Saturday, September 4, 2004


FRANCES MOVING WEST TOWARD WEST PALM BEACH-FORT PIERCE AREA.

EYE SHOWS SIGNS OF TIGHTENING AS IT COMES ONSHORE
RAINFALL ESTIMATES CONTINUE CLIMBING

The hurricane center says that storms of this size usually don't fluctuate in strength, but we cannot always rule out sudden changes in a storm, no matter what historical or climatological averages indicate. After watching the radar closely, and following the upper air patterns, I believe it will strengthen to Cat 3 before landfall. Stalling only allows this monster to further stabilize after being disrupted by the Bahamas and the dry air that got sucked in from the westside. The potential strengthening is also alluded to in the 5:00 PM NHC hurricane discussion.

If you've been watching CNN in the past hour, there is a phenomenon that was briefly explained that may result in the storm strengthening as it moves on shore. It is called "frictional effects" and as pointed out by Accuweather forecasts, is partly responsible for why Tropical Storm Gaston seemingly held intact as it moved over Virginia, although the NHC downgraded the storm.

As the core of the hurricane moves onshore, the friction between land and the storm can cause thunderstorms to actually enhance around the eyewall. The increased uplift in the eyewall can then cause it to tighten up briefly, which increases the wind speeds. So what might be observed are brief wind gusts well above Category 2 strength, and a temporary increase in sustained winds to Category 3 as the main core crosses the coastline.

As of 8:30 PM, winds in Melbourne, FL are sustained at 50-60 mph with 100 mph just offshore. The duration of hurricane force winds will exceed 6 hours for many of these areas. This will put tremendous stress on many buildings, and even though the storm will weaken, the combination of torrential rain and constant battering of waves plus 6 or more hours of 75 mph+ will cause many roofs to be ripped off and the subsequent collapse of those buildings.

POTENTIAL FOR SURPRISE TROPICAL STORM DEVELOPMENT ON
MID-ATLANTIC COAST LATER THIS WEEK... JEANNE JOINS IN.

Strange as it may seem, but the arrival of Frances may spawn the development of a tropical storm by Wednesday or Thursday just off the coast of Virginia. Thunderstorms are already flaring up in this region at present, as indicated on this satellite loop. Here's why I think this has potential:

- The northwest movement of the hurricane has advanced tremendous tropical moisture very close to the Eastern seaboard. This moisture is feeding into an area of 80 F+ waters.

- The top of the hurricane has what is called "outflow" which actually spins clockwise at 35,000 or more feet aloft. This is the moisture that has spiraled upward through the storm and is being exhausted out the top. This outflow extends very far to the north, almost to the NC coast.

- The tremendous outflow is buffeting again the clockwise motion of the high pressure ridge in the northern Atlantic, which is providing low level easterly winds into Frances.

- There is no fast-moving front in the Mid-west ready to push Frances or anything else out to sea anytime soon.

- Thus this whole arrangement of the slow movement of Frances, the lack of a front, and the placement of the high has created another nook of atmospheric instability northeast of the hurricane and southeast of the Chesapeake Bay, about 300 miles out. This has been a breeding ground for tropical systems this year, and it may happen again.

The expected time frame for this event would be a development occuring possibly Wednesday, and as the high slowly moves out, it provides a return flow around the backside which will create a steering current. Were this system to be named, it would be Jeanne, and it would move northwestward at first, then recurve north and then northeast on Thursday or Friday. This would not be a hurricane, but then again, it's been a season of surprises.

Once Frances makes her way permanently into the mainland US in Alabama/Georgia, we will see if this potential development begins to show signs. And then there is IVAN the terr.. okay, not yet. The press is going to so overuse this one that I won't get it started too soon. Mark your calendars for Monday, September 14.

Please feel free to forward this site address to any friends or family you have along the coast from New York on down to Brownsville, TX because we have lots of hurricane season left in front of us.

I would like to retract something said earlier in the posts, simply because I think it was inaccurate to say that the eastern coastal counties would be less prepared for this than they were for Charley. I now think the reverse is true, and I applaud the efforts of the probably-very-exhausted emergency management officials for their work. (Please note: I chose to make this retraction, not because someone called me on it.)

Next update Sunday morning.


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