Hurricane Isaac Discussion Number   8
NWS National Hurricane Center Miami FL       AL102024
500 PM AST Fri Sep 27 2024

Isaac's satellite presentation has improved since this morning. A 
small ragged eye can be seen on infrared imagery with cooler cloud 
tops surrounding it. An AMSR2 microwave pass from earlier today 
showed the mid- and low-level centers co-located with a primary 
band in the northwestern quadrant. Both the SAB and TAFB subjective 
Dvorak classifications suggested that Isaac's intensity has 
increased. Objective guidance aids are also suggesting the same. 
Taking all of these into consideration, the intensity has been 
increased to 75 kt.

The hurricane is moving eastward at 14 kt. Isaac is moving in the 
mid-latitude zonal flow and will gradual turn to the east-northeast 
later today. In about a day or so, Isaac will begin interacting with 
an upper-level trough to its east and turn more northeastward and 
slow down. The latest track forecast is very similar to the previous 
forecast, however, the day four and five track positions were 
adjusted westward as the model guidance has been shifting in this 
direction.  

Isaac is close to its peak intensity as the window for strengthening 
is ending soon. By Saturday, it will move over cooler waters, into 
an area of strong vertical wind shear, and a dry mid-level airmass. 
The peak intensity has been adjusted upward to 80 kt because of the 
recent strengthening.  On Saturday, Isaac is expect to gradually 
weaken and this trend will continue for the reminder of the forecast 
period. Simulated satellite imagery from the global models show 
Isaac losing its deep convection by Monday and the official forecast 
now predicts the hurricane to become a post-tropical cyclone by 60 
h. 

FORECAST POSITIONS AND MAX WINDS

INIT  27/2100Z 37.8N  45.3W   75 KT  85 MPH
12H  28/0600Z 38.8N  42.7W   80 KT  90 MPH
24H  28/1800Z 40.3N  39.8W   75 KT  85 MPH
36H  29/0600Z 41.8N  37.9W   70 KT  80 MPH
48H  29/1800Z 43.1N  36.3W   65 KT  75 MPH
60H  30/0600Z 44.4N  34.5W   60 KT  70 MPH...POST-TROPICAL
72H  30/1800Z 45.7N  32.7W   50 KT  60 MPH...POST-TROPICAL
96H  01/1800Z 50.1N  29.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  02/1800Z 52.9N  27.3W   35 KT  40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Bucci/Rosado