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#799166 (Received by flhurricane at: 4:56 AM 29.Aug.2015) TCDAT5 TROPICAL STORM ERIKA DISCUSSION NUMBER 18 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052015 500 AM EDT SAT AUG 29 2015 Erika remains very disorganized with the deep convection still displaced well east and southeast of the apparent center. The initial intensity has been set at 35 kt based on the latest Dvorak classification from TAFB, and these winds are likely occurring well east and northeast of the center. Erika will have to contend with land interaction and strong shear for the next day or so, which should result in the cyclone weakening to a depression later today, if not dissipating entirely. Assuming Erika survives the next 24 hours, some restrengthening is possible over the Gulf of Mexico in a less hostile environment. The low-confidence NHC intensity forecast is similar to the previous one and below the latest intensity consensus. The disorganized center of Erika has been difficult to locate, but my best estimate of the initial motion is 290/17, with the center moving a little to the left of the previous forecast track. Erika should gradually turn toward the northwest and decelerate during the next 36 to 48 hours as it moves around the edge of the subtropical ridge. After that time a northward motion at an even slower forward speed is expected. The new NHC track has been adjusted to the left, especially during the first 48 hours, due to the initial position and motion, and is largely an update of the previous forecast after that time. The NHC forecast is close to the multi-model consensus through 48 hours and is between the consensus and the GFS model after that time. Given the uncertainty in the initial position and motion, and whether Erika even has a closed center, confidence in the details of the track forecast remains low. 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. 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 later today to see if the circulation of Erika has survived its interaction with Hispaniola. An Air Force Reserve Hurricane Hunter aircraft will be investigating Erika later this morning. There is a significant chance that no watches or warnings for Florida will be required. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 19.1N 75.1W 35 KT 40 MPH 12H 29/1800Z 20.3N 77.5W 30 KT 35 MPH 24H 30/0600Z 22.3N 80.3W 30 KT 35 MPH...INLAND 36H 30/1800Z 24.0N 82.1W 30 KT 35 MPH...OVER WATER 48H 31/0600Z 25.3N 83.2W 35 KT 40 MPH 72H 01/0600Z 27.0N 84.0W 35 KT 40 MPH 96H 02/0600Z 29.5N 84.5W 40 KT 45 MPH 120H 03/0600Z 31.0N 84.5W 25 KT 30 MPH...INLAND $$ Forecaster Brennan |