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#939251 (Received by flhurricane at: 4:39 PM 09.Sep.2018) TCDAT3 Hurricane Helene Discussion Number 10 NWS National Hurricane Center Miami FL AL082018 500 PM AST Sun Sep 09 2018 Deep convection has increased in coverage and intensity over the southern portion of the circulation, and microwave imagery suggests that an inner core is beginning to develop. Helene`s maximum winds are boosted to hurricane strength, 65 kt, based on Dvorak Current Intensity numbers from SAB and TAFB. The cyclone should continue to traverse warm waters and be in a low-shear environment for the next couple of days. Therefore, additional intensification is called for during the next 48 hours. Afterwards, increasing south-southwesterly shear should cause gradual weakening. The official intensity forecast is close to the model consensus, IVCN. Helene is moving just north of due west, or 280/11 kt. There are no significant changes to the track forecast philosophy for this advisory. Helene should move generally west-northwestward along the south side of a weak mid-level ridge for the next couple of days. After that, a mid-level trough digging along 40W-45W longitude should induce a turn toward the northwest and eventually north. The official track forecast is very similar to the one from the previous cycle through 72 hours, and is nudged a little to the east after that time. This is fairly close to the latest corrected consensus guidance, HCCA. FORECAST POSITIONS AND MAX WINDS INIT 09/2100Z 13.4N 26.0W 65 KT 75 MPH 12H 10/0600Z 13.9N 28.1W 75 KT 85 MPH 24H 10/1800Z 14.5N 30.8W 85 KT 100 MPH 36H 11/0600Z 15.2N 33.3W 90 KT 105 MPH 48H 11/1800Z 15.9N 35.5W 90 KT 105 MPH 72H 12/1800Z 18.0N 38.6W 80 KT 90 MPH 96H 13/1800Z 21.5N 40.5W 65 KT 75 MPH 120H 14/1800Z 27.5N 41.5W 55 KT 65 MPH $$ Forecaster Pasch |