DT wrote:that was a nice hypothesis... but a couple of things...
did we go through this once before? was the dry air suppose to Kill off Isabel this morning then this afternoon?
the analogy to Gordon is kind of stretch... Gordon was MUCH closer to the coast and MUCH smaller in size and was barely at any time a cat 1 hurricane. Arguably Gordon was not.
Moreover arent you carrying the point too far? aren't MOST east coast Mid or late sept hurricanes surrounded by dry air as the near the east coast?
Didnt you also declare Claudette dead in the Gulf too?
Actually the cold front in Isabel's path is very similar to the situation with Gordon in 2000. Sure Gordon was barely a Cat 1, but that shouldn't make any dfference. No, Isabel was not forecast to weaken previously because of dry air entrainment. Wind shear disrupted Isabel's outflow to the west 24 hours ago. No, most east coast late September hurricanes do not have to travel THROUGH a mass of cold air enroute land. This situation is unique.
This is not just a pocket of mid-level dry air out in the middle of the tropics. This is truely a different airmass along the east coast. The air temperatures in the Carolinas and Virginia are in the 50s (low to mid 60s on the coast). Wind is blowing offshore, so the front is not retreating. Taking a look at this morning's WV shot, the dry air has just about replaced that one patch of moisture east of Florida. But, again, it's not just the mid-level dry air, it is the cool, dry surface air over the Carolinas that should be increasingly ingested by Isabel as it approaches the coast.
Once the air is ingested, the immediate effect would be to shut down Isabel's core of convection. This would prevent further intensification and lead to steady weakening. Next, the wind field would expand outward away from the center (this is already happening to a degree, though not entirely due to CAA into the center). Then Isabel's pressure would steadily rise and she would gradually wind down from the current intensity. True, Isabel is not a weak storm like Gordon was. It'll still be a large low pressure area with a large radius of gales, but it won't have the core of 100+ mph winds if the cold air is ingested.
I don't think Isabel will be reduced to just about nothing as Gordon was, but it could be reduced to a strong TS with a very large radius of TS-force winds at landfall.
The thing to watch will be dew points along the coast ahead of Isabel in the next 12-24 hours. If that front retreats northwestward and the CP air along the coast is replaced by MT air, then it shouldn't bother Isabel too much up to landfall.
Noticed your in FB..they said TS winds are possible there but not likely this point 
