Author Archives: jay_hobgood

Fay Transitions to a Tropical Storm

Thunderstorms developed near the center of Fay and an inner core of convection formed.  The thunderstorms released enough latent energy in the middle and upper troposphere to create a warm core.  As a result the structure of Fay changed from a subtropical storm into a tropical storm.  At 11:00 a.m. EDT the center of Tropical Storm Fay was located at latitude 27.9°N and longitude 65.3°W which put it about 305 miles south of Bermuda.  The maximum sustained wind speed was 70 m.p.h. and the minimum surface pressure was 991 mb.

The upper level outflow around Fay is well developed on the west side of the circulation.  It is over warmer Sea Surface Temperatures and some further intensification is possible.  When Fay gets farther north it will run into stronger upper level winds from the west.  Those winds will generate wind shear and start to weaken the storm.

Fay is moving around the western end of a subtropical high pressure system and it should continue to move northward today.  Eventually the upper level westerly winds will force Fay to turn toward the northeast.

The Tropical Storm Watch for Bermuda has been changed to a Tropical Storm Warning.

Subtropical Storm Fay Forms South of Bermuda

A large upper level low pressure system interacting with  the northern end of a tropical wave has produced a subtropical cyclone.  A reconnaissance plane investigated the system this afternoon and found that it had enough organization to be classified as a subtropical storm.  At 5:00 p.m. EDT the center of Subtropical Storm Fay was located at latitude 24.7°N and longitude 64.0°W, which put it about 525 miles south of Bermuda.  Fay was moving toward the north-northwest at 12 m.p.h. The maximum sustained wind speed was 40 m.p.h. and the minimum surface pressure was 1002 mb.

Fay is moving around the western end of a high pressure system located to its east.  It should turn more toward the northeast when it gets farther north and start to feel the influence of the midlatitude westerlies.

Fay currently has the typical hybrid structure of a subtropical cyclone the consists of one long band that coils about half to three quarters of the way around the system.  More thunderstorms are developing closer to the center of circulation.  If an inner core of thunderstorms develops and they release enough energy into the middle and upper levels of the storm to create a warm core, then Fay could make a transition to a tropical storm.

Fay is over warm Sea Surface Temperatures which create a potential for intensification, but it is also experiencing some wind shear from the nearby upper level low.  It could intensify some, especially if it develops an inner core.  Wind shear will increase as Fay moves farther north and it gets closer to upper level westerly winds.

A Tropical Storm Watch has been issued for Bermuda.

 

Typhoon Vongfong Approaching Okinawa

Typhoon Vongfong is approaching Okinawa and the island is already feeling the effects of the large circulation around the typhoon.  Kadena Air Force base has been reporting sustained winds to tropical storm force for 12 hours.  At 4:00 p.m. EDT the current observation at Kadena was heavy rain with northeast winds sustained at 47 m.p.h. and gusts to 71 m.p.h.

At 2:00 p.m. EDT the center of Typhoon Vongfong was located at latitude 23.8°N and longitude 128.9°E which put it about 200 miles south-southeast of Okinawa.  Vongfong was moving toward the north-northwest at 10 m.p.h.  The maximum sustained wind speed was 125 m.p.h. and there were gusts to 155 m.p.h.

Vongfong is starting to experience a little more wind shear and it is moving into a less favorable environment.  However, it is a large typhoon and the weakening process is likely to occur slowly for the next day or so.  As a result Vongfong will bring high winds and heavy rain to Okinawa for another 12-24 hours.

When Vongfong gets north of Okinawa, it will encounter strong westerly winds.  Those stronger winds will turn it toward the northeast.  The westerly winds will also increase wind shear over Vongfong and cause it to weaken more rapidly in a couple of days.  Vongfong could still be a typhoon when in approaches southwestern Japan.

 

Tropical Cyclone Hudhud Intensifying As It Get Closer to India

Tropical Cyclone Hudhud continues to move toward the eastern coast of India and it is not intensifying more rapidly.  At 2:00 p.m. EDT the center of Hudhud was located at latitude 15.9°N and longitude 86.5°E, which put it about 230 miles east-southeast of Visakhapatnam, India.  Hudhud was moving toward the northwest at 7 m.p.h.  The maximum sustained wind speed was 100 m.p.h. and there were gusts to 120 m.p.h.

A high pressure system located northeast of Hudhud is likely to continue to steer it toward the west-northwest or northwest until it reaches India.  Wind shear over Hudhud has decreased and the tropical cyclone is intensifying and it could intensify steadily until it makes landfall.  Hudhud will approach the coast of India near Visakhapatnam in about 36 hours and it will be a strong tropical cyclone when it gets there.  In addition to strong winds and heavy rain, Hudhud could also produce a significant storm surge along the coast.

 

Typhoon Vongfong Turns Northward

Typhoon Vongfong has made the anticipated turn and it is now moving toward the north.  At 5:00 p.m. EDT the center of Typhoon Vongfong was located at latitude 20.3°N and longitude 129.5°E which put it about 440 miles south-southeast of Okinawa.  Vongfong was moving toward the north-northwest at 8 m.p.h.  The maximum sustained wind speed was 150 m.p.h. and there were gusts to 185 m.p.h.

Vongfong is moving around the western end of a subtropical high pressure system, which should continue to steer it in a generally northerly direction for the next 36-48 hours.  When Vongfong nears southwestern Japan, it will begin to encounter upper level westerly winds, which will push it toward the northeast.  The model guidance suggest that Vongfong could be very near the coast of Japan in about 72 hours.

Microwave satellite imagery suggests that a larger outer eye is wrapping around a small inner eye that represents the current center of Vongfong.  The start of an eyewall replacement cycle usually produces weakening of a tropical cyclone, although there can be some fluctuations in intensity.  When Vongfong gets closer to Japan, upper level westerly winds will increase the vertical wind shear.  More wind shear will speed up the weakening trend.  Current guidance suggests that Vongfong could still be a typhoon when it approaches Japan in about three days.  However, it is likely to weaken to a strong tropical storm as it moves across parts of Japan.  Even if it does weaken, Vongfong could still bring gusty winds and locally heavy rainfall.

 

Tropical Cyclone Hudhud Poses Threat to India

A tropical cyclone has formed over the eastern Bay of Bengal and it poses a potential threat to the eastern portion of India.  At 2:00 p.m. EDT the center of Tropical Cyclone Hudhud was located at latitude 13.4°N and longitude 89.6°E, which put it about 625 miles south-southwest of Chittagong in Bangladesh and about 520 miles east-southeast of Visakhapatnam, India.  Hudhud was moving toward the west-northwest at 13 m.p.h.  The maximum sustained wind speed was 60 m.p.h. and there were gusts to 75 m.p.h.

An upper level high located northeast of Hudhud is generating northeasterly winds over the top of the circulation of Hudhud.  Those winds are producing wind shear, which is the main factor limiting the intensification of the tropical cyclone.  At the same time the winds are also enhancing outflow on the western side of the tropical cyclone, which is allowing for it to slowly become better organized.  Some of the guidance suggests that the wind shear will decrease as Hudhud moves farther west and intensification is possible before it makes landfall in India.

Clockwise flow around the upper level high is also steering Hudhud toward the west-northwest and it is expected to continue to travel in the direction for the next few days.  If it maintains its current forward motion, Hudhud will approach the eastern coast of India in about 48-72 hours.  It could make landfall near Visakhapatnam during the weekend.

 

Vongfong Intensifies Rapidly, Now a Super Typhoon

Typhoon Vongfong has been in an environment of warm Sea Surface Temperatures (SSTs) and light upper level winds, which is almost ideal for intensification of a tropical cyclone.  As  result it has intensified very rapidly and it has reached the intensity necessary to be classified as a Super Typhoon.  At 5:00 p.m. EDT the center of Typhoon Vongfong was located at latitude 17.6°N and longitude 133.2°E which put it about 700 miles southeast of Okinawa.  Vongfong was moving toward the west-northwest at 11 m.p.h.  The maximum sustained wind speed was 175 m.p.h., which made it the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale, and there were gusts to 215 m.p.h.  Vongfong is both stronger and larger than Typhoon Phanfone was.

Vongfong is being steered west-northwest by a subtropical high pressure system.  An upper level trough in the westerly flow at higher latitudes will approach Vongfong from the west.  Southerly winds on the east side of the trough will cause Vongfong to make a sharp turn toward the north during the next 24-36 hours.  It appears that Vongfong will continue to move northward during the rest of the week and it could approach southwestern Japan in five or six days.

Vongfong will remain in a very favorable environment for the next 24-48 hours and some further intensification is possible.  Eventually, the winds in the upper level trough will increase the wind shear over Vongfong.  At the same time Vongfong will be moving over cooler SSTs as it gets farther north.  So, a weakening trend could begin in about 48 hours.  However, Vongfong could still be a large typhoon as it approaches Japan.

 

Tropical Storm Watch Issued for Part of Baja California

Although Tropical Storm Simon is moving over cooler Sea Surface Temperatures (SSTs) its circulation is spinning down more slowly than originally anticipated.  As a result, the government of Mexico has issued a Tropical Storm Watch for the portion of the coast of Baja California that extends from Punta Abreojos to Punta Eugenia.

At 5:00 p.m. EDT the center of Tropical Storm Simon was located at latitude 25.8°N and longitude 117.4°W, which put it about 200 miles southwest of Punta Eugenia.  Simon was moving toward the north at 7 m.p.h.  The maximum sustained wind speed was 50 m.p.h. and the minimum surface pressure was 999 mb.  Winds to tropical storm force extended out 120 miles from the center of circulation, which placed them within 80 miles from the coast of Baja California.

Strong southwesterly winds in the upper levels are generating wind shear over the top of Simon.  In addition, it is over cooler SSTs.  The shear and cooler water will continue to weaken Simon.   There is slightly warmer water near the coast of Baja California, which could maintain the circulation long enough for it to make landfall.  Simon is expected to move northeastward toward Baja California and it could possible bring tropical storm force winds to some portions of the coast.  The moisture associated with Simon will also bring an enhanced chance for rain and some areas could get locally heavy rainfall.

 

Typhoon Vongfong Intensifying

Warm Sea Surface Temperatures and limited wind shear allowed Vongfong to intensify on Saturday and it is now a typhoon.  At 8:00 p.m. EDT on Saturday the center of Typhoon Vongfong was located near latitude 12.6°N and longitude 149.9°E which put it about 330 miles east-southeast of Guam.  Vongfong was moving toward the west-northwest at 21 m.p.h.  The maximum sustained wind speed was 80 m.p.h. and there were gusts to 100 m.p.h.

Clockwise flow around a subtropical high pressure system will keep Vongfong moving in a general west-northwesterly direction for several more days.  It could pass very near Guam during the next 24 hours.  Vongfong should remain in a favorable environment and further intensification is possible.

 

Typhoon Phanfone Approaching Japan

Typhoon Phanfone is approaching the southwestern part of Japan.  At 11:00 p.m. EDT the center of Phanfone was located at latitude 28.9°N and longitude 131.4°E which put it about 200 miles south of Miyazaki, Japan and about 670 miles southwest of Tokyo.  Phanfone was moving toward the north at 9 m.p.h.  The maximum sustained wind speed was 115 m.p.h. and there were gusts to 140 m.p.h.

Phanfone is already bringing rain and wind to parts of southwestern Japan.  It could bring gusty winds and locally heavy rainfall as it moves northeastward.  Phanfone is nearing the latitude of stronger upper level westerly winds.  Those winds will soon make Phanfone start to move toward the northeast.  Phanfone will move more quickly toward the northeast on Sunday afternoon and evening and it could be near Tokyo in about 24 hours.  The westerly winds will also increase the wind shear over Phanfone and create a weakening trend.  As more cooler air gets pulled into the circulation, Phanfone will begin a transition to an extratropical cyclone.