Typhoon Meranti Becomes Equivalent of Cat. 5 Hurricane and Threatens Taiwan

Typhoon Meranti rapidly intensified into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale as it moved on a course that threatens Taiwan.  At 11:00 a.m. EDT on Monday the center of Typhoon Meranti was located at latitude 19.2°N and longitude 127.6°E which put it about 495 miles (800 km) southeast of Taiwan.  Meranti was moving toward the west-northwest at 14 m.p.h. (23 km/h).  The maximum sustained wind speed was 180 m.p.h. (290 km/h) and there were wind gusts to 220 m.p.h. (355 km/h).  The minimum surface pressure.

Meranti is a large dangerous typhoon.  The Hurricane Intensity Index (HII) is 42.2.  The Hurricane Size Index (HSI) is 25.5 and the Hurricane Wind Intensity Size Index (HWISI) is 67.7.  Those indices suggest that Typhoon Meranti is capable of causing widespread catastrophic damage.

The structure of Typhoon Meranti is very well organized.  A well formed circular eye is surrounded by a ring of very tall thunderstorms.  Additional strong spiral bands of thunderstorms are rotating around the core of the circulation.  Typhoon Meranti is generating strong upper level divergence which is pumping out mass in all directions.

Typhoon Meranti is moving through an environment that will allow it to maintain much of its intensity until it reaches Taiwan.  It is moving over water where the Sea Surface Temperature is near 31°C.  The upper level winds are weak and there is not much vertical wind shear.  If a rainband wraps around the existing eye, then an eyewall replacement cycle could temporarily weaken Typhoon Meranti.

A subtropical ridge is steering Typhoon Meranti toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track Typhoon Meranti will be very near the southern tip of Taiwan in about 36 hours.  After it moves past Taiwan it is forecast to move into eastern China.

Meranti is an extremely dangerous typhoon.  It is capable of causing widespread catastrophic wind damage.  In addition it will produce very heavy rain and flooding is a serious concern.

Tropical Storm Ian Forms in the Middle of the Atlantic

Tropical Storm Ian formed on Monday in the middle of the Atlantic Ocean.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Ian was located at latitude 21.8°N and longitude 50.4°W which put it about 1140 miles (1840 km) southeast of Bermuda.  Ian was moving toward the northwest at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (95 km/h).  The minimum surface pressure was 1007 mb.

The circulation of Tropical Storm Ian is not well organized.  A large upper low west of Ian is generating strong southwesterly winds which are blowing across the top of the tropical storm.  There is a large cyclonic circulation in the lower levels, but there are no thunderstorms near the center of circulation.  The thunderstorms are forming northeast of the center in a rainband that is well removed from the core of the storm.

Tropical Storm Ian will through a hostile environment during the next several days.  Although Ian will move over water where the Sea Surface Temperature is near 29°C, the upper level trough will continue to cause strong vertical wind shear.  Ian is not likely to strengthen in the short term.  Eventually, later this week Ian will move farther from the upper level trough and it could strengthen somewhat at that time, if the low level circulation persists.

Tropical Storm Ian is moving around the western end of a subtropical ridge which is steering it toward the northwest and that general motion is expected to continue for another day or two.  When Ian moves farther north, it will turn toward the northeast and the tropical storm will begin to move faster.

Typhoon Meranti Strengthens Quickly Into the Equivalent of a Major Hurricane

Typhoon Meranti intensified rapidly on Sunday into the equivalent of a major hurricane.  At 11:00 p.m. EDT on Sunday the center of Typhoon Meranti was located at latitude 18.1°N and longitude 129.7°E which put it about 650 miles (1050 km) east-southeast of Taiwan.  Meranti was moving toward the west-northwest at 17 m.p.h. (27 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 948 mb.

Typhoon Meranti intensified very rapidly on Sunday.  A small, well formed eye developed at the center of Meranti.  A ring of strong thunderstorms surrounds the eye and additional bands of thunderstorms are spiraling around the core of the circulation.  The circulation is very symmetrical.  Thunderstorms in the core of Typhoon Meranti are generating strong upper level divergence which is pumping out large amounts of mass in all directions.  Meranti is a very well organized typhoon.

Typhoon Meranti is moving through a very favorable environment. It is moving over water where the Sea Surface Temperature is near 31°C.  The upper level winds are weak and there is little vertical wind shear.  Meranti will continue to intensify and it could become a Super Typhoon.  If an eyewall replacement cycle occurs, there could be fluctuations in the intensity of Meranti.

A subtropical ridge is steering Typhoon Meranti toward the west-northwest and that general motion is expected to continue for another couple of days.  On its anticipated track Typhoon Meranti will be near northern Luzon, Taiwan and the southern Ryukyu Islands in about 48 hours.  Meranti will be a dangerous typhoon at that time.  It will be capable of significant wind damage.  It will also cause very heavy rain and create the potential for significant flooding.

Tropical Storm Orlene Develops Rapidly West of Mexico

Tropical Storm Orlene developed rapidly southwest of Baja California on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Orlene was located at latitude 16.6°N and longitude 118.3°W which put it about 700 miles (1125 km) southwest of the southern tip of Baja California.  Orlene was moving toward the northwest at 9 m.p.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 1001 mb.

Tropical Storm Orlene organized quickly on Sunday.  A primary rainband wrapped around the center of circulation and an eye appears to be forming.  Additional spiral bands are rotating around the core of Orlene.  Thunderstorms in the core of Tropical Storm Orlene are generating upper level divergence which is pumping out mass in all directions.  The circulation of Orlene is symmetrical and well formed.

Tropical Storm Orlene is moving through a very favorable environment.  It is moving over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and there is little vertical wind shear.  Tropical Storm Orlene will continue to intensify on Monday and it could intensify rapidly for another 24 hours.

Tropical Storm Orlene is moving northwest toward a weakness in the subtropical high and that general motion is expected to continue for another day or two.  Eventually, the subtropical ridge is expected to strengthen and turn Tropical Storm Orlene toward the west.

Tropical Storm Meranti Forms West of Guam

A center of circulation developed within an area of thunderstorms west of Guam on Saturday and the system was designated as Tropical Storm Meranti.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Meranti was located at latitude 16.0°N and longitude 135.8°E which put it about 1070 miles (1725 km) east-southeast of Taiwan.  Meranti was moving toward the west at 13 m.p.h. (20 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 991 mb.

The circulation of Tropical Storm Meranti is still organizing and the distribution of thunderstorms is asymmetrical.  Most of the thunderstorms are occurring east of the center of circulation.  There is a cluster of the thunderstorms just to the east of the center.  There are also two well formed rainbands east of the core of Tropical Storm Meranti.  Additional spiral bands are located in all parts of the tropical storm.  The thunderstorms near the center are generating upper level divergence which is pumping out mass in all directions.

Tropical Storm Meranti is moving through an environment which is favorable for further intensification.  It is moving over water where the Sea Surface Temperature is near 31°C.  An upper level ridge located to the northwest of Meranti is producing northeasterly winds which are blowing across the western portion of the tropical storm.  The upper level winds are weaker over the eastern half of the circulation and the vertical wind shear is only slowing the intensification.  Although there may be some drier air in the western half of the circulation, Tropical Storm Meranti could intensify into a typhoon on Sunday.  Meranti could become a strong typhoon in two or three days.

A subtropical ridge north of Tropical Storm Meranti is steering it toward the west.  The subtropical ridge is forecast to steer Meranti in a general west-northwesterly direction during the next two or three days.  On its anticipated track Tropical Storm Meranti is expected to approach the area of northern Luzon, Taiwan and the southern Ryukyu Islands in about three days.  It could be a strong typhoon at that time.

Hurricane Newton Brings Wind and Heavy Rain to Baja California

Hurricane Newton is bringing wind and heavy rain as it moves over southern Baja California.  At 2:00 p.m. EDT on Tuesday the center of Hurricane Newton was located at latitude 24.7°N and longitude 111.4°W which put it about 75 miles (120 km) west-northwest of La Paz, Mexico.  Newton was moving toward the northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 986 mb.

There are Hurricane Warnings in effect for the portions of the coast from Cabo San Lazaro to Todos Santos, from Los Barriles to Mulege and from Guaymas to Bahia Kino.  Tropical Storm Warnings are in effect for the portions of the coast from Cabo San Lazaro to Punta Abreojos, from Mulege to Bahia San Juan Bautista, from Bahia Tempehuaya to Guaymas and from Bahia Kino to Puerto Libertad.  A Hurricane Watch is in effect for the portion of the coast form Bahia Kino to Puerto Libertad.

Hurricane Newton made landfall on the southern tip of Baja California on Tuesday morning.  It moved along the western coast of the peninsula and the center passed to the west of La Paz, Mexico.  Newton is now moving north across Baja California near Ciudad Constitucion.  Newton is generating winds to hurricane force.  Areas of heavier rain are occurring near La Paz and Mulege.  Very heavy rain is falling where the wind is pushing air up the slopes of mountains and there is a substantial risk of flash flooding in those areas.

The structure of Hurricane Newton is beginning to deteriorate as it interacts with the mountains on Baja California.  The circulation is starting to tilt toward the north as the low level circulation is partially blocked by west coast of Baja while the middle and upper portions of the circulation continue to move north.  The strongest thunderstorms are occurring south of the center of circulation.  Additional strong thunderstorms are occurring rain bands north of the center over the Gulf of California.

Hurricane Newton will weaken as long as the center of circulation is moving over the mountains in southern Baja California.  It is possible that the middle and upper parts of the circulation could temporarily become detached from the existing low level center.  A new low level center could form under the middle and upper parts of the circulation when they emerge over the Gulf of California.  The Sea Surface Temperature in the Gulf of California is 32°C, but Newton will only be over the water for a few hours.  So, the potential for significant re-intensification is slight.

Hurricane Newton is moving around the western end of a ridge of high pressure.  The ridge is steering Newton toward the north.  That general motion is expected to continue for the next few hours and then Hurricane Newton could turn more toward the north-northeast.  On its anticipated track Hurricane Newton will emerge over the Gulf of California near Loreto in about 12 hours.  Newton will make a landfall on the west coast of Mexico in about 18 hours.

Hurricane Newton will continue to bring strong winds and heavy rain to the southern part of Baja California for the rest of Tuesday.  It will also produce heavy rain over portions of western Mexico on Wednesday.  Flash flooding will continue to be a risk in areas of steep terrain.  The remnants of Hurricane Newton could transport moist air over southeastern Arizona and western New Mexico.

Rapidly Intensifying Hurricane Newton Threatens Baja California

Hurricane Newton intensified rapidly from a tropical depression on Monday into a powerful hurricane that threatens Baja California.  At 11:00 p.m. EDT on Monday the center of Hurricane Newton was located at latitude 21.3°N and longitude 109.0°W which put it about 125 miles (200 km) south-southeast of Cabo San Lucas, Mexico.  Newton was moving toward the northwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were wind gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 979 mb.

The government of Mexico has issued a Hurricane Warning for the portion of the coast from Cabo San Lazaro to Mulege including Cabo San Lucas.  A Tropical Storm Warning has been issued for the portions of the coast from Cabo San Lazaro to Punta Abreojos, from Mulege to Bahia San Juan Bautista and from Mazatlan to Puerto Libertad.  A Hurricane Watch has been issued for the portion of the coast from Guaymas to Puerto Libertad.

The circulation of Hurricane Newton organized very rapidly on Monday.  A primary rainband wrapped most of the way around an eye.  Multiple bands of thunderstorms developed outside the eyewall.  Thunderstorms near the core of Hurricane Newton generated strong upper level divergence which pumped out mass and allowed the winds speeds to increased rapidly.  Newton intensified from a tropical depression into a hurricane in 24 hours.  The maximum sustained wind speed has increased from 40 m.p.h. (65 km/h) 24 hours ago to 90 m.p.h. (150 km/h).

Hurricane Newton is in an environment that could allow it to strengthen until it reaches the southern tip of Baja California.  It is moving over water where the Sea Surface Temperature is 29°C.  The upper level winds are light and there is little vertical wind shear.  When Hurricane Newton reaches Baja California, it will weaken as it crossed over the mountains.  However, it could still be a hurricane when it reaches the warm water in the Gulf of California.

Hurricane Newton is moving around the western end of a mid-level ridge.  The ridge should steer it toward the north-northwest for another 12 hours.  When Newton reaches the end of the ridge, it will turn toward the north-northeast.  On its anticipated track Hurricane Newton will reach the southern portion of Baja California in less than 12 hours.  Newton could emerge over the Gulf of California in about 24 hours.  Newton could still be a hurricane when it reaches the western coast of Mexico near Guaymas on Wednesday.

The Hurricane Intensity Index (HII) for Newton is 13.9.  The Hurricane Size Index (HSI) is 12.2 and the Hurricane Wind Intensity Size Index is 26.1.  Given that Hurricane Newton is likely to intensify until it makes landfall in Baja California, it has the potential to cause regional serious wind damage.  Heavy rain and flash flooding will pose an even greater threat in areas of steep terrain.  Newton has the potential to be a destructive hurricane.

Post Tropical Storm Hermine Edges Toward Long Island

The low pressure system that was Tropical Storm Hermine began to move back toward the west on Monday and the motion brought it closer to Long Island.  At 8:00 p.m. EDT on Monday the center of Post Tropical Storm Hermine was located at latitude 39.3°N and longitude 70.3°W which put it about 135 miles south of Nantucket Island.  Hermine was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 997 mb.

A Tropical Storm Warning remains in effect for the portion of the coast from Fire Island Inlet to Port Jefferson Harbor on Long Island and from New Haven, Connecticut to Sagamore Beach, Massachusetts including Block Island, Martha’s Vineyeard and Nantucket Island.  Most of the stronger winds are occurring over water, but a weather station at Nantucket, Massachusetts reported a sustained wind speed of 44 m.p.h. (71 km/h) and a wind gust ot 56 m.p.h. (90 km/h) on Monday.

Post Tropical Storm Hermine has not had the structure of a tropical cyclone for several days.  There are no thunderstorms near the center of circulation.  The taller clouds are all occurring west of the center.  The circulation pulled in drier air which has circulated into the core of the circulation.  An upper level low south of Hermine has generated southeasterly winds which are blowing across the top of the circulation.  The vertical wind shear combined with the drier air to prevent the development of new thunderstorms near the center of circulation.

The environment around Post Tropical Storm Hermine could become a little less hostile on Tuesday.  It will be moving over water where the Sea Surface Temperature (SST) is near 25.5°C.  As Hermine moves west the vertical wind shear will decrease.  However, the cyclone is surrounded by dry air.  If the surface low moves west, the complex environment could allow the system to maintain its intensity for another day or so.  If the surface low moves farther north, it will move over cooler SSTs and the wind speeds will decrease.

The upper low to the south of Post Tropical Storm Hermine and a ridge north of Hermine are combining to steer it toward the west-northwest.  That general motion is expected to continue for a few more hours.  As Post Tropical Storm Hermine interacts with the upper low, it could make a slow cyclonic loop.  On its expected track Hermine could move closer to Long Island on Tuesday.

Post Tropical Storm Hermine will continue to produce modest water rises along the coast.  In addition persistent wind and wave action will generate more beach erosion.

Tropical Storm Newton Forms, Hurricane Warning Issued for Baja California

Tropical Storm Newton formed Sunday within a large area of thunderstorms west of Mexico.  Based on the forecast track and intensity the government of Mexico issued watches and warnings for parts of the west coast of Mexico and Baja California.  A Hurricane Warning was issued for the portion of the coast from La Paz to Santa Fe including Cabo San Lucas.  A Tropical Storm Warning was issued for the portion of the coast from Manzanillo to Cabo Corrientes.  Hurricane Watches were issued for the portions of the coast from La Paz to San Evaristo and from Santa Fe to Cabo San Lazaro.  Tropical Storm Watches were issued for the portions of the coast from San Evaristo to Loreto, from Cabo San Lazaro to Puerto San Andresito and from Mazatlan to Huatabampito.

At 11:00 p.m. EDT on Sunday the center of Tropical Storm Newton was located at latitude 17.0°N and longitude 105.7°W which put it about 490 miles (790 km) southeast of Cabo San Lucas, Mexico.  Newton was moving toward the north-northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1000 mb.

The circulation of Tropical Storm Newton is still organizing.  There is a broad cyclonic rotation southwest of Manzanillo, Mexico.  Clusters of thunderstorms may be spinning up smaller cyclonic circulations within the larger circulation.  Bands of thunderstorms are developing in the southern and eastern of the portions of the larger cyclonic circulation.  There is upper level divergence pumping mass out to the west of the center, but there is no apparent tight core at the center of the circulation.

Tropical Storm Newton is in an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  An upper level ridge over Mexico is producing northeasterly winds which are blowing across the top of Tropical Storm Newton,  The upper level winds are restricting the upper level divergence to the east of Newton,  but the vertical wind shear should not be strong enough to prevent intensification.  It is possible that some drier air from Mexico could be pulled into the eastern half of the circulation.

Tropical Storm Newton is forecast to intensify on Monday.  The broad circulation could slow the rate of intensification until a distinct inner core forms.  Once a core develops, then Tropical Storm Newton could intensify more quickly and a period of rapid intensification may be possible.  Tropical Storm Newton could intensify into a hurricane before it reaches Baja California.

The ridge over Mexico is steering Newton toward the north-northwest and that motion is expected to continue for another day or so.  An upper level trough approaching the west coast of North America is expected to turn Tropical Storm Newton more toward the north as it nears the southern tip of Baja California.  On its anticipated track Tropical Storm Newton could be very near the southern tip of Baja California in about 36 hours.

Post Tropical Storm Hermine Creates Coastal Flood Risk for Northeast U.S.

Although the structure of Tropical Storm Hermine changed significantly on Saturday and the National Hurricane Center designated it as Post Tropical, it still is creating a risk for coastal flooding for the northeastern U.S.  The size of the circulation of Hermine and its proximity to the U.S. is allowing its winds to push water toward portions of the coast.  The largest immediate risk is for the coasts of Virginia, Delaware and New Jersey.  When Hermine moves north, the greater risk will shift to New York, Rhode Island and Massachusetts.

At 11:00 p.m. EDT on Saturday the center of Post Tropical Storm Hermine was located at latitude 36.5°N and longitude 72.1°W which put it about 205 miles (330 km) southeast of Ocean City, Maryland.  Hermine was moving toward the east-northeast at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 998 mb.

A Tropical Storm Warning is in effect for the portion of the coast from Ocracoke Inlet, North Carolina to Watch Hill, Rhode Island including the Chesapeake Bay from Drum Point southward, Delaware Bay, New York City and Long Island.  A Tropical Storm Watch is in effect from Watch Hill, Rhode Island to Sagamore Beach, Massachusetts including Block Island, Martha’s Vineyard and Nantucket.

The circulation of Hermine changed from a tropical cyclone with a tight inner core to structure where area with the maximum wind speed is farther from the center.  In addition all of the thunderstorms near the center dissipated and most of the remaining thunderstorms are well northeast of the center of circulation.  The loss of tropical characteristics are the reason why the National Hurricane Center designated Hermine as Post Tropical.

Future changes of Hermine could continue to be complex.  Dry air has permeated the inner 100 miles (160 km) of the circulation which is devoid of any thunderstorms.  An upper level trough over the northeastern U.S. is forecast to move over the top of Hermine and cut off.  The would create a vertical structure which is the opposite of what is normally found in a tropical cyclone.  However, Hermine is moving over water where the Sea Surface Temperature (SST) is near 30°C.  A combination of cold air aloft in the upper low and warm SSTs could create enough instability to generate the development of new thunderstorms closer to the core of the circulation.  it is possible that Hermine could make a transition back to a more tropical cyclone like structure during the next several days.

The upper level trough is currently steering Hermine toward the east-northeast.  When the trough approaches Hermine, it will steer the storm more toward then north.  However, when the trough moves over the top of Hermine, the steering currents will be weak and Hermine could stall south of Long Island.  It is possible that the counterclockwise rotation in the upper trough could cause the storm to loop once or twice.  If Hermine makes a slow counterclockwise loop, it could move back closer to the coast of New Jersey on Monday.

The wind field in Hermine expanded during the structural changes.  Winds to tropical storm force extend out about 200 miles (320 km).  That makes Hermine about half as big as Hurricane Sandy was in 2012.