Tag Archives: Marianas

Tropical Storm Goni Prompts Watches for Marianas

Tropical Storm Goni formed east of the Marianas on Friday and watches were issued for some of the islands because of the imminent threat it posed.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Goni was located at latitude 13.0°N and longitude 148.0°E which put it about 235 miles (370 km) southeast of Saipan.  Goni was moving toward the west-northwest at 10 m.p.h. (16 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 996 mb.  A Typhoon Watch has been issued for Saipan and Tinian.  A Tropical Storm Watch has been issued for Guam and Rota.

The circulation of Tropical Storm Goni is still organizing.  Most of the thunderstorms are developing in the western half of the circulation.  An upper level ridge is generating easterly winds which are blowing across Goni and those winds are inhibiting the development of convection in the eastern part of the tropical storm.  Goni is moving over water where the Sea Surface Temperatures (SSTs) are near 29°C.  The environment supports intensification and Goni could intensify more rapidly in a day or two when the circulation is more well organized.  Goni could reach typhoon intensity within 48 hours.

A subtropical ridge is steering Goni toward the west-northwest and that general motion is expected to continue during the next few days.  On its anticipated track, the center of Goni could be very near Saipan in about 24 hours.  Goni could be a strong tropical storm on the verge of becoming a typhoon at that time.  Saipan is still recovering from the effects of Typhoon Soudelor.  Strong winds and heavy rain could set back those recovery efforts.

 

Soudelor Almost a Typhoon as It Nears the Marianas

Tropical Storm Soudelor intensified on Saturday and it has almost reached typhoon status.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Soudelor was located at latitude 14.8°N and longitude 147.7°E which put it about 170 miles (275 km) east-southeast of Saipan.  Soudelor was moving toward the west-northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 70 m.p.h. (115 km/h) and there were gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 978 mb.  A Typhoon Warning has been issued for Saipan and Tinian.  A Tropical Storm Warning has been issued for Rota.  A Typhoon Watch has been issued for Agrihan, Pagan and Alamagan.

The structure of Tropical Storm Soudelor improved on Saturday.  A long spiral band wrapped almost entirely around the center of circulation and numerous other spiral bands were apparent on satellite imagery.  There are more thunderstorms on the western side of the circulation.  Soudelor is moving over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of the tropical storm is causing light easterly winds over the circulation.  However, the vertical wind shear is modest and upper level divergence is increasing.  Soudelor is in a favorable environment.  Further intensification is likely and rapid intensification is possible.  Soudelor will very likely be a typhoon when it moves through Marianas.

A subtropical ridge is steering Soudelor toward the west-northwest and that pattern is expected to continue during the next few days.  On its anticipated track Soudelor will be near Saipan and Tinian in about 12 hours.  It could bring strong winds to those locations and other nearby islands.