Tag Archives: Martinique

Tropical Storm Harvey Develops East of Barbados

A reconnaissance plane found that a center of circulation and winds to tropical storm force had developed in a tropical wave previously designated as Invest 91L and Potential Tropical Cyclone Nine.  Based on data collected by the recon plane the National Hurricane Center named the system Tropical Storm Harvey on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Harvey was located at latitude 13.0°N and longitude 55.8°W which put it about 250 miles (400 km) east of Barbados.  Harvey was moving toward the west at 18 m.p.h. (30 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 1004 mb.

A Tropical Storm Warning is in effect for Martinique, Barbados, St. Vincent and the Grenadines, and St. Lucia.  A Tropical Storm Watch is in effect for Dominica.

The circulation of Tropical Storm Harvey became better organized on Thursday.  A low level center of circulation developed and bands of showers and thunderstorms began to revolve around the center.  Intermittent bursts of thunderstorms occurred near and to the west of the center of circulation.  The circulation of Tropical Storm Harvey is asymmetrical.  Most of the stronger thunderstorms are occurring in the western half of the circulation.  The bands in the eastern half of the circulation consist primarily of showers and low clouds.  Thunderstorms near the core of Harvey were generating some upper level divergence which was pumping mass away to the south and west of the tropical storm.

Tropical Storm Harvey will be moving through an environment that will be somewhat favorable for intensification.  Harvey will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge northeast of Puerto Rico is producing northeasterly winds which are blowing toward the top of Tropical Storm Harvey.  Those winds are producing moderate vertical wind shear which is probably the cause of the asymmetrical distribution of thunderstorms.  Tropical Storm Harvey is likely to get better organized on Friday and it could strengthen.  The intensity guidance is mixed.  Some guidance forecasts that Harvey will become a hurricane as it moves over the Caribbean Sea, while other guidance weaken the tropical storm back to a tropical wave.  So far, the guidance has underpredicted the strength of Tropical Storm Harvey and so strengthen would seem more likely.

Tropical Storm Harvey is being steered quickly toward the west by the subtropical high over the Atlantic Ocean.  A general westerly or west-northwesterly track is forecast for the next few days.  On its anticipate track Tropical Storm Harvey could reach Barbados in about 12 hours.  Harvey could also reach Martinique, St. Lucia, St. Vincent and the Grenadines on Friday.  Tropical Storm Harvey will bring gusty winds and locally heavy rain to those islands when it moves over them.

Invest 97L Poses Risk for Caribbean Sea

A tropical disturbance designated as Invest 97L poses a potential risk for locations around the Caribbean Sea.  At 8:00 p.m. EDT on Tuesday the center of Invest 97L was located at latitude 13.1°N and longitude 55.3°W which put it about 285 miles (460 km) east of Barbados.  Invest 97L was moving toward the west at 19 m.p.h. (31 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. (70 km/h).  The minimum surface pressure was 1008 mb.

A U.S. Air Force Reserve Hurricane Hunter aircraft flew a reconnaissance mission into Invest 97L on Tuesday afternoon.  The plane found the there were winds to near tropical storm force, but it could not identify a closed circulation.  The winds on the western side were weaker and the plane was unable to find a surface center.  There does seem to be cyclonic rotation above the surface at least on infrared satellite imagery.

The circulation in Invest 97L is still organizing.  Many of the stronger thunderstorms are forming north and east of the apparent center on satellite imagery.  Rainbands are also forming north and east of the center.  Recent satellite images suggest that some thunderstorms could be developing closer to the center of cyclonic rotation.  The current thunderstorms are generating upper level divergence which is pumping out mass to the north and east of the system.

Invest 97L is moving through an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 29°C.  The upper level winds over the majority of the circulation are relatively weak.  An upper level trough over the Caribbean Sea is generating vertical wind shear over the northern fringe of the circulation.  Invest 97L could become a tropical storm at any time.

A subtropical high pressure system to the north of Invest 97L is steering it toward the west and that general motion is expected to continue for another day or two.  On its anticipated track Invest 97L will move through the Windward Islands near Barbados, St. Lucia, Martinique, and Dominica on Wednesday.  It could bring gusty winds and locally heavy rain to those locations.