on july 15, the system was enhanced to a tropical depression. at 11 pm, the philippine atmospheric geophysical and astronomical services administration issued the no. 1 storm signal to the northern part of isabela province, cagayan province and the bataan islands. as denas continued to approach luzon, the philippine atmospheric geophysical and astronomical services administration issued a second storm signal to the northern part of cagayan province at 5 pm on the 16th.