on september 1, a low pressure area formed to the northeast of guam. on the next day, the jma started monitoring the low pressure area as a tropical depression. soon, the system developed a well-defined but partially exposed low-level circulation center (llcc), prompting the jtwc to issue a tropical cyclone formation alert. on september 3, the central convection around the llcc deepened with favorable equatoward outflow prompting the jtwc to initiate advisories on the system, designating it with "16w". soon, 16w accelerated north at over with its llcc being being consolidated by convection. also, data from an ascat scatterometer pass revealed that the llcc was tightly wrapped with winds prompting the jtwc to upgrade 16w to a tropical storm. an aqua microwave imagery depicted that the llcc remained partially exposed though consolidated with deep central convection. albeit in an area of moderate vertical wind shear, an anticyclone enhanced northeastward outflow while a tropical upper tropospheric trough (tutt cell) suppressed the outflow towards the west. as 16w continued to accelerate north at a staggering , convective banding became fragmented and detached behind the main area of central convection. however, the outflow to the southeast of the storm remained favorable and 16w continued to strengthen, prompting the jma upgraded the system to a tropical storm, naming it "noru".