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| #880230 (Received by flhurricane at: 9:57 PM 21.Nov.2016) TCDAT1 TROPICAL STORM OTTO DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL AL162016 1000 PM EST MON NOV 21 2016 Deep convection continues to burst over the low-level center of Otto. A 2329 UTC WindSat microwave overpass shows that the inner-core structure of the small tropical cyclone has become better organized with a low-level ring feature now evident. Dvorak data T-numbers from SAB and TAFB have increased to 3.0 and 3.5, respectively, and objective T-numbers from UW/CIMSS are 3.2. These data support an initial wind speed of 50 kt, which could be somewhat conservative. The upper-level outflow remains well established over the western and northern portions of the circulation but it remains restricted to the southeast due to southeasterly shear of 15 to 20 kt. The shear is forecast to abate a little during the next couple of days while Otto traverses SSTs of around 29C. These conditions favor intensification and the NHC forecast is near a consensus of the SHIPS and LGEM models, and brings Otto to hurricane strength within 36 hours. Although the NHC forecast does not indicate strengthening between 48 and 72 hours, Otto could become a little stronger after 48 hours and before it moves inland over Central America in about 3 days. After that time, uncertainty remains as to whether the tropical cyclone will survive its crossing of Central America. The NHC forecast continues to show the system as a remnant low over the eastern Pacific, which is supported by most of the global models. Center fixes from the microwave imagery indicate that Otto has been drifting southward this evening. The cyclone is not expected to move much overnight while it remains within an area of weak steering currents. On Tuesday, a mid-level ridge is forecast to begin building to the north of the storm and Otto is forecast to start moving slowly westward. The ridge is expected to remain in place during the remainder of the week and Otto should continue to move generally westward at a slightly faster pace. The new NHC track forecast is similar to the previous advisory, and lies between the latest GFS and ECMWF solutions, which is also near the most recent GFS ensemble mean. FORECAST POSITIONS AND MAX WINDS INIT 22/0300Z 10.9N 79.1W 50 KT 60 MPH 12H 22/1200Z 10.8N 79.3W 55 KT 65 MPH 24H 23/0000Z 10.9N 79.8W 60 KT 70 MPH 36H 23/1200Z 11.1N 80.7W 65 KT 75 MPH 48H 24/0000Z 11.3N 81.5W 70 KT 80 MPH 72H 25/0000Z 11.3N 84.0W 70 KT 80 MPH...INLAND 96H 26/0000Z 11.3N 87.2W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 27/0000Z 10.8N 90.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Brown |
