On July 26, JMA monitored a
low-pressure area near
Chuuk. The system stalled for a few days and was upgraded into a tropical depression on July 27. Early on July 29, the depression showed signs of intensification and with that, JTWC upgraded it to Tropical Storm 11W. Later that day, JMA upgraded 11W to Tropical Storm Halong. In the same time Halong started developing a small, unclear
eye. With this, gale and typhoon force winds were reported over
Guam. Very late on July 30, JMA upgraded Halong to a severe tropical storm. The next day, both agencies upgraded it to a minimal typhoon. In the same time, Halong started its
rapid deepening phase. On August 2, Halong's eye developed clearer than before as the system underwent explosive intensification from a category 1 typhoon to a Category 3 in less than 24 hours.
Rapid deepening continued and it eventually became a category 5 super typhoon, with pressure dropping from 980 to 925
mbar in 48 hours. However, late that day, JMA revised Typhoon Halong's minimum pressure to 920
mbar. On August 4, Halong weakened to a category 4 typhoon, due to it undergoing an
eyewall replacement cycle. The next day, Halong weakened to a minimal typhoon, although it was a deep typhoon due to its pressure. In the same day, its convection was steadily weakening. On August 6, NASA reported that Halong was beginning undergo an
eyewall replacement cycle. This made the JTWC upgrade it to a category 2 typhoon again. Its
eye continued to undergo the eyewall replacement cycle until August 8. On the same day, Halong weakened to a category 1 typhoon and started to affect mainland
Japan. The JTWC downgraded Halong to a tropical storm on August 9, while the JMA followed suit several hours later. Halong made landfall over the southern part of Japan prior to August 10. On August 10, JTWC issued their final bulletin on Halong, as it was leaving the country. The JMA also issued their final advisory on August 11, as it was becoming
extratropical. Its remnants dissipated early on August 15 over
Siberia, as it was absorbed by a developing extratropical system. ==Preparations and impact==