Category Archives: Atlantic, Caribbean, and Gulf of Mexico

Atlantic TCs

Tropical Depression Two Strengthens to Tropical Storm Bill

Former Tropical Depression Two strengthened to Tropical Storm Bill east-northeast of Cape Hatteras on Monday night. At 11:00 p.m. EDT on Monday the center of Tropical Storm Bill was located at latitude 36.7°N and longitude 69.8°W which put it about 335 miles (540 km) east-northeast of Cape Hatteras, North Carolina. Bill was moving toward the northeast at 23 m.p.h. (37 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 1003 mb.

The circulation around former Tropical Depression Two intensified on Monday night and the National Hurricane Center upgraded the system to Tropical Storm Bill. Even though the circulation around Bill was stronger, the distribution of thunderstorms was asymmetrical. The strongest thunderstorms were occurring in bands on the eastern side of Tropical Storm Bill. Bands on the western side of Bill consisted mainly of showers and lower clouds. Winds to tropical storm force extended out 70 miles (110 km) in the southeastern quadrant of Tropical Storm Bill. The wind was blowing at less than tropical storm force in the other quadrants of Bill. An upper level trough east of the Great Lakes was producing strong southwesterly winds that were blowing toward the top of Tropical Storm Bill. Those winds were causing moderate vertical wind shear and they were the cause of the asymmetrical distribution of thunderstorms.

Tropical Storm Bill will move through an environment that will be only marginally favorable for intensification during the next 24 hours. Bill will move over the warmer water in the Gulf Stream where the Sea Surface Temperatures are near 27°C on Tuesday. However, the upper level trough east of the Great Lakes will continue to cause moderate vertical wind shear, which will inhibit intensification. Tropical Storm Bill could intensify a little more on Tuesday, but the wind shear is likely to increase by Tuesday night.

The upper level trough east of the Great Lakes will steer Tropical Storm Bill rapidly toward the northeast. On its anticipated track Tropical Storm Bill will pass southeast of Nova Scotia on Tuesday. Bill could approach southeast Newfoundland on Tuesday night.

Tropical Depression Two Forms East of Cape Hatteras

Tropical Depression Two formed east of Cape Hatteras on Monday morning. At 11:00 a.m. EDT on Monday the center of Tropical Depression Two was located at latitude 35.0°N and longitude 73.7°W which put it about 105 miles (165 km) east of Cape Hatteras, North Carolina. The tropical depression was moving toward the northeast at 21 m.p.h. (33 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 east of North Carolina on Monday morning and the National Hurricane Center designated the system as Tropical Depression Two. Bands of showers and thunderstorms also developed and the bands began to revolve around the center of the depression. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical depression. The removal of mass cause the surface pressure to decrease.

Tropical Depression Two will move through an environment favorable for intensification during the next 24 hours. The tropical depression will move over the warmer water of the Gulf Stream where the Sea Surface Temperatures are near 27°C. An upper level trough east of the Great Lakes will produce southwesterly winds which will blow toward the top of the depression. Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification. Tropical Depression Two will likely strengthen to a tropical storm during the next 12 hours.

The upper level trough east of the Great Lakes will steer Tropical Depression Two rapidly toward the northeast. On its anticipated track Tropical Depression Two will move away from the U.S. It could pass southeast of Nova Scotia on Tuesday.

Low Pressure over Southwest Gulf of Mexico

A broad area of low pressure was over the southwestern Gulf of Mexico on Sunday afternoon. The system was designated as Invest 92L. At 2:00 p.m. EDT on Sunday the center of Invest 92L was located at latitude 20.0°N and longitude 96.0°W which put it about 100 miles (160 km) north-northeast of Veracruz, Mexico. The area of low pressure was nearly stationary. The maximum sustained wind speed was 25 m.p.h. (40 km/h) and there were wind gusts to 35 m.p.h. (55 km/h). The minimum surface pressure was 1010 mb.

The broad area of low pressure exhibited a little more organization on Sunday afternoon. There was an apparent low level center located north-northeast of Veracruz, Mexico. However, there were few thunderstorms near the apparent center. Most of the thunderstorms were occurring far to the east and north of the apparent center. Some of the stronger winds were occurring in the thunderstorms far to the east and north of that center.

Invest 92L is likely to remain over the southwestern Gulf of Mexico during the next several days. The broad area of low pressure will be in an area somewhat favorable for the development of a tropical depression. Invest 92L will be over an area where the Sea Surface Temperatures are near 29°C. It will be under the northern part of an upper level ridge centered south of Mexico. The ridge will produce westerly winds which will blow across the top of the broad low pressure system. The westerly winds will cause moderate vertical wind shear, which will inhibit the formation of a tropical depression. The upper level ridge could move a little farther north in two or three days, which would cause the westerly winds to weaken. If that happens, then the conditions could become more favorable for the formation of a tropical depression. The National Hurricane Center is indicating that the probability is 50% that a tropical depression forms during the next five days.

Tropical Storm Ana Moves away from Bermuda

Tropical Storm Ana moved away from Bermuda on Sunday morning. At 11:00 a.m. EDT on Sunday the center of a Tropical Storm Ana was located at latitude 36.6°N and longitude 59.4°W which put it about 425 miles (690 km) northeast of Bermuda. Ana was moving toward the northeast at 14 m.p.h. (22 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 1007 mb.

Former Subtropical Storm Ana exhibited more of the characteristics of a tropical cyclone on Sunday morning and the National Hurricane Center reclassified Ana as a tropical storm. Most of the thunderstorms and the strongest wind speeds were occurring closer to the center of circulation, which are two important characteristics of a tropical cyclone. The strongest thunderstorms were occurring in narrow bands southeast of the center of Tropical Storm Ana. The strongest winds were occurring in those bands of thunderstorms. Winds to tropical storm force extended out 35 miles (55 km) in the southeastern quadrant of Ana. Bands in the other parts of the circulation consisted primarily of showers and lower clouds. The winds in the other quadrants of Tropical Storm Ana were blowing at less than tropical storm force.

Tropical Storm Ana will move through an environment unfavorable for a tropical storm during the next 36 hours. Ana will move over water where the Sea Surface Temperatures are near 20°C. Some drier air in the middle troposphere will wrap around parts of the circulation and the drier air will inhibit the development of thunderstorms. An upper level trough near the East Coast of the U.S. will move toward Ana. The trough will produce strong southwesterly winds which will cause the vertical wind shear to increase. A combination of more vertical wind shear, dry air and cool Sea Surface Temperatures will cause Ana to weaken.

The upper level trough will steer Tropical Storm Ana toward the northeast. On its anticipated track Tropical Storm Ana will continue to move away from Bermuda and Ana is likely to be absorbed by a cold front early next week.

Subtropical Storm Ana Forms Northeast of Bermuda

Subtropical Storm Ana formed northeast of Bermuda on Saturday morning. At 8:00 a.m. EDT on Saturday the center of a Subtropical Storm Ana was located at latitude 34.2°N and longitude 64.5°W which put it about 180 miles (290 km) northeast of Bermuda. Ana was moving toward the west-southwest at 3 m.p.h. (5 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 1006 mb.

A Tropical Storm Watch was in effect for Bermuda.

More thunderstorms developed near the center of a low pressure system northeast of Bermuda on Saturday morning and the National Hurricane Center designated the system as Subtropical Storm Ana. Thunderstorms were also occurring in bands southwest and northeast of the center of Ana. Bands in the northwestern and southeastern parts of the circulation consisted primarily of showers and lower clouds. The strongest winds were occurring in the northern half of Subtropical Storm Ana. Winds to tropical storm force extended out 200 miles (320 km) to the north of the center of circulation. Winds in the southern half of Ana were blowing at less than tropical storm force.

Subtropical Storm Ana will be in an environment only marginally favorable for intensification during the next 24 hours. Ana will move over water where the Sea Surface Temperatures are near 23°C. It will be near the center of an upper level low. The winds are weak near the center of the low and there will be little vertical wind shear. Some drier air will wrap around parts of the circulation and the drier air will inhibit the development of thunderstorms. Subtropical Storm Ana could get a little stronger on Saturday. An upper level trough near the East Coast of the U.S. will move toward Ana. The trough will produce southwesterly winds which will cause the vertical wind shear to increase on Sunday. More vertical wind shear will cause Ana to start to weaken.

Subtropical Storm Ana is forecast to remain relatively stationary on Saturday while it is near the center of the upper level low. The upper level trough near the East Coast will steer Ana toward the northeast on Sunday. On its anticipated track the center of Subtropical Storm Ana is forecast to remain northeast of Bermuda.

Tropical Storm Watch Issued for Bermuda

A Tropical Storm Watch was issued for Bermuda on Thursday. At 8:00 p.m. EDT on Thursday the center of a nontropical low pressure system designated as Invest 90L was located at latitude 34.9°N and longitude 55.0°W which put it about 635 miles (1010 km) east-northeast of Bermuda. Invest 90L was moving toward the north-northwest at 13 m.p.h. (20 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 1004 mb.

A non-tropical low pressure system east-northeast of Bermuda prompted the Bermuda Weather Service to issue a Tropical Storm Watch. The low pressure system exhibited a non-tropical structure on Thursday night. There were bands of showers and thunderstorms revolving around the center of the low pressure system. However, there were not any thunderstorms near the center of the low. The strongest winds were occurring in the outer part of the circulation around the low. The low pressure system may have also had a cold core in the upper levels.

The surface portion of the low pressure system was rotating counterclockwise around an upper level low. The upper level low was forecast to steer the surface low toward the west on Friday. If the surface low moves westward, it will move over warmer Sea Surface Temperatures. The low pressure system could extract more energy from the Atlantic Ocean and thunderstorms could form near the center of circulation. The structure of the low pressure system could make a transition to a subtropical or a tropical storm. The National Hurricane Center indicated that the probability was 80% that a subtropical or a tropical storm could form during the next 48 hours.

New Normals for Atlantic Hurricane Season

The National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center (CPC) announced that new normals have been computed for the Atlantic Hurricane season. CPC will now use normals based on the averages for the thirty year period from 1991-2020. The new normal number of named storms for the Atlantic basin is 14. The new normal for hurricanes is 7 and the normal for major hurricanes is 3.

Climatologists routinely calculate new normals based on the most recent 30 year period at the end of each decade. The previous normals for the Atlantic basin were based on the period from 1981 to 2010. The previous normal for the number of named storms was 12. The previous normal for the number of hurricanes was 6 and the previous normal for the number of major hurricanes was 3. The increases in the number of named storms and hurricanes reflect a more active period that began in 1995.

Hurricane Iota Drops Heavy Rain over Nicaragua and Honduras

Hurricane Iota was dropping heavy rain over Nicaragua and Honduras on Tuesday morning. At 10:00 a.m. EST on Tuesday the center of Hurricane Iota was located at latitude 13.7°N and longitude 85.2°W which put it about 135 miles (220 km) east of Tegucigapla, Honduras. Iota was moving toward the west at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 980 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Bluefields, Nicaragua to the Honduras/Guatemala border including the Bay Islands.

Hurricane Iota continued to move steadily inland over Nicaragua on Tuesday morning. The center of Iota was just to the east of the border between Nicaragua and Honduras. Hurricane Iota was dropping heavy rain over much of Nicaragua and Honduras. Bands of showers and thunderstorms continued to revolve around the center of Iota. Those rainbands were dropping rain fast enough to cause flash floods over many of the same places that were flooded by Hurricane Eta.

Hurricane Iota will continue to move westward during the next 24 to 36 hours. Iota will weaken to a tropical storm when its center moves over Honduras during the next few hours. Iota will likely be a tropical depression when the center reaches El Salvador on Tuesday night. Even though Hurricane Iota will weaken steadily, it will continue to drop heavy rain over Nicaragua, Honduras and El Salvador. Catastrophic flash floods could occur in that region.

Dangerous Hurricane Iota Hits Nicaragua

Dangerous Hurricane Iota hit Nicaragua with powerful winds and heavy rain on Monday night. At 10:00 p.m. EST on Monday the center of Hurricane Iota was located at latitude 13.6°N and longitude 83.4°W which put it about 30 miles (50 km) south of Puerto Cabezas, Nicaragua. Iota was moving toward the west at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 185 m.p.h. (300 km/h). The minimum surface pressure was 920 mb.

A Hurricane Warning was in effect for the portion of the coast from Sandy Bay Sirpi, Nicaragua to Punta Patuca, Honduras. Tropical Storm Warnings were in effect for the portions of the coast from Bluefields to Sandy Bay Sirpi, Nicaragua and from Punta Patuca to the Honduras/Guatemala border including the Bay Islands. Tropical Storm Warnings were also in effect for San Andres and Providencia Island.

Hurricane Iota was a powerful hurricane when it made landfall on the coast of Nicaragua just to the south of Puerto Cabezas. Iota was at Category 4 on the Saffir-Simpson Scale. Winds to hurricane force extended out 45 miles (75 km) from the center of circulation. Winds to tropical storm force extended out 175 miles (280 km) from the center, The Hurricane Intensity Index (HII) for Hurricane Iota was 33.3. The Hurricane Size Index (HSI) was 16.3 and the Hurricane Wind Intensity Size Index (HWISI) was 49.6. Iota was capable of causing regional significant damage.

Hurricane Iota made landfall on the same portion of the coast of Nicaragua devastated by Hurricane Eta two weeks ago. Iota will compound the damage caused by Eta. Strong winds will cause additional damage and they will destroy temporary shelters erected after Hurricane Eta. The winds blowing water toward the coast could cause a storm surge of up to 20 feet (6 meters) south of Puerto Cabezas.

Hurricane Iota will continue to move toward the west during the next 48 hours. On its anticipated track the center of Iota will move across northern Nicaragua, southern Honduras and El Salvador. The winds around Hurricane Iota will weaken steadily as it moves inland. Iota will drop heavy rain over Nicaragua, Honduras, and El Salvador. The heavy rain will cause flash floods and some floods will occur in the same locations flooded by Hurricane Eta.

Hurricane Iota Rapidly Intensifies to Cat. 5

Hurricane Iota rapidly intensified to Category 5 on the Saffir-Simpson Scale on Monday morning. At 10:00 a.m. EST on Monday the center of Hurricane Iota was located at latitude 13.5°N and longitude 82.0°W which put it about 100 miles (160 km) east-southeast of Cabo Gracias a Dios. Iota was moving toward the west at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 190 m.p.h. (305 km/h). The minimum surface pressure was 917 mb.

A Hurricane Warning was in effect for the portion of the coast from Sandy Bay Sirpi, Nicaragua to Punta Patuca, Honduras and for Providencia Island. A Hurricane Watch was in effect for San Andres. Tropical Storm Warnings were in effect for the portions of the coast from Bluefields to Sandy Bay Sirpi, Nicaragua and from Punta Patuca to the Honduras/Guatemala border including the Bay Islands. A Tropical Storm Warning was also in effect for San Andres.

Hurricane Iota intensified very rapidly on Sunday night and it reached Category 5 on the Saffir-Simpson Scale on Monday morning. A reconnaissance aircraft found a circular eye with a diameter of 14 miles (22 km) at the center of Iota. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Iota. Storms near the core generated strong upper level divergence which pumped mass away from the hurricane in all directions. The removal of large quantities of mass allowed the surface pressure to decrease rapidly which produced the very rapid intensification.

Winds to hurricane force extended out 35 miles (55 km) from the center of Hurricane Iota. Winds to tropical storm force extended out 150 miles (240 km) from the center. The Hurricane Intensity Index (HII) for Hurricane Iota was 35.0. The Hurricane Size Index (HSI) was 13.9 and the Hurricane Wind Intensity Size Index (HWISI) was 48.9. Hurricane Iota was capable of causing catastrophic damage.

Hurricane Iota will move through an capable of supporting a very intense hurricane on Monday. Iota will move over water where the Sea Surface Temperature is near 29°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. If the inner end of a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could begin. An eyewall replacement cycle could cause Hurricane Iota to start to weaken, but Iota could still be at Category 5 when it makes landfall on the northern coast of Nicaragua.

Hurricane Iota will move south of a high pressure system over the western Atlantic Ocean. The high will steer Iota toward the west during the next several days. On its anticipated track Iota could approach the coast a little to the south of the border between Nicaragua and Honduras on Monday night. Hurricane Iota will be a major hurricane when it reaches the coast and it could be at Category 5. Nicaragua and Honduras are still trying to cope with floods and other damage caused by Hurricane Eta. Another major hurricane could have catastrophic consequences for that region.