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#873245 (Received by flhurricane at: 4:59 AM 29.Aug.2016) TCDAT4 TROPICAL DEPRESSION NINE DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092016 500 AM EDT MON AUG 29 2016 The satellite presentation of the depression is quite ragged this morning, with little deep convection over the southeastern Gulf of Mexico or Straits of Florida. The thunderstorm activity that was located to the east and southeast of the center yesterday afternoon and evening, has propagated southwestward and is now located over Cuba and the extreme northern Caribbean Sea, well south of the center due to moderate to strong northerly shear. Data from a NOAA Hurricane Hunter aircraft have been very helpful in locating the low-level center overnight, and wind reports from the aircraft indicate that the depression still has winds of 25 to 30 kt. The intensity forecast for the depression remains of lower confidence than normal. The strong northerly upper-level winds currently over the system are forecast to decrease today, and the depression should be in a more conducive upper-level environment for a day or two. However, the global models indicate that dry mid-level air will remain near and to the northwest of the system, and that, combined with the current poor organization of the depression, suggests that any intensification should be slow to occur during the next day or so. After 48 hours, the upper-level winds should turn southwestward and become more diffluent over the system due to a mid- to upper-level trough that will be digging southward over the eastern United States. This could result in a little more favorable environment, and the NHC forecast calls for gradual intensification between 72 and 120 hours. The NHC forecast remains on the conservative side, and is between the more aggressive statistical guidance and the global models, which do not significantly deepen the system until it moves into the western Atlantic. The aircraft fixes indicate that the depression is moving generally westward at about 8 kt. The tropical cyclone should move westward to west-northwestward today to the south of a low- to mid-level ridge. The depression should turn northwestward and then northward around the western portion of the ridge on Tuesday. After that time, the aforementioned digging trough should begin to steer the cyclone northeastward at a faster forward speed. Most of the track guidance is in agreement with this scenario, although there are some differences on how fast the system will move northeastward toward the Florida peninsula. The update NHC track is close to a consensus of the global models, and is not very different than the previous NHC advisory. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 23.5N 83.9W 30 KT 35 MPH 12H 29/1800Z 23.7N 85.0W 30 KT 35 MPH 24H 30/0600Z 24.1N 86.3W 35 KT 40 MPH 36H 30/1800Z 24.7N 87.1W 35 KT 40 MPH 48H 31/0600Z 25.4N 87.3W 40 KT 45 MPH 72H 01/0600Z 27.8N 85.3W 45 KT 50 MPH 96H 02/0600Z 30.5N 81.0W 50 KT 60 MPH 120H 03/0600Z 33.0N 74.0W 55 KT 65 MPH $$ Forecaster Brown |