View Full Version : Post-Tropical Cyclone COLIN Forecast Discussion Number 9

06-07-2016, 11:40 AM
Issued at 1100 AM EDT TUE JUN 07 2016 000 WTNT43 KNHC 071459 TCDAT3 POST-TROPICAL CYCLONE COLIN DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL032016 1100 AM EDT TUE JUN 07 2016 Satellite and surface observations indicate that Colin has become post-tropical. A pressure minimum has recently passed near NOAA buoy 41013, but the circulation has become so elongated and ill defined that the system can no longer be considered a tropical cyclone. However, strong winds are still occurring along the North Carolina Outer Banks, so advisories will continue on a post-tropical cyclone until these winds subside. The minimum pressure has fallen a few millibars and recent buoy observations have recorded tropical-storm-force winds near the western portion of the deep convection. Assuming stronger winds are occurring within the deep convection and given the fast translational speed of the system, the initial wind speed is increased to 50 kt. The global models indicate that the post-tropical cyclone will deepen due to baroclinic processes during the next day or so, and the NHC intensity forecast calls for some additional strengthening. After that time, the low is expected to gradually weaken over the North Atlantic. The forecast intensities and wind radii of the extratropical low are based on guidance provided by the Ocean Prediction Center. The post-tropical cyclone is moving northeastward at about 31 kt. This general motion with some additional increase in forward speed is expected during the next 24 to 36 hours. After that time, the cyclone should slow as it moves around and is eventually absorbed by a larger low over the North Atlantic. FORECAST POSITIONS AND MAX WINDS INIT 07/1500Z 34.0N 77.0W 50 KT 60 MPH...POST-TROPICAL 12H 08/0000Z 36.9N 70.5W 55 KT 65 MPH...POST-TROPICAL 24H 08/1200Z 41.0N 61.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 36H 09/0000Z 45.0N 53.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 48H 09/1200Z 48.0N 49.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 72H 10/1200Z 51.5N 42.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 11/1200Z 53.5N 36.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 12/1200Z...Absorbed $$ Forecaster Brown

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