Tag Archives: Tropical Depression Seventeen

Tropical Depression 16 Strengthens to Tropical Storm Peter

Former Tropical Depression Sixteen strengthened to Tropical Storm Peter on Sunday morning. At 9:00 a.m. EDT on Sunday the center of Tropical Storm Peter was located at latitude 17.6°N and longitude 56.0°W which put it about 470 miles (755 km) east of the Northern Leeward Islands. Peter was moving toward the west-northwest at 15 m.p.h. (24 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 1008 mb.

Infrared satellite images and satellite derived scatterometer estimates of surface winds indicated that former Tropical Depression Sixteen had strengthened on Sunday morning and the National Hurricane Center designated the system as Tropical Storm Peter. Early morning visible satellite images revealed that strong vertical wind shear was affecting Tropical Storm Peter. An upper level trough north-northeast of Puerto Rico and an upper level ridge east of the Leeward Islands were interacting to produce strong southwesterly winds that were blowing across Peter’s circulation. The low level center of circulation was clearly visible on those images and it was surrounded by showers and lower clouds. Thunderstorms were occurring in bands on the eastern and northern periphery of the circulation around Tropical Storm Peter. Bands in the western and southern parts of Peter consisted primarily of showers and lower clouds.

Tropical Storm Peter will move through an environment marginally favorable for intensification during the next 24 hours. Peter will move over water where the Sea Surface Temperatures are near 29˚C. However, the upper level trough and the upper level ridge will continue to produce strong vertical wind shear. The strong wind shear will inhibit intensification. Tropical Storm Peter could strengthen a little during the next 24 hours. The upper level winds are forecast to get stronger on Monday. Increased vertical wind shear could cause Peter to weaken back to a tropical depression.

Tropical Storm Peter will move around the southern side of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer the depression toward the west-northwest during the next 48 hours. On its anticipated track Tropical Storm Peter could be northeast of the Northern Leeward Islands by Monday morning.

Elsewhere over the Atlantic Ocean, Tropical Depression Seventeen formed southwest of the Cabo Verde Islands. At 5:00 a.m. EDT on Sunday the center of Tropical Depression Seventeen was located at latitude 11.8°N and longitude 28.21°W which put it about 330 miles (530 km) southwest of the Cabo Verde Islands. The tropical depression was moving toward the north-northwest at 14 m.p.h. (22 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 1007 mb. The tropical depression is forecast to move away from the Cabo Verde Islands and to strengthen to a tropical storm.

Tropical Depression Seventeen Forms East of Leeward Islands

Tropical Depression Seventeen formed well east of the Leeward Islands on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Tropical Depression Seventeen was located at latitude 17.0°N and longitude 41.5°W which put it about 1475 miles (2290 km) east of the Northern Leeward Islands.  The depression was moving toward the west at 5 m.p.h. (8 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.

The circulation around a large low pressure system over the tropical Atlantic Ocean east of the Leeward Islands exhibited more organization on Sunday night and the National Hurricane Center designated the system as Tropical Depression Seventeen.  The circulation around the depression was still organizing.  There was a broad center of rotation in the middle of the circulation.  Bands of showers and thunderstorms were revolving the broad center.  The strongest thunderstorms were in bands on the eastern side of the depression.  Storms in bands around the broad center began to generate upper level divergence which pumped mass away from the depression.

Tropical Depression Seventeen will move through an environment favorable for intensification during the next day or two.  The depression will move over water where the Sea Surface Temperature is near 27°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  The large size of the tropical depression and the broad center of circulation will limit the rate at which the depression intensifies.  Tropical Depression Seventeen is likely to strengthen into a tropical storm on Monday.

Tropical Depression Seventeen will move south of a subtropical high pressure system over the Atlantic Ocean.  The high will steer the depression slowly toward the west during the next day or two.  There is a large circulation around a strong tropical wave to the east of Tropical Depression Seventeen.  It is possible that the tropical wave strengthens into a tropical cyclone.  If that happens, then the large circulation could pull the depression back to the east or at least retard its movement toward the west.  On its anticipated track the tropical depression could be northeast of the Leeward islands in a few days.

Tropical Depression Seventeen Develops over Western Gulf of Mexico

Tropical Depression Seventeen developed over the western Gulf of Mexico on Friday.  At 11:00 a.m. EDT on Friday morning the center of Tropical Depression Seventeen was located at latitude 25.6°N and longitude 94.4°W which put it about 320 miles (515 km) south-southwest of Lake Charles, Louisiana.  It was moving toward the north at 16 m.p.h. (26 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.

More thunderstorms developed near the center of a low pressure system over the western Gulf of Mexico on Friday morning and the National Hurricane Center designated the system as Tropical Depression Seventeen.  Bands of showers and thunderstorms were also developing around the depression.  The strongest rainbands were in the eastern half of the circulation.  Bands in the western half of the circulation consisted of more showers and lower clouds.  Storms near the center were generating upper level divergence which was pumping mass away to the northeast of the depression.

Tropical Depression Seventeen is likely to strengthen during the next 12 to 18 hours.  The depression will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough over the south central U.S. and Mexico will produce southwesterly winds which will blow toward the top of the depression.  Those winds will produce moderate vertical wind shear, which will inhibit intensification.  However, the shear will not be strong enough to prevent intensification while the depression is over the Gulf of Mexico.  The wind shear will cause the depression to start a transition to an extratropical cyclone.  A cold front will move toward the depression from the northwest and the depression could merge with the front during the next 24 hours.

The upper level trough will steer the depression toward the north during the next several days.  On its anticipated track the depression will make landfall on the coast of Louisiana during Friday night.  The depression could be a tropical storm when it makes landfall.  It will bring gusty winds to coastal Louisiana.  The depression is likely to drop heavy rain over parts of Louisiana, Mississippi, and eastern Arkansas.  The rain could cause floods in some locations.