 On December 17 , the JTWC began monitoring a tropical depression about 700 km ( 440 mi ) west of Diego Garcia in association with the intertropical convergence zone ( ITCZ ) , designating it as Tropical Cyclone 09S . The next day , the MFR also began classifying the system . The nascent depression moved generally to the southeast , and later more to the south @-@ southeast , ahead of an approaching upper @-@ level trough . On December 20 , the depression intensified into Tropical Storm Alexandra , and that day developed an ill @-@ defined eye , as well as good inflow . The JTWC upgraded Alexandra to the equivalent of a minimal hurricane – with 1 ‑ minute sustained winds of at least 120 km / h ( 75 mph ) on December 21 , but MFR only estimated peak 10 ‑ minute winds of 105 km / h ( 65 mph ) . Although the MFR estimated the storm subsequently weakened , the JTWC assessed that Alexandra continued to intensity to a peak 1 ‑ minute intensity of 195 km / h ( 120 mph ) on December 22 . Around that time , the cyclone had slowed and turned to the east . Increased shear caused gradual weakening , and the strengthening of the subtropical ridge turned Alexandra to the southwest . The JTWC discontinued advisories on December 26 , and Alexandra dissipated three days later well to the east @-@ northeast of Mauritius , or about 1 @,@ 600 km ( 1 @,@ 000 mi ) south of where it first formed . 
