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#892658 (Received by flhurricane at: 4:46 PM 19.Jun.2017) TCDAT2 Tropical Storm Bret Discussion Number 5 NWS National Hurricane Center Miami FL AL022017 500 PM AST Mon Jun 19 2017 An Air Force WC-130 invest mission this afternoon into the disturbance was able - after much effort - to find a well-defined closed circulation. The location of the center was substantially farther west than anticipated, as the system is now moving toward the west-northwest at a very quick 26 kt. Because the system has developed a well-defined center, it is now considered a tropical storm and has been named Bret. Convection continues to display robust bands on the northwestern and southeastern quadrants of the disturbance, as seen in the geostationary satellite and Trinidad radar imagery. The Hurricane Hunter mission also found maximum surface winds of about 35 kt, which agrees with the Dvorak 2.5 CI number from TAFB. These winds are only occurring in the northern semicircle due to the very quick translational velocity of the system. While the convective structure has been impressive today, it appears that the window of opportunity for the system to further develop is closing. Between interaction with the landmass of Venezuela and increasing vertical shear beginning in about a day, the intensity model guidance does not show any significant intensification. The official intensity forecast is steady state for about a day, followed by gradual weakening until dissipation in about three days. An alternative scenario - given that the disturbance has tracked left, or equatorward, of the guidance thus far - is that it could remain south of the forecast track and dissipate over Venezuela and never reach the Caribbean Sea. The system is anticipated to slow somewhat, but still move at a rapid rate toward the west-northwest until dissipation, steered by strong trade winds south of the Bermuda high. The official track forecast is based upon the HCCA corrected consensus technique and is faster compared with the previous advisory, due to the farther west initial position. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 9.4N 59.8W 35 KT 40 MPH 12H 20/0600Z 10.1N 62.1W 35 KT 40 MPH 24H 20/1800Z 11.3N 65.3W 35 KT 40 MPH 36H 21/0600Z 12.2N 68.5W 30 KT 35 MPH 48H 21/1800Z 13.0N 73.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 22/1800Z...DISSIPATED $$ Forecaster Landsea |