Tag Archives: Mexico

Marty Intensifies and Mexico Issues a Tropical Storm Watch

Tropical Storm Marty intensified on Sunday and the government of Mexico issued a Tropical Storm Watch for a portion of the west coast.  At 2:00 p.m. EDT on Sunday the center of Tropical Storm Marty was located at latitude 15.0°N and longitude 102.8°W which put it about 235 miles (380 km) southwest of Acapulco, Mexico.  Marty was moving toward the north-northeast at 6 m.p.h.  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 997 mb.  A Tropical Storm Watch has been issued for the portion of the coast from Acapulco to Lazaro Cardenas, Mexico.

The structure of Tropical Storm Marty improved on Sunday morning.  A long rainband stretched around the southern and eastern sides of the circulation and more thunderstorms developed near the center or circulation.  Marty is over water where the Sea Surface Temperature (SST) is near 30°C, which means there is a lot of energy in the upper ocean.  However, an upper level trough extends from the western Gulf of Mexico across northern Mexico.  The upper level trough is causing westerly winds, which could already be producing vertical wind shear over the northern half of the circulation of Tropical Storm Marty.  Very warm SSTs mean that the potential for intensification exists, but the vertical wind shear will limit how much intensification actually occurs.  If the upper level winds get stronger, they could shear the top half of the circulation away from the bottom half and cause Marty to dissipate.

The upper level trough is beginning to steer Marty toward the north-northeast and the tropical storm is likely to move in that direction over the short term.  The ultimate track of Marty will be determined by the vertical integrity of the circulation and the strength of the vertical wind shear.  If the wind shear is not too strong and the upper and lower portions of the circulation remain together, then the trough will steer all of Marty toward the northeast.  In that case it could make landfall on the Mexican coast in several days.  However, if the vertical wind shear blows then top off of the circulation, then the upper level portion will move northeast toward Mexico, while the lower part of the tropical storm is left behind.  The upper half of the circulation could still bring heavy rain and the potential for floods to parts of Mexico, even if the surface circulation does not make landfall.

Tropical Depression 16E Could Bring Heavy Rain to Southwest U.S.

A center of circulation organized within a cluster of thunderstorms west of Baja California on Sunday and the system was designated Tropical Depression Sixteen-E.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression Sixteen-E (TD16E) was located at latitude 25.0°N and longitude 113.7°W which put it about 90 miles (145 km) west of Cabo San Lazaro, Mexico.  TD16E was moving toward the north-northwest at 14 m.p.h. (22 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 1003 mb.

Tropical Depression 16E has only a few hours before it will move over the central part of Baja California.  Although it is over water where the Sea Surface Temperature is near 27°C little, if any, intensification is expected.  When TD16E crosses Baja California, the terrain and increased vertical wind shear are likely to blow the upper portion of the circulation northward faster than the lower portion of the circulation.  The high clouds could reach parts of the southwestern U.S. within 24 hours.  Moving over mountains will disrupt the lower part of the circulation, but the rotation in the middle levels could persist for several days as it moves northward.

An upper level ridge centered over Texas and an upper level low west of Baja California are combining to steer TD16E northward and that general motion should continue for the next several days.  On its anticipated track TD16E could reach the coast of Baja California near Punta Abreojos in about 12 hours.  It could then move across Baja and the Gulf of California and make a second landfall on the coast west of Hermosillo on Monday morning.  TD16E or its remnants could be approaching southern Arizona later on Monday.  Convection and a flow of moisture associated with TD16E could produce locally heavy rainfall when it is forced to rise of mountains.  It could cause flooding in parts of Baja California, northwestern Mexico and the southwestern U.S.

Linda Rapidly Intensifies Into a Major Hurricane

Hurricane Linda rapidly intensified on Tuesday and it now has a wind speed that qualifies it as a Category 3 Hurricane on the Saffir-Simpson Scale.  This makes Linda the fifth major hurricane in the Eastern North Pacific in 2015.  At 11:00 a.m. EDT on Tuesday the center of Hurricane Linda was located at latitude 21.3°N and longitude 113.9°W which put it about 280 miles (450 km) west-southwest of the southern tip of Baja California.  Linda was moving toward the north-northwest at 14 m.p.h. (22 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 956 mb.

Upper level winds over Linda decreased and the reduction in vertical wind shear allowed it to intensify rapidly during the past 12 hours.  A visible eye and symmetrical eyewall are evidence of a well organized inner core.  Thunderstorms near the center of circulation are generating upper level divergence in all directions which is pumping out mass and causing the pressure to decrease.  Linda could intensify for a few more hours, but it will start to move over much cooler Sea Surface Temperatures (SSTs) later today.  It will be unable to extract enough energy from the cooler water to maintain its intensity and Linda will start to weaken.  As Linda moves farther north, it will also start to encounter stronger upper level winds around the southern portion of an upper level trough near the west coast of the U.S.  Increased vertical wind shear in addition to cooler SSTs will speed up the rate at which Linda weakens.  Since Linda has a large circulation, it could take longer for it to spin down.

An upper level ridge over Mexico is steering Linda toward the north-northwest and that general motion is expected to continue as long as it maintains tall thunderstorms.  When Linda weakens to a tropical storm over cooler water, the circulation will not extend as high in the atmosphere.  After that time Linda will be steered more toward the west by winds lower in the atmosphere.  On its anticipated track Linda will move parallel to the coast of Baja California for several days before turning away from the coast later this week.

Tropical Storm Linda Forms South of Baja California

A spiral band continued to wrap more tightly around the center of circulation inside a large low pressure system west of Mexico on Sunday and the National Hurricane Center designated the system as Tropical Storm Linda.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Linda was located at latitude 14.1°N and longitude 109.0°W which put it about 610 miles (980 km) south of the southern tip of Baja California.  Linda was moving toward the northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1000 mb.

The circulation in Tropical Storm Linda is well organized.  There is one main spiral rainband and multiple outer rainbands.  Outside of the core of the circulation there are fewer thunderstorms east of the center, which could mean that some drier air is being pulled into that part of the storm.  Thunderstorms in the core are generating upper level divergence.  Linda is over water where the Sea Surface Temperatures (SSTs) are above 29°C.  An upper level trough near the west coast of the U.S. and an upper level ridge over northern Mexico are combining to create an outflow channel to the northeast, which is enhancing the flow of mass away from the tropical storm.  There is little vertical wind shear over the top of Linda and the environment is favorable for further intensification.  A period of rapid intensification is possible and Linda is likely to become a hurricane.  Eventually, when it moves farther north, Linda will move into an area of cooler SSTs and more vertical wind shear, which will cause it to weaken.

Linda appears to be moving a little more toward the west-northwest this afternoon.  The upper level ridge over northern Mexico is expected to steer it in a generally northwesterly direction during the next few days.  On its anticipated track, Linda would move west of Baja California during the middle of next week.

Tropical Storm Kevin Forms Southwest of Baja California

Vertical wind shear decreased enough on Thursday to allow more thunderstorms to develop near the center of Tropical Depression 14E and the National Hurricane Center upgraded it to Tropical Storm Kevin.  At 11:00 a.m. EDT on Thursday the center of Tropical Storm Kevin was located at latitude 17.9°N and longitude 115.6°W which put it about 505 miles (815 km) southwest of the southern tip of Baja California.  Kevin was moving toward the north at 6 m.p.h. (9 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1000 mb.

Tropical Storm Kevin is a small tropical cyclone.  Winds to tropical storm force only extend out about 70 miles (115 km) from the center of circulation.  There is one short spiral band wrapping around the northwest side of the center and another short band wrapping around the southwest side of the center.  There are not many thunderstorms in the eastern half of the circulation.  Kevin is over water where the Sea Surface Temperature (SST) is near 29°C.  However, a large, high amplitude upper level trough along the west coast of the U.S. is generating moderate southwesterly winds over the top of Kevin.  The vertical wind shear inhibited the development of Kevin, but the shear seems to have lessened today and the circulation in the tropical storm has consolidated around the center.  Thunderstorms near the center of Kevin are generating upper level divergence over a small area.

As Kevin moves farther north it will move over cooler SSTs.   When it gets north of latitude 22°N, Kevin will move over SSTs cooler than 26°C.  If the vertical wind shear remains moderate, Kevin could intensify further during the next 24 to 48 hours.  After about two days, the tropical storm will move over cooler SSTs and into an area with more vertical wind shear.  At that point Kevin is likely to start to spin down.

A ridge over Mexico is steering Kevin toward the north and that general motion is expected to continue for another day or two.  When Kevin moves over cooler SSTs, the thunderstorms will not be as tall and it will be steered by the winds lower in the atmosphere.  Those winds could push Kevin more toward the west during the weekend.

Dolores Becomes a Major Hurricane

Hurricane Dolores intensified rapidly on Tuesday night and it has reached Major Hurricane status.  At 11:00 a.m. EDT on Wednesday the center of Hurricane Dolores was located at latitude 18.4°N and longitude 110.2°W which put it about 310 miles (500 km) south of Cabo San Lucas, Mexico.  The maximum sustained wind speed was 130 m.p.h. (215 km/h) which made Dolores a Category 3 hurricane on the Saffir-Simpson Scale.  There were wind gusts to 160 m.p.h. (260 km/h) and the minimum surface pressure was 946 mb.

Dolores is currently over water where the Sea Surface Temperature (SST) is around 29°C.  It is generating well developed upper level outflow which is pumping out mass and there is not much vertical wind shear.  Dolores could strengthen some more during the next 24 hours, although eyewall replacement cycles could produce fluctuations in intensity.  When Dolores moves north of latitude 20°N, it will move over cooler SSTs and it should start to weaken.  Given its size and intensity, it could take several days for the circulation around Dolores to spin down.

A ridge in the middle levels is steering Dolores toward the west-northwest.  That general steering pattern is expected to continue during the next few days and Dolores poses no current threat to land.

Tropical Storm Dolores Forms South of Mexico

A low level circulation organized in a large area of thunderstorms south of Acapulco, Mexico on Sunday and the system was classified as Tropical Storm Dolores.  At 2:00 p.m. EDT on Sunday the center of Tropical Storm Dolores was located at latitude 15.6°N and longitude 102.1°W which put it about 145 miles (230 km) south-southwest of Zihuatanejo, Mexico and about 295 miles (475 km) southeast of Manzanillo, Mexico.  Dolores was moving toward the 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 55 m.p.h. (90 km/h).  The minimum surface pressure was 1002 mb.  The government of Mexico has issued a Tropical Storm Watch for the portion of the coast from Lazaro Cardenas to Cabo Corrientes.

The circulation around Dolores is not particularly well organized.  Most of the strong thunderstorms are occurring in the eastern half of the circulation.  There are few thunderstorms in the southwestern part of the tropical storm.  Upper level winds are light over Dolores and the tropical storm is producing strong upper level divergence which is pumping out mass.  Dolores is over water where the Sea Surface Temperatures are near 30°C and there is plenty of energy in the upper ocean to support intensification.  Dolores is close enough to Mexico that it could be pulling in some drier air from land, which may be inhibiting intensification at this time.  The environmental factors would support intensification and rapid intensification may be possible if Dolores moves farther away from the coast of Mexico.

A strong mid-level ridge over Texas and Mexico is steering Dolores toward the west-northwest.  That general steering pattern is expected to continue for the next few days.  On its anticipated track the center of Dolores is forecast to stay west of the coast of Mexico.  However, the proximity of Dolores to the coast prompted the issuance of a Tropical Storm Watch for a portion of the coast.

Hurricane Carlos Weakening Quickly

It appears from satellite imagery that vertical wind shear quickly weakened Hurricane Carlos on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Carlos was located at latitude 18.2°N and longitude 104.5°W which put it about 55 miles (90 km) south-southwest of Manzanillo, Mexico.  Carlos was moving toward the northwest at 5 m.p.h. (7 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 988 mb.  A Hurricane Watch was in effect for the portion of the coast from Playa Perula to Punta San Telmo, Mexico and a Tropical Storm Warning was in effect for the portion of the coast from Cabo Corrientes to Punta San Telmo, Mexico.

After intensifying on Tuesday afternoon and exhibiting well developed upper level divergence, the structure of Hurricane Carlos degenerated quickly on Tuesday night.  Most of the strong thunderstorms dissipated.  Satellite imagery showed an exposed low level center near the Mexican coast, while the upper level canopy was moving westward away from the low level center.  The decoupling of the upper and low parts of the circulation, usually leads to quick weakening of a hurricane.  The small size of Carlos could allow it to weaken even more quickly than an average hurricane.  The most recent satellite images showed a few thunderstorms forming south of the center of circulation.  However, wind shear caused by an upper level ridge north of Carlos may be too strong to allow for the system to regain its vertical integrity.  Tropical cyclones that are sheared apart sometimes have one chance to redevelop.  The low level center is moving closer to the coast of Mexico and interaction with land may prevent any chance for redevelopment.

If the low level center remains separated from the rest of the system and it does not extend higher into the atmosphere, it will be steered by the winds in the lower levels.  Those winds appear to be taking it north-northwest toward the coast.  Carlos could dissipate quickly if it makes landfall, or the circulation could linger for a day or two if it stays farther offshore.

Very Small Hurricane Carlos Moving Just West of Mexico

Hurricane Carlos has a very small circulation and the tropical storm force winds extend out less than 50 miles (80 km) from the center.  At 8:00 p.m. EDT on Monday the center of Hurricane Carlos was located at latitude 17.2°N and longitude 103.3°W which put it about 90 miles (145 km) southwest of Lazaro Cardenas, Mexico and about 140 miles (225 km) south-southeast of Manzanillo.  Carlos was moving toward the west-northwest at 6 m.p.h. (9 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 989 mb.  A Hurricane Watch and a Tropical Storm Warning is in effect for the portion of the coast from Playa Perula to Punta San Telmo.

The small circulation of Hurricane Carlos continues to move over the Pacific Ocean west of Mexico.  It is moving over water where the Sea Surface Temperature is about 29°C.  An upper level ridge north of the hurricane is generating northeasterly winds that are impinging on the northern side of Carlos.  Those winds are inhibiting upper level divergence from the northern side of Carlos.  The small circulation means than any thunderstorms form near the center and the strongest storms are south of the center.  The small circulation also means that wind shear can have a very big effect on Carlos.  Even moderate winds in the upper levels would be strong enough to disrupt the vertical coherence of the hurricane and blow away the upper part of Carlos.  The vertical wind shear is expected to be modest in the short term, and Carlos is forecast to maintain its intensity for a day or two.  However, it would not take much increase in the wind shear to blow the top off Carlos.

The upper level ridge is expected to continue to steer Carlos toward the west-northwest for 24 to 36 hours.  After that time two scenarios are possible.  In one scenario the upper level ridge weakens and Carlos turns northward and moves very close the coast of Mexico near Cabo Corientes.  In an alternative scenario the ridge maintains its intensity and it steers Carlos toward the west-northwest for the next few days.  A third scenario, which could occur at any time, would happen if wind shear blows the top off of Carlos.  In that case the surface circulation would be steered westward by the lower level flow until it dissipated.  These three possible scenarios make the future track of Carlos very uncertain.

Small Tropical Storm Carlos Moving West of Acapulco

Carlos weakened to a tropical storm as it moved west of Acapulco, Mexico on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Carlos was located at latitude 16.7°N and longitude 101.3°W which put it about 95 miles (150 km) west of Acapulco and about 110 miles (175 km) southeast of Lazaro Cardenas.  Carlos was moving toward the northwest at 6 m.p.h. (9 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 998 mb.  Carlos is a small tropical cyclone.  The tropical storm force winds only extend out about 50 miles (80 km) from the center and it has a Hurricane Size Index (HSI) of 1.7.  The government of Mexico has issued a Hurricane Warning for the portion of the coast that extends from Punta San Telmo to Tecpan de Galeana.  A Hurricane Watch has been issued for the portion of the coast from Playa Perula to Punta San Telmo.

Carlos was nearly stationary for several days and its winds mixed cooler water to the surface.  In addition the circulation pulled in drier air from Mexico as it got closer to the coast.  The combined effects of cooler water and drier resulted in less energy to drive the circulation and Carlos weakened to a tropical storm on Sunday.  Late in the day it started to move toward the northwest and get away from the cooler water.  Carlos is moving over an area where the Sea Surface Temperature (SST) is near 30°C.  Recent satellite images indicate that stronger thunderstorms are forming near the center of circulation.  The flow around Carlos is still pulling in drier air from Mexico and there are fewer thunderstorms in the northern half of the tropical storm.  The small size of Carlos means that it can strengthen or weaken more quickly than a larger storm because there is less mass to accelerate.  The upper level winds over Carlos have lessened and there is not as much vertical wind shear.  If Carlos remains over water, it is likely to intensify back to a hurricane on Monday.

An upper level ridge over Mexico is moving slowly toward the east and it is starting to steer Carlos toward the northwest.  The ridge is expected to continue to steer the tropical storm toward the northwest or west-northwest on Monday.  As Carlos approaches the western end of the ridge is expected to turn more toward the west-northwest.  There is some uncertainty about where the turn will occur.  Guidance from some models have Carlos turning farther east and making a landfall between Manzanillo and Cabo Corientes, while some other models have the tropical storm moving farther west before turning.  Either scenario is plausible and hence, the high degree of uncertainty about the future track of Carlos.