 In addition to the named storms , there were several other storms during the season that were warned on . On September 10 , 1991 , the JTWC began monitoring a tropical depression in the northeastern portion of the basin . The system moved southeastward , and according to the agency intensified into a 85 km / h ( 50 mph 1 ‑ minute sustained ) tropical storm on September 12 . By the next day , the storm dissipated after turning back to the north . 
