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Tropical Storm Emily forms from Invest 91L

By: Dr. Jeff Masters, 12:09 AM GMT on August 02, 2011

Tropical Storm Emily formed this afternoon after investigation by the Hurricane Hunters. While dodging the Lesser Antilles islands, the Hunters managed to find a closed surface circulation. Emily is currently located near 15.2°N, 62.0°W, and has maximum sustained winds of 40 mph. Thunderstorm activity has grown in size and intensity over the past 6 hours, and mid-level circulation is still elongated, but strong. The environment around Emily hasn't changed much from this morning. The moisture within the storm is still relatively high, although there continues to be a lingering dry, Saharan air mass to its north, which could become a factor in intensification. Wind shear is still high (30-40 knots) on the north side, as well.

Figure 1. Visible satellite of Tropical Storm Emily at 7:30pm EDT as it moves west into the Caribbean.

Forecast For Emily
The official track forecast is that Emily will continue to travel west-northwest through the Caribbean and cross Hispaniola Wednesday morning, after which it turns slightly more to the north for a potential landfall along the Florida east coast as a hurricane. Models continue to be split between Emily entering the Gulf of Mexico or recurving before making landfall along the East Coast. In the camp of an eastern Gulf of Mexico track are the CMC, NOGAPS, and the UKMET models. The ECMWF has been trending that way, as well. The GFS continues to favor a northwest track towards Florida before taking a turn to the northeast. The HWRF has been forecasting an eastern coast of Florida solution, and continues to do so in the 12Z run. The GFDL remains conservative and forecasts that the system will turn north and northeast well before making any connection with the U.S. coast. It is notable that although there is still much disagreement on where this system will go, but the models have been trending west in their tracks over the past few days. As the official track forecast from the National Hurricane Center illustrates, this is a U.S. landfall threat.

Figure 2. Official five-day track forecast for Tropical Storm Emily.

The National Hurricane Center forecasts that Emily will probably strengthen into a hurricane. In the 12Z runs, the GFDL brings Emily up to category 2 strength, and HWRF forecasts it to max out at category 1. DSHIPS (the SHIPS model that takes into account land interaction) forecasts maximum intensity of a moderate tropical storm. General consensus continues to be that Emily will reach a peak intensity somewhere between a moderate tropical storm and a moderate category 1 hurricane. Now that Emily has developed, and when the models ingest some data from the Hurricane Hunter missions, we will have more certainty in an intensity forecast.

Dr. Rob Carver might have an update later this evening, and I'll definitely be back tomorrow, early afternoon, with a new post on Emily.



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