Category Archives: Atlantic, Caribbean, and Gulf of Mexico

Atlantic TCs

Tropical Storm Fay Forms East of Cape Hatteras

Tropical Storm Fay formed east of Cape Hatteras on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Fay was located at latitude 35.5°N and longitude 74.9°W which put it about 40 miles (65 km) east-northeast of Cape Hatteras, North Carolina.  Fay was moving toward the north at 7 m.p.h. (11 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 1005 mb.

A Tropical Storm Warning was issued for the portion of the coast from Cape May, New Jersey to Watch Hill, Rhode Island including Long Island and Long Island Sound.

A new center of circulation formed near the northern end of a band of showers and thunderstorms which was on the eastern side of a larger low pressure system that was previously designated as Invest 98L.  A reconnaissance aircraft detected winds to tropical storm force and the National Hurricane Center designated the system as Tropical Storm Fay.  Fay is the sixth named Atlantic tropical storm of 2020 and it formed earlier than any other sixth Atlantic tropical storm in the satellite era.

The circulation around Tropical Storm Fay was asymmetrical.  The strongest winds were occurring a band of showers and thunderstorms on the eastern side of Fay.  The inner end of the band was wrapping around the northern side of the center of circulation.  Bands on the western side of the tropical storm consisted primarily of showers and lower clouds.  Storms near the center began to generate upper level divergence which was pumping mass away to the north and east of the tropical storm.  Winds to tropical storm force extended out about 140 miles (225 km) in the eastern half of Tropical Storm Fay.  The winds in the western half of Fay were blowing at less than tropical storm force.

Tropical Storm Fay will move through an environment somewhat favorable for intensification during the next 18 to 24 hours.  Fay will move over water where the Sea Surface Temperature is near 26°C.  An upper level trough over the eastern U.S. will produce southwesterly winds which will blow toward the top of the tropical storm.  Those winds will impede upper level divergence to the west of Tropical Storm Fay and they will cause moderate vertical wind shear.  The wind shear will inhibit intensification, but it will not likely to be strong enough to prevent Fay from strengthening.  Tropical Storm Fay could intensify during the next 12 to 18 hours.

The upper level trough and a high pressure system over the Atlantic Ocean will interact to steer Tropical Storm Fay toward the north during the next day or two.  On its anticipated track the center of Tropical Storm Fay could approach southern New Jersey on Friday afternoon.  Fay could move across Long Island on Friday night.

Since the strongest rainband and winds are on the eastern side of Tropical Storm Fay, the portion of the coast south of New Jersey may not experience tropical storm force winds.  Gusty winds are likely along the coast of New Jersey, Long Island, southeastern New York, Connecticut and Rhode Island.  Heavy rain could also fall in those locations.  Easterly winds blowing around the northern side of Tropical Storm Fay will push water toward the coast.  The water level could rise several feet (one meter) at some locations.  Waves could also cause some beach erosion.

Potential Tropical Development Near East Coast of U.S.

There is the potential for the development of a tropical cyclone near the East Coast of the U.S. during the next several days.  A low pressure system, currently designated as Invest 98L developed over the northern Gulf of Mexico during the weekend.  The low moved slowly toward the northeast across the southeastern U.S.  At 2:00 a.m. EDT on Wednesday the low level center of Invest 98L was located at latitude 33.3°N and longitude 80.5°W which put it about 25 miles (40 km) west of Charleston, South Carolina.  The low was moving toward the east at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 25 m.p.h. (40 km/h) and there were wind gusts to 35 m.p.h. (55 km/h).  The minimum surface pressure was 1013 mb.

Invest 98L currently consists primarily of a lower level circulation.  Much of the circulation is over land and the center is west of Charleston, South Carolina.  Many of the bands revolving around the center of the low pressure system consist of showers and lower clouds.  There are bands of showers and thunderstorms on the far eastern edge of the circulation which is over the Gulf Stream.  An upper level trough over the southeastern U.S. is producing westerly winds which are blowing across the top of the low level circulation.

Invest 98L will move into an environment more favorable for the development of a tropical cyclone.  It will move over water where the Sea Surface Temperature is near 27°C when the center moves over the Atlantic Ocean.  The upper level trough will over the southeastern U.S. will cause moderate vertical wind shear.  The wind shear will inhibit development.  If thunderstorms develop closer to the center of circulation, those storms could cause the circulation grow vertically into the middle and upper troposphere.  If the thunderstorms release enough latent energy in the middle and upper troposphere, a warm core could form and Invest 98L could become a tropical cyclone.

The National Hurricane Center indicated in the 8:00 a.m. EDT Tropical Weather Outlook on Wednesday that the probability was 70% that a tropical or subtropical cyclone could form during the next five days.  An upper level trough approaching the eastern U.S. will steer the low pressure system toward the north-northeast during the next few days.  On its anticipated track the low pressure system will move near the East Coast of the U.S.  A reconnaissance aircraft is tentatively scheduled to investigate Invest 98L later on Wednesday, if necessary.

Tropical Depression Five Strengthens into Tropical Storm Edouard

Former Tropical Depression Five strengthened into Tropical Storm Edouard northeast of Bermuda on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Edouard was located at latitude 37.2°N and longitude 56.9°W which put it about 685 miles (1100 km) south-southwest of Cape Race, Newfoundland.  Edouard was moving toward the northeast at 35 m.p.h. (56 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 Edouard became the earliest fifth named storm to form over the Atlantic Ocean during the satellite era since 1966.

Former Tropical Depression Five exhibited greater organization on satellite imagery and the National Hurricane Center designated the system as Tropical Storm Edouard.  More thunderstorms formed in bands east of the center of circulation.  Bands in the northern and western parts of Edouard consisted primarily of showers and lower clouds.  Winds to tropical storm force were occurring within 60 miles of the center in the southeastern quadrant of Tropical Storm Edouard.  The winds in the other parts of Edouard were blowing at less than tropical storm force.

Tropical Storm Edouard will move through an environment that could allow for a little more intensification during the next 12 hours.  Edouard will move over water where the Sea Surface Temperature is near 24°C.  It will move under the southern fringe of the upper level westerly winds in the middle latitudes.  Those winds will blow toward the top of the circulation and they will cause moderate vertical wind shear.  The relatively cool water temperatures and moderate vertical wind shear will limit future intensification.  Tropical Storm Edouard could get a little stronger on Monday.  Edouard will move over cooler water later on Monday and it will start a transition to an extratropical cyclone.

Tropical Storm Edouard will move around the northern side of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Edouard toward the northeast.  On its anticipated track Tropical Storm Edouard will pass well south of Newfoundland.

Tropical Depression Five Forms West-southwest of Bermuda

Tropical Depression Five formed west-southwest of Bermuda on Saturday morning.  At 11:00 a.m. EDT on Saturday the center of Tropical Depression Five was located at latitude 31.1°N and longitude 68.7°W which put it about 245 miles (390 km) west-southwest of Bermuda.  The depression was moving toward the east-northeast 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 1009 mb.

Visible satellite images showed that a small low pressure system west-southwest of Bermuda exhibited more organization on Saturday morning and the National Hurricane Center designated the system as Tropical Depression Five.  The circulation around Tropical Depression Five was small but it was fairly well organized.  The depression had a well defined center of circulation.  Thunderstorms were occurring in bands south and east of the center.  Bands in the northwestern part of Tropical Depression Five consisted primarily of showers and lower clouds.  Storms near the center of circulation were generating upper level divergence which was pumping mass away to the east of the depression.

Tropical Depression Five will move through an environment somewhat favorable for intensification during the next 12 to 24 hours.  The depression will move over water where the Sea Surface Temperature is near 25.5°C.  It will move under the southern edge of the upper level westerly winds in the middle latitudes.  Those winds will cause moderate vertical wind shear, but the shear may not be strong enough to prevent some intensification.  Tropical Depression Five could strengthen into a tropical storm during the next 24 hours.

Tropical Depression Five will move around the northwestern part of a subtropical high pressure system over the Atlantic Ocean.  The high will steer the depression toward the east-northeast during the next several days.  On its anticipated track Tropical Depression Five will move near Bermuda on Saturday night.  The depression could be a tropical storm when it passes by Bermuda.

Tropical Storm Dolly Develops Southwest of Newfoundland

Tropical Storm Dolly developed southwest of Newfoundland on Tuesday.  At 1:00 p.m. EDT on Tuesday the center of Tropical Storm Dolly was located at latitude 39.4°N and longitude 61.9°W which put it about 660 miles (1065 km) southwest of Cape Race, Newfoundland.  Dolly was moving toward the east-northeast at 13 m.p.h. (20 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. (5 km/h).  The minimum surface pressure was 1002 mb.

Former Subtropical Depression Four strengthened on Tuesday and its structure continued to make a transition to a more tropical cyclone like appearance.  A band of showers and thunderstorms wrapped closely around the southern side of the center of circulation.  The strongest winds were occurring in that band.  Other bands of showers and thunderstorms were revolving around the center of circulation.  A scatterometer on board a satellite estimated that there were winds above tropical storm force and the National Hurricane Center designated the system as Tropical Storm Dolly.  The winds to tropical storm force extended out 65 miles (105 km) on the southern side of Dolly.  The winds in the other parts of the circulation were generally blowing at less than tropical storm force.

Tropical Storm Dolly will move through an environment that could be favorable for intensification during the next 6 to 12 hours.  Dolly will move near the northern part of the Gulf Stream where the water is near 26°C.  It will move around the southeastern part of a weakening upper level low.  The upper low will produce some vertical wind shear, but the shear will not be strong enough to prevent intensification during the next 6 to 12 hours.  Tropical Storm Dolly is likely to move north of the Gulf Stream on Wednesday.  When Dolly moves over colder water it will start to weaken.

Tropical Storm Dolly will move around the southeastern side of the upper low during the next few hours.  The upper low will weaken on Wednesday and both the upper low and Dolly will be steered toward the northeast by a larger upper level trough over eastern North America.  On its anticipated track Tropical Storm Dolly could bring gusty winds and rain to southeastern Newfoundland on Wednesday night and Thursday.

Subtropical Depression Four Forms Southeast of Cape Cod

Subtropical Depression Four developed southeast of Cape Cod, Massachusetts on Monday afternoon.  At 5:00 p.m. EDT on Monday the center of Subtropical Depression Four was located at latitude 38.2°N and longitude 65.7°W which put it about 310 miles (495 km) southeast of Cape Cod, Massachusetts.  The depression was moving toward the east-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 1009 mb.

The structure of a previously non-tropical low pressure system southeast of Cape Cod evolved into a more symmetrical circular shape on Monday.  Bands of showers and thunderstorms revolved more closely around the center of the low.  The low pressure system exhibited a more tropical like structure on visible satellite imagery.  However, the National Hurricane Center (NHC) observed that the surface low was under an upper low which meant the system had a cold core in the upper troposphere.  So, NHC designated the system as Subtropical Depression Four when it initiated advisories on Monday afternoon.

The circulation around Subtropical Depression Four had a hybrid structure with a tropical like appearance in the lower levels and a non-tropical cold core in the upper levels.  The depression will move through an environment favorable for intensification during the next 12 to 18 hours.  The core of the depression will move near the northern part of the Gulf Stream where the Sea Surface Temperature is near 26°C.  It will move near the south side of the core of the upper low where the winds are weaker.  Those winds will cause some vertical wind shear, but the shear will not be too strong during the next 12 hours.  The depression could strengthen into a subtropical storm.  There is a chance that the circulation could develop a warm core in the upper levels if the depression stays near the Gulf Stream.  The warm water in the Gulf Stream and the cold air in the upper troposphere will enhance instability which will contribute to the development of thunderstorms.  If thunderstorms release enough latent energy in the upper troposphere, then a warm core could form and the system could make an additional transition into a tropical storm.

Subtropical Depression Four is likely to move in tandem with the upper low during the next day or two.  The upper low will move toward the east-northeast on Tuesday and then it will move more toward the northeast on Wednesday.  On its anticipated track Subtropical Depression Four will move away from the northeast U.S.  The depression will remain south of Nova Scotia, but it could pass near southeastern Newfoundland on Thursday.

Tropical Depression Cristobal Brings Rain to Lower Mississippi River Valley

Tropical Depression Cristobal brought rain to the lower Mississippi River Valley on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Depression Cristobal was located at latitude 34.8°N and longitude 92.8°W which put it about 10 miles (15 km) west of Little Rock, Arkansas.  Cristobal was moving toward the north-northwest at 17 m.p.h. (28 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 994 mb.

Tropical Depression Cristobal moved northward across Louisiana and Arkansas on Monday.  Steadier rain fell in the northern part of the circulation around Cristobal.  Diverging air from a surface high pressure system east of the Great Lakes converged with the circulation around the northern side of Tropical Depression Cristobal to produce rising motion.  The rising motion produced the steadier rain.  Thunderstorms in bands in the southern and eastern parts of Cristobal dropped locally heavy rain over parts of Louisiana, Mississippi and Alabama.  Jackson, Mississippi received 2.49 inches (6.3 cm) of rain.  Little Rock, Arkansas received 1.49 inches (3.8 cm) of rain.

Tropical Depression Cristobal will move around the western side of a high pressure system.  The high will steer Cristobal toward the north during the next several days.  The circulation around Tropical Depression Cristobal retained tropical characteristics on Monday night.  Radiosonde data from Little Rock and Jackson, Mississippi showed that there was still a warm core in the middle troposphere.  Cristobal is forecast to make a gradual transition to an extratropical cyclone during the next 24 to 36 hours.  The circulation could strengthen during the extratropical transition and a Gale Warning has been issued for Lake Michigan.  Flood Watches were also in effect for locations from Mississippi to Wisconsin.

Tropical Storm Cristobal Causes Storm Surge on Gulf Coast

Tropical Storm Cristobal caused a storm surge on the Gulf Coast on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Cristobal was located at latitude 30.3°N and longitude 90.2°W which put it about 20 miles (30 km) north-northwest of New Orleans, Louisiana.  Cristobal was moving toward the north-northwest at 10 m.p.h. (16 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 993 mb.

A Tropical Storm Warning remained in effect for the portion of the coast from Morgan City, Louisiana to the Okaloosa/Walton County Line in Florida.

The large circulation around Tropical Storm Cristobal blew water toward the northern coast of the Gulf of Mexico on Sunday.  The wind produced a rise in the water level from northwest Florida to southeast Louisiana.  The highest storm surges occurred along the coast of Mississippi and southeast Louisiana.  The water level reached 7.47 feet (2.28 m) at the Waveland Yacht Club in Mississippi.  The storm surge was 7.62 feet (2.32 m) at Shell Beach in Louisiana.  The storm surge covered coastal roads in Grand Isle, Louisiana and Biloxi, Mississippi.

The broad center of Tropical Storm Cristobal passed across the Lower Mississippi River delta on Sunday afternoon before it moved over New Orleans.  Cristobal began to weaken slowly as it moved inland.  Winds to tropical storm force were still occurring in the southeastern part of the circulation which was still over the Gulf of Mexico.  Most of the rain was falling in bands on the northern side of Tropical Storm Cristobal.  Locally heavy rain fell over Northwest Florida, Southwest Alabama, Southern Mississippi and Southeastern Louisiana.

Tropical Storm Cristobal will move around the western end of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer Cristobal toward the north during the next several days.  On its anticipated track Tropical Storm Cristobal will move over Louisiana and Arkansas on Monday.  Cristobal will continue to weaken slowly as it moves farther inland.  Tropical Storm Cristobal will drop locally heavy rain over parts of Mississippi, eastern Louisiana, Arkansas and Missouri.  Flood Watches have been issued for some of those areas.

Large Tropical Storm Cristobal Churns Toward Louisiana

Large Tropical Storm Cristobal churned toward the coast of Louisiana on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Cristobal was located at latitude 26.2°N and longitude 90.2°W which put it about 200 miles (320 km) south of Grand Isle, Louisiana.  Cristobal was moving toward the north at 12 m.p.h. (19 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 993 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Intracoastal City, Louisiana to the Okaloosa/Walton County Line in Florida including Lake Pontchartrain and Lake Maurepas.

The circulation around Tropical Storm Cristobal continued to be very large.  Winds to tropical storm force extended out 250 miles (400 km) to the east of the center of Cristobal.  A thunderstorm in a rainband on the eastern periphery of the circulation around Tropical Storm Cristobal produced a tornado near Orlando, Florida.  Winds to tropical storm force extended out 160 miles (260 km) in the western half of the circulation.  The winds were blowing at less than tropical storm force near the center of circulation.  The center passed just to the west of NOAA buoy 42001 on Saturday evening.  The buoy measured a surface pressure of 29.34 inches (993.8 mb).  More thunderstorms appeared to be forming north and south of the center of circulation on Saturday night.

Tropical Storm Cristobal will move through an environment favorable for intensification during the next 12 to 18 hours.  Cristobal will move over water where the Sea Surface Temperature is near 27°C.  It will move under the western side of an upper level ridge.  The ridge will produce southerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear but the the shear will not be great enough to prevent intensification.  Tropical Storm Cristobal will strengthen on Sunday.  If thunderstorms consolidate around the center of circulation, then there is a chance that Cristobal could strengthen into a hurricane.

Tropical Storm Cristobal will move around the western end of a subtropical high pressure system on Sunday.  The high will steer Cristobal toward the north.  A ridge in the middle troposphere will move north of Tropical Storm Cristobal later on Sunday.  The ridge will turn Cristobal toward the north-northwest.  On its anticipated track Tropical Storm Cristobal will approach the coast of Louisiana on Sunday afternoon.  The center of Cristobal could make landfall between Grand Isle and Morgan City.

Tropical Storm Cristobal will bring gusty winds to Northwest Florida, Southwest Alabama, Southern Mississippi and Southeastern Louisiana.  Those winds will push water toward the coast.  A storm surge of 1 to 4 feet (0.3 to 1.3 meters) will be possible.  The water level could rise 3 to 6 feet (1 to 2 meters) in parts of southeastern Louisiana.  Areas outside of levee protection systems could go under water.  Tropical Storm Cristobal will drop heavy rain over parts of southern Mississippi and Southeastern Louisiana.  Flash Flood Watches have been issued for those regions.

Tropical Storm Cristobal Slowly Strengthens

Tropical Storm Cristobal slowly strengthened on Saturday morning.  At 11:00 a.m. EDT on Saturday the center of Tropical Storm Cristobal was located at latitude 24.2°N and longitude 90.1°W which put it about 345 miles (555 km) south of the Mouth of the Mississippi River.  Cristobal was moving toward the north at 12 m.p.h. (19 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 994 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Intracoastal City, Louisiana to the Okaloosa/Walton County Line in Florida.

Although Tropical Storm Cristobal still did not exhibit the typical structure of a tropical storm, the circulation around it was more organized on Saturday morning.  A band of showers and thunderstorms wrapped around the western and southern sides of the center of circulation.  The strongest winds were occurring in a part of this band about 100 miles (160 km) south of the center of Cristobal.  A few thunderstorms formed just to the west of the center of circulation.  The structure of the wind field around Tropical Storm Cristobal was still asymmetrical.  Winds to tropical storm force extended out 240 miles (390 km) to the east of the center of circulation.  Winds to tropical storm force only extended out 140 miles (220 km) on the western side of Cristobal.

Tropical Storm Cristobal will move through an environment favorable for intensification during the next 24 hours.  Cristobal will move over water where the Sea Surface Temperature is near 27°C.  It will move under the western side of an upper level ridge.  The ridge will produce southerly winds which will blow toward the top of the circulation.  Those winds will produce some vertical wind shear, but the shear will not be great enough to prevent intensification.  The flow around the ridge will enhance upper level divergence to the northeast of Cristobal.  Enhanced upper level divergence could pump away enough mass to allow the surface pressure to decrease.  Tropical Storm Cristobal will strengthen during the next 24 hours.  If more thunderstorms form close to the center of circulation and an inner core develops, then there is a chance Cristobal could intensify into a hurricane.

Tropical Storm Cristobal will move around the western side of a subtropical high pressure system.  The high will steer Cristobal toward the north during the next 18 to 24 hours.  A ridge in the middle levels will move north of Tropical Storm Cristobal on Sunday afternoon.  That ridge could force Cristobal to move toward the north-northwest for a few hours.  On its anticipated track the center of Tropical Storm Cristobal could approach the coast of Louisiana on Sunday afternoon.

The large circulation around Tropical Storm Cristobal means that it will bring gusty winds to Northwest Florida, Southwest Alabama, Southern Mississippi, and Southeast Louisiana.  Those winds will push water toward the coast and they will cause a storm surge on the northern Gulf Coast.  The water level could rise 1 to 4 feet (0.3 to 1.3 meters) along the coast.  The storm surge could be 3 to 6 feet (1 to 2 meters) in parts of southeast Louisiana.  Areas outside levee systems could go under water.  Tropical Storm Cristobal will also drop heavy rain over southern Mississippi and southeastern Louisiana.  Fresh water flooding could occur.  Flood Watches have been issued for parts of those regions.