Tuesday, September 02, 2008

Three Tropical Storms

Graphic Courtesy Hurricane City

T.S. Hanna: In what NHC describes as a "low confidence" forecast, it is said early this afternoon that --
There is nearly an equal probability of Hanna being a tropical storm or hurricane at day 3.
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Slow and erratic motion is expected today but Hanna should start moving Northwestward tonight or tomorrow.
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On the forecast track... Hanna is expected to approach the East Coast of Florida... Georgia... or South Carolina in 2 to 3 days. It should be stressed that the expected angle of approach and track uncertainty make it impossible to narrow down the potential impact area.
Ike has a compact and well-defined circulation.
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Model guidance remains in excellent agreement regarding the track of Ike. Most models... except for the GFDN... are tightly clustered within the first 48 hours then only slightly diverge beyond that to day 5. * * * We couldn't have asked for better agreement in the guidance.
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Given the small size of the system... it is probably more susceptible to the dry air and will probably remain so until it can develop just enough deep convection to isolate itself. The statistical-dynamical models such as the Ships and LGEM indicate gradual intensification to a hurricane before northeasterly shear increases over the system in 48 hours. The GFDL and HWRF apparently ignore such shear and forecast Ike to be a major hurricane in 3-4 days.
T.S. Jospehine:
Wind shear is essentially non-existent over the cyclone... so steady strengthening seems likely in the short term... and could be rapid... .
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Wind shear will probably increase in a couple of days... though all of the objective guidance calls for a weakening trend to start by 72 hours.
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Models are in very good agreement through 48 hours but then diverge markedly... with the GFS turning the cyclone westward and the GFDL and HWRF taking it northwestward.

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