I suspect Isaac's track is still not carved in stone as far as Arkansas is concerned.
The latest track from the National Hurricane Center still shows Isaac coming up into south central Arkansas (Thursday afternoon), then through central Arkansas (Thursday night into Friday) and into north central Arkansas (Friday).
However, some of the latest computer models have been hinting that Isaac's track may be a little farther to the west. This is something we will need to watch in subsequent forecasts to see if there is a westward shift later on.
Of course, the effects of a tropical weather system spread out well away from where the center of the system is. This would mean that heavy rain would likely spread into southern Arkansas late Wednesday night into Thursday, and spread through most other areas from Thursday night through Friday, then taper off Friday night into Saturday.
The graphic below shows a general idea of rainfall amounts. Again, though, do not take the amounts and their positioning to be exact. If the track of Isaac shifts somewhat, so will the axis of heavy rain.
Note that the map does now show some rainfall amounts exceeding 6 inches. When we have excessive rainfall, maps like these are usually too low on the maximum amount.
With the current track, the greatest threat of tornadoes would be over the eastern half of Arkansas.
I will issue the next message early Wednesday morning.