Monthly Archives: November 2023

Tropical Depression Forms Southeast of Yap

A tropical depression formed over the Western North Pacific Ocean southeast of Yap on Sunday morning. At 10:00 a.m. EST on Sunday the center of Tropical Depression 17W was located at latitude 7.2°N and longitude 139.9°E which put it about 205 miles (320 km) southeast of Yap. The tropical depression was moving toward the west-northwest at 11 m.p.h. (17 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.

More thunderstorms formed in a low pressure system over the Western North Pacific Ocean southeast of Yap on Sunday morning and both the Japan Meteorological Agency and the U.S. Joint Typhoon Warning Center designated the system as a tropical depression. The distribution of thunderstorms in Tropical Depression 17W was asymmetrical. Thunderstorms were occurring in bands in the western half of the tropical depression. Bands in the eastern side of Tropical Depression 17W consisted primarily of showers and lower clouds.

Tropical Depression 17W was moving under the southern part of an upper level ridge over the Western North Pacific Ocean. The upper level ridge was producing easterly wind that were blowing toward the top of the tropical depression’s circulation. Those winds were causing moderate vertical wind shear. The moderate vertical wind shear was causing the asymmetrical distribution of thunderstorms.

Tropical Depression 17W will move through an environment somewhat favorable for intensification during the next 48 hours. The tropical depression will move over water where the Sea Surface Temperatures are near 29°C. However, the upper level ridge over the Western North Pacific will continue to cause moderate vertical wind shear. The wind shear will inhibit intensification, but the shear probably will not be strong enough to prevent some strengthening. Tropical Depression 17W is likely to gradually intensify to a tropical storm during the next 48 hours.

Tropical Depression 17W will move south of an upper high pressure system over the Western North Pacific Ocean. The high pressure system will steer the tropical depression toward the west during the next 48 hours. On its anticipated track, Tropical Depression 17W will move south of Yap.

Potential Development over Southwestern Caribbean Sea

A tropical cyclone could potentially develop over the Southwestern Caribbean Sea during the next week. An area of low pressure is expected to form near the surface over the Southwestern Caribbean Sea during the next few days. The low pressure system will form in an environment that will be favorable for the development of a tropical cyclone. The low pressure system will form over water where the Sea Surface Temperatures are near 30°C. It will form under an upper level ridge that will be over the Southwestern Caribbean Sea. The upper level winds will be weak in the ridge and there will be little vertical wind shear. The low pressure system could gradually organize into a tropical cyclone. The U.S. National Hurricane Center is indicating that the probability is 30% that a tropical cyclone forms over the Southwestern Caribbean Sea during the next seven days.

Former Tropical Storm Pilar Weakens

Former Tropical Storm Pilar weakened on Sunday. At 10:00 p.m. EST on Sunday the center of former Tropical Storm Pilar was located at latitude 10.7°N and longitude 114.8°W which put it about 900 miles (1450 km) south-southwest of Baja California. Pilar 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 1006 mb.

An upper level trough west of Baja California produced strong southwesterly winds that blew across the top of former Tropical Storm Pilar. Those winds caused strong vertical wind shear and they blew the upper and middle portions of Pilar’s circulation northeast of the circulation in the lower levels. Although there was still a well defined circulation in the lower levels of the atmosphere, the circulation of former Tropical Storm Pilar consisted of showers and lower clouds. The wind shear blew the tops off of any clouds that rose higher into the atmosphere.

Former Tropical Storm Pilar will move through an environment that will be unfavorable for intensification during the next several days. Pilar will move over water where the Sea Surface Temperatures are near 29°C. However, the upper level trough west of Baja California will continue to cause strong vertical wind shear. The strong wind shear will prevent inhibit intensification. The lower level circulation of former Tropical Storm Pilar will spin down gradually during the next several days.

Former Tropical Storm Pilar will move around the southern part of a high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Pilar toward the west-northwest during the next several days. On its anticipated track, former Tropical Storm Pilar will remain far to the southwest of Baja California.

Tropical Storm Pilar Keeps Moving West

Tropical Storm Pilar kept moving westward over the Eastern North Pacific Ocean south of Baja California on Saturday. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Pilar was located at latitude 10.5°N and longitude 111.6°W which put it about 865 miles (1390 km) south of Baja California. Pilar was moving toward the west at 14 m.p.h. (22 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 Pilar strengthened a little on Saturday as it continued to move westward south of Baja California. More thunderstorms formed in bands that were revolving around the center of Pilar’s circulation. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 70 miles (110 km) in the northern part of Tropical Storm Pilar. The winds in the southern side of Pilar’s circulation were blowing at less than tropical storm force.

Tropical Storm Pilar will move through an environment that will be somewhat favorable for intensification during the next 24 hours. Pilar will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southern part of an upper level ridge over the Eastern North Pacific Ocean. The upper level ridge will produce easterly winds that will blow toward the top of Pilar’s circulation. Those winds will cause some vertical wind shear. The wind shear will inhibit intensification, but the shear may not be strong enough to prevent intensification. Tropical Storm Pilar could strengthen on Sunday.

Tropical Storm Pilar will move around the southern part of a high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Pilar toward the west during the next 24 hours. On its anticipated track, Tropical Storm Pilar will remain far to the south of Baja California on Sunday.

Tropical Storm Pilar Speeds Westward

Tropical Storm Pilar sped westward over the Eastern North Pacific Ocean south of Mexico on Friday. At 5:00 p.m. EDT on Friday the center of Tropical Storm Pilar was located at latitude 10.1°N and longitude 104.0°W which put it about 560 miles (905 km) south-southwest of Zihuatanejo, Mexico. Pilar was moving toward the west at 20 m.p.h. (32 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 1002 mb.

Tropical Storm Pilar weakened on Friday as it sped westward over the Eastern North Pacific Ocean. Thunderstorms were occurring in a couple of bands west and south of the center of Pilar’s circulation. Bands in the eastern and northern parts of Tropical Storm Pilar consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 80 miles (130 km) in the northern side of Pilar’s circulation. The winds in the southern half of the circulation were blowing at less than tropical storm force.

Tropical Storm Pilar will move through an environment that will be unfavorable for intensification during the next 24 hours. Pilar will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southern part of a narrow, west to east upper level ridge over the Eastern North Pacific Ocean. The upper level ridge will produce easterly winds that will blow toward the top of Pilar’s circulation. Those winds will cause moderate vertical wind shear. The moderate vertical wind shear could cause Tropical Storm Pilar to weaken a little more on Saturday.

Tropical Storm Pilar will move around the southern part of a high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Pilar toward the west during the next 24 hours. On its anticipated track, Tropical Storm Pilar will continue to move farther away from Mexico on Saturday.

Tropical Storm Pilar Moves South of Mexico

Tropical Storm Pilar moved south of Mexico on Thursday evening. At 11:00 p.m. EDT on Thursday the center of Tropical Storm Pilar was located at latitude 10.7°N and longitude 99.2°W which put it about 465 miles (750 km) southwest of Salina Cruz, Mexico. Pilar was moving toward the west-southwest at 22 m.p.h. (35 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 998 mb.

There were not a lot of thunderstorms in the circulation around Tropical Storm Pilar on Thursday evening. A few thunderstorms persisted in a band on the northern side of the center of Pilar’s circulation. Bands in the other parts of Tropical Storm Pilar consisted primarily of showers and lower clouds. The circulation around Tropical Storm Pilar was small. Winds to tropical storm force extended out 80 miles (130 km) from the center of Pilar.

Tropical Storm Pilar will move through an environment that will be unfavorable for intensification during the next 24 hours. Pilar will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southern part of an upper level ridge over the Gulf of Mexico. The upper level ridge will produce northeasterly winds that will blow toward the top of Pilar’s circulation. A surface high pressure system that extends from the eastern U.S. across the Gulf of Mexico will produce strong northeasterly winds in the lower levels. The winds in the lower levels of the atmosphere will be stronger than the winds in the upper levels. The difference in wind speed will cause moderate vertical wind shear. The wind shear will inhibit intensification. In addition, the high pressure system will continue to pump cool dry air over the Gulf of Tehuantepec. The effects of the cool dry air and the moderate vertical wind shear will cause Tropical Storm Pilar to weaken on Friday.

Tropical Storm Pilar will move around the southern part of the surface high pressure system. The high pressure system will steer Pilar toward the west-southwest during the next 24 hours. On its anticipated track, Tropical Storm Pilar will move farther away from Mexico on Friday.

Tropical Storm Pilar Moves West and Weakens

Tropical Storm Pilar moved toward the west and weakened on Wednesday. At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Pilar was located at latitude 12.4°N and longitude 92.6°W which put it about 315 miles (505 km) southeast of Salina Cruz, Mexico. Pilar was moving toward the west at 12 m.p.h. (19 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 1002 mb.

Tropical Storm Pilar weakened on Wednesday. Many of the thunderstorms in Pilar’s circulation dissipated during the day. There were still a few thunderstorms in a band just west of the center of Tropical Storm Pilar. Bands in the other parts of Pilar’s circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 80 miles (130 km) from the center of Tropical Storm Pilar.

A large surface high pressure system over the eastern U.S. extended across the Gulf of Mexico to eastern Mexico. The high pressure system produced brisk northeasterly winds that transported cool dry air over the Gulf of Tehuantepec. The circulation around the western side of Tropical Storm Pilar appeared to pull some of the cool dry air into the tropical storm. The drier air reduced the relative humidity which caused the thunderstorms in Pilar to dissipate.

Tropical Storm Pilar will move through an environment that will be unfavorable for intensification during the next 24 hours. Pilar will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southern part of an upper level ridge over the Northwestern Caribbean Sea. The upper level ridge will produce easterly winds that will blow toward the top of Pilar’s circulation. The surface high pressure system will continue to produce northeasterly winds in the lower levels. Easterly winds in the upper levels and northeasterly winds in the lower levels will cause moderate vertical wind shear. The wind shear will inhibit intensification. In addition, the high pressure system will continue to pump cool dry air over the Gulf of Tehuantepec. The effects of the cool dry air and the moderate vertical wind shear will cause Tropical Storm Pilar to continue to weaken on Thursday.

Tropical Storm Pilar will move around the southern part of the surface high pressure system. The high pressure system will steer Pilar toward the west-southwest during the next 24 hours. On its anticipated track, Tropical Storm Pilar will remain south of Mexico on Thursday.

Tropical Storm Pilar Stalls Southwest of El Salvador

Tropical Storm Pilar stalled southwest of El Salvador on Tuesday evening. At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Pilar was located at latitude 11.9°N and longitude 89.4°W which put it about 125 miles (200 km) south of San Salvador, El Salvador. Pilar was moving toward the north at 2 m.p.h. (3 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 994 mb.

A Tropical Storm Watch was in effect for the entire coast of El Salvador. A Tropical Storm Watch was in effect for the Pacific coast of Honduras including the Gulf of Fonseca. A Tropical Storm Watch was in effect for the portion of the coast from Puerto Sandino, Nicaragua to the border with Honduras.

Tropical Storm Pilar intensified a little more on Tuesday. Even though the wind speed increased, the distribution of thunderstorms in Pilar remained asymmetrical. The strongest thunderstorms were occurring in bands in the northwestern part of Pilar’s circulation. There were also thunderstorms in the northeastern part of Tropical Storm Pilar. Bands in the southern half of Pilar’s circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 90 miles (145 km) from the center of Tropical Storm Pilar.

Tropical Storm Pilar will move through an environment that will be marginally favorable for intensification during the next 24 hours. Pilar will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southern part of an upper level ridge over the Northwestern Caribbean Sea. The upper level ridge will produce easterly winds that will blow toward the top of Pilar’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification. If the wind shear increases, it could cause Tropical Storm Pilar to weaken a little on Wednesday. Otherwise, Pilar could maintain its intensity during the next 24 hours.

A large high pressure system over the eastern U.S. extends across the Gulf of Mexico to eastern Mexico. The high pressure system will start to steer Tropical Storm Pilar back toward the west during the next 24 hours. On its anticipated track, Pilar will start to move farther away from El Salvador on Wednesday. Bands in the eastern part of Tropical Storm Pilar could bring gusty winds and locally heavy rain to the coast of El Salvador, southwestern Honduras and northwestern Nicaragua. Prolonged, heavy rain could cause flash floods in some locations.