Tag Archives: Mexico

Andres Intensifies Into a Hurricane

The core of the circulation of Andres became more circular and symmetrical on Friday and an eye has been visible intermittently during the day.  The National Hurricane Center classified Andres as a hurricane in its 5:00 p.m. EDT advisory on Friday.  At that time the center of Hurricane Andres was located at latitude 12.8°N and longitude 114.8°W which put it about 770 miles south-southwest of the southern tip of Baja California, Mexico.  Andres was moving toward the northwest at 7 m.p.h.  The maximum sustained wind speed was 75 m.p.h. and there were wind gusts to 90 m.p.h.  The minimum surface pressure was 990 mb.

As the circulation consolidated in the center of Andres strong thunderstorms pushed higher into the atmosphere around the eye.  Those thunderstorms pumped mass away from the center and caused the pressure at the surface to decrease.  Andres is over water where the Sea Surface Temperature (SST) is between 28°C and 29°C which means there is enough energy in the upper ocean to support further intensification.  It also remains in an area where the vertical wind shear is low.  So, further intensification is likely during the next day or two.  As Andres moves farther north, it will gradually move over cooler SSTs and when it gets near latitude 20°N it will begin to be affected by upper level southwesterly winds.  Cooler SSTs and more wind shear will likely cause Andres to weaken during the early part of next week.

Andres is near a weakness in the mid-level ridge that has been steering the hurricane.  The weakness in the ridge caused Andres to turn toward the northwest and its forward speed to decrease.  After an upper level trough moves east of the ridge in a day or two, the ridge will strengthen and extend westward.  That will cause Andres to move more toward the west again.  On its anticipated track Andres poses no threat to Mexico.

TD One-E Intensifies Quickly Into Tropical Storm Andres

A favorable environment caused Tropical Depression One-E to intensify quickly into Tropical Storm Andres on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Andres was located at latitude 11.8°N and longitude 113.3°W which put it about 800 miles south-southwest of the southern tip of Baja California.  Andres was moving toward the west-northwest at 10 m.p.h.  The maximum sustained wind speed was 70 m.p.h. and there were gusts to 85 m.p.h.  The minimum surface pressure was 994 mb.

Andres exhibits a more organized circulation pattern on satellite imagery.  The end of the primary rainband wrapped completely around the center of circulation and an eye appears on some satellite images.  There are more thunderstorms in the rainbands and upper level outflow continues in all directions.  Andres is moving over water where the Sea Surface Temperature (SST) is near 29°C.  Although there are strong upper level westerly winds north of 20°N and brisk upper level easterly winds near the Equator, Andres is moving through a region where the upper level winds are light.  There is little vertical wind shear to inhibit the  intensification of Andres during the next day or so.  It will gradually move over water where the SSTs are slightly cooler, but there should still be plenty of energy in the upper ocean to support further intensification.  Andres is likely to become a hurricane on Friday and it could continue to intensify rapidly for another 12 to 24 hours.

An upper level trough passing well to the north of Andres is weakening the ridge that has been steering Andres toward the west-northwest.  The effect of the trough will likely be to slow the forward motion of Andres and temporarily make it move more toward the northwest.  After the upper level trough moves off to the northeast, the ridge is likely to strengthen again.  As the ridge strengthens, it will start to steer Andres more toward the west.  On its projected track Andres poses no current threat to Mexico.

 

Tropical Depression One-E Forms Southwest of Mexico

A well developed cyclonic circulation formed at the surface in a large area of thunderstorms southwest of Mexico and the National Hurricane Center classified the system as Tropical Depression One-E.  At 5:00 a.m. EDT on Thursday the center of Tropical Depression One-E (TD1E) was located at latitude 11.0°N and longitude 110.4°W which put it about 685 miles southwest of Manzanillo, Mexico.  TD1E was moving toward the west-northwest at 15 m.p.h.  The maximum sustained wind speed was 35 m.p.h. and there were gusts to 45 m.p.h.  The minimum surface pressure was 1005 mb.

The circulation around TD1E is still in the organizational stage and there are more strong thunderstorms in the southern half of the circulation.  TD1E is in an environment that is very favorable for intensification.  It is moving over water where the Sea Surface Temperatures (SSTs) are around 29°C to 30°C.  It is an area between upper level easterly winds near the Equator and stronger upper level westerly winds farther north.  There are lighter upper level winds over TD1E and the light winds allowed it to develop strong upper level outflow in all directions.  Warm SSTs and strong upper level divergence should allow TD1E to intensify during the next several days and a period of rapid intensification is quite possible once the circulation is fully organized.

An upper level ridge to the northeast of TD1E is steering it toward the west-northwest.  As TD1E gets closer to a weakness in the western portion of the ridge, it is expected to turn toward the northwest and slow down.  On its anticipated path TD1E poses no immediate threat to the west coast of Mexico.

Tropical Storm Vance Intensifies Into a Hurricane

After an extended period when drier air and wind shear inhibited the organizational processes in Tropical Storm Vance, it has intensified rapidly in recent hours and it is now a hurricane.  At 10:00 a.m. EST on Sunday the center of Hurricane Vance was located at latitude 11.9°N and longitude 107.5°W which put it about 535 miles south-southwest of Manzanillo, Mexico.  Vance was moving toward the northwest at 15 m.p.h.  The maximum sustained wind speed was 80 m.p.h. and the minimum surface pressure was 990 mb.

Vance is moving around the western end of a ridge of high pressure over Mexico.  A large upper level trough west of California will begin to affect Vance as it moves farther north.  The trough is expected to turn Vance toward the northeast early next week.  The track forecast becomes more challenging for the period when Vance could be approaching the coast of Mexico.  Much of the guidance from the numerical models suggests that the upper level winds could be strong enough to separate the upper portion of Vance’s circulation from the lower level rotation.  If that happens, then the middle and upper portions of the circulation could be transported across Mexico, while the surface low gets left behind and meanders southeast of Baja California.

Vance is over water where the Sea Surface Temperature is near 29°C and the upper level winds are relatively light.  So, the period of rapid intensification could continue for another 12-24 hours.  When the upper level trough approaches Vance from the northwest on Monday, the wind shear will increase and Vance will start to weaken and it could weaken quickly.  Even if the low level center of Vance does not make landfall, moisture in the middle and upper portions of the circulation could enhance precipitation over Mexico next week.

Tropical Storm Vance Forms South of Acapulco

More thunderstorms developed near the center of a slow moving area of low pressure south of Mexico and the National Hurricane Center classified the system as Tropical Storm Vance.  At 5:00 p.m. EDT the center of Vance was located at latitude 11.0°N and longitude 101.0°W which put it about 415 miles south of Acapulco, Mexico.  Vance was moving toward the west at 5 m.p.h.  The maximum sustained wind speed was 40 m.p.h. and the minimum surface pressure was 1005 mb.  Vance is the 20th named tropical cyclone for form over the Eastern North Pacific during 2014, which is the most since 1992.

Vance is being steered toward the west by an upper level ridge to its north.  Vance is expected to take a long, clockwise path as it moves around the western edge of the ridge.  Some recent guidance from numerical models suggests that Vance could move farther westward than was indicated in previous model forecasts.   Eventually, when Vance moves farther north, it is anticipated that it will be turned northeastward by a large trough off the west coast of North America.  The trough could pull Vance toward the west coast of Mexico sometime next week.

There are southwesterly winds blowing over the top of Vance in the upper levels and the result is that most of the thunderstorms are developing north and east of the center.  The shear is expected to decrease on Friday.  Vance will be moving over Sea Surface Temperatures (SSTs) that are warmer than 29°C.  So, there will be sufficient energy for intensification and some guidance is indicating that Vance could become a hurricane.   When the upper level trough begins to affect Vance, the wind shear will increase and it could be on a weakening trend when it turns toward the coast of Mexico next week.

Tropical Depression Nine Forms Over Bay of Campeche

More thunderstorms formed near the center of a small low pressure system over the Bay of Campeche and the National Hurricane Center classified the low as Tropical Depression Nine (TD9) at 11:00 p.m. EDT on Tuesday.  The center of TD9 was located at latitude 19.4°N and longitude 92.9°W which put it about 160 miles west of Campeche, Mexico and about 850 miles west-southwest of Key West, Florida.  TD9 was moving toward the east at 6 m.p.h.  The maximum sustained wind speed was 35 m.p.h. and the minimum surface pressure was 1000 mb.  The government of Mexico has issued a Tropical Storm Warning for the portion of the coast from Celestun to Frontera.

Westerly winds in the upper levels are still creating wind shear over the top of TD9 and most of the thunderstorms are located in the eastern half of the circulation.  However, the upper level wind speed is expected to diminish and TD9 is likely to intensify into Tropical Storm Hanna on Wednesday.  The westerly winds are also likely to continue to push TD9 toward the east or east-northeast during the next 24 hours.

 

Potential Tropical Cyclone Developing Over Bay of Campeche

A reconnaissance plane found a small center of low pressure within a broader area of low pressure over the Bay of Campeche on Tuesday afternoon.  The plane also found winds to near tropical storm force.  At the 3:00 p.m. EDT the low was centered at latitude 19.3°N and longitude 93.7°W which put it about 350 miles northwest of Campeche, Mexico and about 850 miles west-southwest of Key West, Florida.  The low was moving toward the east at 6 m.p.h.  The maximum sustained wind speed was 38 m.p.h. and the minimum surface pressure of 1001 mb.

Thunderstorms are forming mainly on the southern and eastern sides of the center.  The low could be pulling in some of the drier air over the northern Gulf of Mexico, which may be limiting convection on the northwest side of the low.  Westerly winds in the upper levels are also generating wind shear, which is inhibiting the development of the low.  On the other hand, the low is over Sea Surface Temperatures (SSTs) that are warmer than 29°C and there is plenty of energy in the ocean to support the development of a tropical cyclone.  The pressure has fallen about 5-6 mb in the past 12 hours and so the low appears to be getting stronger.  If more thunderstorms form around the center of the low, it could be classified as a tropical depression or a tropical storm.

The westerly winds in the upper and middle levels are pushing the low slowly toward the east.  Guidance from the forecast models seems to be divided into two main possibilities.  One group of models keeps the low relatively weak and forecasts it to move eastward across the Yucatan peninsula and into the northwestern Caribbean Sea before turning it northeastward and moving the low across the Bahamas.  A second group of models predicts that the low will be a bit stronger and that the upper level flow will turn it northeastward sooner and move the low across southern Florida.  If that second scenario occurs, the low could bring stronger winds and heavy rainfall to parts of south Florida.

 

Simon Intensifies Into a Major Hurricane

Hurricane Simon intensified rapidly on Saturday and it is now a Major Hurricane.  At 5:00 p.m. EDT the center of Hurricane Simon was located at latitude 20.6°N and longitude 115.0°W which put it about 365 miles west-southwest of the southern tip of Baja California and about 495 miles south of Punta Eugenia, Mexico.  Simon was moving toward the west-northwest at 14 m.p.h.  The maximum sustained wind speed was 120 m.p.h. and the minimum surface pressure was 950 mb.

Simon is the 8th hurricane to reach Major Hurricane intensity over the Eastern North Pacific during 2014.  This ties the record for the most Major Hurricanes in one year in that basin, which was set previously in 1983, 1992 and 1993.

Simon is moving around the western edge of a ridge centered over northern Mexico.  It should turn more toward the north on Sunday.  As Simon moves farther north, it will eventually move toward the northeast.  It could approach Baja California by the middle of next week.

Simon may be on the threshold of an eyewall replacement cycle.  If it goes through one of those cycles, there will be some fluctuations in intensity.  When Simon moves west of Baja California it will move over cooler Sea Surface Temperatures and begin to weaken.  Simon is likely to be a weakening tropical cyclone when it nears Baja California.

 

TD 18E Intensifies into Tropical Storm Rachel

Tropical Depression 18-E which formed earlier today has intensified into Tropical Storm Rachel.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Rachel was located at latitude 15.3°N and longitude 107.4°W which put it about 325 miles southwest of Manzanillo, Mexico and about 550 miles south-southeast of the southern tip of Baja California.  Rachel was moving toward the west at 12 m.p.h.  The maximum sustained wind speed was 40 m.p.h. and the minimum surface pressure was 1004 mb.

A strong upper level ridge over northern Mexico has been producing northeasterly winds and wind shear over the circulation of Rachel.  The wind shear has been the reason why most of the thunderstorms have been located west of the center of circulation.  The northeasterly winds diminished slightly during recent hours and more thunderstorms developed closer to the center.  The improved organization allowed the wind speed at the surface to increase and Rachel became a tropical storm.  The upper level winds could decrease further and some additional intensification is possible.

A ridge in the middle levels is likely to steer Rachel to the west-northwest during the next day or two.  As Rachel moves farther north, it could be affected by a mid-level trough (i.e. a shortwave trough) in the westerly flow in about 72 hours.  If Rachel is strong enough and tall enough, then the mid-level trough could turn Rachel back to the northeast, which could move it toward Baja California.  If Rachel is weaker and the circulation does not extend as high into the atmosphere, then the mid-level trough may not affect the movement of Rachel.  In that case, it would probably continue to move west and dissipate over cooler Sea Surface Temperatures.

 

Tropical Storm Polo Moving Northwest

Tropical Storm Polo continues to move northwestward parallel to the west coast of Mexico.  At 11:00 p.m. EDT on Thursday the center of Polo was located at latitude 18.4°N and longitude 106.6°W which put it about 150 miles south-southwest of Cabo Corrientes, Mexico and about 375 miles southeast of the southern tip of Baja California.  Polo was moving toward the northwest at 9 m.p.h.  The maximum sustained wind speed was 70 m.p.h. and the minimum surface pressure was 981 mb.

An upper level ridge over northwestern Mexico is producing northeasterly winds that are creating wind shear over Polo.  The wind shear is limiting thunderstorm activity on the northern side of the storm.  It is also possible that Polo is close enough to Mexico that it may be pulling some drier air into the northern half of the circulation.  Both of those factors are inhibiting intensification of Polo.

A high pressure system in the middle levels over Mexico is steering Polo toward the northwest.  The tropical storm is starting to move a little more quickly.  Numerical models are suggesting that the mid-level high will strengthen and eventually turn Polo more toward the west.  Most guidance predicts that Polo will move southwest of Baja California.  However, based on the faster motion the government of Mexico has issued a Tropical Storm Watch for a portion of southern Baja California from Santa Fe to La Paz.  A Tropical Storm Warning remains in effect for a portion of the coast from Punta San Telmo to Playa Perula.  A Tropical Storm Watch continues for the portion of the coast from Playa Perula to Cabo Corrientes.