Tropical depression 09W was located in the northwest Pacific east of the Philippines when it was upgraded today to tropical storm PRAPIROON. The tropical storm is in a favorable environment for intensification. Vertical wind shear is low above the tropical cyclone and sea surface temperatures are warm below.

NASA's GPM core observatory satellite had a good view of tropical storm PRAPIROON on June 29, 2018 at 0246 UTC. PRAPIROON was just barely a tropical storm with maximum sustained wind speeds estimated at about 35 kts (40.3 mph). GPM's Microwave Imager (GMI) and Dual-Frequency Precipitation Radar (DPR) instruments measured precipitation around PRAPIROON. GPM showed that intensifying tropical storm PRAPIROON was fairly large with it's most intense rainfall located in the southern half of the storm. GPM's radar (DPR Ku Band) scanned convective storms in a feeder band on the southwestern side of the tropical storm where it found that some very intense storms there were dropping rain at a rate of over 192 mm (7.6 inches) per hour.

This 3-D view of tropical storm PRAPIROON's precipitation, looking toward the southwest, used data captured by GPM's radar (DPR Ku Band). GPM's DPR probes provided excellent information about the powerful storms in the large rain band wrapping around PRAPIROON's western side. Storm top heights in that part of the storm were measured by GPM's radar reaching heights above 12.5 km (7.8 miles).

The Joint Typhoon Warning Center (JTWC) predicts that PRAPIROON will move toward the north-northwest and intensify into a typhoon tomorrow. PRAPIROON is expected to continue intensifying and have peak wind speeds of about 75 kts (86 mph) as it passes over the East China Sea in a few days. PRAPIROON is predicted by the JTWC to be a minimal typhoon with winds of 65 kts (74.8 mph) as it approaches South Korea on July 2, 2018.