Monthly Archives: September 2016

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.

Tropical Storm Namtheun Bringing Wind and Rain to Southwest Kyushu

Tropical Storm Namtheun brought wind and rain to southwestern Kyushu on Saturday as the center moved just west of the coast.  At 8:00 p.m. EDT on Saturday the center of Tropical Storm Namtheun was located at latitude 31.4°N and longitude 129.6°E which put it about 85 miles (135 km) south of Nagasaki, Japan.  Namtheun was moving toward the north-northwest at 6 m.p.h. (10 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 985 mb.

Tropical Storm Namtheun has a small, but well organized circulation.  There is the remnant of the eye that existed when Namtheun was a typhoon.  A broken ring of thunderstorms surrounds the remnant eye.  Several spiral rainbands are rotating around just outside the small core of Namtheun.  Winds to tropical storm force extend out about 60 miles (95 km) from the center of circulation.

Tropical Storm Namtheun is moving through an environment that is marginally favorable for a tropical storm.  It is moving over water where the Sea Surface Temperature (SST) is near 29°C.  A large upper level trough is producing southerly winds which are blowing across the top of Tropical Storm Namtheun.  Those winds are generating moderate vertical wind shear and they are inhibiting the upper level divergence to the south of the tropical storm.  The marginally favorable environment could allow Tropical Storm Namtheun to maintain its intensity for another 12 to 24 hours.  After that time it will move over cooler SSTs and start to weaken faster.

The upper level trough is steering Tropical Storm Namtheun toward the north and that general motion is expected to continue for another 12 hours or so.  After that time, southwesterly winds are expected to turn Tropical Storm Namtheun more toward the northeast.  On its anticipated track Tropical Storm Namtheun will move close to Nagasaki, Fukuoka, Kitakyushu and the southwestern portion of Honshu.

Tropical Storm Namtheun’s small size should keep the wind damage minimal.  It could cause locally heavy rainfall and the potential for flooding, but the areal extent of any floods should be limited.

Hurricane Lester Passing North of Hawaii

Hurricane Lester passed north of Hawaii on Saturday.  All Hurricane Watches were cancelled, although the surf on the north coasts of the islands should be increased by the waves generated by Hurricane Lester.  At 5:00 p.m. EDT on Saturday the center of Hurricane Lester was located at latitude 22.4°N and longitude 155.4°W which put it about 175 miles (285 km) east-northeast of Honolulu, Hawaii.  Lester was moving toward the west-northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 85 m.p.h. (140 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 985 mb.

Hurricane Lester weakened slowly on Saturday as it moved north of the Hawaiian Islands.  An upper level trough northwest of Lester produced southwesterly winds that blew across the top of the hurricane.  The vertical wind shear tilted the circulation toward the northeast with height.  The wind shear also inhibited the upper level divergence to the south of the center of Lester.  Less upper level divergence meant that the hurricane could not pump out as much mass and the surface pressure slowly rose.

Hurricane Lester is moving through an environment that is likely to weaken it further.  Lester is moving over water where the Sea Surface Temperature (SST) is 27°C.  So, there is enough energy to support the hurricane.  However, the upper level trough will continue to create vertical wind shear and the shear will continue to weaken Hurricane Lester.

Hurricane Lester is moving around the western end of a subtropical ridge which is steering toward the west-northwest.  That general motion is expected to continue for several more days.  When Hurricane Lester gets farther north the westerlies in the middle latitudes will turn it toward the northeast.  On its anticipated track Hurricane Lester will stay north of the Hawaiian Islands.

Hurricane Hermine Making Landfall in North Florida

After intensifying into a hurricane on Thursday, Hurricane Hermine is making landfall near St. Marks, Florida.  At midnight EDT the center of Hurricane Hermine was located at latitude 29.8°N and longitude 84.2°W which put it about 20 miles (30 km) south of St. Marks, Florida.  Hermine was moving toward the north-northeast at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 984 mb.

A Hurricane Warning is in effect from Suwannee River to Mexico Beach, Florida.  A Hurricane Watch is in effect from Anclote River to Suwannee River and from Mexico Beach to the Walton County/Bay County line.  A Tropical Storm Warning is in effect from Englewood to Suwannee River and from Mexico Beach to the Walton County/Bay County line.  A Tropical Storm Warning is also in effect from the Flagler County/Volusia County line to Duck, North Carolina including Pamlico and Albemarle Sounds.  A Tropical Storm Watch is in effect from Duck, North Carolina to Sandy Hook, New Jersey including the Chesapeake Bay from Smith Point southward and southern Delaware Bay.

The circulation of Hurricane Hermine organized quickly on Thursday.  It developed an eye with a mostly complete eyewall.  Spiral rainbands developed with strong winds in the eastern half of the circulation.  Upper level divergence to the east of Hermine pumped out mass and allowed the surface pressure to decrease.  The circulation is still asymmetrical with most of the stronger winds east of the center, but it looks a lot more typical of hurricanes that move toward the northern coast of the Gulf of Mexico.

Hurricane Hermine will weaken after it makes landfall.  It could interact with a cold front moving into the southeastern U.S.  It is possible that Hermine could develop a hybrid structure that is part tropical and part extratropical.  Hermine could have winds to tropical storm force as it passes over the Mid-Atlantic coast.  The stronger winds are likely to be out over the Atlantic Ocean and winds should be weaker farther inland.

An upper level trough is steering Hurricane Hermine toward the north-northeast and a general northeasterly motion is expected to continue for another 36 hours.  Later in the weekend a surface high pressure system could move north of Hermine and stall its progress.  Hermine could be stationary for a time.  On its anticipated track center of Hermine is likely to pass east of Tallahassee, Florida.  The center could pass north of Savannah, Georgia before coming near Charleston, South Carolina.  Hermine is likely to move near Cape Hatteras, North Carolina and out into the Atlantic Ocean.

Hurricane Hermine is capable of causing regional minor wind damage.  It is likely to cause widespread power outages.  The coast of the northeastern Gulf of Mexico is susceptible to storm surges and high water will effect that area overnight.  Locally heavy rainfall will create the potential for flooding.  When rainbands move ashore, wind shear could spin up tornadoes.  As Hermine moves near the Mid-Atlantic coast, easterly winds could cause water rises.

The Hurricane Intensity Index (HII) for Hurricane Hermine is 11.5.  The Hurricane Size Index (HSI) is 14.0.  The Hurricane Wind Intensity SIze Index (HWISI) is 25.5.  These indices are very similar to the ones for Hurricane Isaac before it hit the coast of Louisiana n 2012.  The HII for Isaac was 11.5.  Its HSI was 16.7 and its HWISI was 28.2.  This means that Hurricane Hermine is as strong and just smaller than Hurricane Isaac was just before it made landfall.  Hurricane Isaac did hit a more populated and more built up region.  Hurricane Isaac did 970 million dollars worth of insured damage.  It caused 407 million dollars to be paid out for flood insurance.  It is estimated that Hurricane Isaac caused 2.35 billion dollars worth of damage in the U.S.

Typhoon Namtheun Heads for Southern Japan

Typhoon Namtheun spun up quickly on Thursday and moved steadily toward Kyushu in southern Japan.  At 11:00 p.m. EDT on Thursday the center of Typhoon Namtheun was located at latitude 26.6°N and longitude 130.8°E which put it about 335 miles (540 km) south of Kagoshima, Japan.  Namtheun was moving toward the north at 7 m.p.h. (11 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 975 mb.

Typhoon Namtheun developed quickly from a low pressure system along a surface trough.  Namtheun has a small but very well organized circulation.  It has a tiny pinhole eye surrounded by a ring of strong thunderstorms.  Several other rainbands are spiraling around the ring of strong thunderstorms.  The thunderstorms are generating upper level divergence which is pumping out mass in all directions.  The upper level divergence is slightly less to the west of the center of circulation.

Typhoon Namtheun is in an environment favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  Although there is a large upper level trough over eastern Asia which contains strong southwesterly winds, Typhoon Namtheun developed east of those strong winds.  It is in an area where the upper level winds are weaker and there is little vertical wind shear.  Namtheun is likely to intensify more during the next day or two.  However, Namtheun’s small circulation means that it will respond very rapidly to positive or negative changes in its surrounding environment.

A ridge to the east of Namtheun is steering the typhoon toward the north and that general motion is expected to continue for several more days.  On its anticipated track Typhoon Namtheun could be very near the southern tip of Kyushu within 48 hours.  It could bring strong winds and heavy rain to parts of southern Japan.

Hurricane Watch Issued for Hawaii as Hurricane Lester Moves Closer

As Hurricane Lester moved steadily closer to Hawaii on Thursday, a Hurricane Watch was issued for Hawaii County and Maui County including Maui, Molokai, Lanai and Kahoolawe.

At 8:00 p.m. EDT on Thursday the center of Hurricane Lester was located at latitude 18.5°N and longitude 145.4°W which put it about 640 miles (1030 km) east of Hilo, Hawaii.  Lester was moving toward the west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 145 m.p.h. (235 km/h).  The minimum surface pressure was 960 mb.

The symmetrical circulation of Hurricane Lester is very well organized.  There is a circular eye with a diameter of 25 miles (40 km).  A ring of strong thunderstorms completely surrounds the eye.  Multiple spiral rainbands are rotating around periphery of the circulation.  Hurricane Lester is generating strong upper level divergence which is pumping mass out in all directions.

Hurricane Lester is currently moving through a favorable environment.  It is over water where the Sea Surface Temperature is near 27°C.  The upper level winds are light and there is little vertical wind shear.  Hurricane Lester will be moving over some of the same water that Hurricane Madeline passed over a few days ago.  If Madeline stirred any cooler water to the surface, it could cause Hurricane Lester to weaken.  When Hurricane Lester gets closer to Hawaii an upper level trough will produce stronger upper level southwesterly winds and the wind shear will increase.  Lester should weaken as it gets closer to Hawaii.

A subtropical ridge has been steering Hurricane Lester toward the west.  The western end of the ridge is expected to weaken and that will cause Lester to move more toward the west-northwest.  On its anticipate track Hurricane Lester could approach Hawaii on Saturday morning.