What's Off The Coast of SC?

[Guest]

http://iwin.nws.noaa.gov/iwin/images/ecirloop.gif

What's the blob off SC? Could this be the 4th system to form off the coast of the Carolinas this season?

Also, look at the spinning system sitting on top of the Bahamas!

[PurdueWx80]

That's an upper level low over the Bahamas - it has been there for several days and hasn't budged. It will play some part in the ultimate fate of Frances, what yet, is too early to speculate. If it stays there all day it will ventilate her, but also probably steer her further north. The "blob" off the SC coast is just a blow up of thunderstorms along a convergence zone left behind by Gaston. This happens with nearly every tropical system. It won't develop.

[Cookiely]

That spinning "blob" has been ahead of Frances for quite some time. I noticed it a couple of days ago.

[Guest]

Thanx Purdue. "Ventilate", does this mean that it will weaken Frances? Thanks for the lessons!

[PurdueWx80]

Ventilation is what creates the outflow - it is good if the storm wants to keep developing. Helps keep the thunderstorms from choking themselves. If Frances and the low are too close to one another, the upper low imparts shear that would tend to weaken her. There was a similar upper low with Charley that simply moved right out of the way and stayed in a perfect position for ventilation.

[Guest]

Yikes. It would seem that if Frances were a weaker system that the upper low would help to steer the hurricane; in this case, sounds like Frances just blows past the upper low and continues on a forward path? In this vein, isn't it possible that the stronger the storm the less likely it is to be affected by steering mechanisms like troughs/ridges?