Monthly Archives: July 2020

Hurricane Douglas Prompts Hurricane Warning for Oahu

The approach of Hurricane Douglas prompted the issuance of a Hurricane Warning for Oahu on Saturday afternoon.  At 5:00 p.m. EDT on Saturday the center of Hurricane Douglas was located at latitude 19.5°N and 150.1°W which put it about 325 miles (525 km) east of Hilo, Hawaii.  Douglas was moving toward the west-northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were wind gusts to 110 m.p.h. (175 km/h).  The minimum surface pressure was 984 mb.

A Hurricane Warning was in effect for Oahu.  Hurricane Watches were in effect for Hawaii, Maui, Lanai, Molokai and Kahoolawe.  Tropical Storm Warnings were in effect for Hawaii, Maui, Lanai, Molokai and Kahoolawe.  Tropical Storm Watches were in effect for Kauai and Niihau.

Hurricane Douglas weakened gradually on Saturday as it moved over cooler water.  Douglas was moving over water where the Sea Surface Temperature was near 25°C.  As a result of the cooler water, thunderstorms did not grow as high in the atmosphere.  There was still an eye at the center of circulation, but breaks began to appear in the ring of storms around the eye.  Most of the stronger thunderstorms were in the northern half of the circulation.  Bands in the southern half of the circulation consisted mainly of showers and lower clouds.   Winds to hurricane force extended out about 30 miles (50 km) from the center of circulation.  Winds to tropical storm force extended out about 110 miles (175 km) from the center.

Hurricane Douglas will move around the southern side of a subtropical high pressure system over the North Pacific Ocean.  The high will steer Douglas toward the west-northwest during the next several days.  On its anticipated track Hurricane Douglas will pass north of the Big Island of Hawaii on Sunday morning.  The core of Douglas could pass near Oahu on Sunday night.

Hurricane Douglas will bring gusty winds to the Hawaiian Islands.  The strongest winds could occur on Oahu.  Winds speeds will be greater at higher elevations.  Douglas could drop heavy rain on the sides of the islands where the wind blows up the slopes.  Flash flooding will be possible.

Hanna Strengthens to a Hurricane Near South Texas

Former Tropical Storm Hanna strengthened into a hurricane near the coast of South Texas on Saturday morning.  At 8:00 a.m. EDT on Saturday the center of Hurricane Hanna was located at latitude 27.1°N and longitude 96.0°W which put it about 100 miles (160 km) east-southeast of Corpus Christi, Texas.  Hanna was moving toward the west at 9 m.p.h. (15 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. (150 km/h).  The minimum surface pressure was 982 mb.

A Hurricane Warning was in effect for the portion of the coast from Port Mansfield to Mesquite Bay, Texas.  Tropical Storm Warnings were in effect for the portions of the coast from Barra de Mezquital, Mexico to Port Mansfield and from Mesquite Bay to High Island, Texas.

A NOAA aircraft detected winds to hurricane force in former Tropical Storm Hanna on Saturday morning and the National Hurricane Center upgraded Hanna to a hurricane.  The circulation around Hurricane Hanna was well organized.  A circular eye with a diameter of 25 miles (40 km) was at the center of circulation.  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 were revolving around the core of Hanna.  Storms near the core were generating upper level divergence which was pumping mass away from the hurricane.  Winds to hurricane force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 90 miles (150 km) from the center.

Hurricane Hanna will move through an environment favorable for strengthening during the next few hours.  Hanna will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Hanna will continue to intensify until it makes landfall on the coast of South Texas.

Hurricane Hanna will move south of a high pressure system that stretches across the southern U.S.  The high will steer Hanna a little to the south of due west.  On its anticipated track the center of Hurricane Hanna will make landfall on Padre Island later today.  The northern part of the eyewall will pass near Corpus Christi and that city could experience winds to hurricane force.  The southern part of the eyewall will pass near Port Mansfield which could also experience hurricane force winds.  The core of Hanna will pass north of Brownsville, but Brownsville, Harlingen and Mcallen could all experience winds to tropical storm force.

Easterly winds will blow water toward the coast of South Texas and they will cause a significant storm surge.  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.  Hurricane Hanna will also drop heavy rain over South Texas.  Isolated locations could receive over a foot (0.3 meters) of rain and flash flooding is likely.

Elsewhere, Tropical Storm Gonazalo was quickly nearing Trinidad.  At 8:00 a.m. EDT on Saturday  the center of Tropical Storm Gonzalo was located at latitude 10.3°N and longitude 59.8°W which put it about 100 miles (160 km) east of Trinidad.  Gonzalo was moving toward the west at 18 m.p.h. (30 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 1009 mb.

Tropical Storm Warnings were in effect  for Tobago and Grenada.

Tropical Storm Hanna Prompts Hurricane Warning for Texas

A strengthening Tropical Storm Hanna prompted the issuance of a Hurricane Warning for a portion of the coast of Texas on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Hanna was located at latitude 27.3°N and longitude 94.3°W which put it about 195 miles (310 km) east of Corpus Christi, Texas.  Hanna was moving toward the west 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 999 mb.

A Hurricane Warning was in effect for the portion of the Texas coast from Baffin Bay to Mesquite Bay.  Tropical Storm Warnings were in effect for the portions of the coast from the Mouth of the Rio Grande River to Baffin Bay and from Mesquite Bay to San Luis Pass, Texas.

Tropical Storm Hanna exhibited much more organization on Friday afternoon.  A primary rainband wrapped around the southern and eastern sides of the center of Hanna.  The northern end of the rainband appeared to be wrapping around the rest of the center of circulation and an eye seemed to be forming.  Bands of showers and thunderstorms were revolving around the center of Tropical Storm Hanna.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical storm.  The removal of mass was allowing the surface pressure to decrease.  Winds to tropical storm force extended out 60 miles (95 km) from the center for circulation.

Tropical Storm Hanna will move through an environment favorable for intensification during the next 18 hours.  Hanna will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Hanna will continue to intensify.  If an eye and eyewall form completely, then Hanna could strengthen rapidly during the 6 to 12 hours prior to landfall.  Tropical Storm Hanna is very likely to intensify into a hurricane.

Tropical Storm Hanna will move south of a high pressure system that stretches across the southern U.S.  The high will steer Hanna toward the west during the next 24 hours.  On its anticipated track Tropical Storm Hanna will reach the coast of Texas near Corpus Christi during the middle of the day on Saturday.

Tropical Storm Hanna is very likely to be a hurricane when it makes landfall.  It will bring strong winds to the portion of the coast near where the eye makes landfall.  Strong winds blowing water toward the coast could create a storm surge of 6 to 8 feet (2 to 3 meters) near and to the north of where the eye makes landfall.

Elsewhere, a trade wind surge hit Tropical Storm Gonzalo from the northeast.  The surge caused increased low level wind shear and it brought drier air.  The increased shear and drier air caused Gonzalo to weaken.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Gonzalo was located at latitude 10.0°N and 55.6°W which put it about 390 miles (625 km) east of the southern Windward Islands.  Gonzalo was moving toward the west at 18 m.p.h. (30 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 1008 mb.

Tropical Storm Warnings were in effect for Barbados, Tobago, Grenada, and St. Vincent and the Grenadines.

Hurricane Douglas Prompts Watches for Hawaii

Hurricane Douglas prompted the issuance of Hurricane Watches for some of the Hawaiian Islands on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of Hurricane Douglas was located at latitude 17.0°N and longitude 143.5°W which put it about 785 miles (1260 km) east of Hilo, Hawaii.  Douglas was moving toward the west-northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  The minimum surface pressure was 967 mb.

Hurricane Watches were issued for Hawaii, Maui, Lanai, Molokai and Kahoolawe.

Hurricane Douglas continued on a track toward the Hawaiian Islands on Friday, which prompted the issuance of Hurricane Watches.  Douglas was weakening slowly as it moved over slightly cooler water.  In addition, Hurricane Douglas appeared to go through an eyewall replacement cycle which may have contributed to the weakening.  Even though it had weakened, Douglas remained a powerful, well organized hurricane.  There was a circular eye at the center of circulation.  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 were revolving around the core of Hurricane Douglas.  Storms near the core were generating upper level divergence which was pumping mass away from the hurricane.

Winds to hurricane force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 120 miles (195 km) from the center of Douglas.  The Hurricane Intensity Index (HII) for Hurricane Douglas was 20.6.  The Hurricane Size Index (HSI) was 9.9 and the Hurricane Wind Intensity Size Index (HWISI) was 30.5.  Hurricane Douglas was capable of causing localized major damage.

Hurricane Douglas will move through an environment less favorable for major hurricanes during the next several days.  Douglas will move over water where the Sea Surface Temperature is near 25°C.  So, Hurricane Douglas will not be able to extract as much energy from the upper ocean.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  The lack of wind shear will allow Hurricane Douglas to weaken gradually.

Hurricane Douglas will move south of a subtropical high pressure system over the Eastern and Central North Pacific Ocean.  The high will steer Douglas toward the west-northwest.  On its anticipated track Hurricane Douglas will approach Hawaii on Sunday.

Tropical Depression Eight Strengthens to Tropical Storm Hanna

Former Tropical Depression Eight strengthened to Tropical Storm Hanna on Thursday night and a Tropical Storm Warning was in effect for a large portion of the coast of Texas.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Hanna was located at latitude 26.2°N and longitude 91.4°W which put it about 385 miles (620 km) east-southeast of Corpus Christi, Texas.  Hanna was moving toward the west-northwest at 7 m.p.h. (11 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 1002 mb.

A Tropical Storm Warning was in effect for the portion of the coast from the Mouth of the Rio Grande River to San Luis Pass, Texas.  A Tropical Storm Watch was in effect for the portion of the coast from San Luis Pass to High Island, Texas.

A NOAA aircraft detected winds to tropical storm force in former Tropical Depression Eight on Thursday night and the National Hurricane Center upgraded the system to Tropical Storm Hanna.  The surface pressure was decreasing and Tropical Storm Hanna was exhibiting greater organization.  A band of thunderstorms was wrapping around the southern and eastern sides of the center of circulation.  Thunderstorms were forming in other bands the were revolving around the center of circulation.  Storms near the center began to generate upper level divergence which was pumping mass away from the tropical storm.  The removal of mass allowed the surface pressure to decrease.  Winds to tropical storm force extended out 35 miles (55 km) from the center in the eastern quadrant of Tropical Storm Hanna.  Winds in the other parts of Hanna were blowing at less than tropical storm force.

Tropical Storm Hanna will move through an environment favorable for intensification during the next 36 hours.  Hanna will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Hanna will continue to intensify and there is a chance it could strengthen into a hurricane.

Tropical Storm Hanna will move south of a high pressure system that extends from the Atlantic Ocean across the southern U.S.  The high will steer Hanna slowly toward the west.  On its anticipated track Tropical Storm Hanna will approach the coast of Texas near Corpus Christi on Saturday.  Hanna could be a strong tropical storm or a hurricane when it reaches the coast.

Elsewhere, Tropical Storm Gonzalo continued to churn toward the Windward Islands.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Gonzalo was located at latitude 9.9°N and longitude 50.6°W which put it about 730 miles (1170 km) east of the southern Windward Islands.  Gonzalo was moving toward the west 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. (120km/h).  The minimum surface pressure was 1000 mb.

A Hurricane Watch was in effect for Barbados and St. Vincent and the Grenadines.  A Tropical Storm Watch was in effect for Tobago and Grenada.

Hurricane Douglas Strengthens to a Major Hurricane

Hurricane Douglas strengthened to a major hurricane on Thursday morning.  At 5:00 a.m. EDT on Thursday the center of Hurricane Douglas was located at latitude 13.1°N and longitude 134.7°W which put it about 1470 miles (2365 km) east-southeast of Hilo, Hawaii.  Douglas was moving toward the west-northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  The minimum surface pressure was 967 mb.

Hurricane Douglas strengthened rapidly into a major hurricane during the past 24 hours.  A circular eye formed at the center of Douglas.  A ring of 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 Douglas.  Storms near the core were generating strong upper level divergence which was pumping mass away from the hurricane.  Winds to hurricane force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 100 miles (160 km) from the center.

Hurricane Douglas will move through an environment favorable for intensification during the next 12 to 24 hours.  Douglas will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Douglas could strengthen on Thursday.  Douglas will start to move over slightly cooler water on Friday.  It is likely to weaken slowly once the core of the circulation moves over the cooler water.

Hurricane Douglas will move south of a subtropical high pressure system over the Eastern North Pacific Ocean.  The high will steer Douglas toward the west-northwest during the next few days.  On its anticipated track Hurricane Douglas could approach Hawaii on Sunday.  Watches could be issued for Hawaii later this week.

Tropical Depression Eight Forms Over Gulf of Mexico

Tropical Depression Eight formed over the Gulf of Mexico on Wednesday night and a Tropical Storm Watch was issued for the coast of Texas.  At 11:00 a.m. EDT on Wednesday the center of Tropical Depression Eight was located at latitude 25.9°N and longitude 88.2°W which put it about 530 miles (855 km) east-southeast of Port Oconnor, Texas.  The depression 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 wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1009 mb.

A Tropical Storm Watch was issued for the portion of the coast of Texas from Port Mansfield to High Island.

More thunderstorms formed near the center of a low pressure system over the Gulf of Mexico on Wednesday night and the National Hurricane Center designated the system as Tropical Depression Eight.  The thunderstorms were forming in bands in the northern half of the circulation.  Bands in the southern half of the depression consisted primarily of showers and lower clouds.

Tropical Depression Eight will move through an environment favorable for intensification during the next 36 hours.  The depression will move over water where the Sea Surface Temperature is near 30°C.  An upper level low over the southwestern Gulf of Mexico will produce southerly winds which will blow toward the top of the depression.  Those winds will cause some vertical wind shear, but the shear will not be enough to prevent intensification.  Tropical Depression Eight is likely to strengthen into a tropical storm during the next 36 hours.

Tropical Depression Eight will move south of a subtropical high pressure system that extends from the western Atlantic Ocean across the southern U.S.  The high will steer the depression toward the west-northwest.  On its anticipated track Tropical Depression Eight could approach the coast of Texas on Friday night.  It is likely to be a tropical storm when it approaches the coast.

Elsewhere, Tropical Storm Gonzalo strengthened as it moved toward the Windward Islands and a Hurricane Watch was issued for Barbados.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Gonzalo was located at latitude 9.9°N and longitude 45.9°W which put it about 1045 miles (1685 km) east of the southern Windward Islands.  Gonzalo was moving toward the west at 12 m.p.h. (19 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 998 mb.

Tropical Storm Douglas Strengthens Into a Hurricane

Former Tropical Storm Douglas strengthened into a hurricane east of Hawaii on Wednesday morning.  At 11:00 a.m. EDT on Monday the center of Hurricane Douglas was located at latitude 11.8°N and longitude 129.5°W which put it about 1785 miles (2870 km) east-southeast of Hilo, Hawaii.  Douglas was moving toward the west at 15 m.p.h. (24 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 993 mb.

Former Tropical Storm Douglas exhibited more organization on satellite images.  The inner end of a rainband wrapped around the center of circulation and an eye was visible intermittently on satellite images.  Bands of showers and thunderstorms were revolving around the center of Hurricane Douglas.  Storms near the center were generating upper level divergence which was pumping mass away from the hurricane.  Winds to hurricane force extended out 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out 80 miles (130 km) from the center.

Hurricane Douglas will move through an environment favorable for intensification during the next several days.  Douglas 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 Douglas will continue to intensify and it could strengthen into a major hurricane.

Hurricane Douglas will move south of a subtropical high pressure system over the Eastern North Pacific Ocean.  The high will steer Douglas toward the west-northwest.  On its anticipated track Hurricane Douglas could approach Hawaii on Sunday.  Watches could be issued for Hawaii later this week when Douglas moves closer.

TD 7 Strengthens Into Tropical Storm Gonzalo

Former Tropical Depression Seven strengthened into Tropical Storm Gonzalo on Wednesday morning.  At 11:00 a.m.  EDT on Wednesday the center of Tropical Storm Gonzalo was located at latitude 9.9°N and longitude 43.6°W which put it about 1205 miles (1935 km) east of the southern Windward Islands.  Gonzalo was moving toward the west at 14 m.p.h. (22 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 1000 mb.

The circulation around former Tropical Depression Seven exhibited much better organization on Wednesday morning and the National Hurricane Center designated the system as Tropical Storm Gonzalo.  A band of thunderstorms curved around the southern and eastern sides of the center of circulation.  The inner end of the band appeared to be wrapping farther around the center and visible satellite images suggested that an eye could be forming.  Bands of showers and thunderstorms were revolving around the center of Gonzalo.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical storm.  The circulation around Tropical Storm Gonzalo was small.  Winds to tropical storm force only extended out 25 miles (40 km) from the center of circulation.

Tropical Storm Gonzalo will move through an environment favorable for intensification.  Gonzalo will move over water where the Sea Surface Temperature is near 29.5°C.  It will move through a region where the upper level winds are weak and there will be little vertical  wind shear.  Tropical Storm Gonzalo is likely to intensify and it could strengthen into a hurricane during the next 36 hours.  Small tropical cyclones like Gonzalo can change intensity rapidly if they move into a different type of environment.

Tropical Storm Gonzalo will move south of the subtropical high pressure system over the North Atlantic Ocean.  The high will steer Gonzalo toward the west.  On its anticipated track Tropical Storm Gonzalo could approach the Windward Islands on Saturday.  Watches could be issued for some of those islands when Gonzalo moves closer.

Elsewhere, more thunderstorms were developing around a low pressure system over the Gulf of Mexico that is currently designated as Invest 91L.  At 8:00 a.m. EDT on Wednesday the center of Invest 91L was located at latitude 25.7°N and longitude 87.9°W which put it about 645 miles (1040 km) east-southeast of Corpus Christi, Texas.  The low pressure system was moving toward the west-northwest at 12 m.p.h. (19 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 1011 mb.  The National Hurricane Center was indicating the probability was 50% that the low pressure system would develop into a tropical cyclone.

Tropical Depression Seven Forms East of Windward Islands

Tropical Depression Seven formed east of the Windward Islands on Tuesday afternoon.  At 5:00 p.m. EDT on Tuesday the center of Tropical Depression Seven was located at latitude 9.8°N and longitude 40.4°W which put it about 1420 miles (2285 km) east of the southern Windward Islands.  It was moving toward the west-northwest at 8 m.p.h. (13 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 1009 mb.

An area of low pressure between the coast of Africa and the Windward Islands exhibited more organization on Tuesday afternoon and the National Hurricane Center designated the system as Tropical Depression Seven.  The circulation around Tropical Depression Seven was still organizing.  Bands of showers and thunderstorms were developing and the bands were revolving around the center of circulation.  Storms near the center started to generate upper level divergence which was pumping mass away from the tropical depression.

Tropical Depression Seven will move through an environment favorable for intensification during the next several days.  The depression will move over water where the Sea Surface Temperature is near 29.5°C.  It will move through a region where the upper level winds will be weak and there will be little vertical wind shear.  Tropical Depression Seven is likely to strengthen into a tropical storm during the next 24 hours.

Tropical Depression Seven will move south of a subtropical high pressure system over the Atlantic Ocean.  The high will steer the depression toward the west during the next few days.  On its anticipated track Tropical Depression Seven could approach the Windward Islands on Saturday.

Elsewhere, a tropical wave over the eastern Gulf of Mexico was designated as Invest 91L on Tuesday afternoon.  At 2:00 p.m. EDT on Tuesday the center of Invest 91L was located at latitude 25.2°N and longitude 84.7°W which put it about 200 miles (320 km) west of Key West, Florida.  It was moving toward the west-northwest at 18 m.p.h. (30 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 1014 mb.  The National Hurricane Center indicated that there was a 40% probability of the formation of a tropical depression.