Monthly Archives: August 2016

Tropical Storm Chanthu Passes East of Tokyo

Tropical Storm Chanthu brought wind and rain to the east coast of Honshu as the center passed east of Tokyo on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Chanthu was located at latitude 37.4°N and longitude 141.6°E which put it about 105 miles (170 km) northeast of Tokyo, Japan.  Chanthu was moving toward the north-northeast at 12 m.p.h. (19 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 995 mb.

Tropical Storm Chanthu is starting the transition from a tropical cyclone to an extratropical cyclone.  It is still moving over water where the Sea Surface Temperature (SST) is near 26°C, but Chanthu will move over colder water during the next 24 hours.  An upper level trough west of Japan will sweep northwesterly winds over the top of Tropical Storm Chanthu.  The increased vertical wind shear will tilt the circulation of Chanthu toward the northeast.  The trough also contains cooler air.  A combination of cooler SSTs, more vertical wind shear and cooler air aloft will alter the structure of Chanthu and it will begin to look more like an extratropical cyclone on Wednesday.

The upper level trough will steer Chanthu in a generally north-northeasterly direction during the next 24 hours.  On its anticipated track Tropical Storm Chanthu will move roughly parallel to the coast of Honshu.  Chanthu is expected to move across Hokkaido later on Wednesday.

The rainbands in Tropical Storm Chanthu are capable of producing locally heavy rainfall.  Some flooding is possible in eastern Honshu and Hokkaido.  Wind damage should be minimal although fishing boats and other vessels along the northeast coast of Japan will have to deal with wind and waves.

Tropical Storm Chanthu Forms South of Japan

A center of circulation consolidated near a cluster of thunderstorms south of Japan on Saturday and the system was designated as Tropical Storm Chanthu.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Chanthu was located at latitude 21.2°N and longitude 143.1°E which put it about 295 miles (475 km) south-southeast of Iwo To.  Chanthu was moving toward the northeast at 14 m.p.h. (23 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 998 mb.

Although a distinct center of circulation exists in the lower levels of Tropical Storm Chanthu, the storm is not well organized.  Southwesterly winds in the upper levels are causing vertical wind shear which is tilting the upper portion of the circulation toward the northeast.  Most of the thunderstorms associated with Tropical Storm Chanthu are occurring in the northeastern quadrant of the circulation.  Several broken rainbands extend into the southern portion of the circulation, but there are few thunderstorms in the western half of Chanthu.

Tropical Storm Chanthu is moving through an environment that is marginally favorable for intensification.  Chanthu is moving over water where the Sea Surface Temperature is near 30°C.  However, an upper level trough west of Chanthu is causing the southwesterly winds which are blowing across the top of the tropical storm.  Moderate vertical wind shear will inhibit intensification in the short term.  As Tropical Storm Chanthu moves farther north, it could move into a region where the upper level winds are not as strong.  If the vertical wind shear decreases, then Chanthu could intensify.

Winds from the upper level trough are steering Tropical Storm Chanthu toward the northeast.  As the tropical storm moves farther north, a subtropical ridge located east of Chanthu will steer it more toward the north.  On its anticipated track, the center of Tropical Storm Chanthu is expected to pass east of Iwo To in about 24 hours.  Tropical Storm Chanthu could be approaching the coast of Japan near Tokyo in about three or four days.

Tropical Storm Javier Near Southern Tip of Baja California

Tropical Storm Javier moved slowly toward the southern tip of Baja California on Monday night.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Javier was located at latitude 22.5°N and longitude 109.7°W which put it about 30 miles (50 km) south-southeast of Cabo San Lucas, Mexico.  Javier was moving toward the northwest at 5 m.p.h. (8 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 999 mb.

The government of Mexico has discontinued all Hurricane Warnings and Watches.  A Tropical Storm Warning remains in effect for the portion of the coast from San Evaristo to Cabo San Lazaro.  A Tropical Storm Watch is in effect for the portion of the coast from San Evaristo to Loreto and from Cabo San Lazaro to Puerto San Andresito.

Javier is a small tropical storm.  Winds to tropical storm force only extend out about 60 miles (95 km) from the center of circulation.  The circulation of Tropical Storm Javier weakened during the past few hours.  Data from a NOAA Hurricane Hunter Research aircraft indicated that drier air in the middle levels had been pulled into the circulation of Javier.  The ingestion of the drier air weakened many of the thunderstorms and the wind speed decreased.  In addition an upper level ridge over northern Mexico appears to be causing easterly winds to blow across the top of Javier.  The vertical wind shear is tilting the circulation and the upper levels of Javier are tilted to the west of the surface center.

Tropical Storm Javier is in an environment that is not favorable for intensification.  Javier is over water where the Sea Surface Temperature is near 28°C, but the water west of Baja California is cooler.  The tropical storm is ingesting drier air and it is encountering vertical wind shear.  The proximity of Tropical Storm Javier to Baja California may also cause the terrain to disrupt the circulation.  Tropical Storm Javier may be able to maintain its intensity at times, but it is likely to weaken during the next several days.

Tropical Storm Javier is moving around the western end of a ridge over Mexico which has been steering it toward the northwest.  Since the thunderstorms in Javier are not as tall, it is being steered by winds lower in the atmosphere and those steering currents appear to be weaker.  As a result, Tropical Storm Javier moved much more slowly on Monday night.  When a tropical cyclone moves very close to Baja California, the terrain has an impact on the structure of the storm and its ultimate motion.  It is possible that the upper and lower portions of Tropical Storm Javier’s circulation could be sheared apart.  If that happens, the lower portion of the circulation could drift slowly along the west coast of Baja California.  The middle and upper portions of the circulation could be pulled north into the southwestern U.S. by an upper level trough off the west coast of the U.S.

The primary risks posed by Tropical Storm Javier are locally heavy rainfall and flash floods.  Steep terrain in parts of Baja California exacerbate the flood risk in those areas.  It is possible that some moisture associated with Tropical Storm Javier could be pulled into the southwestern U.S. later this week.  If that happens, the moisture will enhance rainfall over parts of Arizona and surrounding states.

Tropical Storm Javier Forms and Heads for Baja California

Tropical Storm Javier formed west of Mexico on Sunday and headed for Baja California.  At 11:00 p.m. EDT the government of Mexico issued Hurricane Warnings and Hurricane Watches for part of Baja California.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Javier was located at latitude 20.6°N and longitude 107.7°W which put it about 210 miles (340 km) southeast of Cabo San Lucas, Mexico.  Javier was moving to the northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 999 mb.

The government of Mexico has issued a Hurricane Warning for the portion of the coast from Cabo San Lucas to Todos Santos.  A Hurricane Watch and a Tropical Storm Warning has been issued for the portions of the coast from Todos Santos to Cabo San Lazaro and from Cabo San Lucas to Los Barriles.  A Tropical Storm Warning has been issued for the portion of the coast from Los Barriles to San Evaristo.  A Tropical Storm Watch has been issued for the portion of the coast from San Evaristo to Loreto.

Part of the middle and upper level structure associate with Tropical Storm Earl moved westward across Mexico and interacted with a surface trough of low pressure near the west coast of Mexico.  The middle and upper rotation was transported to the surface and a small low pressure system formed southwest of Manzanillo, Mexico.  The system was originally designated Tropical Depression 11-E early on Sunday.  A weather station at Manzanillo reported a wind from the southeast at 46 m.p.h. (74 km/h) at 11:00 a.m. EDT on Sunday and the National Hurricane Center upgraded the system to Tropical Storm Javier.

Javier is a small tropical storm and the circulation is still organizing.  The tropical storm force winds are occurring within 100 miles (160 km) of the center of Tropical Storm Javier.  Most of the thunderstorms are in the western western half of the tropical storm and many are located close to the center of circulation.  The thunderstorms near the center of Javier are generating upper level divergence but it is primarily moving away to the west of the tropical storm.

Tropical Storm Javier is in an environment that is somewhat favorable for intensification.  It is moving over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge centered near Texas is producing easterly winds that are blowing over the top of Javier.  The easterly winds are causing some vertical wind shear and they are inhibiting upper level divergence to the east of Javier.  Tropical Storm Jaiver may also be drawing in some drier air from Mexico, since it is close to the coast.  The wind shear and drier air will inhibit the rate of intensification, but Tropical Storm Javier should be able to extract enough energy from the warm SSTs to intensify.

Tropical Storm Javier is moving around the western end of the upper level ridge centered near Texas.  Clockwise flow around that ridge is steering Javier toward the west-northwest.  As Javier nears the western end of the ridge, it will turn more toward the north.  On its anticipated track Tropical Storm Javier could approach the southern tip of Baja California by late Monday.

Tropical Storm Javier could do some wind damage, but the primary risks will be locally heavy rainfall and flash flooding.  Tropical Storm Javier could increase the flow of moist air over the southwestern U.S. later this week and it could enhance the normal August thunderstorm activity in that region.

Tropical Storm Earl Strengthens Near Veracruz

Tropical Storm Earl regained strength on Friday after the center moved over the southern Bay of Campeche near Veracruz, Mexico.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Earl was located at latitude 18.8°N and longitude 95.0°W which put it about 85 miles (135 km) east-southeast of Veracruz, Mexico.  Earl was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 70 m.p.h. (115 km/h).  The minimum surface pressure was 1001 mb.

Because Tropical Storm Earl re-intensified and the radius of tropical storm force winds expanded to the north, the government of Mexico extended Tropical Storm Warnings farther north along the coast.  A Tropical Storm Warning is in effect for the portion of the coast from Puerto Dos Bocas to Tecolutla, Mexico.

Most of the circulation of Tropical Storm Earl remained intact while it moved over land from Belize to the Bay of Campeche.  As a result, the surface part of the circulation on the northern side of Earl began to redevelop quickly as the center approached the water in the Bay of Campeche.  A primary rainband wrapped most of the way around the center of circulation and other rainbands reformed over the Bay of Campeche.  There have been hints on an incipient eye forming at the center of circulation on recent visible satellite images.  Earl is a very well organized tropical storm.

The Sea Surface Temperature is near 30°C in the southern Bay of Campeche.  The upper level winds are weak and there is little vertical wind shear.  Upper level divergence is well formed in Tropical Storm Earl and it is pumping out mass.  The environment is favorable for further intensification.  However, the center of circulation is close to the coast and approximately 40% of the circulation is over land.  So, the proximity to land is the main factor inhibiting further strengthening.  Tropical Storm Earl does have a few hours to intensify and it could get stronger.

A subtropical ridge north of Earl is steering the tropical storm toward the west and that general motion is expected to continue.  On its anticipated track the center of Tropical Storm Earl will be very near Veracruz, Mexico in 10-12 hours.

The winds in Tropical Storm Earl are strong enough to create a storm surge of several feet (1-2 m) near where the center makes landfall and north of that location.  The primary risks from Tropical Storm Earl will be very heavy rainfall and flash flooding.

Tropical Storm Earl Nearing Southern Bay of Campeche

Tropical Storm Earl was maintaining its intensity as it approached the southern Bay of Campeche on Thursday night.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Earl was located at latitude 18.1°N and longitude 91.7°W which put it about 40 miles (65 km/h) south-southeast of Ciudad del Carmen, Mexico.  Earl was moving toward the west-northwest at 10 m.p.h. (16 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 government of Mexico has issued a Tropical Storm Warning for the portion of the coast from Ciudad del Carmen to Laguna Verde.

Despite moving over land for almost 24 hours the structure of Tropical Storm Earl retained much of its integrity.  A primary rainband wrapped around three quarters of the way around the southern and eastern portions of the center center.  A weather station at Ciudad del Carmen reported wind gusts to tropical storm force.  The circulation of Tropical Storm Earl is still generating upper level divergence, especially to the east of Earl.  The upper level divergence pumped out enough mass to allow the surface pressure to remain near 1000 mb.

The center of Tropical Storm Earl could move near the southern Bay of Campeche on Friday morning.  The Sea Surface Temperature is near 30°C in that part of the Bay of Campeche.  If Earl moves along the coast, it is likely to maintain tropical storm intensity for another 24 to 36 hours.  If the center of Earl moves out over the southern Bay of Campeche it could intensify given the organization that still exists in the tropical storm.

A ridge of high pressure is steering Tropical Storm Earl toward the west-northwest and that general motion is expected to continue.  On its anticipated track Tropical Storm Earl could be near Veracruz, Mexico in another 24 hours.  The primary risk associated with Tropical Storm Earl is heavy rain and flooding.  Tropical Storm Earl is still causing heavy rain over parts of Mexico, Honduras and Belize.  However, Earl could also generate some storm surge along portions of the southern Bay of Campeche.

Tropical Storm Omais Forms over the Northern Marianas

A very broad area of low pressure developed enough of the characteristics of a tropical cyclone to be classified as Tropical Storm Omais on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Omais was located at latitude 19.5°N and longitude 146.2°E which put it about 380 miles (615 km) north-northeast of Guam.  Omais was moving toward the north at 3 m.p.h. (5 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 996 mb.

The circulation of Tropical Storm Omais is not well organized.  Several clusters of thunderstorms exist about 100 miles (160 km) east and south of the center of the very broad low pressure system.  No thunderstorms are occurring in the western half of the low or near the center of the circulation.  An inner core does not exist at this time and the strongest winds are occurring in the clusters of thunderstorms well removed from the center.

Tropical Storm Omais is in an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level environment is also somewhat favorable for intensification.  An upper level low is northwest of Omais and an upper level ridge is east of the tropical storm.  Those two features are generating southwesterly winds which are blowing over the top of Tropical Storm Omais.  The vertical wind shear is inhibiting the organization and intensification of Omais.

The environment should allow Tropical Storm Omais to intensify, but the large circulation will reduce the rate of intensification.  As the wind field contracts and the strongest winds move closer to the center of circulation, the structure of Tropical Storm Omais will move closely resemble a typical tropical cyclone.  When an inner core forms at the center of circulation, the rate of intensification may increase.

Tropical Storm Omais is near the western end of a subtropical ridge.  The steering currents are weak, but Omais is likely to move slowly toward the north in the short term.  A faster motion is expected over the weekend.  On its anticipated track Tropical Storm Omais will move near the northernmost Marianas and pass east of Iwo To.

Earl Becomes a Hurricane As It Moves Toward Belize

A NOAA aircraft investigating Tropical Storm Earl found that there were sustained winds to hurricane force and the National Hurricane Center upgrade it to Hurricane Earl at 5:00 p.m. EDT on Wednesday.  At 5:00 p.m EDT the center of Hurricane Earl was located at latitude 17.1°N and longitude 86.0°W which put it about 150 miles (240 km) east of Belize City, Belize.  Earl was moving slightly north of due west at 14 m.p.h. (22 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 988 mb.

A Hurricane Warning is in effect for the Bay Islands of Honduras and the portion of the coast from Puerto Costa Mayo, Mexico to the Belize/Guatemala border.  A Tropical Storm Warning is in effect for the coast of Honduras from Cabo Gracias a Dios to the Honduras/Guatemala border and from Punta Allen, Mexico to Puerto Costa Mayo.

The Hurricane Intensity Index (HII) for Earl is 10.4.  The Hurricane Size Index (HSI) is 8.0 and the Hurricane Intensity Size Index (HWISI) is 18.4.  Those indices mean that Earl is capable of causing localized minor wind damage.

The structure of Hurricane Earl improved significantly on Wednesday as it moved farther from the northern coast of Honduras.  An eye developed at the center of circulation and a band of thunderstorms wrapped about two thirds of the way around the eye.  The eyewall is broken southwest of the center.  Additional bands of thunderstorms are rotating around the periphery of the circulation.  The core of strongest winds is relatively small and only extends about 60 miles (95 km) from the center.  However, outer rainbands extend at least 250 miles (400 km) from the center of circulation and the overall size of Hurricane Earl is much larger than it was yesterday.

Hurricane Earl is moving through an environment that is favorable for further intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  It is located beneath an upper level ridge and the upper level winds are weak.  So, there is little vertical wind shear and the ridge is enhancing the upper level divergence.  Hurricane Earl has another 10 – 15 hours to intensify before it reaches the coast.  Earl will weaken as it moves inland, but it could re-intensify after it moves over the Bay of Campeche.  The amount of re-intensification will depend on how long Hurricane Earl remains over land and where it enters the Bay of Campeche.

A subtropical high pressure system is steering Hurricane Earl on a track that is a little north of due west and that general motion is expected to continue for several more days.  On its anticipated track the center of Hurricane Earl will reach the coast near the border between Mexico and Belize in about 10 – 15 hours.

Since it is a hurricane, Earl will be capable of causing some wind damage.  Hurricane Earl will also create a storm surge near and to the north of where the center makes landfall because the winds will be pushing water toward the coast.  The size and number of the rainbands in Hurricane Earl will create the potential for very heavy rainfall and serious flooding as it moves inland over Belize and Mexico.

Tropical Storm Earl Forms over the Western Caribbean

Based on data collected by an Air Force Reserve Hurricane Hunter reconnaissance plane, the National Hurricane Center designated a system previously known as Invest 97L as Tropical Storm Earl.  At 12:00 p.m. EDT on Tuesday the center of Tropical Storm Earl was located at latitude 16.3°N and longitude 80.2°W which put it about 535 miles (860 km) east of Belize City, Belize.  Earl was moving toward the west at 22 m.p.h. (35 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 1001 mb.

A Hurricane Watch and a Tropical Storm Warning has been issued for the portion of the coast from Punta Allen, Mexico to the Belize/Guatemala border.  A Tropical Storm Warning has been issued for the portion of the coast from Cabo Gracias a Dios to the Honduras/Guatemala border.

The recon plane found a small closed low level center of circulation on the western edge of a cluster of thunderstorms.  The circulation around Tropical Storm Earl is very small.  Winds to tropical storm force only extend out about 80 miles (130 km) from the center of circulation.  Most of the thunderstorms are occurring in the eastern half of the tropical storm.  Those thunderstorms are generating upper level divergence which has pumped out enough mass to allow the surface pressure to decrease a few millibars during the past 12 hours.

The environment around Tropical Storm Earl is somewhat favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 29°C.  An upper level low centered near the western tip of Cuba is producing southwesterly winds which are blowing over the western side of Tropical Storm Earl.  Those westerly winds are producing some vertical wind shear, which is why most of the thunderstorms are in the eastern half of Earl.  The wind shear is inhibiting intensification, but the upper low is forecast to move farther from Earl, which would reduce the shear.  If Earl move north of the coast of Honduras, it should intensify.  However, if the center of circulation moves over Honduras, then Earl could weaken fairly quickly because of its small size.

The subtropical high over the Atlantic Ocean is steering Tropical Storm Earl toward the west at a fairly rapid speed.  The high is expected to continue to steer Earl toward the west during the next several days, but the tropical storm is expected to move a little more slowly on Wednesday.  On its anticipated track the center of Tropical Storm Earl is expected to pass just north of the coast of Belize.  Earl could be very close to Belize in about 36 hours.

Earl is a small tropical storm and the greatest risks are locally heavy rainfall and flash flooding.

Typhoon Nida Makes Landfall Near Hong Kong

Typhoon Nida made landfall on Monday near Hong Kong on the coast of China.  At 5:00 p.m. EDT on Monday the center of Typhoon Nida was located at latitude 22.8°N and longitude 114.4°E which put it about 50 miles (80 km) east-northeast of Hong Kong.  Nida was moving toward the northwest t 13 m.p.h.  The maximum sustained wind speed was 95 m.p.h. (155 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 963 mb.

Typhoon Nida made landfall on the southeast coast of China just to the north of Hong Kong.  The core of Nida is large and the typhoon is capable of causing wind damage on a regional scale.  Wind blowing toward the coast could also generate a storm surge until Typhoon Nida moves farther inland.  However, very heavy rain and fresh water flooding are much greater risks as Nida moves farther inland over China.

A subtropical ridge north of Nida is steering the typhoon toward the northwest and that general motion is expected to continue for the next several days.  The ridge will steer Nida farther inland over southeastern China.  Typhoon Nida’s fairly slow motion and large size mean that heavy rain could fall over an expansive area.  The risk for flooding will continue as Nida moves inland.