Despite being a relatively weak system, Tropical Depression Josie was known for actively enhancing the southwest monsoon that brought widespread flooding over Luzon, Philippines within most of July 2018.

On 06:00 UTC of July 20, the Joint Typhoon Warning Center (JTWC) began tracking a tropical disturbance that had developed about 402 km (250 mi) south-south east of Hong Kong.

[5] The storm's location over favourable environments with low wind shear and warm sea-surface temperatures prompted the JTWC to upgrade the system to a tropical depression and initiate advisories, receiving the designation of 13W.

[12] By 09:00 UTC of July 22, Josie curved northward, and animated satellite imagery showed the storm's structure began to deteriorate.

[18] This also meant that local government officials within the area banned sea travel in the eastern seaboards of Luzon, and advised residents to take appropriate actions against flooding and landslides.

[21] On 5:00 pm local time (09:00 UTC) of the same day, the National Disaster Risk Reduction and Management Council (NDRRMC) issued a "red alert" to all member and government agencies towards the areas that are affected, mainly in the northern provinces.

[24] In Calatagan, Batangas, a boat got capsized due to rough seas spawned by the enhancement of the monsoon and rescued the 57 passengers and 10 crew members safely.