Monthly Archives: September 2019

Tropical Storm Narda Moves Along West Coast of Mexico

Tropical Storm Narda moved along the west coast of Mexico on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Narda was located at latitude 24.0°N and longitude 107.4°W which put it about 85 miles (135 km) northwest of Mazatlan, Mexico.  Narda was moving toward the northwest at 16 m.p.h. (26 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 998 mb.

A Tropical Storm Warning was in effect for the portion of the coast from San Blas to Guaymas, Mexico.

The center of Tropical Storm Narda move just to the west of the coast of Mexico on Monday, which allowed Narda to strengthen during the day.  A distinct low level center of circulation was evident on satellite images.  The center was over the warm water in the Eastern North Pacific Ocean.  A ring of strong thunderstorms formed around the center of circulation and the strongest winds were occurring in that ring of storms.  Storms near the center of Narda were generating upper level divergence.  Bands of showers and thunderstorms were revolving around the center of Tropical Storm Narda.  The strongest rainbands were over the Eastern North Pacific Ocean west of Mexico.  Winds to tropical storm force extended out about 60 miles (95 km) from the center of circulation.  The stronger winds were also occurring in the rainbands over the water.

Tropical Storm Narda could strengthen further during the next 12 to 24 hours, if the center of circulation remains over water.  Narda will move over a portion of the Eastern North Pacific Ocean where the Sea Surface Temperature is near 29°C.  An upper level ridge over Mexico was producing southeasterly winds which were blowing toward the top of the circulation.  Those winds were causing some vertical wind shear, but the shear was not strong enough to prevent intensification.  However, the center of Tropical Storm Narda is very near the west coast of Mexico and Narda will start to weaken again whenever the center moves inland.

The upper level ridge over Mexico will continue to steer Tropical Storm Narda toward the northwest for several more days.  On its anticipated track the center of Tropical Storm Narda will continue to move very close to the west coast of Mexico.  Any wobble toward the east could bring the center of Narda inland again.  Tropical Storm Narda will bring gusty winds and locally heavy rain to coastal parts of Sinaloa and Sonora.  Locally heavy rain could cause flash floods in some parts of western Mexico.

Hurricane Lorenzo Prompts Watches for the Azores

The risk posed by Hurricane Lorenzo prompted the issuance of watches for the Azores.  At 11:00 p.m. EDT on Sunday the center of Hurricane Lorenzo was located at latitude 27.6°N and longitude 43.5°W which put it about 1195 miles (1920 km) west-southwest of the Azores.  Lorenzo was moving toward the north-northeast at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h).  The minimum surface pressure was 952 mb.

Hurricane Watches were issued for the western and central Azores including Flores, Corvo, Faial, Pico, Sao Jorge, Graciosa, Terceira.  Tropical Storm Watches were issued for the eastern Azores including Sao Miguel and Santa Maria.

Hurricane Lorenzo weakened on Sunday when it moved into a less favorable environment.  Lorenzo moved over water where the Sea Surface Temperature was a little cooler.  In addition, an upper level trough west of Hurricane Lorenzo was producing southwesterly winds which were blowing toward the top of the circulation.  Those upper level winds were causing more vertical wind shear.  The combination of cooler water and more shear was responsible for weakening Hurricane Lorenzo.

Even though Hurricane Lorenzo weakened on Sunday it remained a large and powerful hurricane.  Winds to hurricane force extended out about 90 miles (145 km) from the center of circulation.  Winds to tropical storm force extended out about 250 miles (400 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Lorenzo was 19.2.  The Hurricane Size Index (HSI) 32.6 was and the Hurricane Wind Intensity Size Index (HWISI) was 51.8.  Hurricane Lorenzo was capable of causing widespread serious damage.

Hurricane Lorenzo is likely to continue to weaken slowly during the next several days because of the less favorable environment consisting of cooler water and more vertical wind shear.  Since the circulation around Lorenzo is so large, the hurricane will weaken slowly.

The upper level trough will steer Hurricane Lorenzo toward the northeast during the next two or three days.  On its anticipated track Hurricane Lorenzo could reach the Azores by Tuesday night.  Lorenzo could be a large hurricane capable of causing widespread serious damage when it reaches the Azores.

Typhoon Mitag Nears Northeast Taiwan

Typhoon Mitag moved nearer to northeastern Taiwan on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Typhoon Mitag was located near latitude 22.3°N and longitude 122.7°E which put it about 180 miles (290 km) south-southeast of Taipei, Taiwan.  Mitag was moving toward the northwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 976 mb.

Former Tropical Storm Mitag strengthened into a typhoon on Sunday.  A circular eye appeared at the center of Typhoon Mitag on satellite images.  The eye was surrounded by a ring of thunderstorms.  There were some breaks in the ring of storms, but the strongest winds were occurring in the ring.  Bands of showers and thunderstorms were revolving around the core of Typhoon Mitag.  Storms near the core were generating upper level divergence which was pumping mass away in all directions.  Winds to typhoon force extended out 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 185 miles (295 km) from the center.

Typhoon Mitag will move through an environment favorable for intensification during the next 12 to 24 hours.  Mitag 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 not too strong and there will not be a lot of vertical wind shear.  Typhoon Mitag could strengthen on Monday if the center of circulation does not pass over northeastern Taiwan.  If the center of Mitag does move over Taiwan, then the typhoon will weaken,

Typhoon Mitag will move around the western end of a ridge of high pressure over the Western North Pacific Ocean.  The ridge will steer Mitag toward the north-northwest.  On its anticipated track the center of Typhoon Mitag will be near northeastern Taiwan within 12 hours.  Mitag could drop heavy rain over parts of Taiwan and flash floods are possible.  Rainbands in the eastern side of the typhoon will bring gusty winds and heavy rain to the southern Ryukyu Islands.  Typhoon Mitag could approach the east coast of China near Taizhou in about 36 hours.

Tropical Storm Narda Brings Rain to Mexico

Tropical Storm Narda brought rain to parts of the west coast of Mexico on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression Narda was located at latitude 19.1°N and longitude 103.3°W which put it about 55 miles (90 km) east of Manzanillo, Mexico.  Narda was moving toward the northwest at 20 m.p.h. (32 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 former Tropical Storm Narda made landfall on the west coast of Mexico between Lazaro Cardenas and Manzanillo on Sunday.  Narda weakened to a tropical depression after the center moved over land.  Bands of showers and thunderstorms were dropping locally heavy rain along and just inland of the portion of the coast from Acapulco to Manzanillo, Mexico.  The rain could be heavy enough in some locations to cause flash floods.

Tropical Depression Narda is moving around the western side of a high pressure system over Mexico.  The high is steering Narda quickly toward the northwest.  Tropical Depression Narda will move along the west coast of Mexico during the next day or two.  The center of Narda could move back over the Eastern North Pacific Ocean near Cabo Corrientes.  Tropical Depression Narda will continue to drop heavy rain near the coast while it moves toward the northwest.

Hurricane Lorenzo Strengthens to Cat. 5 Southwest of the Azores

Hurricane Lorenzo strengthened to Category 5 on the Saffir-Simpson Scale on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Hurricane Lorenzo was located at latitude 24.2°N and longitude 44.9°W which put it about 1420 miles (2285 km) southwest of the Azores.  Lorenzo was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 925 mb.

Hurricane Lorenzo strengthened to Category 5 farther east in the Atlantic Ocean than other hurricane on record.  Lorenzo appeared to complete an eyewall replacement cycle earlier on Saturday and then it start to strengthen quickly.  A circular eye with a diameter of 35 miles (55 km) became evident at the center of circulation.  A ring of very 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 Lorenzo.

The circulation around Hurricane Lorenzo was large.  Wins to hurricane force extended out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 275 miles (445 km) from the center.  The Hurricane Intensity Index (HII) was 35.0.  The Hurricane Size Index (HSI) was 21.2 and the Hurricane Wind intensity Size Index (HWISI) was 56.2.

Hurricane Lorenzo will remain in a very favorable environment for another 12 to 24 hours.  It will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough will approach Lorenzo from the west later on Sunday.  The trough will produce southwesterly winds which will create more wind shear.  Hurricane Lorenzo will start to weaken when the wind shear increases.  Lorenzo will also move over cooler water on Monday, which will cause more weakening.

The upper level trough will steer Hurricane Lorenzo toward the northeast during the next few days.  On its anticipated track Hurricane Lorenzo could approach the Azores on Tuesday night.  Lorenzo is likely to be a hurricane when it reaches the Azores.  Hurricane Lorenzo will eventually make a transition to a strong extratropical cyclone.  It could be near Ireland in four or five days.

Tropical Storm Narda Forms South of Mexico

Tropical Storm Narda formed south of Mexico late on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Narda was located at latitude 15.4°N and longitude 100.6°W which put it about 115 miles south-southwest of Acapulco, Mexico.  Narda was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 40 m.p.h. (15 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1000 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Acapulco to Cabo Corrientes, Mexico.

An area of low pressure exhibited more organization late on Saturday and the National Hurricane Center designated the system as Tropical Storm Narda.  A low level center of circulation formed within the area of low pressure.  Bands of showers and thunderstorms developed and began to revolve around the center of circulation.  Many of the stronger thunderstorms were in bands in the western half of the circulation.  Bands in the eastern half of the circulation contained more showers and lower clouds.  An area of winds to tropical storm force was occurring about 120 miles (195 km) southeast of the center of circulation.

Tropical Storm Narda will move through an environment only marginally favorable for intensification on Sunday.  Narda will move over water where the Sea Surface Temperature is near 29°C.  However, an upper level ridge over Mexico will produce northeasterly winds which will blow toward the top of the circulation.  Those winds will cause moderate vertical wind shear which will inhibit intensification.  In addition, the circulation could draw drier air into the northern portion of the tropical storm.  Tropical Storm Narda is not likely to strengthen much during the next 12 to 24 hours.

The ridge over Mexico will steer Tropical Storm Narda toward the northwest during the next several days.  On its anticipated track Tropical Storm Narda will approach the coast of Mexico near Lazaro Cardenas in about 12 hours.  Narda will move along the coast toward Cabo Corrientes.  Tropical Storm Narda could drop locally heavy rain in parts of Guerrero, Michoacan, Colima and Jalisco.  The rain could cause flash floods in some locations.

Tropical Storm Mitag Forms Southeast of Ryukyu Islands

Tropical Storm Mitag formed southeast of the Ryukyu Islands on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Mitag was located at latitude 16.4°N and longitude 131.5°E which put it about 730 miles (1180 km) southeast of Ishigaki, Japan.  Mitag was movign toward the west-northwest at 27 m.p.h. (44 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 994 mb.

More thunderstorms developed near the center of a low pressure system southeast of the Ryukyu Islands on Friday and the Japan Meteorological Agency designated the system as Tropical Storm Mitag.  The distribution of thunderstorms around Tropical Storm Mitag was asymmetrical.  A few thunderstorms developed near the center of circulation, but most of the thunderstorms were forming in bands in the southern half of the circulation.  Bands in the northern half of Mitag consisted primarily of showers and lower clouds.  Tropical Storm Mitag was moving around the southwestern portion of an upper level ridge over the Western North Pacific Ocean.  The ridge was producing northeasterly winds which were blowing toward the top of Mitag.  Those winds were causing moderate vertical wind shear and they were contributing to the asymmetrical distribution of thunderstorms.

Tropical Storm Mitag will move through an environment somewhat favorable for intensification during the next two days.  Mitag will move over water where the Sea Surface Temperature is near 29°C.  Mitag will move around the western end of the upper level ridge where the winds are weaker.  The wind shear is likely to decrease and Tropical Storm Mitag is forecast to strengthen into a typhoon during the weekend.

The ridge over the Western North Pacific Ocean will steer Tropical Storm Mitag toward the northwest during the next 24 to 36 hours.  Mitag will move more toward the north when it moves around the west end of the ridge in about 48 hours.  On its anticipated track Tropcial Storm Mitag could reach the southern Ryukyu Islands in about 48 hours.  Mitag could be a typhoon at that time.

Powerful Hurricane Lorenzo Churns Southwest of the Azores

Powerful Hurricane Lorenzo churned southwest of the Azores on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Lorenzo was located at latitude 20.3°N and longitude 43.6°W which put it about 1575 miles (2535 km) southwest of the Azores.  Lorenzo was moving toward the north-northeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 948 mb.

Hurricane Lorenzo weakened slowly on Friday, but it remained a large and powerful hurricane.  Winds to hurricane force extended out 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out about 250 miles (400 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Lorenzo was 23.6.  The Hurricane Size Index (HSI) was 20.7 and the Hurricane Wind Intensity Size Index (HWISI) was 44.3.  Hurricane Lorenzo was capable of causing major damage.

Hurricane Lorenzo weakened on Friday because it moved into a less favorable environment.  Lorenzo continued to move over water where the Sea Surface Temperature was near 27°C.  However, an upper level trough west of Lorenzo was producing southwesterly winds which were causing moderate vertical wind shear.  in addition, Hurricane Lorenzo appeared to be drawing drier air into the western half of the circulation.  The effects of increased vertical wind shear and drier air caused Lorenzo to weaken.

Hurricane Lorenzo will continue to move through a less favorable environment and weaken.  Since Lorenzo is a large hurricane, it will weaken more slowly than a smaller hurricane would.  As a result, Lorenzo will likely remain a hurricane for several more days.

The upper level trough will steer Hurricane Lorenzo toward the northeast during the next few days.  On its anticipated track Hurricane Lorenzo will likely approach the Azores on Tuesday.  Lorenzo is likely to still be a hurricane at that time.

Elsewhere over the Atlantic Ocean, Tropical Depression Karen weakened to a trough southeast of Bermuda on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of former Tropical Depression Karen was located at latitude 29.3°N and longitude 58.5°W which put it about 425 miles (685 km) south-southeast of Bermuda.  Karen was moving toward the northeast at 6 m.p.h. (10 km/h).  The maximum sustained wind sped 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.

Lorenzo Rapidly Strengthens Into a Major Hurricane

Hurricane Lorenzo rapidly strengthened into a major hurricane west of the Cabo Verde Islands on Thursday.  At 6:00 a.m. EDT on Thursday the center of Hurricane Lorenzo was located at latitude 15.2°N and longitude 39.3°W which put it about 995 miles (1600 km) west of the Cabo Verde Islands.  Lorenzo was moving toward the west-northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 955 mb.

Lorenzo was a large well organized a 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 Lorenzo.  Storms around the core were generating strong upper level divergence which was pumping mass away from the hurricane.  Winds to hurricane force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 210 miles (335 km) from the center.

Hurricane Lorenzo will move through an environment favorable for intensification during the next day or so.  Lorenzo will move over water where the Sea Surface Temperature is near 27°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Lorenzo is likely to strengthen to Category 4 on the Saffir-Simpson Scale during the next 24 hours.  Lorenzo will move over cooler water during the weekend, which will cause the hurricane to weaken.

Hurricane Lorenzo will move around the western end of a ridge of high pressure over North Africa and the eastern Atlantic Ocean.  The ridge will steer Lorenzo toward the north during the weekend.  On its anticipated track Hurricane Lorenzo could approach the Azores next week.

Elsewhere over the Atlantic Ocean Tropical Storm Karen moved farther away from Puerto Rico.  At 5:00 a.m. EDT in Thursday the center of Tropical Storm Karen was located at latitude 25.5°N and longitude 63.5°W which put it about 520 miles (835 km) north-northeast of San Juan Puerto Rico.  Karen was moving toward the north-northeast at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1004 mb.

Tropical Cyclone Hikaa Makes Landfall on Central Coast of Oman

Tropical Cyclone Hikaa made landfall on the central coast of Oman near Duqm on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Cyclone Hikaa was located at latitude 19.6°N and longitude 56.4°W which put it about 85 miles (135 km) west of Duqm, Oman.  Hikaa was moving toward the west 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 981 mb.

Tropical Cyclone Hikaa was the equivalent of a hurricane/typhoon when it made landfall on the central coast of Oman.  Hikaa brought wind and rain to Masirah Island before it reached the coast of Oman.  Tropical Cyclone Hikaa brought strong winds and locally heavy rain to the coast near Duqm when it made landfall.  The circulation around Tropical Cyclone Hikaa was small.  Winds to tropical storm force only extended out 60 miles (95 km) from the center of circulation.  The small size of Hikaa will limit the potential for serious damage to locations close to the track of the tropical cyclone.

Tropical Cyclone Hikaa will drop heavy rain over portions of east-central Oman.  The rain could be heavy enough to cause flash floods in some locations.  Hikaa will weaken quickly as it moves into the drier environment over central Oman.  The small circulation around Tropical Cyclone Hikaa means that it will spin down fairly quickly now that it is over land.