Tag Archives: Guatemala

Strong Shear Weakens Adrian to a Tropical Depression

Strong vertical wind shear weakened Tropical Storm Adrian to a tropical depression on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Depression Adrian was located at latitude 10.5°N and longitude 93.1°W which put it about 420 miles (675 km) south-southeast of Salina Cruz, Mexico.  Adrian was moving toward the northwest at 5 m.p.h. (7 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 1007 mb.

An upper level ridge east of Adrian generated strong southeasterly winds which produced strong vertical wind shear and literally blew the top off of the tropical storm.  The upper half of the circulation was carried well to the northwest of low level circulation.  The low level circulation consists low clouds and weak showers.  No new thunderstorms have formed in the low level circulation since it decoupled from the upper half of the circulation.

Strong upper level winds are likely to continue to create strong vertical wind shear on Thursday.  Tropical Depression Adrian is likely to remain weak on Thursday.  If the low level circulation persists for several more days, then the upper level winds could weaken.  The Sea Surface Temperature is near 30°C.  So, if there is still a low level circulation, some strengthening could occur when the upper level winds diminish.

Tropical Storm Adrian Develops South of Guatemala

Tropical Storm Adrian developed south of Guatemala on Tuesday.  Adrian became the earliest tropical storm to form over the Eastern North Pacific Ocean during the satellite era.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Adrian was located at latitude 9.5°N and longitude 92.3°W which put it about 360 miles (575 km) southwest of San Salvador, El Salvador.  Adrian 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 1005 mb.

A well defined low level center of circulation developed within a large area of thunderstorms over the Eastern North Pacific Ocean on Tuesday and the National Hurricane Center classified the system as Tropical Storm Adrian.  A primary rainband wrapped about half way around the western side of the center of circulation.  Additional bands of showers and thunderstorms formed farther away from the center.  There were more thunderstorms west of the center, but bands were forming in all quadrants of Tropical Storm Adrian.  The strongest winds were occurring close to the center of circulation, which is the typical structure of a tropical cyclone.  Thunderstorms near the core of Adrian were beginning to generate upper level divergence which was pumping away mass.

Tropical Storm Adrian will be moving through an environment that will be favorable for intensification.  Adrian will move over water where the Sea Surface Temperature will be about 30.5°C.  An upper level ridge east of Adrian is producing southeasterly winds which are blowing toward the top of the circulation.  Those winds are causing some vertical wind shear, but the shear should not be great enough to prevent intensification.  Tropical Storm Adrian is likely to intensify during the next several days and it could become a hurricane later this week.

Adrian is moving around the southwestern part of a subtropical ridge, which is steering the tropical storm toward the west-northwest.  A general west-northwesterly motion is expected to continue for several more days.  When Adrian reaches the western end of the ridge later this week, the tropical storm will turn toward the north and it will move closer toward the coast.

Possible Tropical Development South of El Salvador

A broad area of low pressure has formed over the Eastern North Pacific Ocean south of El Salvador.  The environment is favorable for the development of a tropical cyclone.  The National Hurricane Center (NHC) has designated the low pressure system as Invest 90E.  NHC is indicating that there is a 50% probability of the formation of a tropical depression during the next 48 hours and an 80% probability of formation during the next five days.

At 2:00 p.m. EDT on Monday the center of Invest 90E was located at latitude 7.9°N and longitude 89.5°W which put it about 370 miles (595 km) south of San Salvador, El Salvador.  Invest 90E was stationary.  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 1008 mb.

More thunderstorms formed on Monday around a broad area of low pressure south of El Salvador.  Visible satellite imagery suggested a broad counterclockwise rotation of the area of thunderstorms, but there were no indications of a well developed core of the circulation.  Several smaller centers of rotation were visible within the broad low pressure system, but these may be transient features.  The broad area of thunderstorms was producing upper level divergence.  The divergence is pumping out mass and if that continues, then the surface pressure will decrease.

The area of low pressure is in an environment favorable for tropical development.  It is moving over water where the Sea Surface Temperature is near 30°C.  The low is sitting underneath an upper level ridge and the winds in the upper level are weak.  There is little vertical wind shear and there is nothing to inhibit upper level divergence.  The circulation should continue to organize, which is why the probability of formation of a tropical cyclone is high.

The area of low pressure is in an area where the steering currents are weak and Invest 90E was nearly stationary on Monday.  A high pressure system northeast of the broad area of low pressure system is expected to strengthen.  When that happens, the high is likely to steer the area of low pressure toward the northwest.

Otto Becomes a Hurricane, Watches and Warnings Issued

Tropical Storm Otto intensified into a hurricane on Tuesday as it meandered over the southwestern Caribbean Sea.  At 4:00 p.m. EST on Tuesday the center of Hurricane Otto was located at latitude 10.5°N and longitude 79.6°W which put it about 235 miles (375 km) east of Limon, Costa Rica.  Otto was moving toward the west at 2 m.p.h. (3 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 984 mb.

Hurricane Watches have been issued for the portion of the coast from the Costa Rica/Panama border to Bluefields, Nicaragua.  Tropical Storm Warnings have been issued for the portion of the coast from Nargana to Colon, Panama and for San Andres Island, Colombia.  Tropical Storm Watches have been issued for the portions of the coast from Colon, Panama to the Panama/Costa Rica border and from Bluefields to Sandy Bay Sirpi, Nicaragua.

The inner core of Hurricane Otto became more circular and symmetrical on Tuesday.  An eyelike feature appeared on microwave satellite imagery and hints of an eye were seen intermittently on visible imagery during the day.  There appeared to be breaks in the eyewall on the southeast side of the eye.  Most of the stronger thunderstorms are forming northwest of the eye.  Convective activity outside the core of Hurricane Otto is more asymmetrical.  There are some thinner rainbands north and west of the center where winds from a high pressure system are converging into the circulation of Otto.  There are fewer showers and thunderstorms in the southeastern quadrant of the circulation.  Thunderstorms around the center of the hurricane are generating upper level divergence at the very top of the circulation.

Hurricane Otto has a very small circulation.  Winds to hurricane force only extend out about 10 miles (15 km) from the center of circulation.  Winds to tropical storm force only extend out about 70 miles (110 km) from the center.  The Hurricane Intensity Index (HII) for Otto is 10.4.  The Hurricane Size Index (HSI) is 3.2 and the Hurricane Wind Intensity Size Index (HWISI) is 13.6.

Hurricane Otto will be moving through an environment that will be favorable for intensification.  It will move over water where the Sea Surface Temperature is 29°C.  An upper level ridge located east of Otto is generating southeasterly winds which are blowing against the upper portion of the circulation of the hurricane.  Those winds appear to be hitting Otto just under the level of upper level divergence at the top of the circulation.  So, the upper level winds and vertical wind shear appear to be restricting upper level divergence to the south of the circulation, but they do not appear to be completely blocking divergence.  The speed of the upper level winds is forecast to decrease.  If the vertical shear decreases, then Hurricane Otto could strengthen.

A ridge of high pressure is forecast to build north of Hurricane Otto.  That ridge will steer Otto toward the west and the hurricane could start to move faster on Wednesday.  On its anticipated track Hurricane Otto could approach the coast of Costa Rica and Nicaragua on Thursday.

Hurricane Otto is a small hurricane, but it could cause localized minor wind damage.  Heavy rain, flash floods and mudslides are a much greater threat.  Hurricane Otto could bring flooding rains to portions of Nicaragua, Honduras, Panama, Costa Rica, Guatemala and El Salvador.

On a historical note Hurricane Martha formed during this time of year in 1969 in almost exactly the same area where Hurricane Otto formed.  Hurricane Martha moved southward and weakened.  Martha officially made landfall in Panama as a tropical storm, but it did cause flooding rains and fatalities in parts of Costa Rica.

TD 16 Becomes Tropical Storm Otto

The National Hurricane Center named former Tropical Depression 16 as Tropical Storm Otto on Monday afternoon based on data from satellites.  At 4:00 p.m. EST the center of Tropical Storm Otto was located at latitude 11.3°N and longitude 79.2°W which put it about 315 miles (505 km) east of Bluefields, Nicaragua.  Otto was stationary.  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 1000 mb.

The structure of Tropical Storm Otto has not changed appreciably during today.  Most of the thunderstorms are occurring in bands north and west of the center of circulation.  There are fewer thunderstorms in the southeastern quadrant of the circulation.  Otto is a small tropical storm.  Winds to tropical storm force only extend out about 35 miles (55 km) from the center.  Thunderstorms are generating upper level divergence which is pumping mass out north and west of the tropical storm.

Tropical Storm Otto will move through an environment that will be favorable for intensification.  It will move over water where the Sea Surface Temperature will be near 29°C unless Otto moves so slowly that its own circulation mixes cooler water to the surface.  Southerly winds in the upper levels are generating moderate vertical wind shear, but those winds are expected to weaken.  When the vertical shear diminishes, Tropical Storm Otto will be likely to intensify and it could become a hurricane.

Tropical Storm Otto is currently in a region where the steering currents are weak.  However, a ridge of high pressure is forecast to build north of Otto, and the ridge is likely to steer the tropical storm toward the west.  On its anticipated track Tropical Storm Otto could approach the coast of Nicaragua and Costa Rica in 48 to 72 hours.

Tropical Storm Otto could be a hurricane by the time it reaches the coast of Nicaragua and Costa Rica.  Otto will be capable of bringing gusty winds and heavy rain to portions of Nicaragua, Costa Rica, northern Panama, Honduras, El Salvador and southern Guatemala.  The locally heavy rain could produce flash floods and mudslides in areas of steep terrain.

Tropical Storm Earl Strengthens Near Veracruz

Tropical Storm Earl regained strength on Friday after the center moved over the southern Bay of Campeche near Veracruz, Mexico.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Earl was located at latitude 18.8°N and longitude 95.0°W which put it about 85 miles (135 km) east-southeast of Veracruz, Mexico.  Earl was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 70 m.p.h. (115 km/h).  The minimum surface pressure was 1001 mb.

Because Tropical Storm Earl re-intensified and the radius of tropical storm force winds expanded to the north, the government of Mexico extended Tropical Storm Warnings farther north along the coast.  A Tropical Storm Warning is in effect for the portion of the coast from Puerto Dos Bocas to Tecolutla, Mexico.

Most of the circulation of Tropical Storm Earl remained intact while it moved over land from Belize to the Bay of Campeche.  As a result, the surface part of the circulation on the northern side of Earl began to redevelop quickly as the center approached the water in the Bay of Campeche.  A primary rainband wrapped most of the way around the center of circulation and other rainbands reformed over the Bay of Campeche.  There have been hints on an incipient eye forming at the center of circulation on recent visible satellite images.  Earl is a very well organized tropical storm.

The Sea Surface Temperature is near 30°C in the southern Bay of Campeche.  The upper level winds are weak and there is little vertical wind shear.  Upper level divergence is well formed in Tropical Storm Earl and it is pumping out mass.  The environment is favorable for further intensification.  However, the center of circulation is close to the coast and approximately 40% of the circulation is over land.  So, the proximity to land is the main factor inhibiting further strengthening.  Tropical Storm Earl does have a few hours to intensify and it could get stronger.

A subtropical ridge north of Earl is steering the tropical storm toward the west and that general motion is expected to continue.  On its anticipated track the center of Tropical Storm Earl will be very near Veracruz, Mexico in 10-12 hours.

The winds in Tropical Storm Earl are strong enough to create a storm surge of several feet (1-2 m) near where the center makes landfall and north of that location.  The primary risks from Tropical Storm Earl will be very heavy rainfall and flash flooding.

Earl Becomes a Hurricane As It Moves Toward Belize

A NOAA aircraft investigating Tropical Storm Earl found that there were sustained winds to hurricane force and the National Hurricane Center upgrade it to Hurricane Earl at 5:00 p.m. EDT on Wednesday.  At 5:00 p.m EDT the center of Hurricane Earl was located at latitude 17.1°N and longitude 86.0°W which put it about 150 miles (240 km) east of Belize City, Belize.  Earl was moving slightly north of due west at 14 m.p.h. (22 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 Warning is in effect for the Bay Islands of Honduras and the portion of the coast from Puerto Costa Mayo, Mexico to the Belize/Guatemala border.  A Tropical Storm Warning is in effect for the coast of Honduras from Cabo Gracias a Dios to the Honduras/Guatemala border and from Punta Allen, Mexico to Puerto Costa Mayo.

The Hurricane Intensity Index (HII) for Earl is 10.4.  The Hurricane Size Index (HSI) is 8.0 and the Hurricane Intensity Size Index (HWISI) is 18.4.  Those indices mean that Earl is capable of causing localized minor wind damage.

The structure of Hurricane Earl improved significantly on Wednesday as it moved farther from the northern coast of Honduras.  An eye developed at the center of circulation and a band of thunderstorms wrapped about two thirds of the way around the eye.  The eyewall is broken southwest of the center.  Additional bands of thunderstorms are rotating around the periphery of the circulation.  The core of strongest winds is relatively small and only extends about 60 miles (95 km) from the center.  However, outer rainbands extend at least 250 miles (400 km) from the center of circulation and the overall size of Hurricane Earl is much larger than it was yesterday.

Hurricane Earl is moving through an environment that is favorable for further intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  It is located beneath an upper level ridge and the upper level winds are weak.  So, there is little vertical wind shear and the ridge is enhancing the upper level divergence.  Hurricane Earl has another 10 – 15 hours to intensify before it reaches the coast.  Earl will weaken as it moves inland, but it could re-intensify after it moves over the Bay of Campeche.  The amount of re-intensification will depend on how long Hurricane Earl remains over land and where it enters the Bay of Campeche.

A subtropical high pressure system is steering Hurricane Earl on a track that is a little north of due west and that general motion is expected to continue for several more days.  On its anticipated track the center of Hurricane Earl will reach the coast near the border between Mexico and Belize in about 10 – 15 hours.

Since it is a hurricane, Earl will be capable of causing some wind damage.  Hurricane Earl will also create a storm surge near and to the north of where the center makes landfall because the winds will be pushing water toward the coast.  The size and number of the rainbands in Hurricane Earl will create the potential for very heavy rainfall and serious flooding as it moves inland over Belize and Mexico.

Tropical Storm Earl Forms over the Western Caribbean

Based on data collected by an Air Force Reserve Hurricane Hunter reconnaissance plane, the National Hurricane Center designated a system previously known as Invest 97L as Tropical Storm Earl.  At 12:00 p.m. EDT on Tuesday the center of Tropical Storm Earl was located at latitude 16.3°N and longitude 80.2°W which put it about 535 miles (860 km) east of Belize City, Belize.  Earl was moving toward the west at 22 m.p.h. (35 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 1001 mb.

A Hurricane Watch and a Tropical Storm Warning has been issued for the portion of the coast from Punta Allen, Mexico to the Belize/Guatemala border.  A Tropical Storm Warning has been issued for the portion of the coast from Cabo Gracias a Dios to the Honduras/Guatemala border.

The recon plane found a small closed low level center of circulation on the western edge of a cluster of thunderstorms.  The circulation around Tropical Storm Earl is very small.  Winds to tropical storm force only extend out about 80 miles (130 km) from the center of circulation.  Most of the thunderstorms are occurring in the eastern half of the tropical storm.  Those thunderstorms are generating upper level divergence which has pumped out enough mass to allow the surface pressure to decrease a few millibars during the past 12 hours.

The environment around Tropical Storm Earl is somewhat favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 29°C.  An upper level low centered near the western tip of Cuba is producing southwesterly winds which are blowing over the western side of Tropical Storm Earl.  Those westerly winds are producing some vertical wind shear, which is why most of the thunderstorms are in the eastern half of Earl.  The wind shear is inhibiting intensification, but the upper low is forecast to move farther from Earl, which would reduce the shear.  If Earl move north of the coast of Honduras, it should intensify.  However, if the center of circulation moves over Honduras, then Earl could weaken fairly quickly because of its small size.

The subtropical high over the Atlantic Ocean is steering Tropical Storm Earl toward the west at a fairly rapid speed.  The high is expected to continue to steer Earl toward the west during the next several days, but the tropical storm is expected to move a little more slowly on Wednesday.  On its anticipated track the center of Tropical Storm Earl is expected to pass just north of the coast of Belize.  Earl could be very close to Belize in about 36 hours.

Earl is a small tropical storm and the greatest risks are locally heavy rainfall and flash flooding.