Current Location: 14.5N, 39.2W
Geographic Reference: 1455 miles east of St. Lucia
Movement: West at 15 mph
Max Winds: 50 mph gusting to 65 mph
Current Hurricane Severity Index: 3 out of a possible 50 points (1 size, 2 intensity)
Max Predicted Hurricane Severity Index: 9 out of a possible 50 points (3 size, 6 intensity)
Current Radius of Tropical Storm-Force Winds: 50 miles
Max Predicted Radius of Tropical Storm-Force Winds: 80 miles
Organizational Trend: Slowly Strengthening
Forecast Confidence: Average
Key Points
1. Isaac is predicted to strike the central Lesser Antilles as a hurricane early on Thursday morning.
2. Weakening is expected in the Caribbean due to strong wind shear.
Our Forecast
Satellite imagery indicates that Isaac is a relatively small tropical storm. Our forecast takes Isaac to hurricane strength over the next 48 hours as it tracks nearly due west. Isaac is predicted to track in between St. Lucia and Martinique late Wednesday night as a hurricane, but there is considerable uncertainty as to its intensity as it nears the Caribbean. Increasing wind shear could cause Isaac to drop below hurricane strength as it nears the islands. Once in the Caribbean, Isaac is predicted to track a little south of west. Steadily increasing wind shear should weaken Isaac to a remnant low in 6-7 days. Currently, long-range models do not indicate any threat to the northwest Caribbean or the Gulf of Mexico.
Expected impacts on Land
Central Lesser Antilles: Widespread power outages are expected within about 45 miles of the center, along with moderate structural damage. Flooding and mudslides are likely to cause some damage and travel delays.
Our next advisory will be issued by 4 PM AST / 3 PM CDT.
Meteorologist: Chris Hebert
| Forecast Confidence: Average | Hurricane Severity Index | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Fcst Hour | Valid | Lat. | Lon. | Max Sustained Winds | Max Gusts | Category | Size | Intensity | Total |
| 0 | 9AM CDT Sun Sep 09 | 14.50N | 39.20W | 50 mph | 65 mph | Tropical Storm | 1 | 2 | 3 |
| 24 | 9AM CDT Mon Sep 10 | 14.80N | 44.50W | 65 mph | 75 mph | Tropical Storm | 2 | 3 | 5 |
| 48 | 9AM CDT Tue Sep 11 | 14.60N | 50.70W | 75 mph | 85 mph | Category 1 | 3 | 5 | 8 |
| 72 | 9AM CDT Wed Sep 12 | 14.70N | 56.70W | 80 mph | 90 mph | Category 1 | 3 | 5 | 8 |
| 84 | 9PM CDT Wed Sep 12 | 14.90N | 59.60W | 85 mph | 100 mph | Category 1 | 3 | 6 | 9 |
| 96 | 9AM CDT Thu Sep 13 | 15.40N | 63.00W | 70 mph | 80 mph | Tropical Storm | 2 | 4 | 6 |
| 108 | 9PM CDT Thu Sep 13 | 15.40N | 66.40W | 60 mph | 70 mph | Tropical Storm | 2 | 3 | 5 |
| 120 | 9AM CDT Fri Sep 14 | 15.40N | 69.20W | 40 mph | 50 mph | Tropical Storm | 1 | 1 | 2 |
| 144 | 9AM CDT Sat Sep 15 | 14.90N | 75.00W | 30 mph | 40 mph | Tropical Depression | 0 | 0 | 0 |
| 168 | 9AM CDT Sun Sep 16 | 14.20N | 79.60W | 30 mph | 35 mph | Remnant Low | 0 | 0 | 0 |
The yellow cone represents track error from the previous five hurricane seasons. Over the past five hurricane seasons, the center of the storm tracked within the yellow cone 75% of the time. The cone does not represent the forecast uncertainty in the current advisory for this storm. In addition, hurricane-force winds, very high tides, large waves, and heavy rainfall can often extend well outside the yellow cone.
