Tropical Storm Mekkhala Nears Southern Ryukyu Islands

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Tropical Storm Mekkhala was nearing the southern Ryukyu Islands on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Mekkhala was located at latitude 24.1°N and longitude 125.6°E which put the center about 45 miles (75 km) south of Miyakojima, Japan.  Mekkhala was moving toward the north-northeast at 13 m.p.h. (21 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 986 mb.

Former Typhoon Mekkhala weakened to a tropical storm as it approached the southern Ryukyu Islands on Wednesday.  An upper level ridge over China continued to produce northeasterly winds that blew toward the top of Mekkhala’s circulation.  Those winds caused strong vertical wind shear.  The strong vertical wind shear caused former Typhoon Mekkhala to weaken to a tropical storm.

The northeasterly winds in the upper levels also continued to blow the tops off of many of the thunderstorms that tried to form in the northern half of Tropical Storm Mekkhala.  A few more thunderstorms did develop near the center of Mekkhala’s circulation.  Thunderstorms were also occurring in bands in the southern half of Tropical Storm Mekkhala.  Bands in the northern half of Mekkhala still consisted primarily of showers and lower clouds.  Storms near the center of Mekkhala generated upper level divergence that pumped mass away to the south and west of the typhoon.  However, the removal of mass in the upper levels was less than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure continued to increase on Wednesday.

The size of the circulation around Tropical Storm Mekkhala increased a little on Wednesday.  Winds to tropical storm force extended out 165 miles (265 km) from the center of Mekkhala’s circulation.

Tropical Storm Mekkhala will move through an environment that will be unfavorable for intensification during the next 24 hours.  Mekkhala will move over water where the Sea Surface Temperatures are near 27°C.  However, the upper level ridge over China will continue to cause vertical wind shear.  The vertical wind shear may be a little less on Thursday.  Tropical Storm Mekkhala could maintain its intensity during the next 24 hours if the vertical wind shear is a little less.

Tropical Storm Mekkhala will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Mekkhala toward the northeast during the next 24 hours.  On its anticipated track, Tropical Storm Mekkhala will pass over Miyakojima during the next few hours.  Mekkhala could be near Okinawa in 12 hours.

Tropical Storm Mekkhala will bring strong winds and locally heavy rain to the southern Ryukyu Islands including Ishigakijima and Miyakojima.  Heavy rain could cause flash floods in some locations.  Mekkhala will also bring gusty winds and locally heavy rain to Okinawa.

Elsewhere over the Western North Pacific Ocean, former Tropical Depression Higos strengthened back to a tropical storm on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Higos was located at latitude 18.3°N and longitude 137.1°E which put the center about 540 miles (870 km) south-southwest of Iwo To.  Higos was moving toward the northwest at 14 m.p.h. (22 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 1002 mb.

Typhoon Mekkhala Weakens

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Typhoon Mekkhala weakened on Tuesday as it moved toward the southern Ryukyu Islands.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Mekkhala was located at latitude 21.3°N and longitude 124.7°E which put the center about 235 miles (380 km) south of Miyakojima, Japan.  Mekkhala was moving toward the north at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 974 mb.

Typhoon Mekkhala weakened on Tuesday.  An upper level ridge over China produced northeasterly winds that blew toward the top of Mekkhala’s circulation.  Those winds caused strong vertical wind shear.  The strong vertical wind shear caused Typhoon Mekkhala to weaken.

The northeasterly winds in the upper levels also blew the tops off of many of the thunderstorms in the northern half of Typhoon Mekkhala.  Thunderstorms were still occurring in bands in the southern half of Mekkhala’s circulation.  Bands in the northern half of Typhoon Mekkhala consisted primarily of showers and lower clouds.  Storms near the center of Mekkhala generated upper level divergence that pumped mass away to the south and west of the typhoon.  However, the removal of mass in the upper levels was less than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure increased on Tuesday.

Even though Typhoon Mekkhala weakened on Tuesday, the size of Mekkhala’s circulation did not change much.  Winds to typhoon force extended out 65 miles (105 km) from the center of Typhoon Mekkhala.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Mekkhala’s circulation.

Typhoon Mekkhala will move through an environment that will be unfavorable for intensification during the next 24 hours.  Mekkhala will move over water where the Sea Surface Temperatures are near 28°C.  However, the upper level ridge over China will continue to cause strong vertical wind shear.  Typhoon Mekkhala will continue to weaken during the next 24 hours because of the strong vertical wind shear.

Typhoon Mekkhala will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Mekkhala toward the north during the next 24 hours.  On its anticipated track, Typhoon Mekkhala will reach the southern Ryukyu Islands in less than 24 hours.

Typhoon Mekkhala will bring strong winds and locally heavy rain to the southern Ryukyu Islands including Ishigakijima and Miyakojima.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, former Tropical Storm Higos weakened to a tropical depression as it moved west of the Marianas.  At 11:00 p.m. EDT on Tuesday the center of Tropical Depression Higos was located at latitude 15.4°N and longitude 141.3°E which put the center about 225 miles (360 km) west-northwest of Guam.  Higos was moving toward the west-northwest at 11 m.p.h. (17 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 Higos Forms Near the Marianas

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Tropical Storm Higos formed over the Western North Pacific Ocean near the Marianas on Monday evening.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Higos was located at latitude 14.8°N and longitude 145.1°E which put the center about 20 miles (30 km) south of Tinian.  Higos was moving toward the west-northwest at 11 m.p.h. (17 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 1005 mb.

Tropical Storm Warnings are in effect for Tinian and Saipan.

A low pressure system near the Marianas strengthened on Monday evening and the Japan Meteorological Agency designated the system as Tropical Storm Higos.

A weather station at the Saipan International Airport (PGSN) reported a sustained wind speed of 38 m.p.h. (61 km/h) and a wind gust of 60 m.p.h. (96 km/h).

The distribution of thunderstorms in Tropical Storm Higos was asymmetrical.  Thunderstorms were occurring in bands in the northern and western parts of Higos’ circulation.  Bands in the southern and eastern parts of Tropical Storm Higos consisted primarily of showers and lower clouds.  Storms near the center of HIgos began to generate upper level divergence that pumped mass away to the west of the tropical storm.

The distribution of wind speeds in Tropical Storm Higos was also asymmetrical.  Winds to tropical storm force extended out 80 miles (130 km) in the northern half of Higos’ circulation.  The winds in the southern half of Tropical Storm Higos were blowing at less than tropical storm force.

Tropical Storm Higos will move through an environment that will be somewhat favorable for intensification.  Higos will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the southern part of an upper level ridge that is south of Japan. The upper level ridge will produce easterly winds that will blow toward the top of Higos’ circulation.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Tropical Storm Higos could intensify during the next 24 hours.

Tropical Storm Higos will move around the western end of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer HIgos toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Higos will move gradually away from the Marianas.

Tropical Storm Higos will bring gusty winds and locally heavy rain to Tinian and Saipan.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Typhoon Mekkhala started to move toward the southern Ryukyu Islands.  At 11:00 p.m. EDT on Monday the center of Typhoon Mekkhala was located at latitude 19.2°N and longitude 125.1°E which put the center about 370 miles (595 km) south of Miyakojima, Japan.  Mekkhala was moving toward the west-northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 943 mb.

Typhoon Mekkhala Strengthens to Equivalent of Cat. 4 Hurricane

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Typhoon Mekkhala strengthened to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Monday as it moved over the Western North Pacific Ocean east of northern Luzon.  At 11:00 a.m. EDT on Monday the center of Typhoon Mekkhala was located at latitude 18.3°N and longitude 125.9°E which put the center about 305 miles (490 km) east of Aparri, Philippines.  Mekkhala was moving toward the west-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 937 mb.

Typhoon Mekkhala strengthened to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Monday.  A circular eye with a diameter of 25 miles (40 km) was present at the center of Typhoon Mekkhala.  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 center of Mekkhala’s circulation.  Storms near the center of Mekkhala generated strong upper level divergence that pumped mass away from the typhoon.  The removal of large amounts of mass caused the surface pressure to decrease.

The distribution of winds speeds in Typhoon Mekkhala was fairly symmetrical.  Winds to typhoon force extended out 25 miles (40 km) from the center of Mekkhala’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Typhoon Mekkhala.

The Hurricane Intensity Index (HII) for Typhoon Mekkhala is 29.9. The Hurricane Size Index (HSI) is 10.0 and the Hurricane Wind Intensity Size Index (HWISI) is 39.9.  Typhoon Mekkhala is similar in intensity to Hurricane Charley when Charley hit Southwest Florida in 2004.  Mekkhala is a little larger than Charley was.

Typhoon Mekkhala will move through an environment favorable for intensification during the next 24 hours.  Mekkhala will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the middle of an upper level ridge that is southwest of Japan. The upper level winds are weak in the middle of the ridge and there will be little vertical wind shear.  Typhoon Mekhala could intensify during the next 24 hours unless the inner end of a rainband wraps around the existing eye and eyewall.  If concentric eyewalls form, then an eyewall replacement cycle would cause Mekkhala to weaken.  Typhoon Mekkhala could strengthen to the equivalent of a Category 5 hurricane, if there is no eyewall replacement cycle.

Typhoon Mekkhala will move around the southwestern part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Mekkhala toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Mekkhala will move toward the southern Ryukyu Islands.  Mekkhala could approach the southern Ryukyu Islands in 60 hours.

Typhoon Mekkhala Rapidly Intensifies to Equivalent of Major Hurricane

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Typhoon Mekkhala rapidly intensified to the equivalent of a major hurricane on Sunday.  At 11:00 p.m. EDT on Sunday the center of Typhoon Mekkhala was located at latitude 17.7°N and longitude 127.4°E which put the center about 415 miles (670 km) east-southeast of Aparri, Philippines.  Mekkhala was moving toward the west at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 961 mb.

Typhoon Mekkhala rapidly intensified to the equivalent of a major hurricane.  The inner end of a rainband wrapped around the center of Mekkhala’s circulation.  A circular eye with a diameter of 25 miles (40 km) formed at the center of Typhoon Mekkhala.  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 center of Mekkhala’s circulation.  Storms near the center of Mekkhala generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The distribution of winds speeds in Typhoon Mekkhala became more symmetrical on Sunday.  Winds to typhoon force extended out 25 miles (40 km) from the center of Mekkhala’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Typhoon Mekkhala.

The Hurricane Intensity Index (HII) for Typhoon Mekkhala is 20.6.  The Hurricane Size Index (HSI) is 10.0 and the Hurricane Wind Intensity Size Index (HWISI) is 30.6.  Typhoon Mekkhala is similar in intensity to Hurricane Delta when Delta hit Southwest Louisiana in 2020.  Mekkhala is a little smaller than Delta was.

Typhoon Mekkhala will move through an environment favorable for intensification during the next 24 hours.  Mekkhala will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge that is southwest of Japan.  The upper level winds are weak in the middle of the ridge and there will be little vertical wind shear.  Typhoon Mekhala will intensify during the next 24 hours.  Mekkhala could continue to intensify rapidly during the next few hours.

Typhoon Mekkhala will move around the southwestern part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Mekkhala toward the west-northwest during the next 24 hours.  On its anticipated track, Typhoon Mekkhala will move closer to northern Luzon. Mekkhala is likely to move more slowly in a couple of days when it reaches the western end of the high pressure system.  Typhoon Mekkhala is also likely to move toward the north when it reaches the western end of the high pressure system

Mekkhala Strengthens to a Typhoon

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Former Tropical Storm Mekkhala strengthened to a typhoon over the Western North Pacific Ocean east of Luzon on Saturday night.  At 5:00 a.m. EDT on Sunday the center of Typhoon Mekkhala was located at latitude 16.4°N and longitude 131.3°E which put the center about 710 miles (1145 km) east-southeast of Aparri, Philippines.  Mekkhala 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 988 mb.

Former Tropical Storm Mekkhala strengthened to a typhoon on Saturday night.  The inner end of a rainband wrapped around the southern side of Mekkhala’s circulation.  Other bands of showers and thunderstorms were revolving around the center of Typhoon Mekkhala.  Storms near the center of Mekkhala generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The strongest winds were occurring in the northern side of Typhoon Mekkhala.  Winds to typhoon force extended out 25 miles (40 km) in the northern half of Mekkhala’s circulation.  Winds to tropical storm force extended out 105 miles (165 km) in the northern side of Typhoon Mekkhala.  Winds to tropical storm force only extended out 40 miles (65 km) in the southern half of Mekkhala’s circulation.

Typhoon Mekkhala will move through an environment favorable for intensification during the next 24 hours.  Mekkhala will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the southern part of an upper level ridge that is southwest of Japan. The upper level ridge will produce easterly winds that will blow toward the top of Mekkhala’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Typhoon Mekhala will intensify during the next 24 hours.  Mekkhala could strengthen to the equivalent of a major hurricane during the next few days.

Typhoon Mekkhala will move around the southwestern part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Mekkhala toward the west-northwest during the next 24 hours.  On its anticipated track, Typhoon Mekkhala will move toward northern Luzon.  Mekkhala is likely to move more slowly in a couple of days when it reaches the western end of the high pressure system.

Tropical Storm Mekkhala Develops North of Yap

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Tropical Storm Mekkhala developed over the Western North Pacific Ocean north of Yap on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Mekkhala was located at latitude 14.2°N and longitude 138.0°E which put the center about 315 miles (510 km) north of Yap. Mekkhala was moving toward the west-northwest at 16 m.p.h. (26 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 1000 mb.

Former Tropical Depression 07W strengthened north of Yap on Friday and the Japan Meteorological Agency designated it as Tropical Storm Mekkhala.

More thunderstorms developed near the center of Tropical Storm Mekkhala on Friday.  More thunderstorms also formed in the bands revolving around the center of Mekkhala’s circulation.  Storms near the center of Mekkhala generated more upper level divergence that pumped mass away from the tropical storm.  The removal of more mass caused the surface pressure to decrease.

Despite the fact that Tropical Storm Mekkhala strengthened on Friday, the distribution of wind speeds was very asymmetrical.  Winds to tropical storm force extended out 115 miles (185 km) in the northern side of Mekkhala’s circulation.  Winds to tropical storm force extended out only 25 miles (40 km) in the southern side of Tropical Storm Mekkhala.

Tropical Storm Mekkhala will move through an environment favorable for intensification during the next 24 hours.  Mekkhala will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the southern part of an upper level ridge that is southwest of Japan.  The upper level ridge will produce northeasterly winds that will blow toward the top of Mekkhala’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Tropical Storm Mekhala will intensify during the next 24 hours.  Mekkhala is likely to strengthen to a typhoon during the weekend.

Tropical Storm Mekkhala will move around the southwestern part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Mekkhala toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Mekkhala will move away from Yap.

Tropical Depression Forms West of Guam

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Tropical Depression 07W formed over the Western North Pacific Ocean west-southwest of Guam on Thursday night.  At 11:00 p.m. EDT on Thursday the center of Tropical Depression 07W was located at latitude 13.1°N and longitude 142.5°E which put the center about 150 miles (240 km) west-southwest of Guam.  Tropical Depression 07W was moving toward the west-northwest at 17 m.p.h. (28 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 1005 mb.

A low pressure system over the Western North Pacific Ocean west-southwest of Guam strengthened on Thursday night and both the Japan Meteorological Agency and the U.S. Joint Typhoon Warning Center classified the system as a tropical depression.

The distribution of thunderstorms in Tropical Depression 07W was asymmetrical.  Thunderstorms were occurring in bands in the southern half of the tropical depression.  Bands in the northern half of Tropical Depression 07W consisted primarily of showers and lower clouds.  Storms near the center of circulation began to generate upper level divergence that pumped mass away to the west of the tropical depression.  The removal of mass caused the surface pressure to decrease.

Tropical Depression 07W will move through an environment mostly favorable for intensification during the next 24 hours.  The tropical depression will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the southern part of an upper level ridge that is southwest of Japan.  The upper level ridge will produce northeasterly winds that will blow toward the top of the tropical depression.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Tropical Depression 07W is likely to intensify to a tropical storm during the next 24 hours.  It could strengthen to a typhoon during the weekend.

Tropical Depression 07W will move around the southwestern part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer the tropical depression toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Depression 07W will move away from the Marianas.

Tropical Storm Arthur Weakens

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Former Tropical Storm Arthur weakened on Wednesday evening as it moved along the coast near Galveston, Texas.  At 11:00 p.m. EDT on Wednesday the center of Tropical Depression Arthur was located at latitude 29.7°N and longitude 94.5°W which put the center about 35 miles (55 km) north-northeast of Galveston, Texas.  Arthur was moving toward the northeast 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 gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1000 mb.

An upper level trough over the central U.S. was producing westerly winds that were blowing across the top of Tropical Depression Arthur on Wednesday evening.  The upper level winds blew the tops off of many of the thunderstorms in Arthur.  A few thunderstorms were still occurring in bands in the eastern periphery of Arthur’s circulation.  The other bands revolving around the center of Arthur consisted primarily of showers and lower clouds.

Tropical Depression Arthur will move around the northwestern side of a high pressure system that extends from the western Atlantic Ocean to over the Gulf of Mexico.  The high pressure system will steer Arthur toward the northeast during the next 24 hours.  On its anticipated track, Tropical Depression Arthur will move near the border between Texas and Louisiana on Thursday.  Arthur will start to move toward the east by Friday.

Tropical Depression Arthur could interact with a stationary front to drop heavy rain over parts of the Southeast U.S.  Heavy rain could cause floods in some locations.

Flood Watches are in effect for southeast Texas, most of Louisiana, the southern half of Mississippi, central Alabama, Northwest Florida, and northern Georgia.

Tropical Storm Arthur Develops Near Texas Coast

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Tropical Storm Arthur developed near the coast of Texas on Wednesday morning.  At 12:30 p.m. EDT on Wednesday the center of Tropical Storm Arthur was located at latitude 28.8°N and longitude 95.5°W which put the center about 40 miles (65 km) southwest of Galveston, Texas. Arthur was moving toward the northeast at 9 m.p.h. (15 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 999 mb.

A Tropical Storm Warning is in effect for the portion of the coast from Sargent, Texas to Morgan City Louisiana.

A low pressure system near the coast of Texas, formerly called Potential Tropical Cyclone One, strengthened on Wednesday morning and the U.S. National Hurricane Center designated the system as Tropical Storm Arthur.

The strongest winds were occurring in bands in the eastern and northern sides of Tropical Storm Arthur.

A weather station in Galveston, Texas, (KGLS) reported a sustained wind speed of 39 m.p.h. (63 km/h) and a wind gust of 59 m.p.h. (95 km/h).

NOAA buoy 42035 which is east of Galveston, Texas reported a sustained wind speed of 45 m.p.h. (75 km/h) and a wind gust of 52 m.p.h. (83 km/h).

A weather station on oil platform Galveston 209A (KGVW) reported a sustained wind speed of 70 m.p.h. (113 km/h) and a wind gust of 80 m.p.h. (130 km/h).  It should be noted that the weather station is 121 feet (37 meters) above sea level.

The distribution of thunderstorms in Tropical Storm Arthur was asymmetrical.  Thunderstorms were occurring in bands in the eastern and northern parts of Arthur’s circulation.  Bands in the western and southern parts of Tropical Storm Arthur consisted primarily of showers and lower clouds.

The surface center of Tropical Storm Arthur appeared to be east of a low in the middle troposphere based on visible satellite loops.  The middle level low was producing southwesterly winds that were blowing toward the top of Arthur’s circulation.  Those winds were causing strong vertical wind shear.  The vertical wind shear was causing the asymmetrical distribution of thunderstorms.

The strongest winds were occurring in the bands of thunderstorms in the eastern and northern parts of Tropical Storm Arthur.  Winds to tropical storm force extended out 175 miles (280 km) in the eastern half of Arthur’s circulation.  Winds in the western half of Tropical Storm Arthur were blowing at less than tropical storm force.

Tropical Storm Arthur will move around the northwestern side of a high pressure system that extends from the western Atlantic Ocean to over the Gulf of Mexico.  The high pressure system will steer Arthur toward the northeast during the next 24 hours.  On its anticipated track, Arthur will move inland near the border between Texas and Louisiana in a few hours.

Tropical Storm Arthur will move through an environment that will be marginally favorable for intensification during the next few hours.  Arthur will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southern part of an upper level trough that is over the central U.S.  The upper level trough will produce westerly winds that will blow toward the top of Arthur’s circulation.  Those winds will cause strong vertical wind shear.  The vertical wind shear will inhibit development, but the wind shear may not be enough to prevent some intensification.  Tropical Storm Arthur could intensify during the next few hours before it makes landfall in Louisiana.

Tropical Storm Arthur will bring gusty winds and heavy rain to parts of the southeastern U.S.  Heavy rain is likely to cause floods in some locations.

Flood Watches are in effect for southeast Texas, most of Louisiana, the southern half of Mississippi, central Alabama, Northwest Florida, and northern Georgia.

Tropical Storm Arthur could also cause a storm surge of up to 4 feet (1 meter) along the coast of Louisiana.