Atlantic/2019/20L/Archive/6

Tropical Storm Sebastien	Winds: 45 kt
	Pressure: 1001 mbar
Advisory 6 / 11:00 PM AST Wednesday, October 20, 2019
Sebastian remains disorganized, albeit less so than for previous advisories. A large mass of deep convection has developed, and the low-level circulation is positioned near the western edge of this center. The evening ASCAT passes missed, but satellite intensity estimates are a little higher than earlier, and so I have taken the liberty to increase Sebastien's maximum strength to 45kt tonight. The cyclone is beginning to intensify, and this makes sense given that shear vectors have become better aligned to the Sebastien's forward motion. Enhanced upper-level divergence will continue to promote convective activity, and models are in good agreement that further intensification is likely over the next 36 hours. Sebastien is still expected to become a Category 1 hurricane prior to extratropical transition. Like I mentioned in the previous advisory, models have been struggling with the timing of transition and dissipation, and so I expect Sebastien to remain tropical for yet another 48 hours. Dissipation has been moved back a day. The system turned north earlier this afternoon, and a curve toward the northeast should ensue by this time tomorrow ahead of an upper-level trough. Sebastien poses no threat to land. FORECAST MAX WINDS INIT 21/0300Z 45 KT 50 MPH 12H 21/1200Z 50 KT 60 MPH 24H 22/0000Z 60 KT 70 MPH 36H 22/1200Z 65 KT 75 MPH 48H 23/0000Z 65 KT 75 MPH...POST-TROP/EXTRATROP 73H 24/0000Z 55 KT 65 MPH...POST-TROP/EXTRATROP 96H 25/0000Z...DISSIPATED
Forecaster TAWX14
THIS FORECAST IS NOT AN OFFICIAL PRODUCT