Tropical Storm Don (Updated 8:30am CDT, 7/28/2011)

The National Hurricane Center has now extended the tropical storm watch down from Port Mansfield, TX (from last night) to Brownsville, TX.  A tropical watch means tropical storm force conditions (winds, seas, and precipitation) are possible within the next 48 hours.

Figure 1. Showing current tropical storm watches/warnings

Tropical Storm Don’s location and information:

Location: 29.0N 89.9W
About 545mi  ESE of Corpus Christi, TX
About 495mi ESE of Brownsville, TX
Max sustained winds: 40 mph, 65 km/hr
Present movement: WNW or 300 degrees at 10 mph, 17 km/hr
Minimum Central Pressure: 1000mb, 29.53 in.

Don continues to move towards the Texas coast.  According to water vapor imagery, Don will continue to move into drier air, which may slow it down or deform the storm a little bit.  Mid-level wind shear will be at a minimum ahead of Don, and sea surface temperatures (SST) are plenty warm for development.  Therefore, the only criteria that will hinder any fast development will be the subsiding air out ahead of it.  Forecast models are still in disagreement on intensity and location of this storm.  Many dynamical forecasting models still do not have this storm at tropical storm strength, or if they do, they have it dissipating quickly before making landfall.  The majority of the statistical, tropical models, on the other hand, do show strengthening a little.  For now, I am leaning towards the tropical models, unless I see otherwise in the next few hours.  Perhaps the reason for the confusion of the forecast tracks are:  being unable to locate a storm center and determining the area and strength of the mid-level ridge.

I will continue updating my blog throughout the day.

Figure 2. 12Z Water vapor imagery of the Gulf of Mexico. This image shows the drier air ahead of Don. This may hinder any further fast development of the storm. We'll have to see how this plays out.

Figure 3. 12Z 850mb Vorticity and my forecast path. Red lines represent possible areas of where the center of the storm could pass over.

Figure 4. 12Z Mid-level wind shear. Don is moving into an area with minimal wind shear. This may help it strengthen a little.

Figure 5. NHC's projected forecast track of Hurricane Don. Courtesy of: National Hurricane Center.

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About Brian

University of Oklahoma graduate with a degree in Meteorology. Follow me on Twitter: @WeatherInformer
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