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#898619 (Received by flhurricane at: 10:38 PM 16.Aug.2017) TCDAT3 Hurricane Gert Discussion Number 17 NWS National Hurricane Center Miami FL AL082017 1100 PM AST Wed Aug 16 2017 Gert has maintained an eye with very cold cloud tops mainly over the northern and western portions of the circulation, which is rather remarkable for a system at 40N latitude. The current intensity is set a little higher, to 90 kt, in agreement with the latest Dvorak estimates from TAFB and SAB. The cyclone has continued to traverse warm waters, but very soon will encounter a much cooler ocean to the north of the Gulf Stream. Thus, rapid weakening is forecast, similar to the latest model consensus. In 36 hours the global model guidance depicts the system becoming embedded in a distinct baroclinic zone, so Gert should have become an extratropical storm by that time. The extratropical cyclone is forecast to merge with another large low over the north Atlantic after 72 hours. Gert has continued to accelerate and is now moving east-northeastward near 32 kt. A slightly faster motion is expected on Thursday in the strong flow to the southeast of a mid-tropospheric cyclone nearing Newfoundland. Later in the forecast period, the post-tropical system is likely to turn northeastward and slow down significantly while it interacts with the other large low. The track, intensity, and wind radii forecasts have incorporated guidance from NOAA`s Ocean Prediction Center. Swells from Gert should continue to affect the northeast U.S. coast and Atlantic Canada through Thursday. These swells are likely to produce dangerous surf and rip current conditions. Please consult products from your local weather forecast office for more information. FORECAST POSITIONS AND MAX WINDS INIT 17/0300Z 40.1N 58.4W 90 KT 105 MPH 12H 17/1200Z 42.6N 52.1W 75 KT 85 MPH 24H 18/0000Z 46.5N 43.8W 60 KT 70 MPH 36H 18/1200Z 50.5N 38.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 48H 19/0000Z 52.5N 35.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 72H 20/0000Z 53.5N 31.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 21/0000Z...DISSIPATED $$ Forecaster Pasch |