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#880161 (Received by flhurricane at: 4:15 AM 21.Nov.2016) TCDAT1 TROPICAL DEPRESSION SIXTEEN DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL162016 400 AM EST MON NOV 21 2016 The cloud pattern associated with the low pressure system located over the southwestern Caribbean Sea has become better organized over the past 12 hours, including the development of some banding features. An Air Force Reserve reconnaissance aircraft yesterday between 1900-2000 UTC indicated that the low had a well-defined circulation center, along with flight-level winds of 38 kt and SFMR surface winds of 32-34 kt in no-rain areas. Since that time, an intense convective burst with cloud tops of -88C developed near the center between 0400-0500 UTC, which likely helped to spin up the inner-core circulation a little more. In addition, ship C6VG7 located 90-100 nmi southeast of the center has been reporting winds as high 38 kt at an elevation of 34 meters, which adjusts to a 10-meter wind of 30-32 kt. Although cloud tops have warmed since that earlier strong convective burst occurred, the overall convective cloud pattern has improved since the recon flight yesterday. Therefore advisories are being initiated on this system as a 30-kt depression, which could be conservative. The depression has been meandering in the same general area for the past 12 hours or so, and little motion is expected today and early Tuesday while the cyclone remains trapped within a blocking ridge pattern. By 36-48 hours, an east-west oriented ridge is forecast by the global models to develop across the Greater Antilles and the Bahamas, which is expected to nudge the depression in a slow westward direction for the remainder of the forecast period, with landfall possibly occuring after 72 hours. The system is expected to move across Central America and into the eastern North Pacific by 120 hours as a remnant low. The NHC official forecast track lies close to the various consensus model forecasts. Marginal environmental conditions are only expected to support slow strengthening for the next 36 hours or so. After that, the moderate vertical wind shear currently affecting the cyclone is forecast to decrease to less than 10 kt while mid-level humidity values increase to more than 70 percent. This should allow for the depression to strengthen into a hurricane by 72 hours before landfall occurs. By 96 hours, the cyclone is expected to be inland over Central America and undergoing rapid weakening due to the interaction with the mountainous terrain of that region. The intensity forecast closely follows the consensus intensity model IVCN. FORECAST POSITIONS AND MAX WINDS INIT 21/0900Z 11.5N 79.4W 30 KT 35 MPH 12H 21/1800Z 11.4N 79.4W 35 KT 40 MPH 24H 22/0600Z 11.4N 79.5W 40 KT 45 MPH 36H 22/1800Z 11.4N 79.8W 45 KT 50 MPH 48H 23/0600Z 11.3N 80.5W 55 KT 65 MPH 72H 24/0600Z 11.3N 82.0W 65 KT 75 MPH 96H 25/0600Z 11.3N 84.7W 45 KT 50 MPH...INLAND 120H 26/0600Z 11.0N 88.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Stewart |