Ed Mahmoud wrote:Googled Hazel on Wiki at lunch to grab the track of a mid-October storm that hit the East Coast for the "season winding down" thread. Aircraft found, per Wiki, 150 mph winds just before landfall in the Carolinas, and Hazel was declared extra-tropical after landfall, and after that, produced a 113 mph wind gust in NYC, still the record for a gust.
Now, I know the 2007 heat potential map may not be all that similar to the 1954 map, but I am rather certain, based on my knowledge of Sputnik and all, satellite temperature/heat content maps of 1954 are unavailable. But is there really enough heat potential for a storm to become a Cat 4 just offshore the Carolinas?
Now, Hazel is still distinct from the front as it makes landfall, but I'm wondering how much enhancement it might have been getting from the approaching trough.
There's no way to get a truly good idea about the extent of BE without reconnaissance data or satellite imagery. You wouldn't be able to get a good idea about how far along it was in the ET process unless there was a clear indication of it in the network of surface and ship observations, and at that point in time, it was likely a tenuous proposition.
I think of other Northeast storms of late September and October. The 1938 New England hurricane supposedly had a forward speed of 50 mph. That is well embedded in the jet, I'd dare say, and was probably well on the way to extratropical transition, even if it wasn't yet interacting with a front. I doubt it had a symmetric windfield, and I'd guess if satellite had been available, I doubt it would have looked much like a classic tropical cyclone.
No storm moving with a forward speed of 50 MPH is going to have a symmetric ground-relative wind field! As to whether the storm was maintaining it's structure as a TC rather than transitioning to an ET, It would depend upon the mean layer wind field. I've seen some storms that have maintained their structure longer than others while becoming embedded in the westerlies. Other times (and I'd say more often) the system elongates and transitions to ET rather quickly because of increasing shear in the form of stronger winds aloft than at the lower and mid levels.
The bottom line here is...one can doubt and suppose all day and night, however without any hard data as your evidence, you won't get (m)any converts.
So, where does one draw the line between baroclinic enhancement and extra-tropical transition?
Pretty easily actually. BE implies intensification via forced ascent, and
does not necessitate any sort of transition. For example, the interaction of a TUTT trough/low and a T-wave in the deep tropics can be considered a form of BE.
On the other hand, ET can occur with or without intensification. Some storms intensify, others weaken, depending upon the position of the jet, SSTs, etc. For example, when a strong hurricane has gained enough latitude to recurve into the westerlies, some weakening (in the form of lowering of the MSW and/or rising of the MCP) is more likely to occur along with an expansion of the overall wind field/gale radii during ET.
