Former Tropical Storm Pena weakened to a trough of low pressure on Thursday morning.  At 10:00 a.m. EST on Thursday the center of former Tropical Storm Pena was located at latitude 9.8°N and longitude 173.4°W which put the center about 1300 miles (2090 km) southwest of Honolulu, Hawaii.  Pena was moving toward the west at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1006 mb.

Former Tropical Storm Pena weakened to a trough of low pressure over the Central North Pacific Ocean on Thursday morning.  Pena was moving into a large mass of drier air that was east of the International Date Line.  It was also moving under the eastern side of an upper level trough that was near the International Date Line.  The upper level trough was producing southwesterly winds that were blowing toward the top of Pena’s circulation.  Those winds were causing moderate vertical wind shear.  The drier air and moderate vertical wind shear caused all of the thunderstorms in former Tropical Storm Pena to dissipate.

There were no thunderstorms near the center of former Tropical Storm Pena to generate upper level divergence.  Convergence of mass in the lower levels of the atmosphere caused the surface pressure to increase.

Former Tropical Storm Pena will move through an environment that will be unfavorable for a tropical cyclone during the next 24 hours.  Pena will move over water where the Sea Surface Temperatures are near 29°C.  However, the upper level trough near the International Date line will continue to cause moderate vertical wind shear.  Pena will also continue to move through the large mass of drier air that is east of the International Date Line.  Former Tropical Storm Pena will continue to weaken because of the moderate vertical wind shear and the drier air.

Former Tropical Storm Pena will move around the southern side of a high pressure system that is over the Central North Pacific Ocean.  The high pressure system will steer Pena toward the west during the next 24 hours.  On its anticipated track, former Tropical Storm Pena will continue to move farther away from Hawaii.