Monthly Archives: August 2017

Tropical Storm Banyan Forms Near Wake Island

Tropical Storm Banyan formed quickly near Wake Island on Friday.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Banyan was located at latitude 17.9°N and longitude 167.2°E which put it about 140 miles (225 km) south-southeast of Wake Island.  Banyan was moving toward the west-northwest at 16 m.p.h. (26 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 1003 mb.

The circulation of Tropical Storm Banyan organized quickly.  It developed a distinct center of circulation.  Thunderstorms formed north and south of the center, but there were more thunderstorms south of the center.  Additional bands of showers and thunderstorms began to develop in the outer parts of the circulation.  The thunderstorms in the core of Tropical Storm Banyan were generating upper level divergence which was pumping away mass.  The circulation of Tropical Storm Banyan is relatively small.  Winds to tropical storm force only extend out about 40 miles (65 km) from the center of circulation.

Tropical Storm Banyan will move through an environment that will be favorable for intensification.  Banyan will move over water where the Sea Surface Temperature is near 30.5°C.  An upper level ridge north of Banyan is producing easterly winds which are blowing toward the top of the circulation.  Those winds are weak and there is not much vertical wind shear.  Tropical Storm Banyan is likely to intensify during the next day or two and it could intensify quickly at times.

Tropical Storm Banyan is moving near the western end of a subtropical ridge to its north.  The ridge is currently steering Banyan toward the west-northwest, but the tropical storm is expected to turn more toward the north when it reaches the end of the ridge.  On its anticipated track Tropical Storm Banyan will move over Wake Island in about 12 hours.  Banyan will cause gusty winds and heavy rain when it moves over Wake Island.

Hurricane Franklin Brings Wind and Heavy Rain to Mexico

Hurricane Franklin brought gusty winds and heavy rain to parts of Mexico when it made landfall on Wednesday night.  The center of Hurricane Franklin made landfall between Veracruz and Nautla near the town of Lechuguillas, Mexico.  The maximum sustained wind speed was 85 m.p.h. (140 km) at the time of landfall, which made Franklin a Category 1 hurricane on the Saffir-Simpson Scale.  Franklin weakened to a tropical storm as it moved inland during the night.

At 8:00 a.m. EDT on Thursday the center of Tropical Storm Franklin was located at latitude 19.8°N and longitude 98.3°W which put it about 60 miles (95 km) east-northeast of the Mexico City, Mexico.  Franklin was moving toward the west at 15 m.p.h. (24 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 997 mb.

A Tropical Storm Warning remains in effect for the portion of the coast from Cabo Rojo to Boca Partido, Mexico.

Franklin brought hurricane force winds to the portion of the coast north of Veracruz, Mexico.  Those winds pushed water toward the shore and created a storm surge along the coast.  The highest surge may have reached 6 to 9 feet (2 to 3 meters) near and just to the north of where the center made landfall.  Winds blowing up the slopes of mountains produced very heavy rain and flooding could be occurring in some locations.  The heavy rain will continue as Tropical Storm Franklin moves west across central Mexico.

Tropical Storm Franklin will continue to weaken as it moves across Mexico.  Heavy rain will continue to fall over portions of central Mexico and the potential for additional flooding exists.  The mountains are likely to disrupt the low level circulation.  However, the middle and upper portions of the circulation could remain intact.  Some models are forecasting that Franklin, or its remnants, could redevelop when it reaches the Eastern North Pacific Ocean.

Franklin Strengthens Into a Hurricane Northeast of Veracruz

Formerly Tropical Storm Franklin strengthened into a hurricane northeast of Veracruz on Friday afternoon.  Franklin is the first hurricane to form over the Atlantic basin in 2017.  At 5:00 p.m. EDT the center of Hurricane Franklin was located at latitude 20.1°N and longitude 94.9°W which put it about 105 miles (170 km) northeast of Veracruz, Mexico.  Franklin was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 984 mb.

A Hurricane Warning is in effect for the portion of the coast from Puerto de Veracruz to Cabo Rojo, Mexico.  A Hurricane Watch is in effect for the portion of the coast from Cabo Rojo to Rio Panuco.  A Tropical Storm Warning is in effect for the portion of the coast from Puerto Dos Bocas to Puerto de Veracruz and from Tuxpan to Barra del Tordo.

An elliptical eye formed at the center of Hurricane Franklin and a reconnaissance plane detected surface winds in excess of 74 m.p.h. (119 km/h).  Based on data from the plane and an improved appearance on satellite imagery, the National Hurricane Center upgrade Franklin to hurricane status in its 5:00 p.m. EDT advisory.

The structure of Hurricane Franklin improved on Friday.  An elliptical eye oriented north to south formed at the center of circulation.  A ring of thunderstorms completely surrounded the eye.  The strongest winds were occurring in the northeastern part of the ring of storms.  Storms in the core of the circulation were generating upper level divergence which was pumping out mass and allowing the surface pressure to decrease.  A primary band of showers and thunderstorms coiled inward toward the core of Hurricane Franklin,  Additional bands of showers and thunderstorms were revolving around the core of Franklin.  Winds to hurricane force extended out about 35 miles (55 km) northeast of the center of circulation.  Winds to tropical storm force extended out about 140 miles (225 km) on the northern side of Franklin and about 100 miles (160 km) on the southern side of the hurricane).

Hurricane Franklin could intensify further before it makes landfall.  It is moving over water where the Sea Surface Temperature is near 30°C.  An upper level ridge over northern Mexico is generating northerly winds which are blowing toward the top of the circulation.  However, those winds are not very strong and the vertical wind shear is minor and it did not prevent Franklin from becoming a hurricane.  Hurricane Franklin has about another 6 to 12 hours to strengthen.  Once Franklin makes landfall and moves into the mountains, the surface circulation will weaken quickly.

A subtropical ridge is steering Hurricane Franklin toward the west and that general motion is expected to continue.  Hurricanes often turn slightly south of west when the approach the coast of the southwestern Bay of Campeche.  On its anticipated track the center Hurricane Franklin could make landfall on the coast of Mexico north of Veracruz in less than 12 hours.  The most likely landfall would be between Veracruz and Nautla.

Hurricane Franklin will bring strong gusty winds, a storm surge and heavy rain at the coast.  The storm surge could reach 6 to 9 feet (2 to 3 meters) near and just to the north of where the center makes landfall.  Franklin could produce very heavy rain when it reaches the mountains and flash flooding is a serious risk.

Tropical Storm Franklin Moves Over Bay of Campeche and Strengthens

Tropical Storm Franklin moved off the Yucatan peninsula over the Bay of Campeche and began to strengthen on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Franklin was located at latitude 20.3°N and longitude 91.3°W which put it about 325 miles (525 km) east-northeast of Veracruz, Mexico.  Franklin was moving toward the west-northwest at 10 m.p.h. (16 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 996 mb.

A Hurricane Warning was in effect for the portion of the coast from Puerto de Veracruz to Tuxpan, Mexico.  A Hurricane Watch was in effect for the portion of the coast from Tuxpan to Rio Panuco.  A Tropical Storm Waring was in effect for the portion of the coast from Celestun to Puerto de Veracruz and from Tuxpan to Rio Panuco.

Although Tropical Storm Franklin weakened as it moved across the Yucatan peninsula on Tuesday, its circulation maintained its structural integrity.  In fact, a tighter inner core developed at the center of the circulation while the tropical storm moved over land.  New thunderstorms began to form near the center of Tropical Storm Franklin as soon as the center moved back over water.  A primary band of thunderstorms began to wrap tightly around the eastern and northern sides of the center.  Additional bands of showers and thunderstorms began to form over the Bay of Campeche.  Thunderstorms in the core were generating upper level divergence which is pumping away mass.

Tropical Storm Franklin will move over an environment very favorable for intensification on Wednesday.  Franklin will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  An upper level trough over the Bahamas may enhance the upper divergence by creating an outflow channel to the east of Franklin.  Tropical Storm Franklin will intensify on Wednesday and there could be a period of rapid intensification.  Franklin is likely to become a hurricane.

Tropical Storm Franklin is being steered to the west by a subtropical high to its northeast.  A general westerly motion is expected to continue for another day or two.  On its anticipated track Tropical Storm Franklin will approach the coast of Mexico north of Veracruz on Wednesday night.  Franklin will bring gusty winds, heavy rain and a storm surge at the coast.  When Franklin moves inland the mountains will enhance the rising motion and very heavy rain could fall.  The heavy rain could cause flash floods.

Tropical Storm Franklin Makes Landfall on Yucatan

The center of Tropical Storm Franklin made landfall on the southeast coast of the Yucatan peninsula on Monday night.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Franklin was located at latitude 19.1°N and longitude 87.3°W which put it about 75 miles (120 km) east-northeast of Chetumal, Mexico.  Franklin was moving toward the west-northwest at 14 m.p.h. (22 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 995 mb.

A Hurricane Watch is in effect for the portion of the coast from Puerto de Veracruz to Rio Panuco, Mexico.  A Tropical Storm Warning is in effect for the portion of the coast from Chetumal to Sabancuy, Mexico and from Belize City northward to the Belize/Mexico border.  A Tropical Storm Watch is in effect for the portion of the coast from Sabancuy to Puerto de Veracruz, Mexico.

The circulation of Tropical Storm Franklin became better organized on Monday, but thunderstorms were unable to consolidate around the core of the circulation.  A ring of showers and weaker thunderstorms surrounds the center of circulation.  A band of stronger thunderstorms curls around the eastern side of the circulation.  The are weaker bands of showers and thunderstorms in the western half of the circulation.  The thunderstorms in the eastern side of Franklin were generating upper level divergence which was pumping mass away to the east of the tropical storm.

Tropical Storm Franklin will weaken as it moves over the Yucatan peninsula.  Franklin will spend approximately 18 hours over land and it will be a weaker tropical storm or tropical depression by the time it reaches the southern Gulf of Mexico.  The Sea Surface Temperature of the southern Gulf of Mexico is near 30°C.  The upper level winds should be weak and there is likely to be little vertical wind shear when Franklin moves over the southern Gulf.  Franklin is likely to intensify when it moves over the Gulf of Mexico and it could strengthen into a hurricane.

A subtropical high pressure system is steering Tropical Storm Franklin toward the west-northwest and that general motion is expected to continue for another day or two.  On its anticipated track Franklin will move across the Yucatan peninsula on Tuesday.  Franklin will produce gusty winds and locally heavy rainfall.  Floods could occur in some locations.

Tropical Storm Franklin Develops Over Northwest Caribbean Sea

A center of circulation developed in a system previously designated as Potential Tropical Cyclone Seven and the National Hurricane Center named the system Tropical Storm Franklin on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Franklin was located at latitude 16.4°N and longitude 83.0°W which put it about 380 miles (610 km) east-southeast of Chetumal, Mexico.  Franklin was moving toward the west-northwest at 13 m.p.h. (20 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 1006 mb.

A Tropical Storm Warning is in effect for the portion of the coast from Chetumal to Campeche, Mexico.  A Tropical Storm Watch is in effect for the portion of the coast from Belize City, Belize northward to the Belize/Mexico border.

Visible satellite images just before sunset suggested that a center of circulation had formed in the tropical wave previously designated Potential Tropical Cyclone Seven and the National Hurricane Center named it Tropical Storm Franklin.  The circulation of Tropical Storm Franklin is still not well organized.  The apparent center is located near the western edge of an area of thunderstorms.  Most of the thunderstorms are still forming east of the system, which indicates that vertical wind shear is probably still affecting the circulation.  The thunderstorms are producing some upper level divergence which is pumping mass away to the east of the tropical storm.

The environment ahead of Tropical Storm Franklin will become more favorable for intensification.  Franklin will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough west of Franklin is producing westerly winds which are causing the vertical wind shear.  The trough is expected to weaken on Monday and when that happens the shear will diminish.  Warm water and less shear should allow Tropical Storm Franklin to strengthen before it reaches the Yucatan peninsula.  Franklin will weaken when it moves over land, but it is likely to re-intensify when it moves over the southern Gulf of Mexico.

Tropical Storm Franklin is being steered toward the west-northwest by a subtropical high centered over the Atlantic Ocean.  A general west-northwesterly motion is expected to continue.  On its anticipated track Tropical Storm Franklin could approach the Yucatan peninsula in about 24 hours.  Franklin will bring gusty winds and locally heavy rain to that area.  The heavy rain could cause flooding in some locations.

Typhoon Noru Skirts Coast of Shikoku on Way to Honshu

The eye of Typhoon Noru skirted the coast of Shikoku on Sunday as it moved closer to a landfall on Honshu.  At 11:00 p.m. EDT on Sunday the center of Typhoon Noru was located at latitude 33.6°N and longitude 134.5°W which put it about 85 miles (135 km) southwest of Osaka, Japan.  Noru was moving toward the northeast 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 970 mb.

The structure of Typhoon Noru improved on Sunday.  The circulation contracted around an eye with a diameter of approximately 20 miles (32 km).  They eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in the ring of storms.  Additional spiral bands were revolving around the core of Typhoon Noru.

An upper level trough northwest of Japan steered Typhoon Noru toward the northeast on Sunday.  The eye of Noru moved near the south coast of Shikoku.  The eye passed south of Kochi and very near Muroto, Toyo and Kainan.  Typhoon Noru brought gusty winds and heavy rain to the southern parts of Shikoku.

Typhoon Noru is expected to continue to move toward the northeast on Monday.  On its anticipated track the center of Typhoon Noru is expected to skirt the east coast of Shikoku and make landfall on Honshu near Wakayama.   After it makes landfall, Typhoon Noru is forecast to pass near Osaka and Kyoto.  Typhoon Noru will weaken as it moves across Honshu, but it will produce gusty winds and locally heavy rain.  The rain could cause floods in some locations.

Tropical Storm Warning Issued for Mexico Due to Potential Tropical Cyclone Seven

The National Hurricane Center changed the designation of Invest 90L to Potential Tropical Cyclone Seven because of the need to issue a Tropical Storm Warning for portions of Mexico.  At 5: 00 p.m. EDT on Sunday the center of Potential Tropical Cyclone Seven was located at latitude 15.6°N and longitude 82.0°W which put it about 90 miles (145 km) east-northeast of Cabo Gracias a Dios.  It was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1008 mb.

A Tropical Storm Warning has been issued for the portion of the coast from Chetumal to Campeche, Mexico.  A Tropical Storm Watch has been issued for the portion of the coast from Belize City to the Belize/Mexico border.

A broad area of low pressure formed in a strong tropical wave over the northwestern Caribbean Sea.  There is not a well defined center of circulation within the broad area of low pressure.  Most of the thunderstorms are developing in the eastern half of the circulation.  There are few thunderstorms in the western half of the system.  The thunderstorms in the eastern half of the low are generating some upper level divergence which is pumping out mass to the east of the low.

Potential Tropical Cyclone Seven will move through a relatively favorable environment over the northwestern Caribbean Sea.  It will move over water where the Sea Surface Temperature is 30°C.  A small upper level trough to the west of the low is producing westerly winds which are causing moderate vertical wind shear.  The wind shear is probably the reason why most of the thunderstorms are in the eastern side of the circulation.  The upper trough is forecast to weaken and the shear is expected to diminish.  Potential Tropical Cyclone Seven could become a tropical storm over the northwestern Caribbean Sea, which is why the Tropical Storm Warning was issued.

Potential Tropical Cyclone Seven is being steered to the west-northwest by a subtropical high pressure system centered over the Atlantic Ocean.  That general motion is expected to continue for the next several days.  On its anticipated track Potential Tropical Cyclone Seven could reach the Yucatan Peninsula within 36 hours.  It could bring gusty winds and heavy rain when it moves over the Yucatan.  The system could restrengthen when it moves over the southern Gulf of Mexico.

Typhoon Noru Reaches Kyushu

The eye of Typhoon Noru reached the southern coast of Kyushu near Uchinoura on Saturday.  At 11:00 p.m. EDT on Saturday the center of of Typhoon Noru was located at latitude 31.0°N and longitude 131.2°E which put it about 65 miles (105 km) south-southwest of Miyazaki, Japan.  Noru was moving toward the northeast at 8 m.p.h. (13 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 970 mb.

Typhoon Noru weakened as it made a slow clockwise loop on Saturday.  The winds of the typhoon may have mixed cooler water to the surface of the ocean.  Typhoon Noru also appears to be drawing cooler, drier air into the northern half of the circulation.  There is still an eye at the center of Noru, but the strong thunderstorms are all in the southern half of the circulation.  The strongest winds are occurring in the thunderstorms at the southern edge of the eye.  There are several bands of showers and thunderstorms outside the core of Typhoon Noru.

Typhoon Noru is moving over water where the Sea Surface Temperature is near 29°C.  So, there is sufficient energy to support the circulation of a typhoon.  However, drier air in the northern half of the circulation is reducing the amount of energy that is reaching the core of the typhoon.  An upper level trough is approaching Typhoon Noru from the west and the vertical wind shear will increase when the trough gets closer to the typhoon.  Typhoon Noru could maintain its intensity for another 12 to 18 hours, but eventually the combination of drier air, more vertical shear and interaction with land will cause Noru to weaken.

Typhoon Noru was in an area where the steering currents were weak and it made a slow, tight clockwise loop on Saturday.  The upper level trough approaching from the west will start to steer Typhoon Noru toward the northeast.  Noru will move along the south coast of Kyushu.  On its anticipated path the center of Typhoon Noru could be near Kochi on the south coast of Shikoku in about 24 hours.  Noru could be near Osaka and Kyoto on Honshu in about 36 hours.

Typhoon Noru has the potential to bring strong winds, heavy rain and the potential for floods to southern Kyushu, Shikoku and parts of Honshu.

Typhoon Noru Bringing Wind and Rain to Northern Ryukyu Islands

Typhoon Noru was bringing gusty winds and heavy rain to the northern Ryukyu Islands on Friday.  At 5:00 p.m. EDT on Friday the center of Typhoon Noru was located at latitude 29.3°N and longitude 130.3°E which put it about 90 miles (140 km) south of Kagoshima, Japan.  Noru was moving toward the northwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 90 m.p.h. (140 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 959 mb.

The structure of Typhoon Noru has not changed much during the past 24 hours.  A large eye with a diameter of approximately 80 miles (130 km) occupies the center of the typhoon.  A broken eyewall surrounds the eye.  Strong thunderstorms surround the eastern side of the eye, while a broken ring of weaker showers and storms mark the western edge of the eye.  The strongest winds are occurring in the thunderstorms on the eastern edge of the eye.  Thunderstorms in the core of the circulation are generating upper level divergence which is pumping away mass in all directions.  A primary rainband extends from the eastern side of Typhoon Noru around the southern and western sides of the circulation.  Several other shorter bands are outside this primary rainband.  Typhoon Noru continues to exhibit a structure similar to an annular hurricane.

Although the core of Typhoon Noru is fairly large, the overall size of the storm is not as big as some typhoons.  Winds to typhoon force extend out about 40 miles in all directions from the center of circulation.  Winds to tropical storm force extend out about 160 miles (260 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Noru is 13.9.  The Hurricane Size Index (HSI) is 17.0 and the Hurricane Wind Intensity Size Index (HWISI) is 30.9.

Typhoon Noru will be in an environment favorable for intensification for about another 24 hours.  Noru will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of Noru is producing northerly winds which are blowing toward the top of the typhoon.  Those winds are fairly weak and there is not much vertical wind shear.  Typhoon Noru is likely to intensify during the next 24 hours and it could strengthen into the equivalent of a major hurricane again.  In a day or so, an upper level trough will approach from the west and wind shear will increase.  Typhoon Noru will weaken faster after it makes landfall in Kyushu.

Typhoon Noru is moving slowly around the western end of a subtropical ridge.  Noru is in an area where the steering currents are weak and the will remain weak for another 24 to 48 hours.  An upper level trough will approach Noru from the west in a day or so.  Southwesterly winds ahead of the trough will start to steer Typhoon Noru toward the northeast at a faster rate.  On its anticipated track Typhoon Noru could make landfall in Kyushu in less than 36 hours.

The large core and strength of Typhoon Noru make it capable of bringing strong winds and heavy rain to a large area.  Typhoon Noru will continue to bring wind and rain to the northern Ryukyu Islands for another 24 to 36 hours.  Noru could also cause wind damage, heavy rain and floods on Kyushu, Shikoku and western Honshu when it moves over those regions.