When these tropical systems are over open ocean it is hard to get a lot of data to ingest into the models.
In its 11 a.m. Thursday update, the National Hurricane Center said satellite imagery indicated that Isaac remains a poorly organized tropical cyclone, with the low-level center mostly exposed during the past several hours.
It's a detail that almost got lost among all the wind, rain and storm surge data sent out by the National Hurricane Center on Wednesday.
As of 2 p.m., the slow-moving storm barely had Category 1 hurricane strength and was nearly at a standstill over southeastern North Carolina, according to the Associated Press.
Isaac was moving west Wednesday afternoon at a speed of nearly 17 miles per hour.
Isaac had winds of 60 miles per hour, and the hurricane center said gradual weakening is anticipated over the next few days.More news: Bob Woodward's book Fear: Trump in the White House released on Kindle
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A high-surf advisory is issued when breaking wave action poses or is expected to pose a threat to life and property within the surf zone.
"A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 12 to 24 hours".
However, experts remained unsure midday Wednesday where the storm would make landfall in the Carolinas.
Cameras outside the International Space Station captured dramatic views of rapidly strengthening Hurricane Florence at 8:10 a.m. EDT Sept. 10 as it moved in a westerly direction across the Atlantic, headed for a likely landfall along the eastern seaboard of the USA late Thursday or early Friday.
Florence, however, continues to threaten the east coast as a fierce storm that could trigger flooding as far south as Georgia.
On Thursday, Florence was a Category 3 hurricane on the five-step Saffir-Simpson scale with 120-mph winds (193 km).
For the first time since 2008, there are four named storms in the Atlantic. These conditions could allow for regeneration of the system as it approaches Cuba and the Yucatan Peninsula, but given the uncertainty in whether Isaac will survive long enough to take advantage of these conditions, the official forecast still calls for dissipation, the NHC said. A watch is typically issued 48 hours before tropical-storm-force winds are expected to arrive, which makes outside preparations hard or unsafe - and Tropical-storm-force winds are possible within the tropical storm watch area today. While early on Wednesday the odds of it forming dropped, by afternoon forecasters had again increased the chance to 70 percent over two days.