A large area of low pressure east of Guam developed a core of thunderstorms and sufficient organization to prompt its classification as Tropical Storm Phanfone. At 8:00 p.m. EDT on Monday the center of Phanfone was located at latitude 15.4°N and longitude 148.3°W which put it about 160 miles east of Saipan. Phanfone was moving toward the northwest at 15 m.p.h. The maximum sustained wind speed was 50 m.p.h. and there were gusts to 65 m.p.h.
Phanfone is expected to continue to move in a northwesterly direction for the next two or three days as it moves around the western end of a subtropical high pressure system. Later in the week it is expected to take a more northerly turn and it could be south of Japan by the weekend.
Both the oceanic and atmospheric environment around Phanfone’s projected track appear favorable for intensification. Phanfone is expected to become a typhoon later this week and a period of more rapid intensification is possible. Eventually, as Phanfone moves farther north, westerly winds in the upper levels will increase wind shear and begin a weakening trend.
The northeasterly winds in the upper levels that were generating wind shear over Tropical Storm Rachel lessened on Saturday and it intensified into the 12th Eastern North Pacific hurricane of 2014. At 11:00 p.m. EDT on Saturday the center of Hurricane Rachel was located at latitude 20.7°N and longitude 116.6°W which put it about 455 miles west-southwest of the southern tip of Baja California. Rachel was moving toward the north-northwest at 7 m.p.h. The maximum sustained wind speed increased to 85 m.p.h. and the minimum surface pressure decreased to 982 mb.
An upper level ridge over northern Mexico that was generating northeasterly winds over the top of Rachel weakened as a large upper level trough moved over the western U.S. As the vertical wind shear decreased, a ring of thunderstorms developed around the core of the circulation. The formation of an eye and a tight inner core allowed the wind speed to increase rapidly to hurricane intensity. The core of Rachel will remain in an environment that could support further intensification during the next 12-18 hours. Eventually, the upper level trough will increase the wind shear again and the hurricane will move over cooler Sea Surface Temperatures (SSTs). Those factors will produce a weakening trend early next week.
The upper level trough is helping to pull Rachel northward. However, it looks like the trough will move eastward before it can sweep Rachel toward the northeast. Recent guidance from the numerical models suggest that as the trough moves away to the east, Rachel will stall. If it stalls over cooler SSTs, then it will be steered more by lower level winds, once the tall thunderstorms around the eye dissipate. Those winds could push the lower level remnant circulation slowly toward the west or southwest;
Tropical Depression 18-E which formed earlier today has intensified into Tropical Storm Rachel. At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Rachel was located at latitude 15.3°N and longitude 107.4°W which put it about 325 miles southwest of Manzanillo, Mexico and about 550 miles south-southeast of the southern tip of Baja California. Rachel was moving toward the west at 12 m.p.h. The maximum sustained wind speed was 40 m.p.h. and the minimum surface pressure was 1004 mb.
A strong upper level ridge over northern Mexico has been producing northeasterly winds and wind shear over the circulation of Rachel. The wind shear has been the reason why most of the thunderstorms have been located west of the center of circulation. The northeasterly winds diminished slightly during recent hours and more thunderstorms developed closer to the center. The improved organization allowed the wind speed at the surface to increase and Rachel became a tropical storm. The upper level winds could decrease further and some additional intensification is possible.
A ridge in the middle levels is likely to steer Rachel to the west-northwest during the next day or two. As Rachel moves farther north, it could be affected by a mid-level trough (i.e. a shortwave trough) in the westerly flow in about 72 hours. If Rachel is strong enough and tall enough, then the mid-level trough could turn Rachel back to the northeast, which could move it toward Baja California. If Rachel is weaker and the circulation does not extend as high into the atmosphere, then the mid-level trough may not affect the movement of Rachel. In that case, it would probably continue to move west and dissipate over cooler Sea Surface Temperatures.
At 5:00 p.m. EDT on Saturday the center of Tropical Storm Fung-Wong was located at latitude 21.5°N and longitude 120.0°W which put it about 250 miles south-southwest of Taipei Taiwan. Fung-Wong was moving just slightly east of due north at 8 m.p.h. The maximum sustained wind speed was 60 m.p.h. and there were gusts to 75 m.p.h.
Fung-Wong will likely move near or across Taiwan during the next few hours. Locally heavy rainfall will be possible, especially in locations where the circulation around Fung-Wong pushes air up the slopes of mountains. Flooding may be an issue in areas that experience heavy rainfall. The heaviest rainfall will likely occur on the eastern slopes of mountains as Fung-Wong moves across southern Taiwan and brings easterly winds to those areas. However, the potential for flooding along the western slopes of mountains, especially in northern Taiwan, may exist as the tropical storm moves north of the island and the wind shifts to a more westerly direction.
Fung-Wong will likely weaken as the circulation in the lower levels is disrupted by the mountains. It could maintain tropical storm intensity and move toward eastern China once the center emerges back over the water.
Tropical Storm Polo continues to move northwestward parallel to the west coast of Mexico. At 11:00 p.m. EDT on Thursday the center of Polo was located at latitude 18.4°N and longitude 106.6°W which put it about 150 miles south-southwest of Cabo Corrientes, Mexico and about 375 miles southeast of the southern tip of Baja California. Polo was moving toward the northwest at 9 m.p.h. The maximum sustained wind speed was 70 m.p.h. and the minimum surface pressure was 981 mb.
An upper level ridge over northwestern Mexico is producing northeasterly winds that are creating wind shear over Polo. The wind shear is limiting thunderstorm activity on the northern side of the storm. It is also possible that Polo is close enough to Mexico that it may be pulling some drier air into the northern half of the circulation. Both of those factors are inhibiting intensification of Polo.
A high pressure system in the middle levels over Mexico is steering Polo toward the northwest. The tropical storm is starting to move a little more quickly. Numerical models are suggesting that the mid-level high will strengthen and eventually turn Polo more toward the west. Most guidance predicts that Polo will move southwest of Baja California. However, based on the faster motion the government of Mexico has issued a Tropical Storm Watch for a portion of southern Baja California from Santa Fe to La Paz. A Tropical Storm Warning remains in effect for a portion of the coast from Punta San Telmo to Playa Perula. A Tropical Storm Watch continues for the portion of the coast from Playa Perula to Cabo Corrientes.
Tropical Storm Fung-Wong is moving near the northernmost part of the Philippines. At 8:00 p.m. EDT on Thursday the center of Fung-Wong was located latitude 18.0°N and longitude 122.5°E, which put it about 250 miles north-northeast of Manila. Fung-Wong was moving toward the northwest at 20 m.p.h. The maximum wind speed was 45 m.p.h.
The structure around Fung-Wong is not particularly well organized. Most of the thunderstorm activity is occurring southeast of the the center of circulation. Wind shear is inhibiting the intensification of the tropical storm. Slow intensification is possible if the upper level winds slow down.
Fung-Wong is expected to take a turn more toward the north and it could move toward Taiwan during the next 36-48 hours.
The circulation around Polo continues to exhibit increasing signs of intensification and it was upgraded to hurricane status on Wednesday night. Polo is the sixteenth named tropical cyclone to form over the Eastern North Pacific Ocean during 2014 and it is the eleventh to reach hurricane intensity.
At 11:00 p.m. EDT on Wednesday the center of Hurricane Polo was located at latitude 16.4°N and longitude 104.6°W which put it about 180 miles south of Manzanillo, Mexico. Polo was moving toward the west-northwest at 10 m.p.h. The maximum sustained wind speed was 75 m.p.h. and the minimum surface pressure was 988 mb.
The movement of Polo has varied as the circulation has tightened around the core and more well defined spiral bands have developed. In recent hours it has exhibited a more west-northwesterly motion after moving more toward the northwest earlier in the day. Polo appears to be being steered mostly by an upper level high over Mexico. The upper level high should steer Polo on a track that is roughly parallel to the west coast of Mexico. Many of the numerical models are predicting that Polo will pass southwest of Baja California, but as Hurricane Odile showed, it could take a track closer to the coast.
Polo is moving over warm Sea Surface Temperatures and further intensification is likely. As the organization of the circulation increases and an eye forms, a period of more rapid intensification is possible.
The government of Mexico has issued a Tropical Storm Warning for the portion of the coast from Punta San Telmo to Playa Perula. A Tropical Storm Watch has been issued for the portion of the coast from Playa Perula to Cabo Corrientes.
The maximum sustained wind speed in Hurricane Edouard is now 115 m.p.h. which makes it a Category 3 hurricane on the Saffir-Simpson Scale and a Major Hurricane. Edouard is the first Major Hurricane of the 2014 Atlantic hurricane season. It is the first hurricane to reach Major Hurricane intensity over the Atlantic basin since Hurricane Sandy briefly was a Major Hurricane south of Cuba in 2012.
At 11:00 a.m. EDT on Tuesday the center of Hurricane Edouard was located at latitude 31.1°N and longitude 57.8°N which put it about 420 miles east of Bermuda, about 1060 miles east-southeast of Cape Hatteras and about 1720 miles west of Fayal Island in the Azores. Edouard was moving toward the north-northwest at 13 m.p.h. The minimum surface pressure was 955 mb.
Edouard is moving around the western portion of the subtropical high pressure system. It should gradually turn more to the right until it reaches the upper level westerlies which should accelerate it eastward. Some model guidance suggest that Edouard could approach the Azores during the weekend, while other models forecast a track north of the Azores.
Edouard could intensify a little more today, but cooler Sea Surface Temperatures and stronger westerly winds will begin to weaken the hurricane when it turns eastward.
Typhoon Kalmaegi continues to move toward the west-northwest and the center is very near the south coast of China. At 11:00 p.m. EDT on Monday the center of Typhoon Kalmaegi was located at latitude 20.0°N and longitude 111.4°E which put it about 230 miles southwest of Hong Kong. Kalmaegi was moving toward the west-northwest at 18 m.p.h. The maximum sustained wind speed was 80 m.p.h. Kalmaegi has the potential to bring strong winds and heavy rain to portions of southern China and northern Vietnam.