Tropical Storms Sandra and Terry Develop over East Pacific

Tropical Storms Sandra and Terry developed over the Eastern North Pacific Ocean on Sunday afternoon. At 4:00 p.m. EST on Sunday the center of Tropical Storm Sandra was located at latitude 14.0°N and longitude 115.2°W which put it about 705 miles (1135 km) south-southwest of the southern tip of Baja California. Sandra was moving toward the west-northwest at 10 m.p.h. (16 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 1006 mb.

At 4:00 p.m. EST on Sunday the center of Tropical Storm Terry was located at latitude 8.5°N and longitude 102.6°W which put it about 735 miles (1180 km) south of Manzanillo, Mexico. Terry was moving toward the west 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.

Based on data from a scatterometer on a satellite, the National Hurricane Center upgraded former Tropical Depression Nineteen-E to Tropical Storm Sandra on Sunday afternoon. It appeared from later satellite images that Tropical Storm Sandra might already be weakening. A large upper level trough approaching the west coast of the U.S. was producing strong southerly winds that were blowing across the top of Sandra’s circulation. Those winds were causing moderate vertical wind shear. The strong upper level winds blew the tops off thunderstorms near the center of Sandra. The strongest remaining thunderstorms were occurring in bands east of the center. Bands in other parts of Tropical Storm Sandra consisted primarily of showers and lower clouds. The strongest winds were in the eastern half of Sandra. Winds to tropical storm force extended out 90 miles in the eastern half of Sandra. The winds in the western half of the circulation were blowing at less than tropical storm force.

Tropical Storm Sandra will move through an environment mostly unfavorable for intensification during the next several days. Sandra will move over water where the Sea Surface Temperatures are near 27˚C. However, the large upper level trough will continue to produce strong vertical wind shear. The wind shear is likely to prevent Tropical Storm Sandra from strengthening. The strong shear could blow the top off of Sandra’s circulation and Tropical Storm Sandra is more likely to weaken during the next several days. Sandra will move south of a surface high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Sandra toward the west. On its anticipated track Tropical Storm Sandra will move farther away from Mexico.

More thunderstorms developed near the center of former Tropical Depression Eighteen-E on Sunday afternoon and the National Hurricane Center upgraded the system to Tropical Storm Terry. The circulation around Tropical Storm Terry exhibited more organization on satellite images. More thunderstorms also formed in bands revolving around the center of Terry. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 60 miles (95 km) on the eastern side of Terry’s circulation. The winds in the western half of Terry were blowing at less than tropical storm force.

Tropical Storm Terry will move through an environment somewhat favorable for intensification during the next 24 hours. Terry will move over water where the Sea Surface Temperatures are near 28˚C. It will move through a region where the upper level wind are weak and there will be little vertical wind shear. Tropical Storm Terry could slowly intensify during the next 24 hours.

Tropical Storm Terry will move around the southern side of a surface high pressure system over the Eastern North Pacific Ocean. The high will steer Terry toward the west during the next few days. On its anticipated track Tropical Storm Terry will move farther away from Mexico.

Tropical Storm Wanda Speeds Northeast

Tropical Storm Wanda sped toward the northeast over the Atlantic Ocean west of the Azores on Sunday morning. At 4:00 a.m. EST on Sunday the center of Tropical Storm Wanda was located at latitude 38.5°N and longitude 35.5°W which put it about 460 miles (745 km) west of the Azores. Wanda was moving toward the northeast at 17 m.p.h. (28 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 1003 mb.

An upper level trough and a cold front over the central Atlantic Ocean were steering Tropical Storm Wanda quickly to the northeast on Sunday morning. The upper level trough was also producing strong southwesterly winds that were blowing across the top of Wanda’s circulation. Those winds were causing strong vertical wind shear and the shear was causing Tropical Storm Wanda to weaken. The strongest thunderstorms were occurring in a band in the southeastern part of Wanda. Bands in the other parts of the circulation consisted primarily of showers and lower clouds. The strongest winds were occurring with the thunderstorms in the southeastern part of Tropical Storm Wanda. Winds to tropical storm force extended out 70 miles (110 km) in the southeastern quadrant of Wanda. The winds in the other parts of Wanda’s circulation were blowing at less than tropical storm force.

The upper level trough and the cold front will continue to steer Tropical Storm Wanda toward the northeast during the next several days. Tropical Storm Wanda will move through an environment unfavorable for intensification during the next 24 hours. Wanda will move over water where the Sea Surface Temperatures are near 20˚C. The upper level trough will continue to cause strong vertical wind shear. The cold front is moving faster than Tropical Storm Wanda and Wanda is likely to merge with the cold front during the next 24 hours. Strong vertical wind shear and cold water will cause Wanda to make a transition to an extratropical cyclone when it merges with the cold front. On its anticipated track Wanda could approach Ireland as an extratropical cyclone early next week.

Tropical Storm Wanda Turns Back to the South

Tropical Storm Wanda turned back toward the south over the central Atlantic Ocean west of the Azores on Friday morning. At 11:00 a.m. EDT on Friday the center of Tropical Storm Wanda was located at latitude 40.6°N and longitude 37.8°W which put it about 605 miles (970 km) west-northwest of the Azores. Wanda was moving toward the south-southeast at 8 m.p.h. (13 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 994 mb.

Tropical Storm Wanda moved back toward the south on Friday morning as it continued to meander west of the Azores. The circulation around Tropical Storm Wanda remained well organized. The circulation was circular and there was a well defined center. Bands of showers and thunderstorms revolved around the center of Wanda. Storms near the center of circulation generated upper level divergence that pumped mass away to the north of the tropical storm. Winds to tropical storm force extended out 125 miles (200 km) on the western side of Tropical Storm Wanda. Winds to tropical storm force extended out 70 miles on the eastern side of Wanda.

Tropical Storm Wanda will move through an environment that is somewhat favorable for intensification during the next 24 hours. Wanda will move over water where the Sea Surface Temperatures are near 23˚C. Even though the water is colder than in the tropics, colder air in the middle and upper troposphere will allow for enough instability for the formation of thunderstorms. The thunderstorms that form will not rise as high into the atmosphere. Tropical Storm Wanda will move through a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Storm Wanda could extract enough energy from the Atlantic Ocean to be able to strengthen during the next 24 hours.

Tropical Storm Wanda will move south of a high pressure system over the northern Atlantic Ocean during the next 24 hours. The high pressure system will push Wanda back toward the south during the next 24 hours. An upper level trough near the east coast of the U.S. will move eastward during the next several days. The upper level trough will cause the high pressure system to weaken. When the high weakens, the upper level trough will steer Wanda toward the northeast on Saturday. On its anticipated track Tropical Storm Wanda could approach the western Azores on Sunday.

Tropical Depression Forms South of El Salvador

Tropical Depression Eighteen-E formed over the Eastern North Pacific Ocean south of El Salvador in Thursday morning. At 11:00 a.m. EDT on Thursday the center of Tropical Depression Eighteen-E was located at latitude 9.4°N and longitude 90.0°W which put it about 300 miles (485 km) south of San Salvador, El Salvador. The tropical depression was moving toward the west 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 1007 mb.

Thunderstorms formed closer to the center of a small low pressure system south of El Salvador on Thursday morning and the National Hurricane Center designated the system as Tropical Depression Eighteen-E. The strongest thunderstorms were occurring in a band a little to the east of the center of circulation. Storms in that band began to generate upper level divergence that pumped mass away from the tropical depression. Bands in the western half of the depression consisted of showers and lower clouds.

Tropical Depression Eighteen-E will move through an environment somewhat favorable for intensification during the next 48 hours. The depression will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the northern part of an upper level ridge west of Central America. The northern part of the upper level ridge will produce weak westerly winds that will blow toward the top of the depression’s circulation. Those winds will cause some vertical wind shear. The wind shear will inhibit intensification, but it will not be strong enough to prevent the tropical depression from getting stronger. Tropical Depression Eighteen-E is likely to slowly intensify to a tropical storm during the next several days.

Tropical Depression Eighteen-E will move around the southern side of a surface high pressure system over the Eastern North Pacific Ocean. The high will steer the tropical depression toward the west during the next few days. On its anticipated track Tropical Depression Eighteen-E will move farther away from Central America.

Tropical Storm Wanda Wanders West of the Azores

Tropical Storm Wanda continued to wander over the Atlantic Ocean west of the Azores on Wednesday. At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Wanda was located at latitude 39.8°N and longitude 39.5°W which put it about 680 miles (1100 km) west-northwest of the Azores. Wanda was moving toward the north at 10 m.p.h. (16 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 992 mb.

Tropical Storm Wanda exhibited a typical structure for a late season, high latitude tropical storm. A circular eyelike feature was present at the center of Wanda. The eyelike feature was surrounded by a ring of showers and thunderstorms. The strongest winds were occurring in the ring of showers and thunderstorms. Bands of showers and thunderstorms revolved around the core of Tropical Storm Wanda. Since Wanda was over cooler Sea Surface Temperatures, the thunderstorms were not rising as high as they would have if Tropical Storm Wanda was over warmer water in the tropics. Winds to tropical storm force extended out 100 miles (160 km) on the eastern side of Wanda. Winds to tropical storm force extended out 70 miles (110 km) in the western half of the circulation.

Tropical Storm Wanda will move through an environment that is somewhat favorable for intensification during the next 24 hours. Wanda will move over water where the Sea Surface Temperatures are near 22˚C. Even though the water is colder than in the tropics, colder air in the middle and upper troposphere will allow for enough instability for the formation of thunderstorms. Thunderstorms that form will not rise as high into the atmosphere and they will not generate a lot of upper level divergence which could inhibit intensification. Tropical Storm Wanda will move through a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Storm Wanda could extract enough energy from the Atlantic Ocean to be able to strengthen during the next 24 hours.

Tropical Storm Wanda will move west of a high pressure system over the eastern Atlantic Ocean during the next 24 hours. The high will steer Wanda toward the north-northeast during the next 24 hours. A second high pressure system will move north of Tropical Storm Wanda on Friday. The second high will push Wanda back toward the southeast. On its anticipated track Tropical Storm Wanda could approach the western Azores during the weekend.

Wanda Transitions to a Tropical Storm

Former Subtropical Storm Wanda made a transition to a tropical storm on Monday afternoon. At 5:00 p.m. EDT on Monday the center of Tropical Storm Wanda was located at latitude 34.2°N and longitude 42.2°W which put it about 885 miles (1425 km) west-southwest of the Azores. Wanda was moving toward the east-northeast at 7 m.p.h. (11 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 996 mb.

The structure of former Subtropical Storm Wanda changed on Monday. The low level center of Wanda became separated from the upper level low that was previously over the top of it. So, the two centers were no longer vertically stacked. In addition, the wind field around Wanda contracted and the strongest winds were located closer to the center of circulation. Since the new structure of Wanda was more consistent with the structure of a tropical cyclone, the National Hurricane Center reclassified Wanda as a tropical storm.

The circulation around Tropical Storm Wanda was smaller. Winds to tropical storm force extended out 45 miles (75 km) from the center of Wanda. The strongest thunderstorms were occurring in bands on the eastern side of Wanda’s circulation. Since Wanda was over water where the Sea Surface Temperature is near 24˚C, the thunderstorms were not as tall as ones that occur in tropical storms farther south. Bands in the western half of the tropical storm consisted primarily of showers and lower clouds. The storms on the eastern side of Wanda generated upper level divergence that pumped mass away to the northeast of the tropical storm.

Tropical Storm Wanda will move through an environment that is somewhat favorable for intensification during the next 24 hours. Wanda will move over water where the Sea Surface Temperatures are near 24˚C. Tropical Storm Wanda will be on the eastern side of the axis of the upper level trough. The upper level trough will produce southwesterly winds that will blow toward the top of Wanda’s circulation. Those winds will cause some vertical wind shear but the wind shear may be weak enough to allow for some intensification. Sinking, drier air could limit the formation of new thunderstorms on the western side of Wanda’s circulation and that could also inhibit intensification. Since Tropical Storm Wanda is now a smaller, more compact storm, it could extract enough energy from the Atlantic Ocean to be able to strengthen during the next 24 hours.

Since Tropical Storm Wanda is east of the axis of the upper level trough, southwesterly winds will steer Wanda toward the north-northeast during the next 36 hours. Wanda could move more toward the east later this week when it reaches a region where westerly winds are stronger. On its anticipated track Tropical Storm Wanda could approach the western Azores at the end of the week.

Subtropical Storm Wanda Meanders West of the Azores

Subtropical Storm Wanda meandered over the central Atlantic Ocean west of the Azores on Sunday. At 11:00 p.m. EDT on Sunday the center of Subtropical Storm Wanda was located at latitude 35.6°N and longitude 44.1°W which put it about 960 miles (1540 km) west of the Azores. Wanda was moving toward the southwest at 8 m.p.h. (13 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 990 mb.

The circulation of Subtropical Storm Wanda meandered within the larger circulation of an upper level trough west of the Azores on Sunday. Some drier air appeared to enter Wanda’s circulation on Sunday and fewer thunderstorms developed around the center of the subtropical storm. The strongest thunderstorms were occurring in bands in the eastern half of Subtropical Storm Wanda. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 100 miles (160 km) from the center of Wanda.

Subtropical Storm Wanda will move through an environment somewhat favorable for intensification during the next 36 hours. Wanda will move over water where the Sea Surface Temperatures are near 24˚C. It will remain under the axis of the upper level trough and there will be little vertical wind shear. However, drier air could limit the formation of new thunderstorms on the western side of Wanda’s circulation and that could inhibit intensification. Subtropical Storm Wanda could strengthen during the next 36 hours. If more thunderstorms form near the center of circulation Wanda could make a transition to a tropical storm during the next several days.

Subtropical Storm Wanda will meander within the upper level trough during the next 24 hours. The upper level trough will move east and it could move Wanda slowly toward the southeast during the next day or so. On its anticipated track Subtropical Storm Wanda could continue to meander west of the Azores for another day or two.

Subtropical Storm Wanda Develops West of the Azores

Subtropical Storm Wanda developed over the central Atlantic Ocean west of the Azores on Saturday night. At 11:00 p.m. EDT on Saturday the center of Subtropical Storm Wanda was located at latitude 36.2°N and longitude 45.4°W which put it about 1020 miles (1640 km) west of the Azores. Wanda was moving toward the southeast at 21 m.p.h. (33 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.

More thunderstorms formed near the center of a low pressure system over the central Atlantic Ocean and the National Hurricane Center designated the system as Subtropical Storm Wanda. Subtropical Storm Wanda began as an extratropical cyclone that formed near the East Coast of the U.S. The extratropical cyclone brought very strong winds to the northeastern U.S. several days ago before moving toward the central Atlantic Ocean. The extratropical cyclone became vertically stacked where the surface low pressure system was under the axis of the upper level trough. The vertical wind shear decreased when the system became vertically stacked. When the extratropical cyclone moved southeast over warmer water, the temperature difference on the opposing sides of fronts decreased and the fronts weakened. More thunderstorms developed near the center of the low pressure system and it assumed a more circular shape. The strongest winds eventually started to blow closer to the center and the National Hurricane Center designated it as Subtropical Storm Wanda.

Subtropical Storm Wanda exhibited some characteristics of a tropical cyclone. Thunderstorms formed near the center of Wanda. Bands of showers and thunderstorms formed and started to revolve around the center of circulation. The strongest rainband wrapped around the northern and eastern sides of the center of Subtropical Storm Wanda. Even though Wanda exhibited some of the characteristics of a tropical cyclone, it was under the axis of an upper level trough, which is why it was classified as a subtropical storm. Winds to tropical storm force extended out 100 miles (160 km) from the center of Subtropical Storm Wanda.

Subtropical Storm Wanda will move through an environment somewhat favorable for intensification during the next 24 hours. Wanda will move over water where the Sea Surface Temperatures are near 24˚C. It will remain under the axis of the upper level trough and there will be little vertical wind shear. Subtropical Storm Wanda is likely to strengthen during the next 24 hours. There is a chance it could intensify to a hurricane during the next several days.

Subtropical Storm Wanda will move along with the upper level trough during the next 24 hours. The upper level trough will carry Wanda slowly toward the southeast during the next several days. On its anticipated track Subtropical Storm Wanda could meander west-southwest of the Azores for several days.

Medicane Drops Heavy Rain on Sicily

A low pressure system sometimes called a medicane dropped heavy rain over parts of Sicily on Friday. There were reports of flash floods in eastern Sicily. At 8:00 a.m. EDT on Friday the center of the low pressure system was located at latitude 36.5°N and longitude 16.1°E which put it about 50 miles (80 km) southeast of Siracusa, Italy. The low pressure system was nearly stationary. 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.

A small low pressure system located over the Mediterranean Sea just to southeast of Sicily exhibited some of the characteristics associated with tropical cyclones. The low pressure system looked similar to a subtropical cyclone on satellite images. Low pressure systems over the Mediterranean Sea with this type of structure are sometimes called medicanes. The current medicane southeast of Sicily has a symmetrical circulation with a well defined center of circulation. Bands of showers and thunderstorms are revolving around the center of the medicane. The strongest thunderstorms are occurring in bands in the northern and westerns sides of the circulation. Some of those bands dropped heavy rains parts of eastern Sicily. There have been reports of flash floods in some locations because of persistent heavy rain.

The medicane is in an area where the steering winds are weak and it is likely to remain nearly stationary during the next 24 hours. It is in an environment that should allow it to maintain its intensity during the next 24 hours. The medicane will be over water in the Mediterranean Sea where the Sea Surface Temperatures are near 24˚C. It will be in an area where the upper level winds are weak and there will be little vertical wind shear. The strongest winds are likely to remain over the Mediterranean Sea southeast of Sicily. However, rainbands on the western side of the medicane will continue to drop heavy rain over parts of Sicily. Additional flash floods are likely to occur. The medicane is forecast to move southeast toward Libya during the weekend.

Typhoon Malou Brings Strong Winds, Rain to Ogasawara Islands

Typhoon Malou brought strong winds and heavy rain to the Ogasawara Islands on Thursday morning. At 5:00 a.m. EDT on Thursday the center of Typhoon Malou was located at latitude 25.6°N and longitude 141.2°E which put it about 15 miles (25 km) east of Iwo To. Malou was moving toward the north-northeast at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 100 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h). The minimum surface pressure was 967 mb.

The strong inner core of Typhoon Malou passed directly over Iwo To on Thursday morning. An eye with a diameter of 35 miles (55 km) was at the center of Malou. The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms. Winds to typhoon force extended out 70 miles (110 km) from the center of Malou. Winds to tropical storm force extended out 175 miles (280 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Malou was 16.5. The Hurricane Size Index (HSI) was 20.6 and the Hurricane Wind Intensity Size Index (HWISI) was 37.1.

An upper level trough near Japan will steer Typhoon Malou toward the northeast during the next several days. On its anticipated track Malou will move away from the Ogasawara Islands. Typhoon Malou will pass well to the southeast of the larger islands of Japan.

Typhoon Malou will move into an environment unfavorable for tropical cyclones during the next few days. Malou will move over water where the Sea Surface Temperatures are cooler. The upper level trough near Japan will produce stronger southwesterly winds that will blow toward the top of Malou’s circulation. The vertical wind shear will increase as the upper level winds get stronger. The combination of cooler water and stronger vertical wind shear will cause Typhoon Malou to weaken. The cooler water and stronger shear will also cause Malou to make a transition to an extratropical cyclone during the next few days.