Category Archives: Atlantic, Caribbean, and Gulf of Mexico

Atlantic TCs

Subtropical Storm Andrea Develops Southwest of Bermuda

Subtropical Storm Andrea developed southwest of Bermuda on Monday afternoon.  An Air Force Reserve Hurricane Hunter aircraft investigated an area of low pressure southwest of Bermuda on Monday afternoon.  The aircraft determined that there was a well defined center of circulation at the surface and the National Hurricane Center designated the system as Subtropical Storm Andrea.  At 11:00 p.m. EDT on Monday the center of Subtropical Storm Andrea was located at latitude 29.5°N and longitude 68.7°W which put it about 300 miles (485 km) southwest of Bermuda.  Andrea was moving toward the north 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 1006 mb.

The circulation around Subtropical Storm Andrea was asymmetrical.  Most of the thunderstorms and the strongest winds were occurring northeast of the center of circulation.  Bands in other parts of the circulation consisted primarily of lower clouds and showers and the winds were weaker in those parts of Andrea.  An upper low northeast of the Bahamas was producing southerly winds which were blowing toward the top of the circulation.  Those winds were creating moderate vertical wind shear and the shear was the primary cause of the asymmetrical structure of Subtropical Storm Andrea.  The asymmetrical structure was the reason why Andrea was classified as a subtropical storm.  Winds to tropical storm force extended out about 65 miles (105 km) from the center of Andrea in the northeastern quadrant of the circulation.

Subtropical Storm Andrea will move through an environment marginally favorable for intensification on Tuesday.  Andrea will move over water where the Sea Surface Temperature is near 25°C.  The upper low will continue to cause moderate vertical wind shear, but the low could weaken slightly on Tuesday.  If the upper level winds weaken, then Andrea could get stronger.  Stronger upper level westerly winds could affect Subtropical Storm Andrea on Wednesday.  Those winds will cause stronger vertical wind shear which will weaken Andrea.

The upper level low northeast of the Bahamas will steer Subtropical Storm Andrea toward the north during the next 12-18 hours.  After that time the upper level westerly winds are likely to steer Andrea more toward the east.  On its anticipated track Subtropical Storm Andrea could be near Bermuda in about 36 hours.  Andrea could bring gusty winds and rain showers to Bermuda on Wednesday.

NHC Upgrades Hurricane Michael to Cat. 5

The National Hurricane Center (NHC) upgraded Hurricane Michael to Category 5 on the Saffir-Simpson Scale after it completed and released its post storm analysis on Friday.  NHC does a post storm analysis of every tropical cyclone in its area of responsibility after the end of the hurricane season.  The maximum sustained wind speed at the time of landfall in northwest Florida of Hurricane Michael, which was given originally as 155 m.p.h. (250 km/h), was increased to 160 m.p.h. (260 km/h) after the post storm analysis.  Hurricane Michael becomes one of only four hurricanes to make landfall in the U.S. as a Category 5 hurricane.  The other Category 5 hurricanes to hit the U.S. were the Labor Day Hurricane which hit the Florida Keys in 1935, Hurricane Camille which hit Mississippi in 1969 and Hurricane Andrew which hit south Florida in 1992.

The National Hurricane Center prepares a Tropical Storm Report on every tropical cyclone in its area of responsibility and those reports are available on NHC’s web site.  J. L. Beven II, R. Berg and A. Hagen were the authors of the Tropical Cyclone Report on Hurricane Michael.  They explain in the Tropical Cyclone Report how they arrived at the intensity of Hurricane Michael at landfall.  They analyzed aircraft data including flight level winds and SMFR intensities.  They did an analysis of the Dopper wind velocities observed by the WSR-88D radar at Eglin Air Force Base.  They also considered available data on the surface winds and pressures and satellite derived estimates of the intensity of Hurricane Michael.  Based on analysis of all of that information, they concluded that the intensity of Hurricane Michael when it made landfall in northwest Florida was 160 m.p.h. (260 km/h).  Their full Tropical Cyclone Report on Hurricane Michael is available on NHC’s website at https://www.nhc.noaa.gov/data/tcr/AL142018_Michael.pdf.

Oscar Strengthens Into a Hurricane Southeast of Bermuda

One time subtropical storm and former Tropical Storm Oscar strengthened into a hurricane southeast of Bermuda on Sunday.  At 5:00 p.m. EDT on Sunday the center of Hurricane Oscar was located at latitude 25.7°N and longitude 55.5°W which put it about 725 miles (1165 km) southeast of Bermuda.  Oscar was moving toward the west at 16 m.p.h. (26 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 989 mb.

A small eye formed at the center of former Tropical Storm Oscar and the National Hurricane Center upgraded Oscar to a hurricane.  A thin ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several short bands of showers and thunderstorms were revolving around the core of Hurricane Oscar.  Storms near the core were generating upper level divergence which was pumping mass away from the hurricane.

The circulation around Hurricane Oscar is relatively small.  Winds to hurricane force extend out only about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extend out about 115 miles (185 km) from the center.

Hurricane Oscar will move through an environment favorable for intensification for another day or two.  Oscar will move over water where the Sea Surface Temperature is near 27°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Because of its relatively small circulation, Hurricane Oscar could intensify rapidly while it is in a favorable environment.  Oscar will get stronger during the next 36 to 48 hours and some models are forecasting that it will become a major hurricane.  An upper level trough moving off the East Coast of the U.S. will produce southwesterly winds which will cause the vertical wind shear to increase by Wednesday.

Hurricane Oscar will move around the western end of a ridge of high pressure over the Atlantic Ocean on Monday and Tuesday.  The ridge will steer Oscar toward the west for another 12 to 24 hours.  Hurricane Oscar will move more toward the north when it reaches the western end of the ridge.  On its anticipated track Hurricane Oscar will pass east of Bermuda on Tuesday.  The upper level trough will steer Oscar rapidly toward the northeast on Wednesday.

Oscar Transitions to a Tropical Storm

Former Subtropical Storm Oscar transitioned to a tropical storm on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Oscar was located at latitude 25.7°N and longitude 51.4°W which put it about 930 miles (1495 km) east-southeast of Bermuda.  Oscar was moving toward the west-southwest at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 994 mb.

The structure of the circulation of former Subtropical Storm Oscar changed to a shape more like a tropical cyclone and the National Hurricane Center reclassified Oscar as a tropical storm.  A band of showers and thunderstorms wrapped more tightly around the eastern side of the center of circulation.  The strongest winds were occurring about 30 miles (50 km) from the center.  Other bands of showers and thunderstorms were starting to form in the eastern half of the circulation.

Tropical Storm Oscar will move through an environment somewhat favorable for intensification during the next 36 hours.  Oscar will move over water where the Sea Surface Temperature is near 27°C.  An upper level low southeast of Oscar will produce northerly winds which will blow toward the top of the tropical storm.  However, the core of Tropical Storm Oscar will remain south of the strongest upper level winds on Sunday.  Tropical Storm Oscar could intensify into a hurricane by Monday.

The upper level low is steering Tropical Storm Oscar quickly toward the west-southwest.  That motion is forecast to continue for anther 24 hours.  A large upper level trough over the eastern U.S.  will produce southwesterly winds which will start to turn Oscar toward the northeast in about 36 to 48 hours.  On its anticipated track Tropical Storm Oscar could be southeast of Bermuda on Monday night.

Subtropical Storm Oscar Develops East of Bermuda

Subtropical Storm Oscar developed east of Bermuda on Friday night.  At 11:00 p.m. EDT on Friday the center of Subtropical Storm Oscar was located at latitude 26.7°N and longitude 45.7°W which put it about 1210 miles (1940 km) east-southeast of Bermuda.  Oscar was moving toward the north-northwest 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 gust to 60 m.p.h. (95 km/h).  The minimum surface temperature was 1005 mb.

More thunderstorms developed closer to the center of a low pressure system east-southeast of Bermuda on Friday night and the National Hurricane Center designated the system as Subtropical Storm Oscar.  The strongest winds were occurring in a band of showers and thunderstorms about 80 to 100 miles (130 to 160 km) east of the center of the low pressure system.  Several other bands were forming southeast of the center of circulation.  Bands in other parts of Subtropical Storm Oscar consisted primarily of showers and low clouds.

Subtropical Storm Oscar will move through an area somewhat favorable for intensification.  Oscar will move over water where the Sea Surface Temperature is near 27°C.  An upper level low will move just to the south of Subtropical Storm Oscar.  The upper level low will produce easterly winds which will blow toward the top of the subtropical storm.  Those winds will cause moderate vertical wind shear which will inhibit intensification on Saturday.  In a day or so Oscar will move northwest of the upper level low and the vertical wind shear will decrease.

The upper level low will steer Subtropical Storm Oscar toward the north-northwest on Saturday.  When Oscar moves farther way from the upper level low, it will move south of a ridge of high pressure over the Atlantic Ocean.  The ridge will steer Subtropical Storm Oscar toward the west on Sunday and into early next week.  On its anticipated track Subtropical Storm Oscar could be southeast of Bermuda by Monday night.

Hurricane Leslie Speeds Toward Portugal and Spain

After spending almost three weeks meandering around the Central Atlantic Ocean, Hurricane Leslie sped toward Portugal and Spain on Friday afternoon.  At 2:00 p.m. EDT on Friday the center of Hurricane Leslie was located at latitude 33.3°N and longitude 26.1°W which put it about 515 miles (830 km) west of Madeira, Island.  Leslie was moving toward the east-northeast at 33 m.p.h. (54 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 971 mb.

A Tropical Storm Warning was in effect for Madeira Island.

The circulation around Hurricane Leslie remained well organized.  A small circular eye was at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  The ring of storms was thinner west of the eye.  Several bands of showers and thunderstorms north and east of the eye were revolving around the core of Hurricane Leslie.  Bands south and west of the center of circulation consisted mostly of showers and lower clouds.  Winds to hurricane force extended out about 70 miles (110 km) from the center of Hurricane Leslie.  Winds to tropical storm force extended out about 230 miles (370 km) from the center of circulation.  Much of the stronger winds were occurring in the southern half of the circulation.

Hurricane Leslie will be moving through an environment unfavorable for a hurricane.  Leslie is currently over water where the Sea Surface Temperature is near 25°C, but it will move over cooler water during the next 24 to 36 hours.  An upper level trough south of Iceland is producing strong westerly winds which are blowing toward the top of Hurricane Leslie.  Those winds will cause significant vertical wind shear, but Hurricane Leslie will move south of the strongest winds.  A combination of cooler water and strong vertical wind shear will cause Hurricane Leslie to make a transition to a strong extratropical cyclone during the next day or so.

The upper level trough south of Iceland will steer Hurricane Leslie quickly toward the east-northeast.  On its anticipated track Hurricane Leslie will approach southern Portugal on Sunday morning.  Leslie will likely be a strong extratropical cyclone at that time.  Leslie will bring strong winds and heavy rain to parts of Portugal and Spain during the weekend.  Heavy rain could cause flash floods in some locations.

Hurricane Michael Makes Landfall in Northwest Florida

Powerful Hurricane Michael made landfall in Northwest Florida Wednesday afternoon.  The center of Hurricane Michael officially made landfall between Panama City and Mexico Beach, Florida.  At 2:00 p.m. EDT on Wednesday the center of Hurricane Michael was located at latitude 30.0°N and longitude 85.5°W which put it about 20 miles (30 km) southeast of Panama City, Florida.  Michael was moving toward the north-northeast at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 180 m.p.h. (290 km/h).  The minimum surface pressure was 919 mb.

Hurricane Michael intensified rapidly right up to landfall on the Gulf Coast.  The minimum surface pressure decreased from 933 mb to 919 mb in the six hours prior to landfall.  With a maximum sustained wind speed of 155 m.p.h. (250 km/h) Hurricane Michael was at the top end of Category 4 on the Saffir-Simpson Scale.  Michael is the strongest hurricane on record to make landfall on that portion of the Gulf Coast and it was one of the most intense hurricanes to make landfall anywhere along the coast of the U.S. during the month of October.

Even though Hurricane Michael is moving inland, a Hurricane Warning remains in effect for the portion of the coast from the Alabama-Florida border to Suwanee River, Florida.  A Tropical Storm Warning is in effect from the Suwanee River to Chassahowitzka, Florida.  A Tropical Storm Warning is also in effect for the Atlantic Coast from Fernandina Beach, Florida to Duck, North Carolina including Albemarle and Pamlico Sounds.  A Tropical Storm Watch remains in effect from Chassahowitzka to Anna Maria Island, Florida.

Winds to hurricane force extended out about 45 miles (75 km) from the center of Hurricane Michael at the time of landfall.  Winds to tropical storm force extended out about 185 miles (290 km) from the center of circulation.  The Hurricane Intensity Index (HII) was 33.3.  The Hurricane Size Index (HSI) was 16.1 and the Hurricane Wind Intensity Size Index (HWISI) was 49.4.  Hurricane Michael will cause regional significant damage.

Tyndall Air Force Base reported a wind gust of 119 m.p.h. (191 km/h).  The Florida State University Panama City Campus reported a wind gust of 116 m.p.h. (187 km/h).   The Panama City Treatment Plant reported a wind gust of 94 m.p.h. (151 km/h).

The coast along the northeastern Gulf of Mexico is very vulnerable to storm surges.  The winds were pushing water toward the coast in the eastern half of the circulation of Hurricane Michael.  Some locations could have a storm surge of 10 to 15 feet (3 to 5 meters).  There have already been reports of damage due to storm surge.

An upper level trough will steer Hurricane Michael toward the northeast.  Michael will weaken as it moves inland, but it will carry hurricane force winds over northeastern Florida, extreme southeastern Alabama and southern Georgia.  The center of Hurricane Michael will pass between Dothan, Alabama and Tallahasse, Florida.  it will move toward Albany, Georgia and then pass south of Macon, Georgia.  Michael will move across South Carolina and North Carolina as a tropical storm before exiting the U.S. near Norfolk, Virginia.

Hurricane Michael will cause widespread power outages and numerous outages are already occurring in northwest Florida.  Michael will also produce locally heavy rain and flash floods could occur as it moves inland.  Wind and rain will disrupt efforts in South Carolina and North Carolina to recover from the effects of Hurricane Florence.

One of the most unusual aspects of Hurricane Michael was that it intensified rapidly right up until it made landfall in northwest Florida.  In the past most major hurricanes weakened while they approached the coast along the northern Gulf of Mexico.  Those hurricanes encountered drier air and more vertical wind shear and they weakened.  The Sea Surface Temperatures in the northern Gulf of Mexico is 2°C to 3°C warmer than normal and that may have contributed to the rapid intensification of Hurricane Michael before landfall.  Hurricane Camille in 1969 also intensified right up until it made landfall in Mississippi.  However, Camille occurred in August, while Hurricane Michael occurred in October.

Powerful Hurricane Michael Nearing North Florida

Powerful hurricane Michael was nearing north Florida on Wednesday morning.  Michael intensified rapidly to Category 4 on the Saffir-Simpson Scale during the overnight hours.  At 8:00 a.m. EDT on Wednesday the center of Hurricane Michael was located at latitude 29.0°N and longitude 86.3°W which put it about 90 miles south-southwest of Panama City, Florida.  Michael was moving toward the north at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 933 mb.

A Hurricane Warning was in effect for the portion of the coast from the Alabama-Florida border to Suwanee River, Florida.  Tropical Storm Warnings were in effect for the portions of the coast from the Alabama-Florida border to the Alabama-Mississippi border and from Suwanee River to Chassahowitzka, Florida.  A Tropical Storm Warning was in effect for the Atlantic Coast from Fernandina Beach, Florida to Surf City, North Carolina.  Tropical Storm Watches were in effect for the portions of the coast from the Alabama-Mississippi border to the Mouth of the Pearl River and from Chassahowitzka to Anna Maria Island, Florida.  A Tropical Storm Watch was also in effect from Surf City to Duck, North Carolina including Albemarle and Pamlico Sounds.

Hurricane Michael intensified rapidly during the past 12 hours.  An eye with a diameter of 20 miles (32 km) is surrounded by a ring of strong thunderstorms.  The strongest winds are occurring in that ring of storms.  Storms near the core of Hurricane Michael are generating strong upper level divergence which is pumping large quantities of mass away from the hurricane.  The removal of mass allowed the surface pressure to decrease rapidly to 933 mb.

Winds to hurricane force extend out about 45 m.p.h. (75 km/h) from the center of Hurricane Michael.  Winds to tropical storm force extend out about 185 miles (290 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Michael is 29.9.  The Hurricane Size Index (HSI) is 16.1 and the Hurricane Wind Intensity Size Index (HWISI) is 46.0.  Hurricane Michael is capable of causing regional significant damage.

Hurricane Michael is stronger than any other hurricane to hit north Florida in the historical record.  Michael is similar in intensity to what Hurricane Charley was when Charley hit southwest Florida in 2004.  Hurricane Michael is bigger than Charley was in 2004.

An upper level trough over the Central U.S. and a subtropical high pressure system over the western Atlantic Ocean are combining to steer Hurricane Michael toward the north.  The trough will turn Michael toward the northeast when it reaches the coast.  On its anticipated track Hurricane Michael will make landfall near Panama City and Port St. Joe, Florida in about six hours.

Hurricane Michael will bring destructive winds to the coast of north Florida.  The strongest winds will be near the center and east of the center.  Those winds will push water toward the coast and a storm surge of 10 to 15 feet (3 to 5 meters) will occur east of where the center of Michael makes landfall.  The coast of the northeast Gulf of Mexico is very vulnerable to storm surges and significant damage will occur.

The center of Hurricane Michael will move between Dothan, Alabama and Tallahassee, Florida.  It will pass near Albany, Georgia and then move south of Macon, Georgia.  The center of Michael could move near Columbia, South Carolina and then it could exit the East Coast of the U.S. near Norfolk, Virginia.

Michael will bring hurricane force winds to northeast Florida, extreme southeast Alabama and southern Georgia.  There will be widespread power outages.  Winds to tropical storm force will occur in South Carolina and North Carolina.  Hurricane Michael will drop locally heavy rain when it moves inland.  The wind and rain will disrupt efforts to recover from the effects of Hurricane Florence in South Carolina and North Carolina.

Michael Strengthens to a Major Hurricane

Hurricane Michael strengthened into a major hurricane on Tuesday afternoon.  At 5:00 p.m. EDT on Tuesday the center of Hurricane Michael was located at latitude 26.0°N and longitude 86.4°W which put it about 290 miles (470 km) south of Panama City, Florida.  Michael was moving toward the north at 12 m.p.h. (19 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 957 mb.

A Hurricane Warning is in effect for the portion of the coast from the Alabama-Florida border to the Suwanee River, Florida.  Tropical Storm Warnings are in effect for the portions of the coast from the Alabama-Florida border to the Alabama-Mississippi border, from Suwanee River to Chassahowitzka, Florida and from Fernandina Beach, Florida to South Santee River, South Carolina on the Atlantic Coast.  Tropical Storm Watches are in effect for the portions of the coast from the Alabama-Mississippi border to the Mouth of the Pearl River, from Chassahowitzka to Anna Maria Island, Florida and from South Santee, River South Carolina to Duck, North Carolina including Albemarle and Pamlico Sounds.

The inner core of Hurricane Michael tightened on Tuesday afternoon.  The diameter of the eye decreased from 30 miles (50 km) to 22 miles (35 km).  The ring of thunderstorms around the eye tightened around the smaller eye and the strongest winds were closer to the center of circulation.  Storms around the core of Michael were generating upper level divergence which was pumping mass away from the hurricane.  The removal of mass allowed the surface pressure to decrease from 965 mb to 957 mb during the past six hours.

Winds to hurricane force extend out about 45 miles (75 km) from the center of Hurricane Michael.  Winds to tropical storm force extend out about 170 miles (280 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Michael is 22.1.  The Hurricane Size Index (HSI) is 14.6 and the Hurricane Wind Intensity Size Index (HWISI) is 36.7.  Hurricane Michael is capable of causing regional major damage.

Hurricane Michael will move through an environment favorable for intensification for another 12 to 18 hours.  Michael will move over water where the Sea Surface Temperature is near 29°C.  An upper level trough over the Central U.S. is producing westerly winds which are blowing toward the top of Hurricane Michael, but those winds are not causing enough vertical wind shear to prevent intensification.  Hurricane Michael could intensify to Category 4 on the Saffir-Simpson Scale before it makes landfall.

Hurricane Michael is moving between a subtropical high pressure system over the western Atlantic Ocean and the upper level trough over the Central U.S.  Those two weather systems are steering Michael toward the north and that general motion is expected to continue for another 12 hours.  On its anticipated track Hurricane Michael will make landfall near Panama City and Port St. Joe, Florida early on Wednesday afternoon.  The upper level trough will steer Michael more toward the northeast after it makes landfall.  The center of Michael is likely to move between Dothan, Alabama and Tallahassee, Florida and it could pass near Albany, Georgia.

Hurricane Michael will bring strong winds to northwest Florida, extreme southeast Alabama and southern Georgia.  There will be wind damage and widespread power outages could occur.  The coast of the northeastern Gulf of Mexico is very vulnerable to storm surges.  Hurricane Michael will produce a storm surge of 10 to 15 feet (3 to 5 meters) at some points along the coast.  Michael will drop locally heavy rain.  Although Hurricane Michael will weaken when it moves inland, it will bring gusty winds and heavy rain to South Carolina and North Carolina.  Hurricane Michael will hinder efforts in those states to recover from the effects of Hurricane Florence.

Michael Strengthens Into a Hurricane, Watches Issued for Gulf Coast

Former Tropical Storm Michael strengthened into a hurricane on Monday morning and Watches were issued for portions of the Gulf Coast.  At 11:00 a.m. EDT on Monday the center of Hurricane Michael was located at latitude 21.2°N and longitude 84.9°W which put it about 50 miles (80 km) south of the western end of Cuba.  Michael was moving toward the north at 7 m.p.h. (11 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 982 mb.

A Hurricane Watch was in effect for the portion of the coast from the Alabama-Florida border to Suwanee River, Florida.  Tropical Storm Watches were in effect for the portions of the coast from the Alabama-Florida border to the Alabama-Mississippi border and from Suwanee River to Anna Maria Island, Florida.  A Hurricane Warning was in effect for the Cuban province of Pinar del Rio.  Tropical Storm Warnings were in effect for the Cuban province of Isle of Youth and for the portion of the coast from Tulum to Cabo Catoche, Mexico.

Hurricane Michael continued to organize quickly.  A circular eye with a diameter of about 30 miles (50 km) was forming at the center of Michael.  A ring of strong thunderstorms was wrapping around the eye and the strongest winds were occurring in the ring of storms.  Several bands of showers and thunderstorms were wrapping around the core of Hurricane Michael.  Storms near the core were generating upper level divergence which was pumping mass away from the hurricane.

Winds to hurricane force extended out about 30 miles (50 km) primarily to the northeast of the center of Hurricane Michael.  Winds to tropical storm force extended out about 175 miles (280 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Michael was 10.4.  The Hurricane Size Index (HSI) was 6.8 and the Hurricane Wind Intensity Size Index (HWISI) was 17.2.

Hurricane Michael will move into an environment that will become increasingly favorable for intensification.  Michael will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough over the Gulf of Mexico was producing westerly winds which were blowing toward the top of the circulation.  Those winds were causing some vertical wind shear.  However, the upper level trough will move westward away from Hurricane Michael and the wind shear will decrease.  Hurricane Michael will continue to strengthen when it moves over the Gulf of Mexico and it could intensify rapidly once the eye and eyewall are fully formed.  Hurricane Michael is likely to strengthen into a major hurricane.

Hurricane Michael will move around the western end of a subtropical high pressure system centered over the western Atlantic Ocean.  The high will steer Michael in a northerly direction during the next several days.  It will get bigger and stronger during the next 48 hours.  On its anticipated track Hurricane Michael will approach the northeast coast of the Gulf of Mexico on Wednesday.  It is likely to be a major hurricane at that time.  Hurricane Michael has the potential to cause a storm surge of 10 to 15 feet (3 to 5 meters) at the coast.  It will bring strong winds which could cause regional major damage and result in significant power outages.  Locally heavy rain could cause flooding in some locations.