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Tropical Storm Edouard Discussion Number 3

Statement as of 11:00 PM EDT on August 03, 2008

the maximum winds are set at 45 kt based on peak flight-level winds
of 54 kt and a visual estimate of 55 kt prior to 00z from the Air
Force reconnaissance aircraft. Since then...convection over the
center has largely diminished...and the earlier intensification
trend has no doubt stopped for the time being. Northerly shear is
still affecting the cyclone...and water vapor imagery shows some
mid-level dry air near and to the north of the center. Global model
guidance indicates that this shear should diminish over the next
day or so...and Edouard could find itself in a difluent upper
environment that would favor intensification as it moves into the
northwestern Gulf. The GFDL...SHIPS...lgem...and superensemble all
make Edouard a hurricane. The latter three models...however...are
heavily influenced by the recent strengthening trend...a trend
which is no longer occurring. Consequently...the official forecast
lies slightly below this guidance...bringing Edouard to just below
hurricane strength.

The initial motion is 270/4. The cyclone is expected to move to the
west and then west-northwest through landfall around the periphery
of mid- to upper-level high pressure over the south-central United
States. Model guidance is in good agreement on this scenario.
However...because Edouard is moving at a very oblique angle to the
coastline...small errors in the forecast track would result in
large differences in the landfall location. Consequently...and as
illustrated by the NHC wind speed probability product...the chances
of experiencing tropical storm conditions are roughly equal from
Morgan City all the way to Galveston Bay. The official forecast is
adjusted slightly north of the previous advisory and is close to
the center of a relatively narrow guidance envelope.

Forecast positions and Max winds

initial 04/0300z 28.1n 88.5w 45 kt
12hr VT 04/1200z 28.2n 89.7w 45 kt
24hr VT 05/0000z 28.6n 91.9w 50 kt
36hr VT 05/1200z 29.3n 94.1w 60 kt
48hr VT 06/0000z 30.0n 96.5w 40 kt...inland
72hr VT 07/0000z 31.0n 101.0w 20 kt...remnant low
96hr VT 08/0000z...dissipated

$$
forecaster Franklin