Monthly Archives: May 2021

Tropical Storm Blanca Develops Southwest of Mexico

Tropical Storm Blanca developed southwest of Mexico on Monday. At 5:00 p.m. EDT on Monday the center of Tropical Storm Blanca was located at latitude 13.5°N and longitude 108.9°W which put it about 520 miles (840 km) south-southwest of Manzanillo, Mexico. Blanca 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 1003 mb.

Former Tropical Depression Two-E strengthened on Monday afternoon and the National Hurricane Center named the system Tropical Storm Blanca. The circulation around Blanca organized quickly on Monday. More thunderstorms formed near the center of circulation. The inner end of a rainband wrapped around the center of circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. The circulation around Tropical Storm Blanca was small. Winds to tropical storm force extended out 25 miles from the center of Blanca.

Tropical Storm Blanca will move through an environment favorable for intensification during the next 24 hours. Blanca will move over water where the Sea Surface Temperatures are near 29°C. It will move through an area where the upper level winds are weak and there will be little vertical wind shear. Tropical Storm Blanca will intensify during the next 24 hours and it could strengthen to a hurricane.

Tropical Storm Blanca will move south of a subtropical high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Blanca toward the west-northwest during the next two days. On its anticipated track Tropical Storm Blanca will move away from Mexico.

TD 04W Strengthens to Tropical Storm Choi-wan East of Mindanao

Tropical Depression 04W strengthened to Tropical Storm Choi-wan east of Mindanao on Sunday. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Choi-wan was located at latitude 8.2°N and longitude 130.4°E which put it about 260 miles (420 km) east of Mindanao. Choi-wan was moving toward the northwest at 9 m.p.h. (15 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 997 mb.

The circulation around former Tropical Depression 04W exhibited more organization on Sunday night and the Japan Meteorological Agency named the system as Tropical Storm Choi-wan. Although the circulation around Choi-wan exhibited more organization, the distribution of thunderstorms was asymmetrical. The strongest thunderstorms were occurring in bands in the western side of Tropical Storm Choi-wan. Bands in the eastern half of the tropical storm consisted of showers and lower clouds. Storms west of the center of Choi-wan generated upper level divergence that pumped mass away to the west and south of the tropical storm. Winds to tropical storm force extended out 85 miles (135 km) from the center of circulation.

Tropical Storm Choi-wan will move through an environment favorable for intensification during the next 24 hours. Choi-wan will move over water where the Sea Surface Temperatures are near 30°C. It will move under the southeastern part of an upper level ridge centered northeast of the Philippines. The ridge will produce easterly winds which will blow toward the top of the tropical storm. Those winds are the reason for the asymmetrical distribution of thunderstorms and they will continue to cause vertical wind shear. The wind shear will not be enough to prevent intensification, but the shear will limit the rate of intensification. Tropical Storm Choi-wan will likely intensify during the next 24 hours.

Tropical Storm Choi-wan will move around the western side of a subtropical high pressure system over the Western North Pacific Ocean. The high will steer Choi-wan toward the northwest during the next 36 hours. On its anticipated track Tropical Storm Choi-wan could approach the central Philippines in 36 hours.

Tropical Depression 04W Forms Southwest of Palau

Tropical Depression 04W formed southwest of Palau on Saturday. At 11:00 p.m. EDT on Saturday the center of Tropical Depression 04W was located at latitude 6.8°N and longitude 133.5°E which put it about 75 miles (120 km) southwest of Palau. It was moving toward the west-northwest at 8 m.p.h. (13 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 1003 mb.

The circulation around Tropical Depression 04W was still organizing on Saturday night. Bands of thunderstorms were revolving around the center of the depression. The strongest rainbands were in the western half of the circulation. Bands on the eastern side of the tropical depression consisted mainly of showers and lower clouds. Storms near the center of circulation began to generate upper level divergence that pumped mass away to the west and north of the depression.

Tropical Depression 04W will move through an environment favorable for intensification during the next 24 hours. The tropical depression will move over water where the Sea Surface Temperatures are near 30°C. It will move under the southern side of an upper level ridge east of the Philippines. The ridge will produce easterly winds which will blow toward the top of the depression. Those winds will cause vertical wind shear. The wind shear will not be enough to prevent intensification, but the shear will limit the rate of intensification. Tropical Depression 04W will likely intensify into a tropical storm during the next 24 hours.

Tropical Depression 04W will move around the western side of a subtropical high pressure system over the Western North Pacific Ocean. The high will steer the tropical depression toward the northwest during the next 48 hours. On its anticipated track Tropical Depression 04W will move farther away from Palau. The tropical depression is forecast to pass east of the Philippines.

Tropical Cyclone Yaas Hits Northeast India

Tropical Cyclone Yaas hit northeastern India early on Wednesday. At 5:00 a.m. EDT on Wednesday the center of Tropical Cyclone Yaas was located at latitude 21.8°N and longitude 86.8°E which put it about 115 miles (185 km) southwest of Kolkata, India. Yaas was moving toward the northwest at 7 m.p.h. (11 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 978 mb.

Tropical Cyclone Yaas made landfall on the coast of northeastern India early on Wednesday. The center of Yaas crossed the coastline near Balasore, India. Tropical Cyclone Yaas was the equivalent of a strong tropical storm at the time when it made landfall. Winds to tropical storm force extended out 160 miles (260 km) on the eastern side of Yaas over the northern Bay of Bengal. Winds to tropical storm force extended out 140 miles (225 km) on the western side of the circulation which was over northern Odisha.

Tropical Cyclone Yaas will move slowly toward the northwest over northeastern India during the next day or so. Yaas will weaken gradually as it moves farther inland. Tropical Cyclone Yaas will produce gusty winds over northern Odisha during the next 24 hours. The wind could cause sporadic power outages. Yaas will also drop locally heavy rain over parts of northeastern India and flash floods could occur in some locations. The heaviest rain will fall in the western side of the circulation. Tropical Cyclone Yaas may have caused a storm surge of up to 7 feet (2 meters) along the coast of northern Bay of Bengal. The water level should drop slowly as Yaas moves farther inland and weakens.

Tropical Cyclone Yaas Strengthens to Equivalent of Hurricane/Typhoon

Tropical Cyclone Yaas strengthened to the equivalent of a hurricane/typhoon over the northern Bay of Bengal on Tuesday. At 11:00 a.m. EDT on Tuesday the center of Tropical Cyclone Yaas was located at latitude 20.1°N and longitude 89.1°E which put it about 195 miles (310 km) south of Kolkata, India. Yaas was moving toward the north at 11 m.p.h. (17 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 972 mb.

Tropical Cyclone Yaas intensified to the equivalent of a hurricane/typhoon south of Kolkata on Tuesday. A broken ring of thunderstorms surrounded the center of Yaas and the strongest winds were occurring in the storms in the ring. Bands of showers and thunderstorms were revolving around the center of Tropical Cylone Yaas. Storms near the center of circulation generated upper level divergence that pumped mass away to the west and north of the tropical cyclone. Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Yaas. Winds to tropical storm force extended out 160 miles (260 km) from the center of circulation.

Tropical Cyclone Yaas will move through an environment favorable for intensification during the next 12 hours . Yaas will move over water where the Sea Surface Temperatures are near 30°C. It will move under the southern part of an upper level ridge centered over Bangladesh. The ridge will produce easterly winds which will blow toward the top of the tropical cyclone. Those winds will cause some vertical wind shear, but the shear may not be strong enough to prevent intensification. Tropical Cyclone Yaas could strengthen gradually during the next 12 hours.

Tropical Cyclone Yaas will move around the western side of a high pressure system over Southeast Asia. The high will steer the tropical cyclone toward the north-northwest during the next 36 hours. On its anticipated track Yaas will make landfall on the coastline of Odisha southwest of Kolkata in 15 hours. Tropical Cyclone Yaas will be the equivalent of a hurricane/typhoon when it approaches the coast. Yaas is likely to bring damaging winds and locally heavy rain to the coastal regions of Odisha and West Bengal. Heavy rain could cause flash floods over parts of northeastern India. The coast along the northern Bay of Bengal is very vulnerable to a storm surge. Tropical Cyclone Yaas will cause a dangerous storm surge of up to 9 feet (3 meters) on parts of the coast around the northern Bay of Bengal.

Tropical Cyclone Yaas Intensifies South of Kolkata

Tropical Cyclone Yaas intensified over the northern Bay of Bengal on Monday night. At 11:00 p.m. EDT on Monday the center of Tropical Cyclone Yaas was located at latitude 18.5°N and longitude 88.0°E which put it about 305 miles (495 km) south of Kolkata, India. Yaas was moving toward the north-northwest at 13 m.p.h. (20 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 975 mb.

Tropical Cyclone Yaas strengthened to almost the equivalent of a hurricane/typhoon south of Kokata on Monday night. The distribution of thunderstorms around Yaas remained asymmetrical. Most of the thunderstorms were occurring in bands in the western half of Tropical Cyclone Yaas. Bands in the eastern half of the circulation consisted primarily of showers and lower clouds. The inner end of a rainband wrapped around the western and southern sides of the center of Yaas. Storms near the center of circulation generated upper level divergence that pumped mass away to the west and north of the tropical cyclone. Winds to tropical storm force extended out 160 miles (260 km) from the center of circulation.

Tropical Cyclone Yaas will move through an environment favorable for intensification during the next 24 hours. Yaas will move over water where the Sea Surface Temperatures are near 30°C. It will move under the southwestern part of an upper level ridge over the Bay of Bengal. The ridge will produce easterly winds which will blow toward the top of the tropical cyclone. Those winds will cause some vertical wind shear, but the shear will not be enough to prevent intensification. Tropical Cyclone Yaas will strengthen to the equivalent of a hurricane/typhoon during the next 24 hours.

Tropical Cyclone Yaas will move around the western side of a high pressure system over Southeast Asia. The high will steer the tropical cyclone toward the north-northwest during the next 36 hours. On its anticipated track Yaas will make landfall on the coastline of Odisha southwest of Kolkata in 24 hours. Tropical Cyclone Yaas will be the equivalent of a hurricane/typhoon when it approaches the coast. Yaas is likely to bring damaging winds and locally heavy rain to the coastal regions of Odisha and West Bengal. Tropical Cyclone Yaas will cause a dangerous storm surge of up to 9 feet (3 meters) on parts of the coast around the northern Bay of Bengal.

Tropical Cyclone Forms over Bay of Bengal

A tropical cyclone formed over the Bay of Bengal on Sunday night. At 11:00 p.m. EDT on Sunday the center of a tropical cyclone was located at latitude 16.2°N and longitude 89.8°E which put it about 465 miles (750 km) south-southeast of Kolkata, India. The tropical cyclone was moving toward the northeast at 8 m.p.h. (13 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 993 mb.

A low pressure system over the Bay of Bengal strengthened on Sunday night and the system was designated as Tropical Cyclone 02B by the Joint Typhoon Warning Center. The circulation around the tropical cyclone was still organizing. Many of the thunderstorms were occurring in bands in the outer portion of the circulation around the tropical cyclone. The inner end of a rainband began to wrap around the western side of the center of circulation. The circulation around the tropical cyclone was large. Winds to tropical storm force extended out 175 miles (280 km) from the center of circulation.

The tropical cyclone will move through an environment favorable for intensification during the next 48 hours. It will move over water where the Sea Surface Temperatures are near 31°C. The tropical cyclone will move under the southern part of an upper level ridge over the Bay of Bengal. The ridge will produce easterly winds which will blow toward the top of the tropical cyclone. Those winds will cause some vertical wind shear, but the shear will not be enough to prevent intensification. The tropical cyclone will intensify during the next 24 hours. It could intensify more rapidly once an inner core with an eye and an eyewall form. The tropical cyclone could strengthen to the equivalent of a hurricane/typhoon within 36 hours.

The tropical cyclone will move around the western side of a high pressure system over Southeast Asia. The high will steer the tropical cyclone toward the north-northwest during the next 48 hours. On its anticipated track the tropical cyclone could approach the coastline of Odisha and West Bengal in 48 hours. It will likely be the equivalent of a hurricane/typhoon when it approaches the coast. The tropical cyclone is likely to bring damaging winds, and locally heavy rain. It will also likely cause a dangerous storm surge on parts of the coast around the northern Bay of Bengal.

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.