▁s lack ened ▁early ▁on ▁August   2 7 , ▁and ▁a ▁tim ely ▁mic row ave ▁pass ▁highlight ed ▁the ▁presence ▁of ▁a ▁low - level ▁eye ▁well ▁embedded ▁in ▁the ▁storm ' s ▁central ▁dense ▁over cast , ▁indicating ▁the ▁res umption ▁of ▁Gast on ' s ▁intens ification ▁phase . ▁ ▁Although ▁Gast on ▁continued ▁north west ward , ▁its ▁motion ▁slow ed ▁in ▁a ▁weak ▁ste ering ▁regime . ▁Am id ▁low ▁she ar ▁and ▁warm ▁ocean ▁temper atures , ▁Gast on ▁att ained ▁h urr icane ▁intensity ▁for ▁a ▁second ▁time ▁at ▁ 1 8 : 0 0   UTC ▁on ▁August   2 7 . ▁About ▁ 2 4   h ours ▁later , ▁the ▁storm ▁deep ened ▁to ▁a ▁Category   3 ▁h urr icane ▁on ▁the ▁S aff ir – Sim pson ▁scale , ▁the ▁first ▁major ▁h urr icane ▁of ▁the ▁season , ▁by ▁ 1 8 : 0 0   UTC ▁the ▁next ▁day . ▁With ▁a ▁symmetric ▁ring ▁of ▁deep ▁con ve ction ▁surrounding ▁a ▁distinct ▁eye , ▁Gast on ▁ultimately ▁pe aked ▁with ▁sust ained ▁wind s ▁of ▁ 1 2 0   m ph ▁( 1 9 5   km / h ) ▁six ▁hours ▁later . ▁A ▁mid - level ▁tr ough ▁moving ▁sout heast ward ▁across ▁the ▁North ▁Atlantic ▁er oded ▁a ▁series ▁of ▁rid ges ▁ste ering ▁Gast on , ▁causing ▁the ▁system ▁to ▁dr ift ▁north ▁and ▁n ortheast . ▁Cold ▁water ▁up well ing ▁and