A fourth tropical cyclone formed in the active region over the western Pacific and Australian region.  A low level circulation center developed in an elongated area of thunderstorms south of Kwajalein and the system was classified as Tropical Storm Bavi.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Bavi was located at latitude 7.2°N and longitude 166.7°E which put it about 40 miles southwest of Kwajaein, about 410 miles east-southeast of Ujelang and about 1470 miles east of Guam.  Bavi was moving toward the west at 18 m.p.h.  The maximum sustained wind speed was 40 m.p.h. and there were gusts to 50 m.p.h.  The minimum surface pressure was 996 mb.

The circulation around Bavi is stretched out in the east to west direction and most of the convection and stronger winds are on the northern side of the circulation.  The rapid forward speed is generating vertical wind shear and it is inhibiting the organization around the center of circulation.  Brisk easterly winds in the upper levels are adding to the wind shear.  Bavi is moving over warm Sea Surface Temperatures and it could intensify if the forward motion slows and the wind shear decreases.

A subtropical ridge is steering Bavi in a westerly direction.  The ridge is expected to continue to steer Bavi toward the west or west-northwest over the next several days.   The projected track of Bavi could bring it near Guam in about four days.

Tropical Storm Higos intensified into a typhoon on Sunday.  At 11:00 p.m. EST on Sunday the center of Typhoon Higos was located at latitude 12.3°N and longitude 156.4°E which put it about 780 miles east of Guam.  It was moving toward the west-northwest at 3 m.p.h.  The maximum sustained wind speed was 85 m.p.h. and there were gusts to 100 m.p.h.  The minimum surface pressure was 967 mb.

Higos has been moving slowly through an area where the vertical wind shear was not too strong.  Thunderstorms around the center of circulation supported strong upper level divergence, which pumped out large quantities of mass.  A well developed upper level outflow channel to the northeast enhanced the flow of mass away from the system.  Those processes allowed the surface pressure to decrease and the wind speeds to increase on Sunday.  Higos remains over warm Sea Surface Temperatures and further intensification is possible on Monday.  Eventually, when it moves farther north, Higos will move into an area of stronger wind shear and weaken.

Higos is moving near the western end of a subtropical ridge.  It is in an area of weak steering winds, and Higos is moving slowly.  The increased intensity and vertical height of the circulation make it more likely that Higos will move toward the north as it reaches the western end of the subtropical ridge.  The guidance from numerical models has increased the probability of this track.

Warm Sea Surface Temperatures and limited wind shear allowed Vongfong to intensify on Saturday and it is now a typhoon.  At 8:00 p.m. EDT on Saturday the center of Typhoon Vongfong was located near latitude 12.6°N and longitude 149.9°E which put it about 330 miles east-southeast of Guam.  Vongfong was moving toward the west-northwest at 21 m.p.h.  The maximum sustained wind speed was 80 m.p.h. and there were gusts to 100 m.p.h.

Clockwise flow around a subtropical high pressure system will keep Vongfong moving in a general west-northwesterly direction for several more days.  It could pass very near Guam during the next 24 hours.  Vongfong should remain in a favorable environment and further intensification is possible.