Tropical Storm Malou formed west of the Marianas on Sunday night. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Malou was located at latitude 16.5°N and longitude 138.1°E which put it about 515 miles (830 km) west-northwest of Saipan. Malou was moving toward the north-northwest at 17 m.p.h. (28 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1003 mb.

The circulation around a low pressure system over the Western North Pacific Ocean west of the Marianas strengthened on Sunday night and the Japan Meteorological Agency designated the system as Tropical Storm Malou. The circulation around Tropical Storm Malou was still organizing. There was a broad center of circulation, but there were not many thunderstorms near the center of Malou. Several long rainbands were revolving around the broad center of circulation. The strongest winds were occurring in the eastern half of Malou. Winds to tropical storm force extended out 185 miles (295 km) on the eastern side of Malou. The winds in the western half of Malou’s circulation were blowing at less than tropical storm force.

Tropical Storm Malou will move through an environment favorable for intensification during the next 48 hours. Malou will move over water where the Sea Surface Temperatures are near 29˚C. It will move under an upper level ridge near the Marianas. The upper level winds are weak in the ridge and there will be little vertical wind shear. Tropical Storm Malou is likely to intensify steadily during the next 48 hours. Malou could strengthen to a typhoon in 48 hours.

Tropical Storm Malou will move around the western end of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Malou toward the west-northwest during the next 48 hours. Tropical Storm Malou will turn toward the northeast after it moves around the western end of the ridge. On its anticipated track Malou could approach Iwo To in three days. Malou could be a typhoon when it approaches Iwo To.