Issued at 1100 AM AST Sun Sep 16 2018 413 WTNT43 KNHC 161443TCDAT3Post-Tropical Cyclone Helene Discussion Number 37NWS National Hurricane Center Miami FL AL0820181100 AM AST Sun Sep 16 2018Helene's cloud pattern has transformed into that of anextratropical cyclone, with a large area of cold cloud topslocated well to the north and northwest of the center. An ASCATpass that caught the eastern portion of the circulation revealedmaximum winds of 40 to 45 kt, therefore the initial wind speedremains 45 kt for this advisory. The global models suggest thatthe system will strengthen slightly today due to baroclinicprocesses, and this is reflected in the official forecast.Weakening is anticipated by late Monday, and the system is forecastto be absorbed by a larger low pressure to the northwest of theUnited Kingdom by Tuesday morning.The cyclone is moving quickly northeastward or 055/25 kt. Now thatthe system is embedded within the mid-latitude westerlies, anortheastward motion with some additional increase in forward speedis expected over the next day or so. The global models remain ingood agreement on the track of the post-tropical low, and the newofficial forecast is an update of the previous advisory.This is the last NHC advisory on this system. Interests in Irelandand the United Kingdom should consult products from their localmeteorological service for information about potential impacts fromthe post-tropical cyclone. Local forecasts and warnings for the UKcan be found on the website of the UK Met Office athttps://www.metoffice.gov.uk/. Local forecasts and warnings forIreland can be found on the website of Met Eireannat https://www.met.ie/.FORECAST POSITIONS AND MAX WINDSINIT 16/1500Z 43.8N 25.7W 45 KT 50 MPH...POST-TROPICAL 12H 17/0000Z 45.8N 21.2W 50 KT 60 MPH...POST-TROP/EXTRATROP 24H 17/1200Z 49.0N 14.8W 50 KT 60 MPH...POST-TROP/EXTRATROP 36H 18/0000Z 52.8N 6.2W 40 KT 45 MPH...POST-TROP/EXTRATROP 48H 18/1200Z...ABSORBED$$Forecaster Brown

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