Clark
(Meteorologist)
Fri Sep 03 2004 02:05 AM
Re: Frances

Hi Colleen --

Typically around these storms, you'll see a lot of dry air. As I mentioned in either a previous post or another thread, there is a lot of rising motion inside the core of the hurricane. However, to keep the atmosphere in balance, there must be an equal amount of sinking motion outside of the core of the storm. Some of this is found in the eye, whereas the rest is found outside the storm.

Thus, oftentimes when looking at water vapor with powerful hurricanes, you will see a lot of dry air around the storm. This can even appear to move towards the storm at times. However, it rarely impacts the strength of the storm as it is a natural by-product of the storm itself. Yes, it is true that all instability (like storms) is designed to restore stability, and that over time,a storm will fill (weaken) on it's own, but the impact of this dry air towards causing that isn't a very big one.

A note about the storm for the board --

The overall symmetry of the storm has improved over the past couple of hours. The storm has resumed a more WNW path, as the NHC expected in their 4pm conference call. I've learned that trying to interpret wobbles over water is a fool's errand -- it usually only leads to you to misjudge what is really going on with the storm. It usually takes a couple-few hours of sustained "wobbling" to suggest that a direction has changed. Though, as we've learned, a little wobble can make a big difference; see Charley for a prime example.

Give the storm another 6 hours and it might start to get its act together once again. It's nearing the longer islands of the Bahamas, but moving slowly. If anything, I think the slower motion - despite interaction with land - could help restrengthen the storm as a result of more consistant inflow patterns (even if they are being affected by land). I don't expect a lot of restrengthening - and I use that term as I expect the winds to be more in the cat. 3 range at 11pm - but some is possible. Let's not go wild with the cat 5 or dissipation posts now; neither is very likely to happen. Near the status quo through landfall is about where we should be looking.

Things are still looking primed for a secondary landfall in the Florida panhandle somewhere, but we have another day or two to figure the particulars of that out. Only recently have the models begun to agree on a east coast landfall location; let's see what happens in the next day or so before going any further than that.



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