue in the near term, with a gradual reduction in speed likely as the system becomes better organized.
Isaac is forecast to become a hurricane later today, possibly before reaching the Florida Keys, where a Hurricane Warning continues in effect. Needless to say, all preparations should be complete in this area, as conditions will worsen throughout the day and into tonight.
The "official" NHC forecast then calls for Isaac to enter the southeast Gulf of Mexico during the pre-dawn hours Monday as a hurricane:
The forecast track beyond Monday comes into question, as the consensus of all major computer models has been shifting quite a bit to the left (or West) with the past few runs, with most now focusing on the region from southeast Louisiana to the Mississippi coast for a landfall of the center:
At this time, I feel that the track of the center of Isaac will be to the left of the NHC forecast for Tuesday and Wednesday, near the left side of the white "cone" on their track forecast image. It is important not to focus just on the location of the center, as tropical storm and hurricane conditions will be felt far away from the center, particularly on the "right" (or East) side of the system.
Hurricane Watches were issued for New Orleans, Eastward to the Florida panhandle with the last NHC update, and folks in this region definitely need to prepare for hurricane conditions by Tuesday to Wednesday.
A big negative here is that Isaac will be traveling over very warm waters of the eastern Gulf of Mexico for the next 3 days. This water has been undisturbed since late June and is primed to assist in the rapid intensification of a system such as Isaac.
I believe Isaac will become a major hurricane before landfall, possibly category 3 or even higher based on the latest data. Fortunately, we have a couple of days to monitor this situation, but that's why I'm concerned that folks in the Hurricane Watch area take the matter seriously and prepare for a likely major hurricane. Please take action now if you live in this region, do not wait until it's too late.
Furthermore, if you live in an area along the Louisiana, Mississippi or Alabama coasts, as well as the western portion of the Florida panhandle that is typically evacuated during a category 2 or stronger hurricane, please make sure to have your preparations complete so that you can leave the area before Tuesday.
Back to the near term, spiral bands associated with Isaac will impact much of central and southern Florida today, with locally heavy rainfall and a chance of tornadoes. A Tornado Watch was recently issued for this area:
Rainfall amounts in excess of 6 inches are possible through Tuesday in portions of southern Florida, with heavy rain increasing to the North with time along the central and eastern Gulf Coast:
Keep in mind that the northern and central Gulf Coast portion of the heavy rainfall forecast above is likely to spread further West than indicated by the above image, especially if Isaac tracks further West as I am expecting.
I will issue another detailed post here on the blog later today, and you can also find shorter posts on twitter and facebook throughout the day as well.
For additional information, including the latest satellite and applicable radar imagery, etc., please check out the dedicated page on our sister site, WeatherGuidance.com.
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