Tag Archives: Mexico

Tropical Depression 2E Forms Southwest of Baja California

After a prolonged period of relatively quiet weather over the Eastern North Pacific Ocean, a tropical depression formed southwest of Baja California.  At 11:00 p.m. EDT on Friday the center of Tropical Depression 2E (TD2E) was located at latitude 14.7°N and longitude 116.7°W which put it about 730 miles (1170 km) southwest of the southern tip of Baja California.  TD2E was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1007 mb.

A tropical wave over the Eastern North Pacific Ocean developed a well defined low level circulation and the National Hurricane Center classified the system as Tropical Depression 2E on Friday night.  Although the structure of the low level wind field is symmetrical, most of the thunderstorms are located northwest of the center of circulation.  An upper level ridge north of the depression is generating easterly winds over the top of the circulation.  The vertical wind shear is causing the asymmetrical distribution of the thunderstorms.

The environment around Tropical Depression 2E is marginal for intensification because there are both positive and negative factors.  TD2E is moving over water where the Sea Surface Temperature is near 29°C.  So, there is plenty of energy in the upper ocean to support intensification.  However, the air to the west of the tropical depression is very dry, which will limit the growth of thunderstorms and the formation of rain bands in that part of the system.  In addition moderate vertical wind shear will also inhibit intensification.  Tropical Depression 2E could intensify during the weekend and it has a chance to become the first named storm of the 2016 Eastern Pacific hurricane season.  However, the potential for intensification is limited.

The ridge to the north of TD2E is expected to continue to steer it toward the west-northwest during the next several days.  Tropical Depression 2E poses no threat to land during the next five days.

Possible Hurricane Formation Southwest of Mexico

Guidance from recent runs of the Global Forecasting System (GFS) model indicate that a tropical cyclone could form southwest of Mexico during the next few days.  A tropical wave will move into the Eastern North Pacific Ocean south of Mexico.  The wave will move over water where the Sea Surface Temperature is between 29°C and 30°C.  Vertical wind shear caused by an upper low near the west coast of Mexico will initially inhibit development of the wave.  The GFS model is forecasting that the tropical wave will move into a region where the upper level winds are light and there will not be much vertical wind shear.  If that scenario occurs then a tropical cyclone could develop during the weekend near latitude 10°N and longitude 105°W.

If a tropical cyclone forms, a ridge of high pressure to the north of the cyclone would likely steer it in a generally west-northwesterly direction which would move it away from Mexico.  The environment would be favorable for intensification.  Rapid intensification may be possible and the system could become a major hurricane next week.

The development of this tropical wave could also be a signal that the Eastern North Pacific is getting active.  Although it has been a bit of a slow start to the hurricane season in that basin, the formation of a hurricane during the next week or so would be consistent with the long term climatology for that region.

TD 4 Intensifies to Tropical Storm Danielle As It Nears Mexico

A large area of thunderstorms developed near the center of Tropical Depression 4 during during the overnight hours.  An Air Force Reserve Hurricane Hunter reconnaissance aircraft found sustained winds to tropical storm force and at 8:00 a.m. EDT on Monday the National Hurricane Center classified the system as Tropical Storm Danielle.

At 8:00 a.m. EDT on Monday the center of Tropical Storm Danielle was located at latitude 20.6°N and longitude 96.0°W which put it about 95 miles (150 km) east-southeast of Tuxpan, Mexico.  Danielle was moving toward the west-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1008 mb.  The government of Mexico has issued a Tropical Storm warning for the portion of the coast from Laguna Verde to Rio Panuco.

The center of an upper level ridge moved near the center of Danielle on Sunday night, which caused the upper level winds to be weaker over the core of the circulation.  As a result, a large area of thunderstorms was able to develop and persist around the center of circulation.  Since Danielle was over water where the Sea Surface Temperature was near 30°C, the circulation was able to extract energy from the ocean and Danielle intensified into a tropical storm.

The thunderstorms at the core of Danielle are generating upper level divergence that is pumping mass out in all direction.  The pressure at the surface is likely to decrease which should produce an additional increase in the wind speed.  Danielle will be over very warm water until it makes landfall on the coast of Mexico later today.  It is likely to intensify further before it reaches the coast.

An ridge of high pressure extends from the Atlantic Ocean into the Gulf of Mexico.  The ridge is steering Danielle toward the west-northwest and that general motion is expected to continue.  On its anticipated track the center of Danielle could be very near Tuxpan on the coast of Mexico in about 12 hours.  Danielle could produce a storm surge of several feet along the coast.  It could also cause some wind damage, although that should be minimal.  The increase in thunderstorms near the center of circulation means that Danielle will produce locally heavy rain when it moves inland.  The heavy rain will create the risk of flash floods and mudslides on steeper slopes.

Danielle was designated a tropical storm on June 20, which makes it the fourth Atlantic tropical storm of 2016.  June 20th is the earliest date on record on which the fourth Atlantic tropical storm has formed.  The previous record was June 23, which was the date when Tropical Storm Debbie was named in 2012.   During the record setting year of 2005, the fourth Atlantic tropical storm was not named until July 5.

Tropical Depression 4 Forms Over Bay of Campeche

An Air Force Reserve Hurricane Hunter aircraft investigated an area of low pressure over the Bay of Campeche on Sunday afternoon and found that there was sufficient organization for the National Hurricane Center to designate the system Tropical Depression 4.  At 11:00 p.m. EDT on Sunday the center of Tropical Depression 4 (TD4) was located at latitude 20.1°N and longitude 95.4°W which put it about 145 miles (230 km) east-southeast of Tuxpan, Mexico.  TD4 was moving toward the west at 7 m.p.h. (11 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. (70 km/h).  The minimum surface pressure was 1009 mb.  The government of Mexico has issued a Tropical Storm Warning for the portion of the coast from Laguna Verde to Rio Panuco.

Although the reconnaissance aircraft found that the circulation was better organized than it was on Saturday, it still is not well organized.  There is a distinct center of circulation, but the thunderstorms near the center have been developing and then weakening.  The circulation appears to be somewhat elongated and stretches from the southeast toward the northwest.  A persistent rain band is east and north of the center of circulation and some of the stronger winds are occurring in the rainband.  A new cluster of thunderstorms appears to be developing near the center, and it could represent an improvement in the organization of the depression.

The environment is marginally favorable for intensification.  Tropical Depression 4 is over water where the Sea Surface Temperature is near 30°C.  An upper level ridge is producing some vertical wind shear, but the upper level ridge is also enhancing upper level divergence to the east of the depression.  The depression is close to tropical storm intensity and it has another 12-18 hours to intensify before it makes landfall in Mexico.

A ridge of high pressure that extends from the Atlantic Ocean over the Gulf of Mexico is steering the depression toward the west and that general steering motion is expected to continue.  On its anticipated track, Tropical Depression 4 will make landfall in Mexico on Monday.  The depression could produce locally heavy rainfall and flash flooding will be the primary risk when it makes landfall.

Invest 94L Moves Over Southern Bay of Campeche

A tropical disturbance designated as Invest 94L moved out over the southern Bay of Campeche on Saturday morning.  At 2:00 p.m. EDT on Saturday the center of Invest 94L was located at latitude 19.0°N and longitude 91.8°W which put it about 20 miles (35 km) northeast of Ciudad del Carmen, Mexico.  Invest 94L was moving toward the west-northwest at 8 m.p.h. (13 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 1010 mb.  The National Hurricane Center is putting the probability of development of a tropical cyclone at 50%.  A reconnaissance plane has tentatively been tasked to investigate the system on Sunday afternoon, if necessary.

There is a broad area of lower pressure centered over the extreme southern Bay of Campeche.  However, there is no well formed core at the center of the circulation.  In addition there are only thin fragmented lines of showers and thunderstorms instead of well formed spiral bands.  The circulation seems to exist primarily in the lower portion of the atmosphere.  An upper level ridge east of Invest 94L is providing some upper level divergence.

The center of Invest 94L has moved over water and the Sea Surface Temperatures in the southern Bay of Campeche are 30°C – 31°C.  So there is plenty of energy in the upper ocean to support tropical development.  However, the western side of the upper level ridge is causing southerly winds to blow over the top of Invest 94L which is creating vertical wind shear.  The southern portion of the circulation is still over land, which is also an inhibiting factor.  The combination of positive and negative environmental factors are contributing to the uncertainty over the possible development of Invest 94L.

Invest 94L is being steered toward the west-northwest by a ridge of high pressure to its northeast.  On its anticipated track, the center of Invest 94L will remain over water for another 24 to 48 hours.  That time period represents the window during which Invest 94L could develop into a tropical depression or a tropical storm.  Invest 94L is likely to reach the coast of Mexico in about two days and when it moves inland, the chance for development will end.

Tropical Depression One-E Forms South of Mexico

A low level center of circulation developed near the southern edge of thunderstorms near the coast of Mexico on Monday and the National Hurricane Center designated the system as Tropical Depression One-E.  At 5:00 p.m. EDT on Monday the center of Tropical Depression One-E (TD1E) was located at latitude 14.2°N and longitude 97.0°W which put it about 185 miles (295 km) southwest of Salina Cruz, Mexico.  TD1E was moving toward the northeast at 7 m.p.h. (11 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. (70 km/h).  The minimum surface pressure was 1006 mb.  The government of Mexico issued a Tropical Storm Watch for the portion of the coast that extends from Puerto Escondido to Boca de Pijijiapan, Mexico.

Tropical Depression One-E is not a particularly well organized circulation.  A large upper level trough that extends from west of Mexico over the Gulf of Mexico is producing strong southwesterly winds that are blowing over the top of the depression.  The is the same upper level trough that is also causing the vertical wind shear over Tropical Storm Colin in the Gulf of Mexico.  As a result of the significant vertical wind shear, most of the strong thunderstorms are occurring north and east of the center of circulation.  The wind shear may be causing the tropical depression to be tilted toward the northeast with height.  The low level center of circulation is near the southern edge of the stronger thunderstorms.  The thunderstorms generating some upper level divergence to the east of the depression.

The environment around TD1E is only marginal for further intensification.  The depression is over water where the Sea Surface Temperature is near 31°C.  However, the vertical wind shear is forecast to continue and TD1E does not have much time to intensify before the center moves over land.  Little change in intensity is expected and only slight strengthening may occur before landfall.  TD1E is likely to weaken rapidly after landfall.  However, it will be interesting to see if the middle and upper part of the circulation make it to the Gulf of Mexico.

The upper level trough is expected to continue to steer TD1E toward the northeast.  On its anticipated track, the low level center is forecast to reach the coast of Mexico in 12 to 24 hours.  In cases like this when there is strong vertical wind shear near the coast of Mexico, the upper portion of the circulation sometimes gets separated from the lower level circulation.  In that case, the upper half of the circulation would continue northeast while the lower circulation either lingers near the coast or moves slowly inland and dissipates.

The primary risks from Tropical Depression One-E are locally heavy rain and flash flooding.

Sandra Weakens to a Tropical Storm

Strong vertical wind shear weakened Hurricane Sandra to a tropical storm on Friday.  At 10:00 p.m. EST on Friday the center of Tropical Storm Sandra was located at latitude 21.2°N and longitude 108.8°W which put it about 155 miles (250 km) west of Las Islas Marias and about 205 miles (330 km) southwest of Mazatlan, Mexico.  Sandra was moving toward the north at 10 m.p.h. (16 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 990 mb.  Tropical Storm Warnings are in effect for the portion of the coast from Altata to San Blas, Mexico and for the Las Islas, Marias.

A large upper level trough centered over the southwestern U.S. generated strong southwesterly winds that blew the top half of Hurricane Sandra east of the low level circulation.  The strong wind vertical wind shear will continue, but it will take another day or two for the low level circulation to spin down.  Sandra could weaken to a tropical depression on Saturday and it could be classified as a remnant low by the end of the weekend.

Since the upper portion of the circulation is detached from the lower portion, the surface circulation is being steered by the winds in the lower atmosphere.  A ridge in the lower atmosphere is steering the surface circulation toward the north and that general motion is expected to continue for the next 24 to 48 hours.  On its anticipated track the surface center of Tropical Storm Sandra will pass near the southern tip of Baja California on Saturday.  The surface center could make landfall on the west coast of Mexico on Sunday.

Hurricane Sandra Turns Toward Mexico

Hurricane Sandra moved around the western end of a subtropical ridge and turned toward Mexico on Thursday.  At 10:00 p.m. EST on Thursday the center of Hurricane Sandra was located at latitude 18.0°N and longitude 109.7°W which put it about 340 miles (545 km) south of the southern tip of Baja California and about 490 miles (790 km) south-southwest of Culiacan, Mexico.  Sandra was moving toward the north at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 956 mb.  The government of Mexico issued a Tropical Storm Watch for the coast of Baja California from Todos Santos to Los Barriles.

Hurricane Sandra appeared to develop concentric eyewalls on Thursday.  A primary rainband wrapped around the tiny pinhole eye at the center of the hurricane.  Satellite imagery suggests that the tiny inner eye still exists inside the larger outer eye.  Sandra reached Category 4 on the Saffir-Simpson Scale on Thursday morning, but the formation of concentric eyewalls weakened the hurricane back to Category 3 later in the day.  Sandra remains a well organized hurricane.  It has a well defined core surrounded by a ring of strong thunderstorms.  Spiral bands of storms are in the northeastern quadrant of the circulation.

Hurricane Sandra will move into a less favorable environment on Friday.  It will be over water where the Sea Surface Temperature is near 29°C.  However, a large upper level trough along the west coast of North America will generate strong southwesterly winds.  Those winds will cause strong vertical wind shear, which will tilt the circulation toward the northeast.  The upper level winds will also inhibit upper level divergence from the western part of Sandra.  The strong wind shear will weaken Hurricane Sandra on Friday.  Some models are predicting that the shear could be strong enough to blow the middle and upper parts of the circulation northeast of the low level circulation.  If that happens, then Hurricane Sandy could weaken very quickly,

The upper level trough will steer Hurricane Sandra toward the northeast on Friday.  Sandra will likely move faster toward the northeast by Friday night.  On its anticipated track Sandra could be near the southern tip of Baja California by Friday night and it could approach the west coast of Mexico on Saturday.  Sandra could still be a hurricane when it nears Baja California, but it is more likely to be a tropical storm.  It could be a tropical storm or depression by the time it reaches the west coast of Mexico.

Sandra Quickly Intensifies into a Major Hurricane

Hurricane Sandra intensified quickly into a major hurricane on Wednesday.  At 4:00 p.m. EST on Wednesday the center of Hurricane Sandra was located at latitude 13.0°N and longitude 109.9°W which put it about 685 miles (1100 km) south of the southern tip of Baja California.  Sandra was moving toward the northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) which made Sandra a Category 3 hurricane on the Saffir-Simpson Scale and qualified it as a major hurricane.  There were wind gusts to 140 m.p.h. (225 km/h) and the minimum surface pressure was 967 mb.  Sandra is the ninth major hurricane to form over the Eastern North Pacific during 2015, which is a new record for that basin.

Sandra is a small well organized hurricane.  It has a well defined eye surrounded by a ring of thunderstorms, but hurricane force winds only extend out about 25 miles (40 km) from the center.  Thunderstorms in the core of Sandra are producing upper level divergence which is pumping out mass and allowing the surface pressure to decrease.  Sandra is an environment that favors further intensification.  It is over water where the Sea Surface Temperature is near 30°C.  The upper level winds are light and there is not much vertical wind shear.  Sandra could become a Category 4 hurricane on Thursday.

Hurricane Sandra is moving around the western end of a subtropical ridge to the east of it.  Sandra turned toward the northwest on Wednesday and it will gradually start moving more toward the north on Thursday.  A large deepening upper level trough off the west coast of North American will create southwesterly winds that will start to steer Sandra toward the northeast on Friday.  On its anticipated track Hurricane Sandra will approach the southern tip of Baja California on Friday night.

TD 22E Intensifies to Tropical Storm Sandra

A core circulation organized quickly on Tuesday inside Tropical Depression 22E and it intensified into Tropical Storm Sandra.  At 4:00 p.m. EST on Tuesday the center of Tropical Storm Sandra was located at latitude 11.9°N and longitude 107.2°W which put it about 780 miles south-southeast of the southern tip of Baja California.  Sandra was moving toward the west-northwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 997 mb.

Eastern upper level winds which were blowing over the top of Tropical Depression 22E diminished on Tuesday and the depression intensified into Tropical Storm Sandra.  A primary rainband wrapped around the center of circulation  and an inner core developed near the interior end of the band.  As the band wrapped around the center of circulation a ring of thunderstorms began to take on the structure of an eyewall.  Those thunderstorms also started to generate some upper level divergence.  The circulation of Sandra is still organizing and other spiral bands are starting to form.

Tropical Storm Sandra is in an environment that is favorable for intensification.  It is over water where the Sea Surface Temperature is near 30°C.  Although there is still some vertical wind shear, it is much less than it was on Monday.  A combination of very warm water and little vertical wind shear could allow Sandra to intensify very quickly.  It is likely to become a hurricane with 12 to 18 hours and it could become a major hurricane within 24 to 36 hours.  In a couple of days Sandra will start to encounter strong upper level winds from the southwest.  The increased vertical wind shear at that time will cause it to weaken.

Tropical Storm Sandra is starting to move around the western end of a subtropical ridge that has been steering toward the north.  Sandra should gradually turn toward the north during the next 24 hours.  It is likely to move mainly toward the north until Thursday when southwesterly winds will turn it toward the northeast.  Sandra could be approaching the southern tip of Baja California by Friday night.