NASA's Aqua satellite passed over two developing low pressure areas in the Central Pacific Ocean, just before one of them strengthened into Tropical Storm Pewa.
When NASA's Aqua satellite passed over the Central Pacific on Aug. 16 at 00:35 UTC (8:35 p.m. EDT/Aug. 15), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument captured a visible image of two developing low pressure areas. The low farthest west was called System 91C, and that's the low that strengthened into Tropical Storm Pewa. The low pressure area east of Pewa is System 90C, which has a high chance to develop into a tropical depression.
System 90C is located near 12.6 north and 163.5 west, which is about 775 miles south-southwest of Kauai, Hawaii. System 90C is moving west near 15 mph.
NOAA's Central Pacific Hurricane Center or CPHC noted that outflow from Tropical Storm Pewa is adversely affecting System 90C's chances for developing further. Satellite imagery early on Aug. 16 showed that System 90C appears less organized than it did on Aug. 15. This system has a medium chance, 30 percent, of becoming a tropical cyclone during the next 48 hours.
There's another low pressure area east of System 90C, but it has a "near zero" percent chance of development. The area is actually a trough or elongated area of low pressure, and has not been given a system designation. It is producing disorganized showers and thunderstorms and was moving west at 15 to 20 mph. Because environmental conditions are not favorable, this low is not likely to become a tropical depression in the near future, according to CPHC.
On Aug. 16 at 1500 UTC/11 a.m. EDT/5 a.m. Hawaii Standard Time, Tropical Storm Pewa's maximum sustained winds were near 40 mph/65 kph. Pewa was centered near 10.2 north and 173.5 west, more than 1,250 miles southwest of Kauai, Hawaii. Pewa is moving to the west-northwest at 15 mph. The Central Pacific Hurricane Center forecast for Pewa takes the storm on a northwesterly track with its center staying over open ocean. Pewa is expected to maintain tropical storm status for the next several days.