Monthly Archives: November 2020

Eta Strengthens to a Hurricane, Hurricane Watch for Tampa

A NOAA plane found that former Tropical Storm Eta had strengthened back into a hurricane on Wednesday morning. A Hurricane Watch was issued for a portion of the west coast of Florida that included Tampa and St. Petersburg. At 7:35 a.m. EST on Wednesday the center of Hurricane Eta was located at latitude 25.8°N and longitude 83.8°W which put it about 170 miles (280 km) south-southwest of Tampa, Florida. Eta was moving toward the north-northeast at 15 m.p.h. (24 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 983 mb.

A Hurricane Watch was issued for the portion of the coast from Anna Maria Island to Yankeetown, Florida. The Hurricane Watch included Tampa and St. Petersburg. A Tropical Storm Warning was issued for the portion of the coast from Bonita Beach to the Suwannee River, Florida. The Warning included Tampa and St. Petersburg. A Tropical Storm Warning was also in effect for the Dry Tortugas. A Tropical Storm Watch was issued for the portion of the coast from the Suwannee River to the Aucilla River, Florida.

Former Storm Eta strengthened back to a hurricane on Wednesday morning, but it appeared to be moving back into a pool of drier air over the Gulf of Mexico. Thunderstorms increased around the center of Eta when it was over the warm water in the Loop Current on Tuesday, but the thunderstorms were weakening on Wednesday morning. Thunderstorms near the center of Hurricane Eta were not as tall as they were on Tuesday. The strongest thunderstorms were occurring in bands north and east of the center of Eta. Bands south and west of the center consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 115 miles (185 km) on the eastern side of Hurricane Eta. Winds to tropical storm force extended out 50 miles in the western half of the circulation.

Hurricane Eta will move through an environment marginally favorable for intensification on Wednesday. Eta will move over water where the Sea Surface Temperature is near 27°C. An upper level trough over the central U.S. will produce southwesterly winds which blow toward the top of Eta’s circulation on Wednesday. Those winds will cause vertical wind shear, but the shear may not be strong enough to prevent Eta from getting stronger. The drier air over the Gulf of Mexico will limit intensification. Hurricane Eta is not likely to intensify much more on Wednesday because of the drier air. The upper level trough will move closer to Eta on Thursday and the wind shear will increase. The shear and drier air will cause Eta to weaken after it makes landfall on the west coast of Florida.

The upper level trough will steer Hurricane Eta toward the north-northeast during the next 24 to 36 hours. On its anticipated track the center of Hurricane Eta could approach Tampa on Wednesday night. The center of Eta is forecast to pass just to the west of Tampa and make landfall north of Tampa. Eta could be near hurricane strength when it passes near Tampa. Southwesterly winds blowing around the east side of Tropical Storm Eta could push water into Tampa Bay. Eta could cause a storm surge of up to 7 feet (2 meters). Hurricane Eta will also drop heavy rain over Central Florida. Floods could occur in that area. Eta could also cause widespread power outages in Central Florida.

Elsewhere over the Atlantic Ocean, Tropical Storm Theta churned southwest of the Azores. At 4:00 a.m. EST on Wednesday the center of Tropical Storm Theta was located at latitude 29.4°N and longitude 34.7°W which put it about 740 miles (1190 km) southwest of the Azores. Theta was moving toward the east-northeast at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 989 mb.

Tropical Storm Eta Turns Back Toward Florida

Tropical Storm Eta tuned back toward Florida on Tuesday evening. At 10:00 p.m. EST on Tuesday the center of Tropical Storm Eta was located at latitude 23.8°N and longitude 84.5°W which put it about 120 miles (195 km) west-northwest of the Dry Tortugas. Eta was moving toward the north- northeast at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 992 mb.

A Tropical Storm Warning was issued for the portion of the coast from Bonita Beach to the Suwannee River, Florida. The Warning included Tampa and St. Petersburg. A Tropical Storm Warning was also in effect for the Dry Tortugas. A Tropical Storm Watch was issued for the portion of the coast from the Suwannee River to the Aucilla River, Florida.

The circulation around Tropical Storm Eta exhibited more organization on Tuesday evening. The inner end of a rainband wrapped around the the eastern and northern side of the the center of circulation. There were occasional indications that an eye could be forming at the center of Eta. Bands of showers and thunderstorms were revolving around the center of Tropical Storm Eta. There were more thunderstorms in the bands in the northeastern half of Eta. Bands in the southwestern half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 70 miles (110 km) from the center of circulation.

Tropical Storm Eta will move through an environment more favorable for intensification on Wednesday. Eta will move over water where the Sea Surface Temperature is near 28°C. An upper level trough over the central U.S. will produce southwesterly winds which blow toward the top of Eta’s circulation on Wednesday. Those winds will cause vertical wind shear, but the shear will not be strong enough to prevent Eta from getting stronger. Tropical Storm Eta could strengthen back into a hurricane on Wednesday. The upper level trough will move closer to Eta on Thursday and the wind shear will increase. The shear could get strong enough to cause Eta to weaken.

The upper level trough will steer Tropical Storm Eta toward the north-northeast during the next 24 to 48 hours. On its anticipated track the center of Eta will pass west of the Florida Keys on Wednesday. The center of Tropical Storm Eta could approach Tampa on Thursday morning. Eta could be near hurricane strength when it passes near Tampa. Southwesterly winds blowing around the east side of Tropical Storm Eta could push water into Tampa Bay. Eta could cause a storm surge of up to 7 feet (2 meters).

Elsewhere over the Atlantic Ocean, Subtropical Storm Theta nade a transition to a strong tropical storm. At 10:00 p.m. EST on Tuesday the center of Tropical Storm Theta was located at latitude 29.4°N and longitude 35.5°W which put it about 770 miles (1235 km) southwest of the Azores. Theta was moving toward the east-northeast at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 989 mb.

Vamco Rapidly Intensifies to Typhoon East of Luzon

Former Tropical Storm Vamco rapidly intensified into a typhoon east of Luzon on Tuesday. At 10:00 p.m. EST on Tuesday the center of Typhoon Vamco was located at latitude 14.9°N and longitude 124.0°E which put it about 230 miles (375 km) east of Manila, Philippines. Vamco was moving toward the west at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h). The minimum surface pressure was 973 mb.

Typhoon Vamco intensified rapidly on Tuesday. A circular eye was visible on satellite images. 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 Typhoon Vamco. Storms near the center were generating upper level divergence which was pumping mass away from the typhoon. Winds to typhoon force extended out 30 miles (50 km) from the center of Vamco. Winds to tropical storm force extended out 175 miles (280 km) from the center of circulation.

Typhoon Vamco will move through an environment that will be favorable for intensification during the next 12 hours. Vamco will move over water where the Sea Surface Temperature is near 28°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Vamco will continue to intensify rapidly and it could strengthen to the equivalent of a major hurricane.

Typhoon Vamco will move south of a high pressure system over the Western North Pacific Ocean. The high will steer Vamco toward the west during the next several days. On its anticipated track Typhoon Vamco will make landfall on the east coast of Luzon in about 12 hours. The center of Vamco will pass north of Manila and the core of Typhoon Vamco could come close to San Francisco.

Typhoon Vamco will bring strong winds and heavy rain to Luzon. Vamco will be capable of causing major damage. The heavy rain will cause flash floods in part of Luzon. Typhoon Vamco could cause a storm surge of up to 10 feet (3 meters) on the east coast of Luzon. Vamco will weaken when the center passes over Luzon, but it is likely to still be a typhoon when it passes north of Manila. Typhoon Vamco is also likely to cause widespread power outages on Luzon.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Etau was dropping heavy rain over Cambodia. At 10:00 p.m. EST on Tuesday the center of Tropical Depression Etau was located at latitude 12.5°N and longitude 105.5°E which put it about 100 miles (160 km) northeast of Phnom Penh, Cambodia. Etau was moving toward the west at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 25 m.p.h. (40 km/h) and there were wind gusts to 30 m.p.h. (50 km/h). The minimum surface pressure was 1006 mb.

Tropical Storm Eta Reorganizes Near Western Cuba

Tropical Storm Eta reorganized near western Cuba on Monday night. At 10:00 p.m. EST on Monday the center of Tropical Storm Eta was located at latitude 23.2°N and longitude 85.2°W which put it about 90 miles (145 km) north-northwest of the western tip of Cuba. Eta was moving toward the southwest at 9 m.p.h. (15 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 995 mb.

A Tropical Storm Watch was in effect for the Cuban provinces of La Habana, Artemisa, Mayabeque, Pinar del Rio and the Isle of Youth.

The circulation around Tropical Storm Eta exhibited more organization on Monday night. Thunderstorms redeveloped around the center of circulation. Storms near the center generated upper level divergence which pumped mass away from the tropical storm. Thunderstorms also increased in bands revolving around the center of Tropical Storm Eta. Winds to tropical storm force extended out 120 miles (195 km) on the northern side of Eta. Winds to tropical storm force only extended out 50 miles in the southern half of the circulation.

Tropical Storm Eta will move through an environment more favorable for intensification on Tuesday. Eta will move over the Loop Current which transports warm water from the Caribbean Sea into the southeast Gulf of Mexico. Tropical Storm Eta will be over water where the Sea Surface Temperature is near 29°C. An upper level low centered over Cuba will produce northerly winds which blow toward the top of Eta’s circulation on Tuesday. Those winds will cause vertical wind shear, but the shear will slowly decrease. Tropical Storm Eta will intensify on Tuesday and it could strengthen back into a hurricane.

The upper low over Cuba has been steering Tropical Storm Eta toward the southwest, but the steering winds are likely to weaken on Tuesday. Eta could stall northwest of Cuba. An upper level trough over the Rocky Mountains will move east during the next several days. The southern end of the trough could start to pull Eta toward the north on Wednesday.

Elsewhere over the Atlantic Ocean, an extratropical cyclone southwest of the Azores made a transition to Subtropical Storm Theta. At 10:00 p.m. EST on Monday the center of Tropical Storm Theta was located at latitude 28.8°N and longitude 40.3°W which put it about 995 miles (1600 km) southwest of the Azores. Theta was moving toward the east at 15 m.p.h. (24 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 1000 mb.

Tropical Storm Etau Nears Vietnam, Vamco Threatens Philippines

Tropical Storm Etau neared Vietnam on Monday and newly formed Tropical Storm Vamco threatened the Philippines. At 4:00 a.m. EST on Monday the center of Tropical Storm Etau was located at latitude 12.8°N and longitude 111.6°E which put it about 170 miles (280 km) east of Tuy Hoa, Vietnam. Etau was moving toward the west 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 995 mb.

The distribution of thunderstorms around Tropical Storm Etau was asymmetrical. Etau was moving under the southern part of an upper level ridge over eastern Asia. The ridge was producing easterly winds which were blowing toward the top of Etau. Those winds were causing moderate vertical wind shear. The shear was causing the stronger thunderstorms to occur in bands on the western side of Tropical Storm Etau. The bands in the eastern side of Etau consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 150 miles (240 km) in the northern half of Tropical Storm Etau. Winds to tropical storm force only extended out 50 miles in the southern half of Etau.

Tropical Storm Etau will move south of a high pressure system over eastern Asia. The high will steer Etau toward the west during the next two days. On its anticipated track the center of Etau will make landfall in Vietnam near Tuy Hoa in about 12 hours.

Tropical Storm Etau will move through an environment that should allow it to maintain its intensity until it makes landfall in Vietnam. Etau will move over water where the Sea Surface Temperature is near 28°C. The upper level ridge over eastern Asia will continue to cause moderate vertical wind shear which will limit intensification.

Since the stronger thunderstorms are in the western half of Tropical Storm Etau, heavy rain will fall over central Vietnam before the center of Etau makes landfall. Etau will drop locally heavy rain over central Vietnam, northern Cambodia, southern Laos and northeastern Thailand. The ground is already saturated in that region and flash floods are likely.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Vamco developed east of the Philippines. At 4:00 a.m. EST on Monday the center of Tropical Storm Vamco was located at latitude 12.8°N and longitude 130.6°E which put it about 370 miles (605 km) east of Laoang, Philippines. Vamco was moving toward the northwest at 13 m.p.h. (20 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 1002 mb. Tropical Storm Vamco is forecast to move toward Luzon and to strengthen into a typhoon.

Tropical Storm Eta Drops Heavy Rain on South Florida

Tropical Storm Eta dropped heavy rain on parts of South Florida on Sunday. At 10:00 p.m. EST on Sunday the center of Tropical Storm Eta was located at latitude 24.6°N and longitude 80.5°W which put it about 40 miles (65 km) east of Marathon, Florida. Eta was moving toward the northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 993 mb.

A Hurricane Warning was in effect for the Florida Keys from Ocean Reef to the Dry Tortugas. A Hurricane Watch was in effect for the portion of the coast from Golden Beach to Bonita Beach, Florida. A Tropical Storm Warning was in effect for the portion of the coast from the Brevard/Volusia County Line to Englewood, Florida. A Tropical Storm Warning was in effect for Lake Okeechobee. A Tropical Storm Warning was in effect for the Northwestern Bahamas including the Abacos, Andros Island, the Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence. A Tropical Storm Watch was in effect for the portion of the coast from Englewood to Anna Maria Island, Florida. A Tropical Storm Watch was in effect for the Cuban provinces of La Habana, Artemisa, Mayabeque, Pinar del Rio and the Isle of Youth.

The circulation around Tropical Storm Eta weakened when it moved across Cuba on Sunday morning. Drier air wrapping around the southern side of an upper level low over the northwestern Caribbean Sea was pulled into the core of Tropical Storm Eta and the thunderstorms near the core weakened. Even though the inner core of Eta was weaker, the tropical storm still had a well developed low level circulation. Stronger thunderstorms were occurring in bands north and east of the center of Tropical Storm Eta. Bands south and west of the center consisted primarily of showers and lower clouds.

The asymmetric distribution of thunderstorms and the lack of thunderstorms in the core of Tropical Storm Eta was also affecting the wind pattern. Low pressure at the center of Eta and a strong high pressure system over the Atlantic Ocean generated a strong pressure gradient northeast of the center of circulation. Winds to tropical storm force extended out 300 miles (485 km) to the northeast of the center of Tropical Storm Eta. Several stations along the southeast coast of Florida were reporting winds to tropical storm force. Winds to tropical storm force extended out 150 mile (240 km) northwest and southeast of the center of Eta. Winds to tropical storm force only extended out 40 miles (65 km) in the southwestern quadrant of Eta.

Tropical Storm Eta will move through an environment more favorable for intensification during the next several days. Eta will move over water where the Sea Surface Temperature is near 28°C. The upper level low over the northwestern Caribbean Sea will produce easterly winds which blow toward the top of Eta’s circulation on Monday. Those winds will cause vertical wind shear, but the shear will slowly decrease. Tropical Storm Eta could move over the Loop Current when it moves west of the Florida Keys. The Sea Surface Temperature of the water in the Loop Current is near 29°C. Eta is likely to strengthen to a hurricane when it moves over the Loop Current.

Counterclockwise rotation around the upper low over the northwestern Caribbean Sea will steer Tropical Storm Eta toward the west during the next 12 hours. Eta will move more toward the southwest on Monday night. Eta could stall for a period on Tuesday. An upper level trough over the western U.S. will move toward the Gulf of Mexico. The upper level trough will start to pull Eta toward the north later in the week. Eta could move toward the west coast of Florida on Wednesday.

Tropical Storm Eta will move across the Lower Florida Keys during the next 12 hours. Eta will produce gusty winds over Keys on Monday. Those winds could cause a storm surge of up to 4 feet (1.3 meters). Bands revolving around the northern side of Tropical Storm Eta will continue to drop heavy rain over parts of South Florida. Urban flooding will occur in some locations and Flash Flood Watches are in effect for South Florida.

Tropical Storm Eta Strengthens, Hurricane Watch for Florida

Tropical Storm Eta strengthened a little more Saturday evening and A Hurricane Watch was issued for parts of South Florida and the Florida Keys. At 10:00 p.m. EST on Saturday the center of Tropical Storm Eta was located at latitude 20.7°N and longitude 79.9°W which put it about 140 miles (220 km) west-southwest of Camaguey, Cuba. Eta was moving toward the northeast at 13 m.p.h. (20 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 991 mb.

A Hurricane Watch was in effect for the portion of the coast from Deerfield Beach to Bonita Beach, Florida and for the Florida Keys from Ocean Reef to the Dry Tortugas. A Tropical Storm Warning was in effect for the portion of the coast from the Brevard/Volusia County Line to Englewood, Florida. A Tropical Storm Warning was in effect for the Florida Keys from Ocean Reef to the Dry Tortugas. Tropical Storm Warnings were in effect for the Cayman Islands and the Cuban provinces of Camaguey, Ciego de Avila, Sancti Spiritus, Villa Clara, Cienfuegos and Matanzas. A Tropical Storm Warning was in effect for the Northwestern Bahamas including the Abacos, Andros Island, the Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence. A Tropical Storm Watch was in effect for the portion of the coast from Englewood to Anna Maria Island, Florida. A Tropical Storm Watch was in effect for Lake Okeechobee. A Tropical Storm Watch was in effect for the Cuban provinces of La Habana, Artemisa y Mayabeque, Pinar del Rio and the Isle of Youth.

The circulation around Tropical Storm Eta continued to strengthen on Saturday evening. There were occasional infrared satellite images that suggested a small eye could be forming at the center of Eta. There was a ring of strong thunderstorms around the center and the strongest winds were occurring in that ring of storms. Storms near the core of Eta generated upper level divergence which pumped mass away to the northeast of the tropical storm. The strongest rainbands were in the northern and eastern parts of the circulation around Tropical Storm Eta. Bands south and west of the center consisted primarily of showers and lower clouds. The strongest winds were blowing in the northern half of Eta. Winds to tropical storm force extended out 120 miles (195 km) from the center of circulation.

Tropical Storm Eta will move through an environment favorable for intensification during the few hours. Eta will move over water where the Sea Surface Temperature is near 29°C. An upper level trough over the Gulf of Mexico will produce southwesterly winds which will blow toward the top of Tropical Storm Eta. Those winds will cause moderate vertical wind shear. The shear will inhibit intensification, but it may not be strong enough to prevent Eta from getting stronger. Tropical Storm Eta is likely to weaken when it crosses Cuba on Saturday night. The Sea Surface Temperature of the water north of Cuba is near 29°C. So, Eta is likely to strengthen after it crosses Cuba. Eta could strengthen to a hurricane when it approaches the Florida Keys.

The upper level trough will make a transition to a cutoff low over the southeastern Gulf of Mexico which will be the primary feature steering Eta. Counterclockwise rotation around the cutoff low will pull Eta toward the northeast on Saturday night . On its anticipated track Eta could move across Cuba west of Camaguey on Saturday night. Tropical Storm Eta will drop heavy rain when it moves across Cuba and flash floods could occur. The upper low will steer Eta toward the northwest on Sunday. Eta will approach the Florida Keys on Sunday night. It could be a hurricane at that time. Eta will bring gusty winds and locally heavy rain to the Florida Keys and South Florida. A high pressure system over the Atlantic Ocean will interact with the circulation around the northern side of Eta to produce strong easterly winds which will blow toward the coast of Southeast Florida. Those winds will push water toward the coast and the water level could rise up to six feet (2 meters). The strong winds could also cause widespread power outages in South Florida.

Eta Strengthens Back to Tropical Storm, Warnings Issued for Florida

Former Tropical Depression Eta strengthened back to a tropical storm on Saturday morning and Tropical Storm Warnings for parts of South Florida and the Florida Keys. At 1:00 p.m. EST on Saturday the center of Tropical Storm Eta was located at latitude 20.0°N and longitude 80.1°W which put it about 50 miles (80 km) north of Grand Cayman Island. Eta was moving toward the northeast at 17 m.p.h. (28 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 995 mb.

A Tropical Storm Warning was issued for the portion of the coast from Golden Beack to Chokoloskee, Florida. A Tropical Storm Warning was issued for the Florida Keys from Ocean Reef to the Dry Tortugas. Tropical Storm Warnings were in effect for the Cayman Islands and the Cuban provinces of Camaguey, Ciego de Avila, Sancti Spiritus, Villa Clara, Cienfuegos and Matanzas. A Tropical Storm Warning was in effect for the Northwestern Bahamas including the Abacos, Andros Island, the Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence. Tropical Storm Watches were issued for the portion of the coast from Chokoloskee to Englewood, Florida and from JGolden Beach to the Brevard/Volusia County Line. A Tropical Storm Watch was in effect for Lake Okeechobee. A Tropical Storm Watch was in effect for the Cuban provinces of La Habana, Artemisa y Mayabeque, Pinar del Rio and the Isle of Youth.

Observations from a U.S. Air Force Reserve Hurricane Hunter plane and from Grand Cayman Island indicated that the center of former Tropical Depression Eta reformed in a cluster of thunderstorms near Grand Cayman. The reconnaissance plane was still sampling the circulation around Tropical Storm Eta but the available date suggested that it was much better organized. The inner end of a rainband was wrapping around the eastern and northern part of the center of circulation. Other bands of showers and thunderstorms were revolving around the core of Eta. Storms near the core were generating upper level divergence which was pumping mass away to the northeast of the tropical storm. The removal of mass was allowing the surface pressure to decrease and Tropical Storm Eta was intensifying more quickly. Winds to tropical storm force extended out 60 miles (95 km) from the center of Eta.

Tropical Storm Eta will move through an environment favorable for intensification during the next 12 to 18 hours. Eta will move over water where the Sea Surface Temperature is near 29°C. It will initially be under an upper level ridge where the winds are weaker. There will be less vertical wind shear under the ridge. Eta could intensify rapidly during the next 12 hours and it could strengthen to a hurricane. Eta is likely to weaken when it crosses Cuba on Saturday night . The Sea Surface Temperature of the water north of Cuba is near 29°C. So, Eta is likely to strengthen after it crosses Cuba. Eta could strengthen to a hurricane when it approaches South Florida. An upper level low over the western Gulf of Mexico will produce southwesterly winds which will blow toward the top of Eta on Sunday. Those winds will cause more vertical wind shear, which could limit further intensification of Eta. The wind shear caused by the upper low could eventually cause Eta to develop a structure more like a subtropical cyclone.

An upper low over the western Gulf of Mexico will be the primary feature steering Eta. Counterclockwise rotation around the cutoff low will pull Eta more toward the northeast on Saturday. On its anticipated track Eta could move across Cuba on Saturday night and it could drop heavy rain when it does so. The upper low will steer Eta toward the northwest on Sunday. Eta will approach South Florida and the Florida Keys on Sunday night. It could be a hurricane at that time. Eta will bring gusty winds and locally heavy rain to the Florida Keys and South Florida. A high pressure system over the Atlantic Ocean will interact with the circulation around the northern side of Eta to produce strong easterly winds which will blow toward the coast of Southeast Florida. Those winds will push water toward the coast and the water level could rise up to six feet (2 meters).

Tropical Depression Eta Prompts Watches for South Florida, Keys and Northwest Bahamas

Expected intensification of Tropical Depression Eta prompted the issuance of Tropical Storm Watches for parts of South Florida, the Florida Keys and the Northwestern Bahamas. At 10:00 p.m. EST on Friday the center of Tropical Depression Eta was located at latitude 18.0°N and longitude 85.2°W which put it about 275 miles (445 km) west-southwest of Gran Cayman Island. Eta was moving toward the northeast 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 1002 mb.

Tropical Storm Warnings were in effect for the Cayman Islands and the Cuban provinces of Camaguey, Ciego de Avila, Sancti Spiritus, Villa Clara, Cienfuegos and Matanzas. A Tropical Storm Watch was issued for the coast of South Florida from Jupiter Inlet to Bonita Beach. It included Lake Okeechobee. A Tropical Storm Watch was issued for the Florida Keys from Ocean Reef to the Dry Tortugas. A Tropical Storm Watch was in effect for the Cuban provinces of La Habana, Artemisa y Mayabeque, Pinar del Rio and the Isle of Youth. A Tropical Storm Watch was issued for the Northwestern Bahamas including the Abacos, Andros Island, the Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence.

The structure of the circulation around Tropical Depression Eta exhibited a little more organization on satellite imagery on Friday evening. More thunderstorms developed near the center of Eta. There were also more thunderstorms in bands in the eastern half of the circulation. Bands in the western half of Eta contained more showers and lower clouds. Storms near the center of Eta generated upper level divergence which pumped mass away to the northeast of the depression. Removal of mass could allow the surface pressure to decrease on Saturday.

Tropical Depression Eta will move through an environment favorable for intensification on Saturday. Eta will move over water where the Sea Surface Temperature is near 29°C. It will initially be under an upper level ridge where the winds are weaker. There will be less vertical wind shear under the ridge and Eta is likely to strengthen back to a tropical storm on Saturday. A upper level low over the western Gulf of Mexico will produce southwesterly winds which will blow toward the top of Eta on Sunday. Those winds will cause more vertical wind shear, which could limit further intensification of Eta. Eta is also likely to weaken when it crosses Cuba on Sunday. The Sea Surface Temperature of the water north of Cuba is near 29°C. So, Eta is likely to strengthen after it crosses Cuba. Eta could strengthen to a hurricane when it approaches South Florida. The wind shear caused by the upper low could eventually cause Eta to develop a structure more like a subtropical cyclone.

The upper low over the western Gulf of Mexico will be the primary feature steering Eta. Counterclockwise rotation around the cutoff low will pull Eta more toward the northeast on Saturday. Eta could pass near the Cayman Islands on Saturday. Eta is likely to move across Cuba on Sunday morning and it could drop heavy rain when it does so. The upper low will steer Eta toward the northwest on Sunday. Eta will approach South Florida and the Florida Keys on Sunday night. It could bring gusty winds and locally heavy rain to the Keys and South Florida. A high pressure system over the Atlantic Ocean will interact with the circulation around the northern side of Eta to produce strong easterly winds which will blow toward the coast of Southeast Florida. Those winds will push water toward the coast and the water level will rise several feet.

Tropical Storm Atsani Passes Just South of Taiwan

Tropical Storm Atsani passed just south of Taiwan early on Friday. At 4:00 a.m. EST on Friday the center of Tropical Storm Atsani was located at latitude 21.5°N and longitude 120.7°E which put it about 30 miles (50 km) south of Taiwan. Atsani was moving toward the west-northwest at 12 m.p.h. (19 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 995 mb.

The center of Tropical Storm Atsani passed just to the south of the southern tip of Taiwan early on Friday. Radar images from the Taiwan Central Weather Bureau showed the well organized structure of Tropical Storm Atsani.

There was a small, tight center of circulation. The center was surrounded by a partial eyewall and the strongest winds were occurring in eyewall. Multiple bands of showers and thunderstorms were revolving around the core of Tropical Storm Atsani. Bands in the northern half of Atsani were dropping heavy rain over the southern half of Taiwan. The heaviest rain was falling in parts of southeastern Taiwan where the wind was pushing air up the eastern slopes of mountains. Flash floods are possible in those areas. Winds to tropical storm force extended out 100 miles (160 km) from the center of Atsani.

Tropical Storm Atsani will be in an environment favorable for intensification during the next 12 to 24 hours. Atsani will move over water where the Sea Surface Temperature is near 28°C. It will be in an area where the upper level winds are weaker and there will be little vertical wind shear. Tropical Storm Atsani could intensify during the next 24 hours and there is a chance it could strengthen into a typhoon. An upper level trough over eastern Asia will approach Atsani during the weekend. The trough will produce stronger southwesterly winds which will cause more vertical wind shear. Tropical Storm Atsani will weaken when the wind shear increases. If the shear is strong enough, the upper level winds could blow the top half of Atsani northeast of the low level circulation.

Tropical Storm Atsani will move south of a ridge of high pressure over the Western North Pacific Ocean. The high will steer Atsani toward the west during the next day or so. If the wind shear blows the top half of Tropical Storm Atsani northeast of the lower level circulation, then a surface high pressure system over eastern Asia could push the lower half of Atsani toward the southeast. On its anticipated track Tropical Storm Atsani will pass southeast of Hong Kong and it could eventually move toward Vietnam.

Elsewhere over the Western North Pacific Ocean, the remnants of former Typhoon Goni were dropping heavy rain over parts of Vietnam. At 4:00 a.m. EST on Friday the center of Tropical Depression Goni was located at latitude 13.8°N and longitude 108.3°E which put it about 50 miles (80 km) west of Quy Nhon, Vietnam. Goni was moving toward the west at 7 m.p.h. (11 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 1003 mb. Tropical Depression Goni is dropping heavy rain over ground that is already saturated and the rain will make ongoing floods worse.