Monthly Archives: November 2021

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.