Monthly Archives: August 2020

Typhoon Hagupit Makes Landfall in China

Typhoon Hagupit made landfall in China on Monday.  At 5:00 p.m. EDT on Monday the center of Typhoon Hagupit was located at latitude 28.3°N and longitude 120.8°E which put it about 50 miles (80 km) south-southwest of Taizhou, China and about 235 miles (375 km) south of Shanghai.  Hagupit was moving toward the north-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 978 mb.

Former Tropical Storm Hagupit strengthened quickly to a typhoon before it made landfall on the east coast of China.  A circular eye formed at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storm.  Winds to typhoon force extended out 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out 135 miles (220 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Hagupit was 11.5.  The Hurricane Size Index (HSI) was 12.0 and the Hurricane Wind Intensity Size Index (HWISI) was 23.5.  Typhoon Hagupit was capable of causing regional minor damage.

Typhoon Hagupit will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Hagupit toward the north during the next 24 hours.  On its anticipated track the center of Typhoon Hagupit will pass west of Shanghai in 18 to 24 hours.  Hagupit will bring gusty winds and locally heavy rain to Zhejiang and Jiangsu. Heavy rain could cause flash floods in some locations.  Typhoon Hagupit will also cause a storm surge along the coast of Zhejiang, Jiangsu and Shanghai Shi.

Tropical Storm Isaias Turns Toward the Carolinas

Tropical Storm Isaias turned toward the Carolinas on Monday morning.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Isaias was located at latitude 30.7°N and longitude 80.1°W which put it about 220 miles (350 km) south-southwest of Myrtle Beach, South Carolina.  Isaias was moving toward the north at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 998 mb.

A Hurricane Warning was in effect for the portion of the coast from South Santee River, South Carolina to Surt City, North Carolina.  Tropical Storm Warnings were in effect for the portions of the coast from Altamaha Sound, Georgia to South Santee River, South Carolina and from Surf City North Carolina to Watch Hill, Rhode Island including Albemarle Sound, Pamlico Sound, Long Island and Long Island Sound.  A Tropical Storm Watch was in effect for the portion of the coast from Watch Hill, Rhode Island to Stonington, Maine including Block Island, Martha’s Vineyard and Nantucket.

Tropical Storm Isaias seemed to begin another cycle where the thunderstorm activity pulsed down during the overnight hours.  However, visible satellite and radar images seemed to indicate that thunderstorms were starting redevelop on Monday morning.  A band of thunderstorms appeared to be wrapping around the northern side of the circulation.  Thunderstorms were also increasing in bands in the northern and eastern parts of Isaias.  Bands in the southern and western sides of Isaias consisted primarily of showers and lower clouds.  The circulation of Tropical Storm Isaias could be pulling in some drier air around the southern and western parts of the storm.  That is a fairly typical occurrence with tropical systems moving up the East Coast of the U.S.  Winds to tropical storm force extended out 125 miles (200 km) in the northern and eastern quadrants of Isaias.  The winds in the southern and western parts of the circulation were mostly at less than tropical storm force.

Tropical Storm Isaias will move through an environment somewhat favorable for intensification during the next 12 hours.  Isaias will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough over the Central U.S. will produce southwesterly winds which will blow toward the top of Isaias.  Those winds will cause moderate vertical wind shear which will inhibit intensification.  The wind shear is expected to decrease slightly later on Monday, which could allow Isaias to strengthen into a hurricane.

The upper level trough will steer Tropical Storm Isaias toward the north-northeast during the next several days.  On its anticipated track Tropical Storm Isaias will make landfall near Myrtle Beach, South Carolina on Monday night.  Isaias could be a hurricane when it makes landfall.  Isaias will bring gusty winds and a storm surge of 3 to 6 feet (1 to 2 meters) to the coast near and to the east of where the center makes landfall.  The center of Isaias will move across eastern North Carolina and it could be near Norfolk, Virginia on Tuesday morning.  Tropical Storm Isaias could pass near New York City later on Tuesday.

Tropical Storm Isaias will bring gusty winds to the East Coast of the U.S. from South Carolina to Maine.  Isaias will also drop locally heavy rain from eastern South Carolina to New England.  The National Weather Service has indicated that a Moderate Risk of flash floods exists for the region from eastern South Carolina to eastern Pennsylvania.

Tropical Storm Hagupit Almost a Typhoon

Tropical Storm Hagupit intensified to almost typhoon strength east of Taiwan on Sunday.  At 11:00 p.m. EDT on Sunday the center of Typhoon Hagupit was located at latitude 25.4°N and longitude 123.2°E which put it about 130 miles (215 km) east of Taipei, Taiwan.  Hagupit was moving toward the north-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 985 mb.

The circulation around Tropical Storm Hagupit exhibited much greater organization on Sunday night.  The inner end of a rainband wrapped around the center of circulation and an eye emerged on visible satellite imagery.  The eye was surrounded by a 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 Hagupit.  The strongest rainbands were in the eastern half of the circulation.  Bands in the western half of the tropical storm consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 115 miles (185 km) from the center of circulation.

Tropical Storm Hagupit will move through an environment favorable for intensification during the next 24 hours.  Hagupit 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 Storm Hagupit will intensify into a typhoon during the next 6 to 12 hours.

Tropical Storm Hagupit will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Hagupit toward the north-northwest during the next 24 to 36 hours.  On its anticipated track Hagupit will approach the coast of China south of Shanghai near Wenzhou in about 24 hours.  It will bring gusty winds and locally heavy rain to the east coast of China.  Heavy rain could cause flash floods in some locations.

Elsewhere, former Tropical Storm Sinlaku dropped locally heavy rain on northern Vietnam and Laos.  At 2:00 p.m. EDT on Sunday the center of Tropical Depression Sinlaku was located at latitude 19.7°N and longitude 103.6°E which put it about 150 miles (240 km) north of Vientiane, Laos.  Sinlaku 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 996 mb.

Tropical Storm Isaias Slightly Stronger, Hurricane Watch Issued for Carolinas

Tropical Storm Isaias strengthened slightly on Sunday afternoon and a hurricane Watch was issued for a portion of the Carolinas’ coast.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Isaias was located at latitude 27.8°N and longitude 79.8°W which put it about 65 miles (105 km) southeast of Cape Canaveral, Florida.  Isaias was moving toward the north-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 994 mb.

A Hurricane Watch was issued for the portion of the coast from South Santee River, South Carolina to Surf City, North Carolina.  A Tropical Storm Warning was in effect for the portion of the coast from Sebastian Inlet, Florida to Ocracoke Inlet, North Carolina.  A Tropical Storm Watch was issued for the portion of the coast from Ocracoke Inlet, North Carolina to Watch Hill, Rhode Island including Albemarle Sound, Pamlico Sound, Long Island and Long Island Sound.

Tropical Storm Isaias strengthened a little on Sunday afternoon, but the middle level center of circulation was displaced to the northeast of the surface center.  An upper level trough over the central U.S. extended to the Gulf of Mexico and it was producing westerly winds which were blowing toward the top of Isaias.  Those winds were causing moderate vertical wind shear and they were also causing the displacement of the middle level center of Tropical Storm Isaias.  Thunderstorms continued to develop around the middle level center of circulation.  Those storms generated upper level divergence which pumped mass away to the east of the tropical storm.  Winds to tropical storm force extended out 115 miles (185 km) on the eastern side of Isaias.  Tropical Storm force winds only extended out 65 miles (105 km) on the western side of the circulation.

Tropical Storm Isaias will move through an environment somewhat favorable for intensification during the next 24 hours.  Isaias will move over water where the Sea Surface Temperature is near 30°C.  The direction of the upper level winds will shift to the southwest as the upper level trough approaches Tropical Storm Isaias.  That will cause the vertical wind shear to decrease.  Tropical Storm Isaias could strengthen into a hurricane, if the shear decreases.

Tropical Storm Isaias will move around the western end of a subtropical high pressure system over the North Atlantic Ocean.  The high will steer Isaias toward the north during the next 12 hours.  The upper level trough will steer Tropical Storm Isaias toward the northeast on Monday.  On its anticipated track Isaias will approach the coast of the Carolinas near Myrtle Beach, South Carolina on Monday night.  Isaias could be a hurricane when it makes landfall.  It will bring gusty winds and locally heavy rain to extreme eastern South Carolina, eastern North Carolina and coastal Virginia.  Isaias will cause a storm surge of 3  to 6 feet (1 to 2 meters) near and to the east of where the center makes landfall.  Tropical Storm Isaias will continue to move up the East Coast toward New England.

Isaias Crosses Andros Island, Weakens to Tropical Storm

The center of former Hurricane Isaias crossed Andros Island on Saturday afternoon and it weakened to a tropical storm.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Isaias was located at latitude 25.1°N and longitude 78.7°W which put it about 115 miles (185 km) southeast of Ft. Lauderdale, Florida.  Isaias was moving toward the northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 993 mb.

A Hurricane Warning was in effect for the portion of the coast from Boca Raton, Florida to the Flagler/Volusia County Line.  A Hurricane Waning was also in effect for the Northwestern Bahamas including Andros Island, New Providence, Eleuthera, the Abacos, the Berry Islands, Grand Bahama Island, and Bimini.

Tropical Storm Warnings were in effect for the portions of the coast from Ocean Reef to Boca Raton, Florida and from the Flagler/Volusia County Line to Ponte Vedra Beach, Florida.  A Tropical Storm Warning was also in effect for Lake Okeechobee.  A Tropical Storm Watch was in effect for the portion of the coast from Ponte Vedra Beach, Florida to South Santee River, South Carolina.

The center of former Hurricane Isaias crossed over Andros Island on Saturday afternoon.  Normally, Andros Island does not have much of an impact on hurricanes, but combined with a less favorable environment it contributed to a temporary weakening of Isaias.   Tropical Storm Isaias consisted primarily of bands of showers and lower clouds after crossing Andros Island.  However, new thunderstorms began to develop northeast of the center of circulation during the past several hours and part of the eyewall appeared to be reforming.  Bands in the western and southern parts of Isaias still consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 90 miles (145 km) from the center of circulation.

Tropical Storm Isaias will move through an environment somewhat favorable for intensification during the next 36 hours.  Isaias will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough over the central U.S. will produce westerly winds which blow toward the top of the circulation.  Those winds will cause moderate vertical wind shear, but they are likely to only affect the very top of the tropical storm.  Tropical Storm Isaias will move into a region where there is drier air in the middle and upper troposphere.  The circulation around Tropical Storm Isaias will reorganize and it is likely to strengthen back into a hurricane.

Tropical Storm Isaias will move around the western end of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Isaias toward the northwest during the next 24 hours.  Isaias will move more toward the north later on Sunday.  The upper level trough will turn Isaias toward the northeast on Monday.  On its anticipated track Tropical Storm Isaias is will approach the southeast coast of Florida near Ft. Lauderdale and West Palm Beach on Sunday.  Isaias is likely to be a hurricane when it approaches the coast.

Tropical Storms Sinlaku & Hagupit Form over West Pacific

Tropical Storms Sinlaku and Hagupit formed over the Western North Pacific Ocean on Saturday.  At 11:00 a.m. EDT on Saturday the center of Tropical Storm Sinlaku was located at latitude 19.4°N and longitude 107.1°E which put it about 90 miles (145 km) southeast of Nam Dinh, Vietnam.  Sinlaku was moving toward the 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 993 mb.

The circulation around a low pressure system near Vietnam exhibited greater organization on Saturday and the Japan Meteorological Agency designated the system as Tropical Storm Sinlaku.  Bands of showers and thunderstorms were revolving around the center of Sinlaku.  There were more thunderstorms in the bands on the western side of the circulation.  Winds to tropical storm force extended out 110 miles (185 km) from the center of circulation.

Tropical Storm Sinlaku has about 12 hours to strengthen before it makes landfall in northern Vietnam.  Sinlaku will move over water where the Sea Surface Temperature is near 30°.  It will move under the southeast part of an upper level ridge over Asia.  The ridge will produce easterly winds which will blow toward the top of Sinlaku.  Those winds will cause moderate vertical wind shear and the shear will limit intensification.  Tropical Storm Sinlaku will bring gusty winds and rain to northern Vietnam on Sunday.

The circulation around a second low pressure system east of Taiwan also exhibited more organization on Saturday and the Japan Meteorological Agency designated that system as Tropical Storm Hagupit.  At 11:00 a.m. EDT on Saturday the center of Tropical Storm Hagupit was located at latitude 21.8°N and longitude 126.5°W which put it about 220 miles (350 km) southeast of Ishigaki, Japan.  Hagupit was moving toward the 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 1003 mb.

The circulation around Tropical Storm Hagupit was still organizing on Saturday.  Thunderstorms were developing in bands in the eastern half of Hagupit.  Bands in the western side of the circulation consisted primarily of showers and lower clouds.  Storms near the center of Hagupit were generating upper level divergence which was pumping mass away to the east of the tropical storm.

Tropical Storm Hagupit will move through an environment favorable for intensification.  Hagupit will move over water where the Sea Surface Temperature is near 30°C.  Hagupit will move into a region where the upper level winds are weaker and there will not be a lot of vertical wind shear.  Tropical Storm Hagupit is likely to intensify during the next 24 to 36 hours.

Tropical Storm Hagupit will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high will steer Hagupit toward the northwest during the next several days.  On its anticipated track the center of Tropical Storm Hagupit will pass near Ishigaki, Japan in about 24 hours.  Hagupit will approach the coast of China south of Shanghai in about 48 hours.