Category Archives: Atlantic, Caribbean, and Gulf of Mexico

Atlantic TCs

Hurricane Dorian Strengthens North of Puerto Rico

Hurricane Dorian strengthened north of Puerto Rico on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Dorian was located at latitude 19.7°N and longitude 66.0°W which put it about 90 miles (145 km) north of San Juan, Puerto Rico.  Dorian was moving toward the northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 110 m.p.h. (170 km/h).  The minimum surface pressure was 986 mb.

The circulation around Hurricane Dorian strengthened steadily on Wednesday.  A circular eye with a diameter of 14 miles (22 km) formed at the center of circulation.  A closed ring of thunderstorms surrounded the eye and the strongest winds were occurring in the northeastern part of that ring.  Bands of showers and thunderstorms were revolving around the core of Hurricane Dorian.  Storms near the core were generating upper level divergence which was pumping mass away to the north and northeast of the hurricane.  The circulation around Hurricane Dorian remained fairly small.  Winds to hurricane force extended out about 20 miles (30 km) in the northeastern quadrant of Dorian.  Winds to tropical storm force extended out about 70 miles from the center of circulation.

Hurricane Dorian will move through an environment favorable for intensification during the next several days.  Dorian will move over water where the Sea Surface Temperature is near 29°C.  It will move into an area where the upper level winds are relatively weak and there will be little vertical wind shear.  Hurricane Dorian is very likely to intensify during the next 48 hours and it could intensify rapidly at times.  Dorian is likely to strengthen into a major hurricane.

An upper level low near the Bahamas will pull Hurricane Dorian toward the northwest during the next 24 to 36 hours.  A strong ridge of high pressure will build north of Dorian on Friday.  The high will block Dorian from moving north and it will turn it toward the west-northwest.  On its anticipated track Hurricane Dorian could be near the northern Bahamas on Saturday night.  Dorian could approach the east coast of Florida by later on Sunday.  Dorian is likely to be a major hurricane when it approaches Florida.

Tropical Storm Dorian Strengthens, Hurricane Warnings for Virgin Islands

Tropical Storm Dorian strengthened on Wednesday morning and it was on the verge of becoming a hurricane.  Hurricane Warnings were issued for Vieques, Culebra, the U.S. Virgin Islands and the British Virgin Islands. At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Dorian was located at latitude 17.5°N and longitude 64.5°W which put it about 25 miles (40 km) south of St. Croix.  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 999 mb.

Hurricane Warnings were in effect for Vieques, Culebra, the U.S. Virgin Islands, and the British Virgin Islands.  A Tropical Storm Warning and a Hurricane Watch was in effect for Puerto Rico.  A Tropical Storm Watch was in effect for the portion of the coast of the Dominican Republic from Isla Saona to Samana.

The circulation around Tropical Storm Dorian exhibited much greater organization on Wednesday morning.  A ring of strong thunderstorms wrapped almost completely around the center of circulation.  The strongest winds were occurring in the northeastern part of that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Dorian.  Storms near near the core were generating upper level divergence which was pumping mass away to the north and northeast of the tropical storm.  The circulation also increased in size on Wednesday morning.  Winds to tropical storm force extended out about 70 miles (110 km) from the center of circulation.

Tropical Storm Dorian will move through an environment favorable for intensification during the next few days.  Dorian will move over water where the Sea Surface Temperature is near 29°C.  It will move northeast of an upper level low during the next 24 hours.  The low will produce some southerly winds which will blow toward the top of the circulation, but the winds will not be strong enough to prevent intensification.  The wind shear will decrease on Friday and Dorian could strengthen into a major hurricane near the Bahamas.

The upper level low will help to steer Tropical Storm Dorian toward the northwest during the next 24 to 36 hours.  A ridge of high pressure will build north of Dorian on Friday.  The ridge will block Dorian from moving north and it will steer Dorian toward the west-northwest.  On its anticipated track Tropical Storm Dorian will pass over the Virgin Islands near the eastern end of Puerto Rico today.  Dorian will be near the northern Bahamas on Saturday and it could approach the east coast of Florida by Sunday night.  Dorian could be a major hurricane when it approaches the east coast of the U.S.

Elsewhere over the Atlantic Ocean, former Tropical Storm Erin weakened to a tropical depression.  At 11:00 a.m. EDT on Wednesday the center of Tropical Depression Erin was located at latitude 33.6°N and longitude 72.8°W which put it about 190 miles (305 km) southeast of Cape Hatteras, North Carolina.  Erin was moving toward the northwest at 13 m.p.h. (20 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.

Tropical Storm Dorian Moves Toward Puerto Rico

Tropical Storm Dorian moved toward Puerto Rico on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Dorian was located at latitude 16.0°N and longitude 63.0°W which put it about 275 miles (440 km) east-southeast of Ponce, Puerto Rico.  Dorian was moving toward the northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 1006 mb.

A Hurricane Watch was issued for Puerto Rico.  Tropical Storm Warnings were in effect for Puerto Rico, Culebra, Vieques, the U.S. Virgin Islands and the British Virgin Islands.  A Tropical Storm Watch was issued for the coast of the Dominican Republic from Isla Saona to Puerto Plata.

The original low level center of Tropical Storm Dorian passed south of Barbados and St. Lucia on Tuesday morning.  Dorian dropped heavy rain and there were reports of flash floods on Martinique.  The original center weakened on Tuesday afternoon and a new low level center formed about 60 miles farther to the north.  The formation of a new center of circulation caused the forecast future track of Tropical Storm Dorian to be shifted northward as well.

Even with the formation of a new center of circulation, the overall circulation around Tropical Storm Dorian did not change much on Tuesday.  The circulation around Dorian remained small.  Winds to tropical storm force only extended out about 45 miles (75 km) from the center of circulation.  A broken ring of thunderstorms surrounded the new low level center.  Bands of showers and thunderstorms were revolving the center of Tropical Storm Dorian.  Storms near the center were producing upper level divergence which was pumping mass away to the north of the tropical storm.

Tropical Storm Dorian will move through an environment somewhat favorable for intensification on Wednesday.  Dorian will move over water where the Sea Surface Temperature is near 29°C.  An upper level low northwest of Puerto Rico will produce southerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, which will inhibit intensification.  A large mass of drier air is north of Tropical Storm Dorian and the drier air could also inhibit intensification if it gets pulled into the circulation around Dorian.  The small size of the circulation around Tropical Storm Dorian means that it could weaken or strengthen quickly if the environmental conditions change significantly.  Dorian is likely to weaken when it crosses Puerto Rico on Wednesday night.

The upper low northwest of Puerto Rico will help to steer Tropical Storm Dorian toward the northwest on Wednesday.  On its anticipated track Tropical Storm Dorian could reach Puerto Rico by Wednesday evening.  Dorian will bring gusty winds and it will drop locally heavy rain on Puerto Rico.  Locally heavy rain could cause flash floods in some locations.  A high pressure system will build north of Tropical Storm Dorian on Thursday and Friday.  The high will turn Dorian back toward the west-northwest.  Dorian could approach the east coast of Florida on Sunday.

Elsewhere over the Atlantic Ocean, Tropical Depression Six strengthened into Tropical Storm Erin southeast of Cape Hatteras on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Erin was located at latitude 31.9°N and longitude 72.1°W which put it about 300 miles (485 km) southeast of Cape Hatteras, North Carolina.  Erin was moving toward the west at 2 m.p.h. (3 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. (65 km/h).  The minimum surface pressure was 1005 mb.  Tropical Storm Erin is forecast to move northeast toward Nova Scotia.

Tropical Storm Dorian Brings Wind and Rain to Barbados

Tropical Storm Dorian brought wind and rain to Barbados on Monday night.  Observations made by a U.S. Air Force Reserve Hurricane Hunter aircraft indicated that the center of Tropical Storm Dorian passed just south of Barbados on Monday night.  Dorian brought winds to tropical storm force and locally heavy rain.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Dorian was located at latitude 13.2°N and longitude 59.7°W which put it about 95 miles (155 km) east-southeast of St. Lucia.  Dorian was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 1003 mb.

Tropical Storm Warnings were in effect for Barbados, St. Lucia, Martinique, St. Vincent and the Grenadines. Tropical Storm Watches have been issued for Puerto Rico, Grenada, Dominica, Saba and St. Eustatius.

The circulation around Tropical Storm Dorian remained fairly small on Monday.  Winds to tropical storm force only extended out about 45 miles (75 km) from the center of circulation.  Thunderstorms were occurring primarily in bands in the northern half of the circulation.  Bands in the southern half of the circulation consisted primarily of showers and lower clouds.  Storms near the center of Dorian were generating upper level divergence which was pumping mass away from the tropical storm.

Tropical Storm Dorian will move through an environment somewhat favorable for intensification.  Dorian will move over water where the Sea Surface Temperature is near 29°C.  Tropical Storm Dorian will move south of an upper level ridge.  The ridge will produce easterly winds which will cause some vertical wind shear, but the shear should not be strong enough to prevent intensification.  Dorian will move just south of a large mass of drier air.  It appears that some drier air will get pulled into circulation at times and the drier air will interrupt periods of intensification.  Since the circulation around Tropical Storm Dorian is very small, Dorian could strengthen or weaken very quickly if environmental conditions change.

Tropical Storm Dorian will move south of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Dorian toward the west-northwest during the next several days.  On its anticipated track the center of Tropical Storm Dorian will pass near St. Lucia on Tuesday morning.  Dorian could approach Puerto Rico on Wednesday.

Elsewhere over the Atlantic Ocean, Tropical Depression Six formed off the southeast coast of the U.S.  At 11:00 p.m. EDT on Monday the center of Tropical Depression Six was located at latitude 31.5N and longitude 72.2W which put it about 320 miles southeast of Cape Hatteras, North Carolina. It was moving toward the east at 3 m.p.h. The maximum sustained wind speed was 35 m.p.h. and the minimum surface pressure was 1010 mb.

Stronger Tropical Storm Dorian Causes Warnings for Lesser Antilles

Tropical Storm Dorian strengthened on Sunday and the threat it posed caused warnings and watches to be issued for some of the Lesser Antilles.  Tropical Storm Warnings were in effect for Barbados, St. Lucia, and St. Vincent and the Grenadines.  Tropical Storm Watches were issued for Grenada and Martinique.

At 5:00 p.m. EDT on Sunday the center of Tropical Storm Dorian was located at latitude 11.5°N and longitude 54.2°W which put it about 375 miles (605 km) east-southeast of Barbados.  Dorian was moving a little to the north of due west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 1003 mb.

The circulation around Tropical Storm Dorian exhibited greater organization on Sunday afternoon.  The inner end of a band of showers and thunderstorms wrapped tightly around the northern and western sides of the center of circulation.  The strongest winds were occurring in that band.  Several other bands of showers and storms were revolving around the small core of Dorian.  Storms near the center of circulation were generating upper level divergence which was pumping mass away to the north of the tropical storm.  The circulation around Tropical Storm Dorian was small.  Winds to tropical storm force extended out about 35 miles (55 km) from the center of circulation.

Tropical Storm Dorian will move through an environment mostly favorable for intensification.  Dorian will move over water where the Sea Surface Temperature is near 28.5°C.  It will move through a region where the upper level winds are relatively weak and there will be little vertical wind shear.  A large area of drier air is north of Tropical Storm Dorian.  If the circulation draws drier air into the tropical storm, it would interrupt intensification.  Tropical Storm Dorian is likely to strengthen during the next 24 to 48 hours.  Since Dorian has a small circulation, it could intensify or weaken quickly if the environmental conditions change.

Tropical Storm Dorian will move south of the subtropical high pressure system over the North Atlantic Ocean.  The high will steer Dorian toward the west-northwest during the next few days.  On its anticipated track Tropical Storm Dorian could approach Barbados late on Monday.  It could be a hurricane by that time.  Dorian could reach the southern and central Lesser Antilles on Tuesday.  Tropical Storm Dorian could bring strong winds and heavy rain to those islands.

Tropical Depression Five Strengthens Into Tropical Storm Dorian

Former Tropical Depression Five strengthened into Tropical Storm Dorian east of the Lesser Antilles on Saturday afternoon.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Dorian was located at latitude 10.7°N and longitude 49.1°W which put it about 725 miles (1165 km) east southeast of Barbados.  Dorian was moving toward the west at 12 m.p.h. (19 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 1008 mb.

The circulation around former Tropical Depression Five exhibited greater organization on Saturday afternoon and the National Hurricane Center determined that the system had strengthened to Tropical Storm Dorian.  A band of thunderstorms close to the center of circulation wrapped around the western and southern sides of the center.  The strongest winds were occurring in that band of storms.  Other bands in the western half of the circulation started to revolve around the center of circulation.  Storms near the center began to generate upper level divergence which was pumping mass away to the west of the tropical storm.  The circulation around Tropical Storm Dorian was small.  Winds to tropical storm force extended out about 25 miles (40 km) from the center of circulation.

Tropical Storm Dorian will move through an environment that will be favorable for intensification during the next several days.  Dorian will move over water where the Sea Surface Temperature is near 28°C.  It will move south of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear.  The shear will slow the rate of intensification.  Tropical Storm Dorian will move south of a region of drier air.  If drier air is pulled into the circulation, it will interrupt intensification.  Since Tropical Storm Dorian is so small, it could strengthen or weaken very quickly if the environment changes.  Dorian could strengthen into a hurricane in two or three days.

Tropical Storm Dorian will move south of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Dorian toward the west-northwest during the next few days.  On its anticipated track Tropical Storm Dorian could approach the Lesser Antilles on Tuesday.  Dorian could strengthen into a hurricane by that time.  Watches and/or warnings could be issued for parts of the Lesser Antilles on Sunday.

Tropical Depression Five Forms East of Lesser Antilles

Tropical Depression Five formed east of the Lesser Antilles on Saturday morning.  At 11:00 a.m. EDT on Saturday the center of Tropical Depression Five was located at latitude 10.4°N and longitude 47.9°W which put it about 805 miles (1300 km) east-southeast of Barbados.  It was moving toward the west at 12 m.p.h. (19 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 1010 mb.

Data from satellites indicated that there was a closed circulation around an area of low pressure east of the Lesser Antilles on Saturday morning and the National Hurricane Center designated the system as Tropical Depression Five.  The circulation around Tropical Depression Five was still organizing.  Many of the stronger thunderstorms were occurring in bands west of the center of circulation.  Bands in the eastern half of the circulation consisted primarily of showers and lower clouds.  The circulation around Tropical Depression Five was relatively small.

Tropical Depression Five will move through an environment favorable for slow intensification.  It will move over water where the Sea Surface Temperature is near 28°C.  The depression will move south of an upper level ridge over the western north Atlantic Ocean.  The ridge will produce easterly winds which will cause some vertical wind shear.  There will be some drier air just to the north of the depression.  If the depression pulls some of the drier air into the circulation, that could also interrupt intensification.  The combination of some wind shear and intrusions of drier air will limit the rate at which Tropical Depression Five strengthens.  The depression is forecast to strengthen into a tropical storm.

Tropical Depression Five will move south of a subtropical high pressure system over the Atlantic Ocean.  The high will steer the depression toward the west-northwest during the next few days.  On its anticipated track Tropical Depression Five could approach the Lesser Antilles on Monday night or Tuesday.  The depression could be a tropical storm by that time.

Tropical Storm Chantal Forms Southeast of Nova Scotia

Tropical Storm Chantal formed southeast of Nova Scotia on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Chantal was located at latitude 40.2°N and longitude 56.2°W which put it about 485 miles (780 km) southeast of Halifax, Nova Scotia.  Chantal was moving toward the east at 22 m.p.h. (35 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 1010 mb.

A small low pressure system that was near the coast of the Carolinas during the weekend began to exhibit tropical characteristics on Tuesday night and the National Hurricane Center designated the system as Tropical Storm Chantal.  Thunderstorms developed closer to the center of circulation when the low moved near the Gulf Stream and the strongest winds were occurring closer to the center.  Although the circulation around Chantal looked more tropical, the distribution of thunderstorms was still asymmetrical.  Many of the stronger storms were occurring in the eastern half of the circulation.  Bands in the western half of the circulation consisted primarily of showers and lower clouds.  Tropical Storm Chantal was far enough north that it was in the region of westerly winds in the upper levels.  Those winds were causing moderate vertical wind shear and they were the primary reason for the asymmetrical distribution of thunderstorms.

Tropical Storm Chantal will move through an environment only marginally favorable for intensification during the next several days.  Chantal will move over water where the Sea Surface Temperature is near 25°C.  It will continue to be in a region of moderate westerly winds in the upper levels, which will cause vertical wind shear.  Tropical Storm Chantal could intensify slowly if the upper level winds do not get any stronger.  However, Chantal could weaken if the upper level winds do get stronger.

Tropical Storm Chantal will move around the northern end of a ridge in the middle troposphere over the Atlantic Ocean.  The ridge will steer Chantal toward the east during the next 24 hours.  Chantal could move more toward the southeast on Thursday when it nears the western end of the ridge.  On its anticipated track Tropical Storm Chantal is forecast to make a slow loop in the middle of the Atlantic Ocean.

Tropical Depression Three Forms East of Florida

Tropical Depression Three formed east of Florida on Monday.  More thunderstorms developed near the center of a small low pressure system over the Northwestern Bahamas on Monday afternoon and the National Hurricane Center (NHC) designated the system as Tropical Depression Three.  At 5:00 p.m. EDT on Monday the center of Tropical Depression Three was located at latitude 25.6°N and longitude 78.6°W which put it about 120 miles (195 km) southeast of West Palm Beach, Florida.  The depression was moving toward the northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1013 mb.

More thunderstorms developed around the center of a small low pressure system that was embedded in the northern end of a tropical wave over the Bahamas on Monday.  Most of the thunderstorms were forming in bands on the eastern side of the circulation.  Based on data from satellites NHC determined that a closed circulation had formed at the surface.  There were fewer thunderstorms in the western half of the circulation.  Storms in the eastern half of the depression were exhibiting upper level divergence to the north and east.

Tropical Depression Three will move through an environment somewhat favorable for intensification during the next 24 hours.  The depression will move over water where the Sea Surface Temperature is near 29°C.  It will be in under the western side of an upper level ridge.  The ridge could enhance upper level divergence on Tuesday.  The wind aloft will be relatively weak, although a thin upper trough near the east coast of the U.S. will produce southwesterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear but the shear will not be strong enough to prevent intensification.  The surface pressure is relatively high and that could slow any intensification.  A larger upper level trough will develop over the eastern U.S. on Tuesday and the trough will produce stronger southwesterly winds.  Those winds will create much more shear on Wednesday.

Tropical Depression Three will move around the western end of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer the depression toward the northwest during the next 12 hours.  Tropical Depression Three is likely to more more toward the north later on Tuesday when it reaches the western end of the ridge.  On its anticipated track the center of Tropical Depression Three could be near the southeast coast of Florida in about 12 hours.  The center is not currently forecast to make landfall, but the depression could bring squally weather and an increased chance for rain to the southeast coast of the U.S. during the next several days.

Tropical Storm Barry Drops Heavy Rain Over Lower Mississippi River Valley

Tropical Storm Barry dropped heavy rain over parts of the Lower Mississippi River Valley on Sunday.  The wind speed gradually decreased as Barry moved farther inland on Sunday and it was classified as a tropical depression on Sunday evening.  At 11:00 p.m. EDT on Sunday the center of Tropical Depression Barry was located at latitude 33.5°N and longitude 93.5°W which put it about 70 miles (110 km) north of Shreveport, Louisiana.  Barry was moving toward the north at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1008 mb.

Several rainbands in the southern and eastern portions of the circulation around former Tropical Storm Barry dropped persistent heavy rainfall on Sunday.  One rainband developed in an arc that ran from near Beaumont/Port Arthur, Texas to near Alexandria, Louisiana.  A weather station in Beaumont/Port Arthur measured 4.21 inches (10.69 cm) of rain.  A second rainband stretched from south of Abbeville, Louisiana to west of Baton Rouge.  A weather station in Abbeville measured 4.29 inches (10.90 cm) of rain and a station in Lafayette recorded 3.68 inches (9.34 cm).  A third rainband dropped heavy rain over parts of Mississippi.  A weather station in Hattiesburg, Mississippi measured 4.06 inches (10.31 cm) of rain.  A fourth rainband dropped heavy rain over parts of western Alabama.

The center of Tropical Depression Barry is forecast to move north-northeast across Arkansas on Monday.  Bands of showers and thunderstorms in the eastern side of the circulation around Barry are likely to drop heavy rain over parts of Mississippi, eastern Arkansas, eastern Louisiana, western Alabama and western Tennessee on Monday.  Flash flooding could occur in some locations.