749
WTNT45 KNHC 300835
TCDAT5

Tropical Storm Isaac Discussion Number  18
NWS National Hurricane Center Miami FL       AL102024
900 AM GMT Mon Sep 30 2024

Isaac continues to show signs of transitioning into an extratropical
cyclone.  The central convection has mostly dissipated, and the
system is taking on more of a frontal appearance, with a
zonally-oriented cloud and rain shield over the cyclone`s northern
semicircle.  The current intensity is kept at 55 kt in accordance
with a Dvorak estimate from TAFB, although this is somewhat
uncertain since Isaac no longer appears to be a true tropical
cyclone.

The cyclone continues to move east-northeastward or at about 060/13
kt within a southern branch of the mid-latitude westerlies.  Isaac
is expected to turn toward the northeast during the next couple
of days as it approaches a shortwave ridge just west of the
British Isles.  The official track forecast has been nudged only
slightly eastward in the 2-3 day time frame, towards the latest
corrected dynamical model consensus.

Isaac is moving over cool waters and should complete its
extratropical transition today.  The global models suggest that the
system will gradually weaken during the next few days as it becomes
absorbed within a larger low over the North Atlantic.  The official
intensity forecast is similar to the previous NHC prediction.


FORECAST POSITIONS AND MAX WINDS

INIT  30/0900Z 44.7N  31.3W   55 KT  65 MPH
 12H  30/1800Z 45.8N  28.1W   50 KT  60 MPH...POST-TROP/EXTRATROP
 24H  01/0600Z 47.4N  25.1W   45 KT  50 MPH...POST-TROP/EXTRATROP
 36H  01/1800Z 49.4N  23.3W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  02/0600Z 51.3N  22.3W   40 KT  45 MPH...POST-TROP/EXTRATROP
 60H  02/1800Z 53.0N  21.2W   35 KT  40 MPH...POST-TROP/EXTRATROP
 72H  03/0600Z 54.5N  20.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  04/0600Z...DISSIPATED

$$
Forecaster Pasch