Isaac is approaching the Gulf Coast as a Category 1 hurricane this evening with winds near 80 MPH. The storm will move inland across the Louisiana Coast after Midnight and continue moving Northwest through Louisiana Wednesday. Arkansas will stay dry through tomorrow, but some of the outer rain bands may approach Southern Arkansas by Wednesday Evening. The threat for heavy rainfall will increase rapidly Thursday as the storm pushes North toward Arkansas. Isaac will weaken rather quickly as it moves across land, likely dropping below tropical storm strength by Thursday morning. Below is the Tuesday 10 PM CDT forecast track for Isaac from the National Hurricane Center.
The track shows Isaac weakening to a tropical depression by the time it reaches Arkansas Thursday afternoon. It then moves North straight across Central Arkansas and it Northern Arkansas by Friday morning. This path would bring heavy rains across much of Central Arkansas Thursday into Friday with several inches of rain likely. The Hydro-Meteorological Prediction Center now shows a band of heavy rainfall right through Central Arkansas along and just East of the forecast center.
The forecast shows 3 to as much as 6 inches of rain for Central Arkansas. This forecast is not a lock though, as some of the forecast models show the center of Isaac going much farther West than indicated by the Hurricane Center track.
If the center goes near the Arkansas/Oklahoma border, Central Arkansas would likely still receive some heavy rainfall. Rainfall usually extends out farther from the East of the Center rather than West of the center due to the Gulf moisture drawn Northward on that side. If the center goes very far West, say over Texas and Oklahoma, then the amount of rain we receive would be put into question. Below is a computer model rainfall projection based on Isaac going across Central Oklahoma.
Notice how changing the path of the center just a little drastically changes the amount of rain over Central Arkansas. A track to the West also raises the concern for weak tornadoes, which sometime accompany mainly the Eastern side of tropical systems moving over land. Winds will be a minor concern, as Isaac will be below tropical storm strength as it moves over Arkansas, however, gusty winds to about 30 MPH will be likely, especially near and just to the East of the center.