Monthly Archives: September 2019

Tropical Storm Humberto Develops East of the Bahamas

Former Tropical Depression Nine strengthened into Tropical Storm Humberto east of the Bahamas on Friday night.  At 11:00 p.m. EDT on Friday night the center of Tropical Storm Humberto was located at latitude 25.6°N and longitude 75.2°W which put it about 130 miles (210 km) east-southeast of Great Abaco, Bahamas.  Humberto was moving toward the northwest at 6 m.p.h. (10 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 1008 mb.

Tropical Storm Warnings were in effect for the Abacos, the Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence.

A NOAA research aircraft flying through former Tropical Depression Nine on Friday night determined that the depression had strengthened into Tropical Storm Humberto.  The aircraft reported that the maximum sustained wind speed had increased to 40 m.p.h. (65 km/h).  The circulation around Tropical Storm Humberto was still poorly organized.  A few thunderstorms developed just to the north of the center of circulation.  A band of showers and thunderstorms curved around the eastern side of the circulation.  Bands in the other parts of Tropical Storm Humberto consisted primarily of showers and lower clouds.

Tropical Storm Humberto will move through an environment somewhat favorable for intensification during the next few days.  Humberto will move over water where the Sea Surface Temperature is near 29°C.   A large upper level low over the Gulf of Mexico will produce southerly winds which will blow toward the top of the tropical storm. Those winds will cause moderate vertical wind shear and they will inhibit intensification.  The upper low is forecast to move westward away from Humberto and the wind shear could decrease during the weekend. Tropical Storm Humberto is forecast to slowly become more organized and it could strengthen into a hurricane.

The upper low over the Gulf of Mexico will help to steer Tropical Storm Humberto toward the northwest during the next day or two.  A strong upper level trough over the Great Lakes will start to turn Humberto toward the east later in the weekend.  On its anticipated track the center of Tropical Storm Humberto could move near the Northwestern Bahamas.  If Humberto brings wind and rain to that region, it will hinder efforts to recover from Hurricane Dorian.

Tropical Depression Nine Develops Near the Bahamas

Tropical Depression Nine developed near the Bahamas on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of Tropical Depression Nine was located at latitude 25.6°N and longitude 75.0°W which put it about 140 miles (225 km) east-southeast of Great Abaco, Bahamas.  It was moving toward the northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1009 mb.

Tropical Storm Warnings were in effect for the Abacos, the Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence.  A Tropical Storm Watch was in effect for the portion of the Florida coast from Jupiter Inlet to the Volusia/Brevard County Line.

An Air Force Reserve Hurricane Hunter plane was able to identify a low level center of circulation in a tropical disturbance near the Bahamas on Friday afternoon and the National Hurricane Center designated the system as Tropical Depression Nine.  The center of circulation developed on the southwestern side of a cluster of thunderstorms just east of the Bahamas.  The circulation around the depression was still in the early stages of organization.  Most of the stronger thunderstorms were occurring in the eastern half of the tropical depression.  Bands in the western half of the circulation consisted primarily of showers and lower clouds.

Tropical Depression Nine will move through an environment somewhat favorable for intensification during the next few days.  The tropical depression will move over water where the Sea Surface Temperature is near 29°C.  A large upper level low over the Gulf of Mexico will produce southerly winds which will blow toward the top of the depression.  Those winds will cause moderate vertical wind shear and they will inhibit intensification.  The upper low is forecast to move westward away from the  tropical depression and the wind shear could decrease during the weekend.  Tropical Depression Nine is forecast to slowly become more organized and it could strengthen into a tropical storm.

The upper low over the Gulf of Mexico will help to steer Tropical Depression Nine toward the northwest during the next day or two.  A strong upper level trough over the Great Lakes will start to turn the depression toward the east later in the weekend.  On its anticipated track the center of the depression could move near the Northwestern Bahamas.  If Tropical Depression Nine brings wind and rain to that region, it will hinder efforts to recover from Hurricane Dorian.

Tropical Storm Warnings Issued for Northwestern Bahamas

The government of the Bahamas issued Tropical Storm Warnings for the Northwestern Bahamas on Friday afternoon.  Tropical Storm Warnings were issued for the Abacos, Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence.  A tropical disturbance over the Southeastern Bahamas was forecast to strengthen into a tropical storm, which prompted the issuance of the Tropical Storm Warnings.  The National Hurricane Center (NHC) initiated advisories on the disturbance at 5:00 p.m. EDT on Thursday and NHC designated the system at Potential Tropical Cyclone Nine.

At 5:00 p.m. EDT on Thursday the broad center of Potential Tropical Cyclone Nine was located at latitude 23.7°N and longitude 74.8°W which put it about 235 miles (380 km) southeast of Great Abaco.  It was moving toward the northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1008 mb.

The circulation around Potential Tropical Cyclone Nine was very poorly organized.  There was a very broad center around which the air was turning cyclonically.  An Air Force Reserve Hurricane Hunter reconnaissance plane was finding weak winds near the broad center.  Most of the strong thunderstorms were northeast of the broad center of the disturbance.  The stronger winds here occurring near those thunderstorms.  There did not appear to be any significant banding of the showers and thunderstorms.

A large upper level low over the Gulf of Mexico was producing moderate southerly winds which were blowing across the western side of Potential Tropical Cyclone Nine.  Those winds were causing moderate vertical wind shear.  A small upper level ridge was developing between the upper low over the Gulf and another smaller upper low near Bermuda.  Winds were weaker under the ridge and that was the likely reason the stronger thunderstorms were in the northeastern part of the disturbance.  It is possible that a new center of circulation could develop near one of the clusters of thunderstorms.

Potential Tropical Cyclone Nine will move through an area somewhat favorable for intensification.  It will move over water where the Sea Surface Temperature is near 29°C.  The upper low over the Gulf of Mexico is forecast to move westward which would cause the vertical wind shear to decrease.  If the shear decreases, then a distinct low level center of circulation could develop.  If a distinct center forms, then the system would be designated as a tropical depression.  Potential Tropical Cyclone Nine has the potential to strengthen into a tropical storm during the next 24 to 48 hours.

The future track of Potential Tropical Cyclone Nine will depend on the place where a center of circulation forms and how strong the system becomes.  A stronger tropical cyclone would be steered by winds higher in the atmosphere.  If Potential Tropical Cyclone Nine strengthens significantly then the upper level low over the Gulf of Mexico and the developing upper level ridge will combine to the system toward the northwest during the next day or two.  A cold front moving southeast across the Great Lakes and Ohio River Valley could turn the system toward the northeast later in the weekend.  Under that scenario Potential Tropical Cyclone Nine would move across the Northwestern Bahamas on Friday.  It could approach southeast Florida on Saturday.

On the other hand, if Potential Tropical Cyclone Nine does not develop, or if it remains a weak tropical cyclone, then it would be steered by winds lower in the atmosphere.  In that case the system could be steered more toward the west-northwest and it could move across Florida into the Gulf of Mexico.   The guidance from numerical models is very divergent about the predicted future track of Potential Tropical Cyclone Nine.  In any case the system will bring some wind and rain to the Northwestern Bahamas and that will hinder efforts to recover from Hurricane Dorian.

Tropical Storm Kiko Forms South of Baja California

Tropical Storm Kiko formed south of Baja California on Thursday.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Kiko was located at latitude 16.1°N and longitude 112.2°W which put it about 495 miles (795 km) south-southwest of the southern tip of Baja California.  Kiko was moving toward the west-northwest 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 1004 mb.

A distinct center of circulation developed in a cluster of thunderstorms south of Baja California on Thursday and the National Hurricane Center designated the system as Tropical Storm Kiko.  The circulation around Kiko was still organizing.  The center of circulation was evident on satellite imagery.  Band of showers and thunderstorms were revolving around the center.  Storms near the center of circulation were beginning to generate upper level divergence which was pumping mass away from the tropical storm.  Winds to tropical storm force extended out about 80 miles (130 km) from the center of circulation.

Tropical Storm Kiko will move through an environment favorable for intensification.  Kiko will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Kiko is likely to strengthen into a hurricane.  Kiko could intensify more rapidly once an eye and eyewall form in the inner core of the tropical storm.

Tropical Cyclone Kiko will move south of a subtropical ridge over the Eastern North Pacific Ocean.  The ridge will steer Kiko toward the west-northwest during the next few days.  On its anticipated track Tropical Storm Kiko will move farther away from Baja California.

Tropical Disturbance Brings Rain to Southeastern Bahamas

A tropical disturbance brought rain to the Southeastern Bahamas on Wednesday.  The disturbance was also designated at Invest 95L.  At 8:00 p.m. EDT on Wednesday the center of the tropical disturbance was located at latitude 21.8°N and longitude 74.0°W which put it about 30 miles (50 km) southeast of Acklins Island, Bahamas.  The disturbance was moving toward the west-northwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1010 mb.

The circulation around the tropical disturbance was not well organized on Wednesday.  There were indications of cyclonic turning in the wind flow, but there were no reports of westerly winds at the surface.  The lack of westerly winds indicated that there probably was not a defined center of circulation at the surface.  There were some thunderstorms near the apparent middle of the tropical disturbance.  There was a larger cluster of thunderstorms east of the middle of the disturbance and a second cluster of thunderstorms northeast of the middle of the disturbance.

The tropical disturbance will be in an environment marginally favorable for the development of a tropical cyclone.  The disturbance will move over water where the Sea Surface Temperature is near 29°C.  A large upper level low over the eastern Gulf of Mexico is producing southerly winds which are blowing over the western half of the disturbance.  Those winds are producing moderate vertical wind shear.  There is another, smaller upper level low near Bermuda.  An small upper level ridge is developing between the two upper lows.  The winds are weaker in the ridge which is over the eastern half of the tropical disturbance.  It is possible that a center of circulation could develop in one of the clusters of thunderstorms east and northeast of the middle of the disturbance.  The National Hurricane Center is indicating that there is a 50% probability of development of a tropical cyclone during the next 48 hours and a 70% during the next five days.

The upper low over the Gulf of Mexico and the developing upper ridge are likely to combine to steer the disturbance toward the northwest during the next few days.  It is difficult to anticipate the  track until a distinct center of rotation forms.  If the center reforms east or northeast of the current middle of the disturbance, then that would affect the future track.  On the most probable track the disturbance would move across the southeastern and central Bahamas during the next several days.  It could approach southeast Florida or the Florida Keys on Friday night.  The disturbance could move into the eastern Gulf of Mexico during the weekend.  If the disturbance brings any significant rain to the northern Bahamas, that would hamper efforts to recover from the catastrophic damage caused by Hurricane Dorian.

Typhoon Faxai Hits Tokyo

Typhoon Faxai hit Tokyo, Japan on Sunday.  At 2:00 p.m. EDT on Sunday the center of Typhoon Faxai was located at latitude 35.3°N and 139.7°E which put it about 30 miles (50 km) south of Tokyo, Japan.  Faxai was moving toward the north-northeast at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 110 m.p.h. (170 km/h) and there were wind gusts to 130 m.p.h. (220 km/h).  The minimum surface pressure was 959 mb.

The eye of Typhoon Faxai was very near Tokyo and the northern portion of the eyewall may have been over the city.  The strongest winds were in the ring of thunderstorms around the eye.  Winds to typhoon force extended out about 45 miles (75 km) from the center of Typhoon Faxai.  Winds to typhoon force were likely occurring in the Tokyo metropolitan area.  Winds to tropical storm force extended out about 160 miles (260 km) from the center of Faxai.  Radar operated by the Japan Meteorological Agency indicated that the eyewall and rainbands were dropping heavy rain over the region around Tokyo.  Flash flooding is likely to occur in some locations.

Typhoon Faxai will move northeast across eastern Honshu during the next few hours.  Faxai will be capable of causing serious wind damage while it moves over the region northeast of Tokyo.  Heavy rain is likely to cause flash floods in that area.  Typhoon Faxai will move northeast of Japan on Monday and conditions should improve.

Typhoon Faxai Strengthens to Equivalent of Major Hurricane South of Tokyo

Typhoon Faxai strengthened into the equivalent of a major hurricane south of Tokyo, Japan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Faxai was located at latitude 31.8°N and longitude 139.7°E which put it about 300 miles (485 km) south of Tokyo, Japan.  Faxai was loving toward the northwest at 18 m.p.h. (30 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 944 mb.

Typhoon Faxai intensified rapidly into the equivalent of a major hurricane on Saturday.  There was a small circular eye at the center of circulation.  The eye was surround by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Faxai.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.

The circulation around Typhoon Faxai became more symmetrical on Saturday.  Winds to typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 140 miles (220 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Faxai was 25.1.  The Hurricane Size Index (HSI) was 15.0 and the Hurricane Wind Intensity Size Index (HWISI) was 40.1.  Typhoon Faxai was capable of causing regional major damage.

Typhoon Faxai will move through an environment favorable for powerful typhoons during the next 12 hours.  Faxai will move over water where the Sea Surface Temperature is near 28°C.  It will move under the middle of an upper level ridge where the winds are weak and there will be little vertical wind shear.  Typhoon Faxai is likely to maintain its intensity during the next 12 hours and it could strengthen a little more.  Typhoon Faxai will reach the coast of Honshu in about 12 hours and Faxai will weaken when it moves over land.  Faxai will move under the westerly winds in the middle latitudes in a day or so and the vertical wind shear will increase when that happens.

Typhoon Faxai will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Faxai toward the north during the next 12 to 18 hours.  The high pressure system and the westerly winds in the middle latitude will turn Typhoon Faxai toward the northeast in 18-24 hours.  On its anticipated track Typhoon Faxai will approach the coast of Honshu near Tokyo in about 12 hours.  Faxai will be capable of causing major damage when it reaches Honshu.

Hurricane Dorian Brings Powerful Winds to Nova Scotia

Hurricane Dorian brought powerful winds to Nova Scotia on Saturday.  At 8:00 p.m. EDT on Saturday the center of Hurricane Dorian was located at latitude 45.0°N and longitude 67.9°W which put it about 45 miles (75 km) northeast of Halifax, Nova Scotia.  Dorian was moving toward the northeast at 30 m.p.h. (48 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 960 mb.

Hurricane Warnings were in effect for Lower East Pubnico to Brule, Nova Scotia and from Indian Harbour to Hawke’s Bay, Newfoundland. Hurricane Watches were in effect for Prince Edward Island and for the Magdalen Islands. Tropical Storm Warnings were issued for Prince Edward Island and from Avonport to Lower East Pubnico, Nova Scotia. A Tropical Storm Warning was in effect for New Brunswick from Fundy National Park to Shediac. A Tropical Storm Warning was issued for the portion of the coast from Indian Harbour to Stone’s Cove, Newfoundland. Tropical Storm Warnings were issued for the portions of the coast from Hawke’s Bay to Fogo Island and from Mutton Bay to Mary’s Harbour.

Hurricane Dorian maintained its intensity and increased in size on Saturday while it sped across the northwestern Atlantic Ocean to the Canadian Maritime provinces.  Winds to hurricane force extended out about 115 miles (185 km) on the southern side of Hurricane Dorian.  Winds to tropical storm force extended out about 300 miles (480 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 16.5.  The Hurricane Size Index (HSI) was 26.3 and the Hurricane Wind Intensity Size Index (HWISI) was 42.8.  Hurricane Dorian was capable of causing widespread serious damage.

There were reports of wind damage and widespread power outages around Nova Scotia even before the center of Hurricane reached that area.  The large circulation around Dorian brought tropical storm force winds to Nova Scotia a few hours before the center made landfall.  The center of Hurricane Dorian officially made landfall south of Halifax, Nova Scotia on Saturday evening.

Hurricane Dorian had almost completed a transition to a large powerful extratropical cyclone.  That transition contributed to the increase in size of the circulation.  The strongest part of Hurricane Dorian will move across Nova Scotia during the next few hours.  The winds are likely to cause additional damage on Saturday night.  Hurricane Dorian will race across Nova Scotia, Cape Breton Island and New Brunswick on Saturday night.  Dorian will move over Newfoundland and southeastern Labrador on Sunday.  Hurricane Dorian has the potential to cause serious damage in all of those locations.

Typhoon Lingling Speeds Toward Korea

Typhoon Lingling sped toward the Korean peninsula on Friday.  At 5:00 p.m. EDT on Friday the center of Typhoon Lingling was located at latitude 34.8°N and longitude 125.0°E which put it about 100 miles (160 km) west of Mokpo, South Korea.  Lingling was moving toward the north at 30 m.p.h. (48 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and thee were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 955 mb.

Typhoon Lingling was weakening gradually while it was speeding toward the north.  Lingling was moving over water where the Sea Surface Temperature was near 26°C.  An upper level trough over eastern Asia was producing strong southerly winds which blowing toward the top of the typhoon.  Those winds were causing moderate vertical wind shear.  The circulation around Typhoon Lingling was also pulling in drier air from Asia around the southern side of the circulation.  Even though it was weakening, Lingling remained a dangerous typhoon.  Winds to typhoon force extended out about 45 miles (75 km) from the center of circulation.  The stronger winds were primarily in the eastern half of the circulation.  Winds to tropical storm force extended out about 220 miles (350 km) from the center.

The upper trough over eastern Asia was steering Typhoon Lingling rapidly toward the north.  On its anticipated track Typhoon Lingling could reach the west coast of North Korea in less than 12 hours.  Lingling will be capable of causing serious damage.  It will also drop locally heavy rain over the Korean peninsula which could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, former Tropical Storm Faxai strengthened into a typhoon east of iwo To.  At 5:00 p.m. EDT on Friday the center of Typhoon Faxai was located at latitude 26.1°N and longitude 145.6°E which put it about 325 miles (520 km) east of Iwo To.  Faxai was moving toward the west-northwest at 21 m.p.h. (34 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 979 mb.  Typhoon Faxai is forecast to move toward the northwest and strengthen.  Faxai could intensify into the equivalent of a major hurricane.  Typhoon Faxi could approach the area around Tokyo, Japan in less than 72 hours.

Hurricane Dorian Makes Landfall at Cape Hatteras, Threatens Canadian Maritimes

Hurricane Dorian made an official landfall at Cape Hatteras, North Carolina on Friday morning and posed a serious threat to the Canadian Maritime provinces.  At 5:00 p.m. EDT on Friday the center of Hurricane Dorian was located at latitude 36.9°N and longitude 72.7°W which put it about 330 miles (530 km) south-southwest of Nantucket, Massachusetts.  Dorian was moving toward the northeast at 24 m.p.h. (39 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surace pressure was 958 mb.

A Tropical Storm Warning was in effect for the portion of the coast from the North Carolina/Virginia border to Fenwick Island, Delaware, and for Chesapeake Bay south of Drum Point.  A Tropical Storm Warning was in effect for the portion of the coast from Woods Hole to Sagamore Beach, Massachusetts including Martha’s Vineyard and Nantucket.  A Tropical Storm Warning was in effect for the portion of the coast from Bar Harbor to Eastport, Maine.  A Hurricane Warning was in effect from Hubbards to Avonport, Nova Scotia.  A Hurricane Watch was issued for Prince Edward Island, Avonport to Hubbards, Nova Scotia, the Magdalen Islands, Parson’s Pond to Indian Harbour, Newfoundland.  Tropical Storm Warnings were issued for Prince Edward Island and from Avonport to Hubbards, Nova Scotia.  A Tropical Storm Watch was in effect for New Brunswick from Fundy National Park to Shediac.  A Tropical Storm Watch was issued for Newfoundland from Francois to Boat Harbor.  A Tropical Storm Watch was  issued for the portion of the coast from Parson’s Pond to Triton, and from Indian Harbour to Stone’s Cove, Newfoundland.

The National Hurricane Center determined that the center of Hurricane Dorian passed over Cape Hatteras and identified that as the point of landfall.  Hurricane Dorian has been moving rapidly away from the coast since that time.  Hurricane Dorian remained a large, well organized hurricane.  A circular eye with a diameter of 35 miles (55 km) was apparent on satellite images.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Winds to hurricane force extended out about 80 miles (130 km) from the center of circulation.  Winds to tropical storm force extended out about 230 miles (370 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 13.9.  The Hurricane Size Index (HSI) was 23.3 and the Hurricane Wind Intensity Size Index (HWISI) was 43.2.

Hurricane Dorian will move through an environment favorable for intensification on Saturday.  Dorian will start out over water where the Sea Surface Temperature is near 27°C.  Dorian will move over cooler water later on Saturday.  An upper level trough over the eastern U.S. will contribute to upper level divergence, which may pump out enough mass to allow the surface pressure to decrease.  Hurricane Dorian will start to make a transition to an extratropical cyclone later on Saturday.  The interaction of colder and warmer air could also provide additional energy to the transitioning hurricane.  There is a chance that Hurricane Dorian could strengthen to a Category 2 hurricane on the Saffir-Simpson Scale on Saturday.

The upper level trough over the eastern U.S. will steer Hurricane Dorian rapidly toward the northeast during the weekend.  On its anticipated track, Dorian will pass southeast of Massachusetts on Saturday morning.  Hurricane Dorian could reach Nova Scotia by Saturday afternoon.  Dorian could be one of the strongest hurricanes to affect the Canadian Maritime provinces.  It will be capable of causing widespread serious damage.