Tag Archives: 21E

Tropical Storm Sergio Brings Rain to Baja California

Tropical Storm Sergio brought rain to Baja California on Friday morning.  At 8:00 a.m. EDT on Friday the center of Tropical Storm Sergio was located at latitude 26.8°N and longitude 112.8°W which put it about 45 miles (75 km) southwest of Santa Rosalia, Mexico.  Sergio was moving toward the northeast at 24 m.p.h. (39 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 998 mb.

A Tropical Storm Warning was in effect for the west coast of Baja California from Punta Eugenia to Cabo San Lazaro, Mexico.  A Tropical Storm Warning was also in effect for the east coast of Baja California from Bahia San Juan Bautista to Mulege, Mexico.

Tropical Storm Sergio was weakening as it approached Baja California.  An upper level trough was producing strong southwesterly winds which were blowing across the top of Tropical Storm Sergio.  Those winds were causing strong vertical wind shear and they were in the process of blowing the middle and upper portions of the circulation northeast of the surface circulation.  A combination of strong vertical wind shear and passage over mountains on Baja California will case Tropical Storm Sergio to weaken quickly.

Tropical Storm Sergio will drop locally heavy rain over parts of Baja California and northern Mexico.  The greatest risk from Sergio is the potential for the locally heavy rain to cause flash floods.  The remnants of Tropical Storm Sergio could enhance rainfall in southeastern New Mexico, West Texas, and Oklahoma during the weekend.

Tropical Storm Sergio Cause Warnings for Baja California

Tropical Storm Sergio prompted the issuance of warnings and watches for parts of Baja California on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Sergio was located at latitude 20.0°N and longitude 121.5°W which put it about 770 miles (1240 km) west-southwest of the southern tip of Baja California.  Sergio was moving toward the northeast at 16 m.p.h. (26 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 992 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Punta Eugenia to Cabo San Lazaro, Mexico.  A Tropical Storm Watch was in effect for the portion of the coast from Bahia San Juan Bautista to San Evaristo, Mexico.

Tropical Storm Sergio weakened slightly on Wednesday, but the structure of the circulation remained well organized.  A large clear area at the center of circulation was the remnant of the eye that existed when Sergio was a hurricane.  The remnant of the eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Several thin bands of showers and thunderstorms were revolving around the core of Tropical Storm Sergio.  Winds to tropical storm force extended out about 140 miles (225 km) from the center of Sergio.

Tropical Storm Sergio will move over cooler water on Thursday.  An upper level trough west of California will produce southwesterly winds which will blow toward the top of the circulation.  Those winds will cause moderate vertical wind shear.  The combination of cooler water and more wind shear will cause Tropical Storm Sergio to weaken slowly.

The upper level trough will steer Tropical Storm Sergio toward the northeast during the next several days.  On its anticipated track Tropical Storm Sergio will reach Baja California on Thursday night.  Sergio will bring gusty winds, but locally heavy rain is a greater risk because heavy rain could cause flash floods.

Hurricane Sergio Turns Back Toward Baja California

Hurricane Sergio turned back toward Baja California on Tuesday morning.  At 11:00 a.m. EDT on Tuesday the center of Hurricane Sergio was located at latitude 16.6°N and longitude 127.4°W which put it about 1215 miles (1960 km) west-southwest of the southern tip of Baja California.  Sergio was moving toward the northeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 982 mb.

Hurricane Sergio was slowly weakening.  It appeared that cooler, drier air was entering the western half of the circulation.  Sergio has been moving slowly and its winds may have mixed some cooler water to the surface of the ocean.  Rainbands on the western side of Sergio consisted primarily of showers and lower clouds and thunderstorms in western side of the eyewall were weakening.  Stronger thunderstorms were still occurring in the eastern side of the eyewall and that was where the strongest winds were occurring.  Some strong storms were also occurring in a band southeast of the center of circulation.

Hurricane Sergio will move through an environment that will cause it to continue to weaken slowly.  Sergio is currently over water where the Sea Surface Temperature is near 27°C, but it will move over cooler water in a day or so.  An upper level trough centered west of California will produce southwesterly winds which will cause more vertical wind shear.  The combination of cooler water and more wind shear will cause Hurricane Sergio to weaken to a tropical storm within the next 24 to 36 hours.

The upper level trough will steer Hurricane Sergio toward the northeast during the next several days.  On its anticipated track Sergio could approach central Baja California on Thursday night.  It will likely be a tropical storm at that time.  Tropical Storm Watches could be issued for parts of the coast later today or on Wednesday.  Sergio will bring gusty winds and it will drop locally heavy rain.  The rain could cause flash flooding.  Sergio could also bring some rain to New Mexico and west Texas during the weekend.

Major Hurricane Sergio Churns Southwest of Baja California

Major Hurricane Sergio churned southwest of Baja California.  At 5:00 p.m. EDT on Wednesday the center of Hurricane Sergio was located at latitude 13.3°N and longitude 117.9°W which put it about 845 miles (1360 km) southwest of the southern tip of Baja California.  Sergio was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 955 mb.

Hurricane Sergio is a well organized hurricane.  There is a circular eye at the center of circulation.  A ring of strong thunderstorms surrounds the eye and the strongest winds are occurring in that ring of storms.  Several bands of showers and thunderstorms are revolving around the core of Hurricane Sergio.  Storms near the core are generating strong upper level divergence which is pumping mass away in all directions from the hurricane.

Winds to hurricane force extend out about 45 miles (75 km) from the center of Hurricane Sergio.  Winds to tropical storm force extend out about 150 miles (240 km) from the center of circulation.  The Hurricane intensity Index (HII) for Hurricane Sergio is 23.6.  The Hurrricane Size Index (HSI) is 15.1 and the Hurricane Wind Intensity Size Index (HWISI) is 38.7.

Hurricane Sergio will remain in an environment capable of supporting a major hurricane for several more days.  Sergio will move over water where the Sea Surface Temperature is near 28°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Sergio could strengthen to Category 4 on the Saffir-Simpson Scale.  Hurricane Sergio will move over cooler water in a couple of days and it is likely to weaken when that occurs.

Hurricane Sergio will move south of a subtropical ridge over the Eastern North Pacific Ocean.  The ridge will steer Sergio toward the northwest during the next day or so.  The ridge is forecast to strengthen on Friday and it will steer Sergio more toward the west when that happens.  On its expected track Hurricane Sergio will move gradually farther away from Baja California.

Tropical Storm Rosa Nears Baja California

Tropical Storm Rosa moved nearer to Baja California on Monday morning.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Rosa was located at latitude 27.5°N and longitude 116.5°W which put it about 90 miles (145 km) west-southwest of Punta Eugenia, Mexico.  Rosa was moving toward the north-northeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1000 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Punta Abreojos to Cabo San Quintin, Mexico.  A Tropical Storm Watch was in effect for the portion of the coast from Bahia de los Angeles to San Felipe, Mexico.

Tropical Storm Rosa was weakening as it approached the coast of Baja California.  Rosa was moving over water where the Sea Surface Temperature was near 23°C.  An upper level low west of California was producing southwesterly winds which were blowing toward the top of the circulation.  Those winds were causing significant vertical wind shear.  The effects of cool water and vertical shear were causing most of the stronger thunderstorms to occur northeast of the center of circulation.  Bands south and west of the center consisted primarily of showers and lower clouds.

The center of Tropical Storm Rosa will reach northern Baja California in a few hours.  Rosa will bring some gusty winds when when it reaches the coast, but the greater risk is locally heavy rainfall.  Rosa could drop several inches of rain and flash floods could occur.  The lower level part of Rosa’s circulation will weaken when it crosses Baja California.  However, the upper low west of California will steer the middle and upper parts of Tropical Storm Rosa over the Southwestern U.S.  Rosa, or its remnants, could drop locally heavy rain over that region during the next several days.  Flash Flood Watches have been issued for southeastern California, eastern Nevada, western Arizona, and much of Utah.

Elsewhere over the Eastern North Pacific, Tropical Storm Sergio was strengthening slowly south of Baja California.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Sergio was located at latitude 11.5°N and longitude 109.5°W which put it about 790 miles (1275 km) south of the southern tip of Baja California.  Sergio was moving toward the west at 14 m.p.h. (22 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 995 mb.

Hurricane Rosa Moves Toward Baja California

Hurricane Rosa moved toward Baja California on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Hurricane Rosa was located at latitude 22.4°N and longitude 118.9°W which put it about 440 miles (710 km) south-southwest of Punta Eugenia, Mexico.  Rosa was moving toward the north at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 969 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Punta Abreojos to Cabo San Quintin, Mexico.  A Tropical Storm Watch was in effect for the portion of the coast from Bahia de los Angeles to San Felipe, Mexico.

Hurricane Rosa will move into an environment unfavorable for hurricanes on Sunday.  Rosa will move over water where the Sea Surface Temperature is cooler than 26°C.  In addition an upper level low near the west coast of the U.S. will produce southwesterly winds which will cause vertical wind shear.  The combination of cooler water and more vertical wind shear will cause Hurricane Rosa to weaken.  Rosa could weaken to a tropical storm by Sunday night.

The upper low will steer Hurricane Rosa toward the northeast during the next several days.  On its anticipated track Rosa could reach Baja California on Monday.  It will likely be a tropical storm at that time.  Even though it will weaken, Rosa will drop heavy rain over parts northern Baja California and the southwestern U.S.  The heavy rain could cause flash floods.

Elsewhere over the Eastern North Pacific Ocean Tropical Storm Sergio formed southwest of Acapulco, Mexico.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Sergio was located at latitude 12.3°N and longitude 103.3°W which put it about 390 miles (630 km) southwest of Acapulco, Mexico.  Sergio was moving toward the west 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 60 m.p.h. (95 km/h).  The minimum surface pressure was 1003 mb.

Tropical Storm Tina Forms West of Manzanillo

More thunderstorms formed near the center of a low pressure system west of Mexico on Sunday and the National Hurricane Center classified the system as Tropical Storm Tina.  At 10:00 p.m. EDT on Sunday the center of Tropical Storm Tina was located at latitude 18.5°N and longitude 107.1°W which put it about 185 miles (300 km) west of Manzanillo, Mexico.  Tina was moving toward the north at 3 m.p.h. (5 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.

The circulation of Tropical Storm Tina is not well organized.  Although there is a definite center of circulation in the lower levels, most of the thunderstorms are developing north and east of the center of circulation.  An upper level trough southwest of California is generating southwesterly winds which are blowing across the top of Tropical Storm Tina.  The strong vertical wind shear is tilting the circulation and it is causing the thunderstorms to be concentrated in the northeastern quadrant of the circulation.  The upper level winds are also inhibiting upper level divergence.

Although Tropical Storm Tina is moving over water where the Sea Surface Temperature is near 30°C, the atmospheric environment is unfavorable for intensification.  The strong vertical wind shear will prevent any significant intensification.  In fact, if the upper level winds get much stronger, the shear could blow the top half of the circulation northeast of the bottom half.  In that case the low level circulation will quickly spin down and dissipate.

If the vertical integrity of the circulation is maintained, then the upper level trough will steer Tropical Storm Tina toward the northeast and into Mexico.  However, if the circulation shears apart, a surface high pressure system could steer it slowly toward the west.  In either case the upper level winds could transport some moist air over Jalisco and Colima, where it could enhance rainfall.

TD 21E Intensifies into Tropical Storm Rick

The organization of Tropical Depression 21E improved slightly on Thursday and the National Hurricane Center upgraded it to Tropical Storm Rick.  At 10:00 p.m. EST on Thursday the center of Tropical Storm Rick was located at latitude 15.2°N and longitude 108.1°W which put it about 365 miles (585 km) southwest of Manzanillo, Mexico.  Rick was moving toward the west-northwest at 10 m.p.h. (16 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 1002 mb.

More thunderstorms formed near the center of Tropical Depression 21E for a few hours on Thursday and the improved organization prompted the National Hurricane Center to upgrade the system to Tropical Storm Rick.  The organization of Rick has diminished in recent hours. The stronger thunderstorms are located northwest of the center of circulation and there are few thunderstorms in the rest of the Rick.  An upper level ridge located east of the tropical storm is producing southerly winds over the top of Rick.  The vertical wind shear is causing the stronger thunderstorms to be northwest of the center.

Rick is over water where the Sea Surface Temperature is near 29°C.  So, there is enough energy in the ocean to support intensification.  However, the strong vertical wind shear is likely to limit intensification and it could weaken Rick if it the shear gets stronger.

The ridge east of Rick is expected to strengthen and to continue to steer the tropical storm toward the west-northwest for another day or two.  After that time Rick will reach the western end of the ridge, and the tropical storm will turn more toward the north.

Poorly Organized Tropical Depression 21E Forms West of Mexico

A low level circulation center formed in a cluster of thunderstorms west of Mexico and the National Hurricane Center decided it had enough organization to be classified as a tropical depression.  At 10:00 p.m. EDT on Wednesday the center of Tropical Depression 21E (TD21E) was located at latitude 13.2°N and longitude 106.1°W which put it about 420 miles (675 km) south-southwest of Manzanillo, Mexico.  TD21E was moving toward the north at 2 m.p.h. (3 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 1004 mb.

TD21E looked more well organized earlier today when the low level center of circulation was located within the area of thunderstorms.  The low level center is now southeast of an area of weakening thunderstorms, which is an indication that the tropical depression is poorly organized.  Most of the remaining thunderstorms are located north of the low level center.

The tropical depression is over water where the Sea Surface Temperature is near 30°C.  However, the environment is not really favorable for intensification.  An upper level ridge east of the depression is causing southerly winds over the top of TD21E.  Those winds are generating vertical wind shear over the top of the depression.  The wind shear has blown the thunderstorms north of circulation center.  Some slight intensification may be possible if the wind shear decreases, but the poor organization of the depression will limit any potential strengthening.

If the tropical depression retains its vertical integrity, the southerly winds in the upper levels should push it toward the north.  However, if the wind shear blows the thunderstorms farther north of the low level center of circulation, then the low level center could remain stationary while it spins down.