Tag Archives: EP20

Tropical Storm Selma Makes Landfall in El Salvador

Tropical Storm Selma made landfall in El Salvador on Saturday morning.  Selma weakened to a tropical depression after it moved inland.  At 11:00 a.m. EDT on Saturday the center of Tropical Depression Selma was located at latitude 13.7°N and longitude 88.5°W which put it about 45 miles (75 km) east of San Salvador, El Salvador.  Selma was moving toward the northeast at 8 m.p.h. (13 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 1006 mb.

The coastal warnings and watches for El Salvador and Honduras have been discontinued.

Tropical Depression Selma will continue to weaken as it moves farther inland.  The higher mountains will disrupt the circulation in the lower levels, but the circulation in the middle and upper levels could persist longer.  Tropical Depression Selma will drop locally heavy rain over El Salvador, western Honduras and eastern Guatemala.  The heavy rain could produce flash floods and mudslides.

Tropical Storm Selma Forms South of El Salvador

Tropical Storm Selma formed south of El Salvador on Friday morning.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Selma was located at latitude 11.1°N and longitude 89.5°W which put it about 180 miles (290 km) south of San Salvador, El Salvador.  Selma was moving toward the northwest at 5 m.p.h. (8 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 Tropical Storm Warning has been issued for the entire coast of El Salvador.  A Tropical Storm Watch has been issued for the entire Pacific Coast of Guatemala.

A distinct low level center of circulation formed in a larger area of thunderstorms south of El Salvador on Friday morning and the National Hurricane Center designated the system as Tropical Storm Selma.  The circulation of Tropical Storm Selma is very asymmetrical.  Most of the showers and thunderstorms are located in the western half of the circulation.  There are bands of showers in the eastern half of the circulation.  An upper level ridge centered over the Yucatan Peninsula is producing easterly winds which are blowing over the top of the circulation.  Those winds are causing moderate vertical wind shear which is the primary reason for the asymmetrical structure of the circulation.  Selma is a small tropical storm.  Winds to tropical storm force only extend out about 45 miles (75 km) from the center of circulation.

Tropical Storm Selma will be moving through an environment that is neutral for intensification.  Selma will move over water where the Sea Surface Temperature is near 29°C.  The upper level ridge will continue to cause moderate vertical wind shear.  The shear will inhibit further intensification.  If the upper level winds weaken, then some intensification may be possible.  However, if the upper level winds get stronger, then Selma could weaken to a tropical depression.

A large counterclockwise circulation centered over Nicaragua and Honduras is steering Tropical Storm Selma slowly toward the northwest and the general motion is expected to continue on Friday.  The upper level ridge over the Yucatan Peninsula will weaken on Saturday and that will allow Tropical Storm Selma to move more toward the north.  On its anticipated track Tropical Storm Selma will make landfall on the coast of El Salvador or Guatemala on Saturday.

Tropical Storm Selma will bring some gusty winds to the coast.  However, locally heavy rain and flash floods will be the primary risks associated with Tropical Storm Selma when it makes landfall.

Seymour Strengthens Into a Cat. 4 Hurricane

Hurricane Seymour strengthened into a small but very powerful Category 4 hurricane on the Saffir-Simpson Scale on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Seymour was located at latitude 16.1°N and longitude 117.7°W which put it about 690 miles (1110 km) southwest of the southern tip of Baja California.   Seymour was moving toward the west-northwest at 15 m.p.h.  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 943 mb.

The circulation of Hurricane Seymour is very small, but it is very well organized.  There is a circular eye with a diameter of 10 miles (12 km) which is surrounded by a ring of strong thunderstorms.  Winds to hurricane force only extend out about 18 miles (29 km) from the center of circulation.  Winds to tropical storm force extend out about 80 miles (130 km) from the center.  The Hurricane Intensity Index (HII) is 31.6, but the Hurricane Size Index (HSI) is only 7.1.  The Hurricane Wind Intensity Size Index is 38.7.  Hurricane Seymour is not as strong as Hurricane Patricia was in 2015 and Seymour is smaller than Patricia was.  When Hurricane Patricia had maximum sustained winds of 200 m.p.h. (320 km) its HSI ranged between 11.3 and 13.8.

Hurricane Seymour will remain in a very favorable environment for another 6 to 12 hours.  It will move over water where the Sea Surface Temperature (SST) is near 28°C.  The upper level winds will be light and there will be little vertical wind shear.  Later on Wednesday the upper level winds will increase and Hurricane Seymour will begin to move over cooler SSTs.  The increasingly unfavorable environment will cause Seymour to weaken.  Because of the small size of Seymour’s circulation, wind shear could cause the hurricane to weaken quickly.

Hurricane Seymour is moving around the western end of a ridge that is steering the hurricane toward the west-northwest.  When Seymour reaches the western end of the ridge, the hurricane will begin to move more toward the north.  On its anticipated track Hurricane Seymour will weaken well to the west of Baja California.  An upper level trough moving over the Northern Pacific Ocean could eventually transport some of the moisture from Hurricane Seymour over the western U.S.

Seymour Rapidly Intensifies into a Cat. 2 Hurricane

Tropical Storm Seymour rapidly intensified into a Category 2 hurricane on the Saffir-Simpson Scale on Monday as it moved farther away from Mexico.  At 11:00 p.m. EDT on Monday the center of Hurricane Seymour was located at latitude 15.5°N and longitude 112.6°W which put it about 540 miles (870 km) south-southwest of the southern tip of Baja California.  Seymour was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 976 mb.

Hurricane Seymour intensified very rapidly on Monday.  The maximum sustained wind speed increased from 50 m.p.h. (80 km/h) to 105 m.p.h. (165 km/h) in a 24 hour period.  The circulation contracted and the primary rainband wrapped tightly around a small eye.  Seymour is a very small hurricane and hurricane force winds only extend out about 12 miles (19 km) from the center of circulation.  Winds to tropical storm force only extend out about 70 miles (130 km) from the center.  Although Seymour is a small hurricane, the circulation is well organized.  The small eye is surrounded by an almost continuous ring of thunderstorms.  Several other spiral bands are rotating around the core of Hurricane Seymour.  Thunderstorms in the core are generating upper level divergence which is pumping out mass in all directions.

Hurricane Seymour will remain in a favorable environment on Tuesday.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are light and there is little vertical wind shear.  Hurricane Seymour is likely to intensify on Tuesday and it could become a major hurricane.  When Seymour moves farther to the west, it will be nearer to an upper level trough which will produce southwesterly winds over the hurricane.  Increased vertical wind shear will begin to weaken Hurricane Seymour.

A ridge over Mexico is steering Hurricane Seymour toward the west and that general motion will occur for another 24 to 36 hours.  Hurricane Seymour will approach the western end of the ridge on Wednesday, and the hurricane will turn more toward the north when that happens.  On its anticipated track this turn will occur well to the west of Baja California.

Tropical Storm Seymour Develops Quickly West of Mexico

Tropical Storm Seymour developed quickly west of Mexico on Sunday and it brought to an end a stretch of three quiet weeks over the Eastern North Pacific Ocean.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Seymour was located at latitude 14.4°N and longitude 107.1°W which put it about 370 miles (590 km) south-southwest of Manzanillo, Mexico.  Seymour was moving toward the west-northwest at 15 m.p.h. (24 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 1002 mb.

The circulation in a cluster of thunderstorms organized quickly on Sunday afternoon.  A primary rainband around the northern and western sides of the circulation wrapped almost entirely around the center and an eye appeared to be forming on microwave satellite images.  Additional bands of thunderstorms were developing.  Thunderstorms in the core of Seymour were beginning to generate upper level divergence.

Tropical Storm Seymour will be moving through a very favorable environment.  It is moving over water where the Sea Surface Temperature is near 31°C.  The upper level winds are relatively weak and there is little vertical wind shear.  Tropical Storm Seymour will continue to intensify and it could intensify rapidly.  Seymour will become a hurricane and it could become a major hurricane.

A ridge over Mexico is steering Tropical Storm Seymour toward the west-northwest and that general motion is expected to continue for several more days.  When Seymour reaches the western end of the ridge, it will turn toward the north.  On its anticipated track Tropical Storm Seymour will make the northward turn well to the southwest of Baja California.

Patricia Is Strongest East Pacific Hurricane on Record

Hurricane Patricia continued to intensify rapidly during the overnight hours and it is now the strongest hurricane on record for the Eastern North Pacific.  At 11:00 a.m. EDT on Friday the center of Hurricane Patricia was located at latitude 17.6°N and longitude 105.5°W which put it about 125 miles (200 km) southwest of Manzanillo, Mexico.  Patricia was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 200 m.p.h. (320 km) and there were wind gusts to 245 m.p.h. (400 km/h).  The minimum surface pressure was 880 mb.

A Hurricane Warning is in effect for the portion of the coast between Sas Blas and Punta San Telmo, Mexico.  A Tropical Storm Warning and a Hurricane Watch is in effect for the portion of the coast from Punta San Telmo to Lazaro Cardenas, Mexico.

Hurricane Patricia has broken a number of records.  The maximum sustained wind speed increased from 85 m.p.h. to 200 m.p.h. between 5:00 a.m. EDT on Thursday and 5:00 a.m. EDT on Friday.  The rate of increase of 115 m.p.h. in 24 hours is the fastest rate of intensification observed in the Eastern Pacific. It exceeds the 100 m.p.h. in 24 hours that occurred in Hurricane Linda in 1997.  Interestingly, 1997 was also an El Nino year.  The minimum surface pressure of 880 mb is the lowest ever recorded in the National Hurricane Center’s Area of Responsibility which includes the Atlantic and Eastern North Pacific Oceans.  It is lower than the 882 recorded when Hurricane Wilma was over the Caribbean Sea in 2005.

Hurricane Patricia is an extremely dangerous hurricane.  It has a Hurricane Intensity Index (HII) of 50.0, a Hurricane Size Index (HSI) of 11.3 and a Hurricane Wind Intensity Size Index (HWISI) of 61.3.  Those indices mean that Patricia will be capable of causing catastrophic regional damage when it reaches the west coast of Mexico north of Manzanillo later on Friday.  Hurricane Patricia will be capable of causing catastrophic wind damage, generating a potentially destructive storm surge near the coast and producing heavy rain and flooding as it moves inland.

Category 5 Hurricane Patricia Threatens West Coast of Mexico

Hurricane Patricia continued to intensify very rapidly on Thursday night and it reached Category 5 on the Saffir-Simpson Scale.  At 11:00 p.m. EDT on Thursday the center of Hurricane Patricia was located at latitude 16.2°N and longitude 105.1°W which put it about 200 miles (320 km) south-southwest of Manzanillo, Mexico.  Patricia was moving toward the north-northwest at 10 m.p.h.  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h).  The minimum surface pressure was 924 mb.

The government of Mexico has issued a Hurricane Warning for the portion of the coast from San Blas to Punta San Telmo.  A Hurricane Watch and a Tropical Storm Warning is in effect for the portion of the coast from Punta San Telmo to Lazaro Cardenas.

Hurricane Patricia has a Hurricane Intensity Index (HII) of 35.0.  The Hurricane Size Index (HSI) is 12.4 and the Hurricane Wind Intensity Size Index (HWISI) is 47.4.  Those indices mean that Hurricane Patricia is capable of causing catastrophic regional damage.  Hurricane Patricia is currently about the same size that Hurricane Dennis was before Dennis hit the northern coast of the Gulf of Mexico in 2005.  However, Patricia is stronger than Dennis was at that time.

Hurricane Patricia remains in an environment with warm Sea Surface Temperatures and little vertical wind shear.  Only an eyewall replacement cycle could cause weakening in the short term.  When Hurricane Patricia moves farther north, it will start to encounter upper level winds blowing from the southwest, which will increase the wind shear.  The wind shear could start to weaken Patricia later on Friday.

Hurricane Patricia is moving around the western end of ridge and the hurricane has turned toward the north.  When Patricia encounters the southwesterly winds in the upper levels, it will turn toward the northeast.  On its anticipated track Hurricane Patricia could make landfall on the west coast of Mexico between San Blas and Boca de Apiza on Friday night.  Even though Hurricane Patricia could weaken somewhat before it makes landfall, it will still be a very dangerous hurricane.  Hurricane Patricia poses a major threat to cause significant regional wind damage and a storm surge at the coast.  Heavy rain could produce serious flooding, especially as Patricia moves inland over steeper terrain.

Hurricane Patricia Intensifies Rapidly to Category 4

Hurricane Patricia intensified rapidly on Thursday and it reached Category 4 on the Saffir-Simpson Scale.  The maximum sustained wind speed in Patricia increased from 60 m.p.h. to 130 m.p.h. in 24 hours, which qualified as very rapid intensification.  At 5:00 p.m. EDT on Thursday the center of Hurricane Patricia was located at latitude 15.4°N and longitude 104.6°W which put it about 250 miles (400 km) south of Manzanillo, Mexico.  Patricia was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 953 mb.  The Hurricane Intensity Index (HII) for Patricia was 25.1, the Hurricane Size Index (HSI) was 10.4 and the Hurricane Wind Intensity Size Index was 35.5.  Those indices mean that Patricia is almost as strong and just a little larger than Hurricane Charley was when it hit southwest Florida in 2004.

The government of Mexico has issued a Hurricane Warning for the portion of the coast from San Blas to Punta San Telmo.  It has also issued a Hurricane Watch and a Tropical Storm Warning for the portion of the coast from Punta San Telmo to Lazaro Cardenas.

Patricia is a small hurricane, but it has a very well organized circulation.  A ring of strong thunderstorms surrounds a small, 12 mile (19km), eye (sometimes called a pinhole eye because of the way it looks on satellite images).  Multiple spiral bands are rotating around the core fo the circulation.  Thunderstorms in the core are generating strong upper level divergence in all directions.

Hurricane Patricia remains in a very favorable environment.  It is over water were the Sea Surface Temperature is near 30°C.  An upper level ridge over the top of Patricia is keeping the vertical wind shear to a minimum.  Patricia could intensify further, although if concentric eyewalls develop, then eyewall replacement cycles could produce fluctuations in wind speeds.

Hurricane Patricia is moving around the western end of a ridge that extends from the Gulf of Mexico over Mexico.  When Patricia reaches the end of ridge on Friday, it will turn toward the north.  As the hurricane moves farther north it will encounter westerly winds in the southern end of an upper level trough.  Those winds will turn Hurricane Patricia toward the northeast.

On its anticipated track Hurricane Patricia could approach the west coast of Mexico late on Friday.  It will pose a serious threat to the coast at that time.  Patricia will bring strong winds, heavy rain and a storm surge to the coast.  Very heavy rain could fall as Hurricane Patricia moves inland and serious flooding will be possible, especially in the more mountainous areas of Mexico.  The remnants of Hurricane Patricia could eventually move over parts of Texas and add moisture and rain to that region.

Tropical Storm Patricia Intensifies Quickly and Mexico Issues Warnings

Tropical Storm Patricia reorganized and intensified quickly on Wednesday and the government of Mexico issued warnings for portions of its west coast.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Patricia was located at latitude 13.1°N and longitude 99.5°W, which put it about 265 miles (425 km) south of Acapulco, Mexico and about 515 miles (830 km) southeast of Manzanillo.  Patricia was moving toward the west at 16 m.p.h. (26 km/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 995 mb.

The government of Mexico has issued a Hurricane Warning for the portion of the coast from Cabo Corrientes to Punta San Telmo.  A Tropical Storm Warning and a Hurricane Watch has been issued for the portion of the coast from Punta San Telmo to Lazaro Cardenas.  A Tropical Storm Watch has been issued for the portion of the coast from Lazaro Cardenas to Tecpan de Galeana.

A NOAA aircraft investigated Tropical Storm Patricia on Wednesday and it found that the center of circulation had reorganized farther west of the remnants of the center that existed on Tuesday.  The new center was west of the northerly low level winds blowing out of the Gulf of Tehuantepec and it was in a more favorable environment.  Thunderstorms are developing near the center of circulation and multiple spiral bands are rotating around the center.

Patricia is moving over water where the Sea Surface Temperature is near 31°C and there is a lot of energy in the upper ocean.  The upper level winds are light and there is not much vertical wind shear.  The lack of wind shear is allowing the thunderstorms near the center to pump out mass and the surface pressure is decreasing.  Patricia will remain a favorable environment until it approaches the west coast of Mexico later this week.  Rapid intensification is likely and Patricia could intensify into a major hurricane before it reaches the coast.

A ridge over the Gulf of Mexico and Mexico is steering Patricia toward the west and that motion is expected to continue for another day or so.  After that time Patricia will reach the western end of the ridge and it will turn toward the north.  On its anticipated track Patricia could be nearing the west coast of Mexico on Friday.

 

Tropical Storm Patricia Forms South of Mexico

A center of circulation began to consolidate inside an area of thunderstorms south of the Gulf of Tehuantepec on Tuesday and the National Hurricane Center designated the system as Tropical Storm Patricia.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Patricia was located at latitude 13.1°N and longitude 95.3°W which put it about 220 miles (355 km) south-southeast of Puerto Escondido, Mexico.  Patricia was moving toward the west-southwest at 5 m.p.h. (8 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 1004 mb.

The circulation of Tropical Storm Patricia was still organizing on Tuesday.  A cluster of thunderstorms formed northeast of the center of circulation earlier on Tuesday, but those storms weakened during recent hours.  A primary rainband extends around the western and southern side of the circulation.  However, there is not much convection northwest of the center of circulation.

Tropical Storm Patricia is over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge surrounds Patricia and it should produce light winds near the tropical storm.  Warm SSTs and little vertical wind shear should allow for intensification.  However, closer to the surface northerly winds blowing across the Gulf of Tehuantepec could be transporting some drier air toward the western side of the circulation.  The drier air could explain the current lack of thunderstorms in that part of Patricia.  Over time the favorable large scale environment should allow for intensification and Patricia could eventually become a hurricane.

A ridge of high pressure north of Patricia is steering the tropical storm toward the west.  That steering motion is expected to continue for another day or so.  When Patricia reaches the western end of the ridge, it will turn toward the north.  Patricia could be approaching the western coast of Mexico on Friday and it could be a hurricane at that time.