Monthly Archives: October 2020

Tropical Storm Nangka Makes Landfall in Vietnam

Tropical Storm Nangka made landfall on the coast of northern Vietnam on Wednesday morning.  Nangka weakened to a tropical depression after the center moved over land.  At 8:00 a.m. EDT on Wednesday the center of Tropical Depression Nangka was located at latitude 20.0°N and longitude 105.0°E which put it about 80 miles (130 km) southwest of Hanoi, Vietnam.  Nangka was moving toward the west 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 1002 mb.

The center of Tropical Storm Nangka made landfall on the coast of Vietnam about 70 miles (110 km) southeast of Hanoi on Wednesday morning.  Nangka brought gusty winds and heavy rain to the northern coast of Vietnam.  Nangka quickly weakened to a tropical depression when it moved westward over northern VIetnam.  Bands of showers and thunderstorms dropped locally heavy rain over parts of northern Vietnam.

Tropical Depression Nangka will continue to move toward the west until the circulation spins down over northern Laos on Thursday.  Nangka will continue to drop locally heavy rain over parts of northern Vietnam and northern Laos during the next 24 hours.  Heavy rain could cause flash floods in some locations.

Norbert Regains Tropical Depression Status South of Baja California

Former Tropical Storm Norbert regained tropical depression status south of Baja California on Tuesday afternoon.  At 5:00 p.m. EDT on Tuesday the center of Tropical Depression Norbert was located at latitude 19.8°N and longitude 111.7°W which put it about 245 miles (390 km) south-southwest of the southern tip of Baja California.  Norbert was moving toward the northwest at 13 m.p.h. (20 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 1007 mb.

After strong vertical wind shear weakened former Tropical Storm Norbert on Saturday, the lower levels of the circulation drifted slowly toward the northwest.  The surface circulation around the former tropical storm moved into a region where the upper level winds were not as strong on Monday.  More thunderstorms began to develop in bands revolving around around the center of the surface circulation.  Additional thunderstorms formed near the center of the low on Tuesday afternoon and the National Hurricane Center designated the system as Tropical Depression Norbert.

Tropical Depression Norbert will move through a region somewhat favorable for intensification during the next 12 to 24 hours.  Norbert will move over water where the Sea Surface Temperature is near 28°C during the next 12 hours.  It will remain over water warmer than 26°C until Wednesday afternoon.  After that time Norbert will start to move over even cooler water.  An upper level low west of central Baja California will produce southerly winds which will blow toward the top of Tropical Depression Norbert.  Those winds will produce vertical wind shear, but Norbert will remain east of the strongest shear for another 24 hours.  When Norbert gets closer to the upper level low later on Wednesday, then the shear will increase and will cause it to weaken.

Tropical Depression Norbert will move between the upper level low west of Baja Californa and and upper level ridge over the southwestern U.S. and northern Mexico.  Those two weather systems will steer Norbert toward the northwest during the next several days.  On its anticipated track Tropical Depression Norbert is forecast to move parallel to the west coast of Baja California.

Tropical Storm Nangka Brings Wind and Rain to Hainan

Tropical Storm Nangka brought wind and rain to Hainan Island on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Nangka was located at latitude 19.1°N and longitude 110.0°E which put it about 70 miles south-southwest of Haikou, China.  Nangka was moving toward the west-northwest at 9 m.p.h. (15 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 987 mb.

The center of Tropical Storm Nangka moved directly across Hainan Island on Tuesday.  Nangka strengthened before it made landfall on the east coast of Hainan.  Winds to tropical storm force extended out 200 miles (320 km) from the center of Tropical Storm Nangka.  So, Nangka may have produced tropical storm force winds over much of Hainan.  Thunderstorms near the center of circulation and in bands revolving around the center were dropping heavy rain over parts of Hainan.  The heavy rain was likely to cause flash floods in some locations.

Tropical Storm Nangka will weaken while it moves across Hainan.  Nangka will move into an environment favorable for intensification for about 12 hours when it moves west of Hainan Island.  Nangka will move over water where the Sea Surface Temperature is near 29°C.  It will move under the southern part of an upper level ridge over eastern Asia.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent Tropical Storm Nangka from strengthening again.

Tropical Storm Nangka will move south of a high pressure system over eastern Asia.  The high will steer Nangka toward the west during the next 48 hours.  Tropical Storm Nangka will move west of Hainan Island in about 6 hours.  On its anticipated track Nangka will make landfall on the northern coast of Vietnam southeast of Hanoi in about 18 hours.  Tropical Storm Nangka will bring gusty winds and locally heavy rain to northern Vietnam.  Heavy rain will cause flash floods in some locations.

Tropical Storm Nangka Forms over South China Sea

Tropical Storm Nangka formed over the South China Sea on Monday.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Nangka was located at latitude 18.3°N and longitude 113.8°E which put it about 200 miles (325 km) east of Hainan Island.  Nangka was moving toward the west at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 996 mb.

More thunderstorms developed near the center of a low pressure system over the South China Sea on Monday and the Japan Meteorological Agency designated the system as Tropical Storm Nangka.  The circulation around Tropical Storm Nangka exhibited more organization on Monday.  More thunderstorms formed near the center of Nangka.  Bands of showers and thunderstorms were revolving around the center of circulation.  Storms near the center generated upper level divergence which pumped mass away to the west of the tropical storm.  Winds to tropical storm force extended out 75 miles (120 km) from the center.

Tropical Storm Nangka will move through an environment favorable for intensification during the next 12 to 18 hours.  Nangka will move over water where the Sea Surface Temperature is near 30°C.  It will move south of an upper level ridge over eastern Asia.  The ridge will produce easterly winds which will blow toward the top of Tropical Storm Nangka.  Those winds will cause moderate vertical which shear.  The shear will slow the rate of intensification, but it will not be strong enough to keep Nangka from intensifying.  Tropical Storm Nangka will weaken in a day or so while the tropical storm moves over Hainan Island.  Nangka could restrengthen when it moves west of Hainan.

Tropical Storm Nangka will move south of a high pressure system over eastern Asia.  The high will steer Nangka toward the west-northwest.  On its anticipated track Tropical Storm Nangka will reach Hainan Island in less than 18 hours.  Nangka will bring gusty winds and locally heavy rain to Hainan.  Flash floods could occur in some locations.  Tropical Storm Nangka will reach northern Vietnam in two days.

Elsewhere over the Western North Pacific Ocean, Tropical Depression Chan-hom was weakening southeast of Japan.  At 5:00 a.m. EDT on Monday the center of Tropical Depression Chan-hom was located at latitude 29.2°N and longitude 142.5°E which put it about 400 miles (645 km) south-southeast of Tokyp, Japan.  Chan-hom was moving toward the south at 9 m.p.h (15 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind guts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1000 mb.

Tropical Storm Linfa Makes Landfall in Vietnam

Tropical Storm Linfa made landfall on the coast of Vietnam on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Linfa was located at latitude 15.4°N and longitude 107.4°E which put it about 50 miles (80 km) east of Lamam, Laos.  Linfa was moving toward the west at 6 m.p.h. (10 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 center of Tropical Storm Linfa made landfall on the central coast of Vietnam south of Da Nang on Sunday.  Linfa brought tropical storm force winds to the portion of the coast south of Da Nang.  Tropical Storm Linfa dropped heavy rain over central Vietnam, southern Laos and northeastern Cambodia.  Linfa is forecast to continue to move toward the west and it will be over northeastern Thailand on Monday.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Chan-hom weakened southeast of Japan and a new tropical depression formed west of the Philippines.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Chan-hom was located at latitude 31.1°N and longitude 142.2°E which put it about 300 miles (485 km) south-southeast of Tokyo, Japan.  Chan-hom was moving toward the southeast 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.

At 11:00 a.m. EDT on Sunday the center of Tropical Depression 18W was located at latitude 17.1°N and longitude 118.3°E which put it about 700 miles (1130 km) east of Da Nang, Vietnam.  The depression was moving toward the west at 10 m.p.h. (16 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 1002 mb.

Tropical Storm Linfa Forms East of Vietnam

Tropical Storm Linfa formed east of Vietnam on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Linfa was located at latitude 15.0°N and longitude 109.9°E which put it about 155 miles (250 km) east-southeast of Da Nang, Vietnam.  Linfa was moving toward the west at 21 m.p.h. (34 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 997 mb.

More thunderstorms developed near the center of a low pressure system over the South China Sea east of Vietnam and the Japan Meteorological Agency designated the system as Tropical Storm Linfa on Saturday.  The circulation around Tropical Storm Linfa exhbited better organization.  More thunderstorms formed near the center of circulation.  Bands of showers and thunderstorms were revolving around the center of Linfa.  Storms near the center generated upper level divergence which pumped mass away to the west of the tropical storm.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Linfa.

A high pressure system over eastern Asia will steer Tropical Storm Linfa quickly toward the west during the next two days.  On its anticipated track Linfa will make landfall on the coast of Vietnam south of Da Nang in about 8 hours.  Tropical Storm Linfa will move through an environment favorable for intensification until it makes landfall.  Linfa will move over water where the Sea Surface Temperature is near 29°C.  It will move under the southern part of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of Tropical Storm Linfa.  Those winds will cause moderate vertical wind shear.  The shear will limit the rate of intensification but Linfa will strengthen before it makes landfall.

Tropical Storm Linfa will make landfall on the coast of Vietnam south of Da Nang in a few hours.  Linfa will bring gusty winds and locally heavy rain to parts of central Vietnam, southern Laos, northern Cambodia and northeastern Thailand.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Chan-hom was passing south of Japan.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Chan-hom was located at latitude 32.0°N and longitude 139.8°E which put it about 215 miles (345 km) south of Tokyo, Japan.  Chan-hom was moving toward the east at 15 m.p.h. (24 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.

Hurricane Delta Brings Wind and Rain to Louisiana

Hurricane Delta brought wind and rain to Louisiana on Friday evening.  At 8:00 p.m. EDT on Friday the center of Hurricane Delta was located at latitude 30,0°N and longitude 93.0°W which put it about 25 miles west-southwest of Jennings, Louisiana.  Delta was moving toward the north-northwest at 14 m.p.h. (22 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 surface pressure was 971 mb.

A Hurricane Warning was in effect for the portion of the coast from High Island, Texas to Morgan City, Louisiana.  Tropical Storm Warnings were in effect for the portions of the coast from San Luis Pass to High Island, Texas and from Morgan City, Louisiana to the Mouth of the Pearl River.  The Tropical Storm Warning includes New Orleans, Lake Pontchartrain and Lake Maurepas.

According the National Hurricane Center the center of Hurricane Delta officially made landfall on the coast of Louisiana near Creole.  The maximum sustained wind speed at the time of landfall was 100 m.p.h. (160 km/h).  Winds to hurricane force extended out 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out 160 miles (260 km).

Hurricane Delta weakened on Friday while moved toward the coast of Louisiana.  An upper level trough produced southwesterly winds which blew toward the top of Delta.  Those winds caused moderate vertical wind shear.  The circulation around Hurricane Delta pulled drier air about the southern side of the hurricane.  In addition, Delta moved over cooler water near the coast of Louisiana.  The combination of shear, drier air and cooler water caused the circulation to weaken on Friday afternoon.

Even though it weakened, Hurricane Delta brought strong winds and rain to Louisiana.  A weather station in Lake Charles, Louisiana reported a sustained wind speed of 64 m.p.h. (103 km/h) and a wind gust of 95 m.p.h. (153 km/h).  A weather station at Lake Arthur, Louisiana reported a sustained wind speed of 77 m.p.h. (125 km/h) and a wind gust of 96 m.p.h. (154 km/h).  A weather station at Cameron, Louisiana reported a sustained wind speed of 58 m.p.h. (93 km/h) and a wind gust of 78 m.p.h. (128 km/h).  A weather station at Port Arthur, Texas reported a wind gust of 71 m.p.h. (114 km/h).

Winds blowing around the eastern side of Hurricane Delta pushed water toward the coast and cause a storm surge.  A station at Freshwater Canal Locks in Louisiana reported a water level rise of 8 feet (2.4 meters).  Delta also dropped heavy rain over parts of Louisiana.  Flash Flood Warnings were issued for some of the areas around Lake Charles and Lafayette, Louisiana.

Hurricane Delta will weaken steadily as it moves farther inland.  The upper level trough will steer Delta toward the northeast during the next several days.  On its anticipated track Delta will move across Louisiana toward southwest Tennessee.  The center of Delta will pass near Alexandria and Monroe, Louisiana.  Flash Flood Watches were in effect for Louisiana, northern Mississippi. southeastern Arkansas, and southwestern Tennessee.

Hurricane Delta Nears Louisiana

Hurricane Delta neared the coast of Louisiana on Friday morning.  At 11:00 a.m. EDT on Friday the center of Hurricane Delta was located at latitude 28.0°N and longitude 93.8°W which put it about 130 miles (215 km) south of Cameron, Louisiana.  Delta was moving toward the north at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 962 mb.

A Hurricane Warning was in effect for the portion of the coast from High Island, Texas to Morgan City, Louisiana.  Tropical Storm Warnings were in effect for the portions of the coast from Sargent to High Island Texas and from Morgan City, Louisiana to the Mouth of the Pearl River.  The Tropical Storm Warning included New Orleans, Lake Pontchartrain and Lake Maurepas.

Hurricane Delta started to weaken slowly on Friday morning as it moved into a less favorable environment.  An upper level trough over the south central U.S.  was producing southwesterly winds which were blowing toward the top of Delta.  Those winds were starting to increase the vertical wind shear.  They were also inhibiting upper level divergence to the south of the hurricane which was causing the surface pressure to increase.

Even though it was weakening, Hurricane Delta remained a formidable hurricane.  There was an eye with a diameter of 40 miles (65 km) at the center of Delta.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms revolving the core of Hurricane Delta were already dropping heavy rain over parts of southeast Texas and southwest Louisiana.

Winds to hurricane force extended out 40 miles (65 km) from the center of Hurricane Delta.  Winds to tropical storm force extended out 160 miles (260 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Delta was 20.6.  The Hurricane Size Index (HSI) was 13.8 and the Hurricane Wind Intensity Size Index (HWISI) was 34.4.  Hurricane Delta was capable of causing regional major damage.

The upper level trough over the south central U.S. will steer Hurricane Delta toward the north-northeast during the next 12 to 24 hours.  On its anticipated track Delta will make landfall on the coast of Louisiana east of Cameron in a few hours.  Hurricane Delta will bring strong winds and heavy rain to parts of the area around Lake Charles that were affected by Hurricane Laura a few weeks ago.  Only temporary repairs have been made to numerous structures.  So, wind and rain damage will be greater than they would have been if all buildings were still intact.  Hurricane Delta will also cause a storm surge of 9 to 12 feet (3 to 4 meters) along the coast.  Locally heavy rain will cause flash floods in some locations.  Widespread power outages could also occur.

Delta Strengthens Back to a Major Hurricane

Hurricane Delta strengthened back to a major hurricane on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Hurricane Delta was located at latitude 24.8°N and longitude 93.4°W which put it about 345 miles (555 km) south of Cameron, Louisiana.  Delta was moving toward the northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 959 mb.

A Hurricane Warning was in effect for the portion of the coast from High Island, Texas to Morgan City, Louisiana.  Tropical Storm Warnings were in effect for the portions of the coast from Sargent to High Island, Texas and from Morgan City, Louisiana to the Mouth of the Pearl River.  The Tropical Storm Warning includes New Orleans, Lake Pontchartrain and Lake Maurepas.

Hurricane Delta strengthened steadily on Thursday.  A circular eye with a diameter of 35 miles (55 km) formed at the center of Delta.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Hurricane Delta.  Storms near the core generated upper level divergence that pumped mass away from the hurricane.  The removal of mass allowed the surface pressure to decrease and the wind speed to increase.

The circulation around Hurricane Delta increased in size on Thursday.  Winds to hurricane force extended out 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out 160 miles (260 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Delta was 20.6.  The Hurricane Size Index (HSI) was 12.7 and the Hurricane Wind Intensity Size Index (HWISI) was 33.3.  Delta was capable of causing regional major damage.

Hurricane Delta will move through an environment favorable for intensification during the next 12 to 18 hours.  Delta 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.  Hurricane Delta will continue to intensify in the short term and it could reach Category 4 on the Saffir-Simpson Scale.

Hurricane Delta will move around the western end of a high pressure system on Friday.  The high will steer Delta toward the north.  An upper level trough over the south central U.S. will turn Delta toward the north-northeast on Friday afternoon.  On its anticipated track Hurricane Delta will make landfall on the coast of Louisiana late on Friday afternoon or on Friday evening.

Hurricane Delta could hit the same area southeast of Lake Charles, Louisiana that was affected by Hurricane Laura.  Delta will bring strong winds and heavy rain to Louisiana.  It could cause a storm surge of 10 to 15 feet (3 to 5 meters) along the coast.  A number of structures in the region have temporary blue tarps in place of permanent roofs.  Hurricane Delta could cause more than the usually expected wind and rain damage in areas affected by Hurricane Laura.  There are also likely to be widespread power outages in the area.

Typhoon Chan-hom Turns Toward Japan

Typhoon Chan-hom turned toward Japan on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Typhoon Chan-hom was located at latitude 27.5°N and longitude 132.9°W which put it about 515 miles (825 km) south-southwest of Osaka, Japan.  Chan-hom was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 973 mb.

Typhoon Chan-hom strengthened slowly on Wednesday.  An eye with a diameter of 35 miles (55 km) formed at the center of Chan-hom.  The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Chan-hom.  Storms near the core generated upper level divergence which pumped mass away to the northeast of the typhoon.

The circulation around Typhoon Chan-hom was large.  Winds to typhoon force extended out 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out 200 miles (320 km) from the center of Chan-hom.

Typhoon Chan-hom will move through an environment somewhat favorable for intensification during the next 24 hours.  Chan-hom will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western end of an upper level ridge.  The ridge will produce southerly winds which will blow toward the top of Typhoon Chan-hom.  Those winds will cause moderate vertical wind shear, which will inhibit intensification.  The wind shear will limit intensification, but Chan-hom could get stronger during the next 24 hours.  An upper level trough over eastern Asia will cause stronger southwesterly winds to blow toward Typhoon Chan-hom in a day or so.  Those winds will cause stronger vertical wind shear and they will cause Chan-hom to start to weaken.

Typhoon Chan-hom will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next 48 hours.  The high will steer Chan-hom toward the north during that time period.  The upper trough over eastern Asia will turn Typhoon Chan-hom toward the northeast during the weekend.  On its anticipated track Typhoon Chan-hom will be southeast of Kyushu and south of Shikoku in about 48 hours.