Issued at 1100 AM AST Fri Sep 14 2018 774 WTNT43 KNHC 141441TCDAT3Tropical Storm Helene Discussion Number 29NWS National Hurricane Center Miami FL AL0820181100 AM AST Fri Sep 14 2018Conventional satellite imagery and a 1147 UTC METOP-B AMSUmicrowave image show a deep convective curved band wrapping aroundthe surface circulation in the west semicircle. Additionally, arecent 1148 UTC ASCAT-B scatterometer pass indicates that Helene isa little stronger than earlier estimated. The data showed a numberof 60 kt winds in the northeast quadrant. Based on these data,Helene is still classified as a tropical cyclone, and the initialintensity is bumped up to 60 kt for this advisory.The large-scale models and the statistical intensity guidanceindicate little change in strength during the next 36 hours or so.After that time, some gradual weakening is forecast as Helenecompletes extratropical transition while passing just to the northof the Azores Islands. The ECMWF, UKMET, and the CMC all showHelene absorbed by a larger baroclinic system just beyond the 72hour period, as the cyclone moves over Ireland and the UnitedKingdom.The initial motion is estimated to be northward, or 010/20 kt,within the deep-layer southerly flow produced by a mid-tropospherictrough to the west. A north-northeast to northeast turn is expectedover the weekend as the cyclone quickly moves within themid-latitude westerlies. Only a slight adjustment to the left ofthe previous track forecast was made through 48 hours. The NHCofficial forecast is based primarily on the TVCN multi-modelconsensus.An orange wind warning is in effect for the Azores, equivalent to atropical storm warning. Tropical Storm conditions with gusty windsand heavy rains are likely over the weekend as Helene passes theislands, regardless of whether the cyclone is a tropical storm orpost-tropical.Helene is expected to be a post-tropical cyclone when it approachesIreland and the United Kingdom in a few days. Interests in thoselocations should consult products from their local meteorologicalservice for information about potential impacts from Helene. Localforecasts and warnings for the UK can be found on the website of theUK Met Office at https://www.metoffice.gov.uk/. Local forecastsand warnings for Ireland can be found on the website of Met Eireannat https://www.met.ie/.FORECAST POSITIONS AND MAX WINDSINIT 14/1500Z 32.9N 36.3W 60 KT 70 MPH 12H 15/0000Z 35.5N 35.5W 60 KT 70 MPH 24H 15/1200Z 38.4N 33.4W 55 KT 65 MPH 36H 16/0000Z 40.7N 30.0W 50 KT 60 MPH 48H 16/1200Z 42.7N 25.7W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 17/1200Z 47.4N 16.1W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 18/1200Z...ABSORBED BY FRONT$$Forecaster Roberts

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