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Emily slides west, still a threat for Hispaniola and Cuba

By: Dr. Jeff Masters, 7:37 AM GMT on August 04, 2011

As of 2AM EDT, Tropical Storm Emily was located at 17.1N, 71.3W, about 120 miles south-southeast of Port-au-Prince, Haiti. Emily was moving W at 5 mph with sustained winds of 50 mph. It's central pressure was estimated to be 1006 mb. Tropical storm warnings are in effect for the Dominican Republic, Haiti, the southeast and central Bahamas, the Turks and Caicos islands, and eastern Cuba.

Satellite imagery still shows that the majority of convection associated with Emily is east of the center of circulation.

Figure 1 IR Satellite image of TS Emily taken at 2AM EDT August 4, 2011

Emily and the Turn Northwards

According to the most recent forecast issued by NHC, Emily was forecast to be at 17.5N, 72.5W at 2AM EDT, which is a point 68 miles west-northwest of it's assigned location. This indicates that Emily is not curving northwards as expected. This makes me more skeptical of the computer model forecasts that pull Emily to the northwards sharply towards the southeast coast of Florida before recurving out to sea. All of the 00Z global models (NOGAPS, GFS, and CMC) are in rough agreement.

The forecast tracks provided by the suite of simpler models, the Beta and Advection Models and CLIPER, disagree. They have Emily taking a much more gradual turn to the north, thus moving northwest across Cuba. Given that these models have done a better job of predicting Emily's westwards track, I'm inclined to place more confidence in their predictions. However, the further west Emily goes, the chance that Emily makes landfall in Florida (due to a recurve) goes up. People with interests in Cuba and south Florida should keep an eye on this storm.

My opinion about forecasting Emily's intensity has not changed significantly from last evening's update. If Emily's circulation can survive the mountains of Hispaniola and/or the terrain of Cuba, conditions are favorable for moderate intensification.

The current NHC forecast is shown in Figure 2 and has Emily turning towards the north, passing through the western Bahamas before turning out to sea.

In terms of immediate impacts, 6-12 inches of rain are expected over Haiti, and the Dominican Republic, with 20 inches possible in isolated areas. Flash floods and landslides are expected to be major problems on Hispaniola. Tropical storm winds will reach Haiti today and could reach eastern Cuba later today. Port-au-Prince, Guantanamo and Santiago de Cuba would be good stations to monitor today.

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

Eastern Pacific

Eugene reached category 4 status with estimated winds of 140 mph earlier today. After that peak, Eugene started weakening and now has winds of 120 mph. Further weakening is expected as Eugene moves over cooler waters. Invest 97E is not looking as impressive as it was last night and has a 20% chance of becoming a tropical disturbance in the next 48 hours.

Western Pacific

Typhoon Muifa is now forecast to make landfall near Shanghai, China as the equivalent of a category 3 hurricane. This will be troublesome for one of the busiest ports in the world.

Figure 3 Five-day track forecast for Typhoon Muifa from the Joint Typhoon Warning Center.

Angela will have a full post Thursday morning discussing Emily.

Thanks for reading,

Dr. Rob Carver

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.