ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM TROPICAL STORM COLIN DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL032016 400 PM CDT MON JUN 06 2016 Colin does not look much like a tropical cyclone in satellite imagery this afternoon. The center remains well removed from the showers and thunderstorms, and the reconnaissance aircraft data has found the strongest winds about 200 n mi southeast of the center. The highest flight level winds measured by the aircraft have been 63 kt with SFMR surface winds of 40 kt. Since the plane did not fully sample the convective band, the initial intensity is kept at 45 kt. The global models continue to significantly deepen the cyclone during the next 24 to 48 hours, which is likely due to the interaction of the system with a mid- to upper-level trough that is currently moving southeastward over the Midwest. The intensity forecast calls for an increase in wind speed during the next 24 to 36 hours, then gradual weakening as an extratropical cyclone after day 2. Colin's initial motion is north-northeastward, or 030/20 kt. The cyclone is forecast to accelerate northeastward as it moves along the coast of the southeastern United States later tonight and Tuesday. A continued rapid northeastward motion is expected as the cyclone moves over the North Atlantic within strong southwesterly flow ahead of the aforementioned trough. The track guidance has changed little during first 24 to 36 h, but has shifted northwestward after that time. The NHC forecast has been adjusted accordingly, and is closest to the 12z ECMWF. Due to the displacement of the strong winds and heavy rainfall from the center of Colin, it is important to not focus on the exact forecast track, or on the time or location of landfall. Heavy rainfall, strong winds, and coastal flooding are already affecting much of Florida and portions of the southeast United States. It should be noted that Colin could lose its status as a tropical cyclone while impacts are still occurring along the coast. In this case, NHC will continue to issue advisories and warnings on the post-tropical cyclone. FORECAST POSITIONS AND MAX WINDS INIT 06/2100Z 28.8N 85.5W 45 KT 50 MPH 12H 07/0600Z 31.7N 81.8W 45 KT 50 MPH...INLAND 24H 07/1800Z 35.2N 75.0W 50 KT 60 MPH...POST-TROPICAL 36H 08/0600Z 39.4N 66.3W 55 KT 65 MPH...POST-TROPICAL 48H 08/1800Z 43.0N 58.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 09/1800Z 48.5N 43.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 10/1800Z 53.0N 32.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 11/1800Z 56.5N 28.0W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown NNNN