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| #799118 (Received by flhurricane at: 10:50 PM 28.Aug.2015) TCDAT5 TROPICAL STORM ERIKA DISCUSSION NUMBER 17 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052015 1100 PM EDT FRI AUG 28 2015 Dropsondes from the NOAA P3 flying around Hispaniola were very helpful in locating the mean center of the broad circulation associated with Erika, which is moving over the high terrain of Hispaniola. There is plenty of deep convection associated with the cyclone, and gusts to tropical storm force are being reported in Barahona, on the south coast of the Dominican Republic. Given that the circulation is interacting with land, the initial intensity has been set at 40 kt. Erika is fighting both land and a hostile wind shear environment, and it will be very difficult for the cyclone to recover. Consequently, weakening in the short term is indicated in the NHC forecast, and there is a strong likelihood that Erika will degenerate to a tropical wave during its interaction with land. However, if it survives, there is a very small opportunity for Erika to regain tropical storm strength in the Florida Straits and the southeastern Gulf of Mexico, where the environment is less hostile. It is interesting to note, and to remember, the fact that most of the state-of-the art dynamical models were forecasting Erika to become a strong hurricane up to yesterday, and today basically dissipate the cyclone. The initial motion is uncertain, and the best estimate is toward the west-northwest or 285 degrees at 17 kt. It seems that Erika has changed very little in forward speed since its formation. However, the cyclone is reaching the southwestern edge of the subtropical ridge and the steering currents are weaker. Therefore, Erika is forecast to slow down and turn to the northwest in about two days. Once in the eastern Gulf of Mexico, a more northerly track is anticipated. There is not much track guidance available tonight since most of the models lose the circulation of Erika, and the NHC forecast is following the weak perturbation observed in the model fields. The greatest short-term threat posed by Erika continues to be very heavy rainfall over portions of Hispaniola and eastern Cuba. These rains could produce flash floods and mudslides. We must emphasize that although this would normally be an appropriate time for a tropical storm watch for portions of southern Florida, following typical timelines, we have elected to wait until we see if Erika survives after it passes Hispaniola. There is a significant chance that no watches or warnings for Florida will be required. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 18.5N 72.9W 40 KT 45 MPH...INLAND 12H 29/1200Z 20.0N 75.0W 35 KT 40 MPH...INLAND 24H 30/0000Z 22.0N 78.0W 30 KT 35 MPH...INLAND 36H 30/1200Z 23.5N 80.5W 30 KT 35 MPH...OVER WATER 48H 31/0000Z 25.0N 82.0W 35 KT 40 MPH 72H 01/0000Z 26.5N 83.0W 35 KT 40 MPH 96H 02/0000Z 28.5N 84.0W 40 KT 45 MPH 120H 03/0000Z 31.0N 84.0W 25 KT 30 MPH...INLAND $$ Forecaster Avila |
