Show Selection: |
#892633 (Received by flhurricane at: 11:10 AM 19.Jun.2017) TCDAT2 Potential Tropical Cyclone Two Discussion Number 4 NWS National Hurricane Center Miami FL AL022017 1100 AM AST Mon Jun 19 2017 The convective pattern of the disturbance has become better organized this morning with a ragged band that wraps more than half way around its center. The intensity is assessed at 35 kt based upon the Dvorak 2.5 CI number from TAFB. These winds are likely only occurring in the northern semicircle due to the very quick translational velocity of the system. Intensity model guidance is in good agreement that the environmental conditions may allow for some slight intensification in the next day or so with the system embedded within low vertical shear and an atmosphere that is marginally moist and unstable. Beginning in about 36 hours, however, the shear should go up to either moderate (if the GFS is correct) or high (if the ECMWF is correct) levels because of an approaching tropical upper- tropospheric trough. Because of this increasing shear, all guidance shows the system dissipating before 72 hr and so does the official forecast. An alternative scenario - given that the disturbance has tracked left, or equatorward, of the guidance thus far - is that it could remain south of guidance and dissipate over Venezuela and never reach the Caribbean Sea. The quick motion also makes it ambiguous as to whether the system has a closed, earth-relative circulation center. An Air Force Hurricane Hunter plane is scheduled to investigate the system later today to help in this determination. It is still anticipated that the system will become a tropical storm, but it may be running out of time if it interacts significantly with Venezuela. The system is moving toward the west at a very rapid 22 kt due to the fast low to mid-level tradewinds south of a strong Bermuda high. It is likely that a rapid motion toward the west or west-northwest will continue until dissipation. The official track forecast is based upon the HCCA corrected consensus technique and is slightly south compared with the previous advisory. FORECAST POSITIONS AND MAX WINDS INIT 19/1500Z 8.8N 56.8W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 12H 20/0000Z 9.5N 59.7W 40 KT 45 MPH...TROPICAL CYCLONE 24H 20/1200Z 10.6N 63.1W 40 KT 45 MPH 36H 21/0000Z 11.7N 66.6W 35 KT 40 MPH 48H 21/1200Z 12.6N 70.6W 35 KT 40 MPH 72H 22/1200Z...DISSIPATED $$ Forecaster Landsea |