Tropical Storm Pabuk brought wind and rain to southern Thailand on Friday. At 5:00 p.m. EST on Friday the center of Tropical Storm Pabuk was located at latitude 8.7°N and longitude 98.5°E which put it about 60 miles (95 km) northeast of Phuket, Thailand. Pabuk was moving toward the west-northwest at 10 m.p.h. (16 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.
Tropical Storm Pabuk made landfall near Sichon in southern Thailand. Pabuk brought gusty winds to much of the Isthmus of Kra. It also dropped heavy rain over parts of southern Thailand. Tropical Storm Pabuk weakened when it crossed the Isthmus of Kra, but the core of the circulation appears to have remained intact. Pabuk is moving over the Andaman Sea and it still has a well defined low level center of circulation. Several bands of showers and thunderstorms are revolving around the core of the tropical storm. Additional bands of showers and thunderstorms are located in the northeastern part of the circulation which is over the Gulf of Thailand.
Tropical Storm Pabuk will move into an environment favorable for intensification during the next 24 to 36 hours. Pabuk will move over water where the Sea Surface Temperature is near 28°C. An upper level ridge over the Western North Pacific Ocean will produce southeasterly winds which will blow toward the top of the circulation. Those winds will cause moderate vertical wind shear, which will inhibit intensification. However, the wind shear may not be strong enough to prevent Tropical Storm Pabuk from strengthening.
Tropical Storm Pabuk will continue to move around the western end of the ridge over the Western North Pacific Ocean. The ridge will steer Pabuk toward the west-northwest for another 24 to 36 hours. Pabuk will turn more toward the north when it reaches the western end of the ridge. On its anticipated track Tropical Storm Pabuk will reach the Andaman Islands in about 36 hours.
Elsewhere over the Western North Pacific Ocean, Tropical Depression 01W formed southeast of the Marshall Islands. At 4:00 p.m. EST on Friday the center of Tropical Depression 01W was located at latitude 4.9°N and longitude 174.0°E which put it about 250 miles (400 km) southeast of Majuro, Marshall Islands. It was moving toward the northwest at 15 m.p.h. (24 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 1004 mb. Tropical Depression 01W is forecast to move toward the west-northwest and strengthen. On its anticipated track it could move toward Majuro, Kwajalein, Ujelang, and the Marianas.
Hurricane Pali weakened quickly on Wednesday as it moved closer to the Equator and it is now classified as a tropical storm. At 10:00 p.m. EST on Wednesday the center of Tropical Storm Pali was located at latitude 2.7°N and longitude 172.2°W which put it about 330 miles (530 km) east-northeast of Howland Island. Pali was moving toward the south-southwest at 9 m.p.h. (17 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.
As Hurricane Pali moved closer to the Equator, it moved into an area of strong vertical wind shear and weakened. A large area of thunderstorms east-northeast of Samoa could be consolidating into a new tropical cyclone. That area of thunderstorms is generating a lot of upper level divergence which is spreading across the Equator as strong upper level winds from the south. Those upper level winds created strong vertical wind shear over Pali as the hurricane moved south on Wednesday. The wind shear pushed the upper portion of Tropical Storm Pali toward the north and disrupted the vertical integrity of Pali’s circulation. The lack of vertical integrity resulted in a significant decrease in the surface wind speed on Wednesday.
The environment around Tropical Storm Pali will be unfavorable for intensification for the next several days. The vertical wind shear will continue and it could increase if a tropical cyclone develops east of Samoa. Tropical Storm Pali is expected to continue to weaken on Thursday. However, if the surface circulation remains intact for another 48 hours, the wind shear could decrease during the weekend. The Sea Surface Temperature is near 30°C and so there is sufficient energy to support intensification, if the upper level winds decrease. If there is still a surface circulation on Saturday, then it could begin to reorganize and get stronger. Alternatively, if the wind shear gets stronger, Tropical Storm Pali could dissipate over the weekend.
A subtropical ridge to the northwest of Pali is steering the tropical storm toward the south. As Pali weakens, the low level circulation will be steered more by winds closer to the surface. Those winds are blowing from the east and Tropical Storm Pali or its remnants are expected to move toward the west during the next few days.
Tropical Storm Pali intensified steadily on Monday and it has become a rare January hurricane over the Central Pacific Ocean. At 10:00 p.m. EST on Monday the center of Hurricane Pali was located at latitude 8.1°N and longitude 171.9°W which put it about 1305 miles (2100 km) southwest of Honolulu, Hawaii. Pali was moving toward the east-southeast at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 982 mb.
The structure of Hurricane Pali improved significantly on Monday. A primary rainband wrapped all of the way around the center of circulation and became a well formed eyewall. The eye has been clearly visible on satellite images from the past few hours. Thunderstorms around the eye are generating upper level divergence in all directions which is pumping out mass.
Hurricane Pali is in an environment favorable for intensification. An upper level ridge is generating light westerly winds over the top of Pali, but the vertical wind shear is modest. Hurricane Pali is moving over water where the Sea Surface Temperatures (SSTs) are near 28°C. Wind shear will be the primary factor that will determine intensify changes during the next 24 to 48 hours. If the wind shear remains minimal, then Hurricane Pali will intensify further. If the wind shear increases to the magnitude that existed during the weekend, then Pali will weaken. The most likely scenario is for Pali to intensify during the next 12 to 24 hours, then maintain a steady state or slowly weaken during the middle of the week. Rapid intensification could continue during the next few hours.
Hurricane Pali remains in an area where the steering currents are weak. It could meander slowly toward the southeast or east for another day or two. After that time a subtropical ridge could strengthen and start to steer Pali more toward the west.
Sufficient evidence of a surface center of circulation within a broad area of thunderstorms near the Equator prompted the Central Pacific Hurricane Center to classify the system as Tropical Depression 09C. At 10:00 p.m. EST on Wednesday the center of Tropical Depression 09C (TD09C) was located at latitude 2.8°N and longitude 177.8°W which put it about 1850 miles (2975 km) southwest of Honolulu, Hawaii. TD09C was moving toward the west-northwest at 8 m.p.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 1001 mb.
The circulation of Tropical Depression 09C is not particularly well organized and there may be multiple small centers inside the larger circulation of the system. One small center of circulation is near a cluster of thunderstorms in the northern half of the circulation and that center is currently being designated as the center of TD09C. Another circulation center is near latitude 1.0°N and longitude 174.6°W, but there are no thunderstorms near that center. The main area of thunderstorms is north of the official center of circulation. There are a few partial spiral bands northeast of the center of the depression.
The environment around TD09C is only marginal for intensification. The depression is moving over water where the Sea Surface Temperatures are near 30°C. So, there is plenty of energy in the upper ocean to support intensification. However, a strong upper level ridge east of TD09C is generating strong southeasterly winds over the top of the depression. The strong vertical wind shear is contributing to the poor organization of TD09C. The wind shear is likely to inhibit intensification during the next several days.
A subtropical ridge east of TD09C is expected to steer the depression slowly toward the west-northwest during the next few days. The actual track of TD09C could be somewhat erratic, especially if some of the small centers of circulation dissipate and additional centers form in clusters of thunderstorms that develop. On its anticipated track Tropical Depression 09C could approach Tarawa in about three days and it could be approaching the Marshall Islands this weekend.
The most remarkable thing about Tropical Depression 09C is that is developed so close to the Equator. Conventional wisdom often says that tropical cyclones cannot form near the Equator because the Coriolis effect is too small. However, although tropical cyclones are rare near the Equator, Tropical Depression 09C is another example that they can form in that region.
Another tropical storm formed over the western North Pacific when a circulation developed west of the International Dateline and was designated as Tropical Storm Nangka (11W). At 11:00 p.m. EDT on Friday the center of Tropical Storm Nangka was located at latitude 9.9°N and longitude 169.2°E which put it about 150 miles east-northeast of Kwajalein. Nangka was moving toward the west-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 992 mb.
Tropical Storm Nangka is moving over water where the Sea Surface Temperature is near 30°C. The upper level winds are light and upper level divergence is increasing. However, there is sinking drier air north of the tropical storm and the circulation appears to be pulling some of the drier air into it. As a result many of the stronger thunderstorms are occurring in the western half of the circulation. The drier air could inhibit intensification in the short term. The other favorable environmental factors are likely to produce intensification in the longer term once Nangka moves west of the drier air.
A subtropical ridge north of Nangka is expected to steer it in a west-northwesterly direction during the next few days. On its expected track Nangka will bring wind and rain to a number of atolls in the Marshall Islands. Nangka could approach the Mariana Islands in a few days.