Tag Archives: Nevada

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.

Hurricane Rosa Rapidly Intensifies Into a Major Hurricane Southwest of Baja California

Hurricane Rosa rapidly intensified into a major hurricane southwest of Baja California on Thursday.  At 5:00 p.m. EDT on Thursday the center of Hurricane Rosa was located at latitude 16.9°N and longitude 115.9°W which put it about 570 miles (915 km) southwest of the southern tip of Baja California.  Rosa was moving toward the west at 10 m.p.h. (16 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. (240 km/h).  The minimum surface pressure was 953 mb.

Hurricane Rosa rapidly intensified into a powerful hurricane on Thursday and a circular eye developed at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in the ring of storms.  The circulation around Hurricane Rosa was symmetrical.  Several bands of showers and thunderstorms were revolving around the core of the hurricane.  Storms around the core were generating strong upper level divergence which was pumping mass away from the hurricane.

The circulation around Hurricane Rosa was relatively small.  Winds to hurricane force only extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 115 miles (185 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Rosa was 23.6.  The Hurricane Size Index (HSI) was 9.8 and the Hurricane Wind Intensity Size Index (HWISI) was 33.4.

Hurricane Rosa will continue to move through an environment favorable for intensification during the next 12 to 24 hours.  Rosa 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 during the shorter term.  If a rainband wraps around the existing eye and eyewall, an eyewall replacement cycle could halt the current period of rapid intensification.  Hurricane Rosa will start to move over cooler water during the weekend.  An upper level low west of California will produce southwesterly winds which will blow toward the top of Rosa’s circulation.  Those winds will cause more vertical wind shear and they could cause Rosa to weaken more quickly.

Hurricane Rosa will move around the western end of a ridge of high pressure over northern Mexico on Friday.  Rosa will start to move more toward the north when it moves around the western end of the ridge.  The upper level trough east of California will turn Rosa more toward the northeast during the weekend.  On its anticipated track Rosa could approach Baja California early next week.  It may weaken to a tropical storm before it gets to Baja California, but it still will have the potential to drop heavy rain.

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.

Hurricane Blanca Heading for West Coast of Baja California

Hurricane Blanca turned toward the north-northwest on Saturday and it appears headed toward the west coast of Baja California.  At 11:00 p.m. EDT on Saturday the center of Hurricane Blanca was located at latitude 19.2°N and longitude 110.4°W which put it about 255 miles (415 km) south of Cabo San Lucas, Mexico.  Blanca was moving toward the north-northwest at 10 m.p.h. (17 km/h).  The maximum sustained wind speed was 120 m.p.h. (185 km/h) and there were gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 952 mb.  The Hurricane Intensity Index (HII) was 22.1, the Hurricane Size Index (HSI) was 20.2 and the Hurricane Wind Intensity Size Index (HWISI) was 42.3.  The government of Mexico has issued a Hurricane Watch for the portion of the coast from Cabo San Lucas to Santa Fe.  A Tropical Storm Warning has been issued for the portion of the coast from Loreto to Puerto San Andresito including Cabo San Lucas.  Tropical Storm Watches have been issued for the portions of the coast from Puerto San Andresito to Punta Abreojos and from Loreto to Mulege.

Hurricane Blanca intensified early on Saturday as it was moving over water where the Sea Surface Temperature (SST) was near 28°C.  It is currently over water where the SST is closer to 27°C and it will move over cooler water when it gets north of latitude 20°N.  As a result it will be unable to extract enough energy from the upper ocean to maintain its current intensity.  An upper level ridge over Mexico also seems to be generating some easterly winds near Blanca and those winds are responsible for vertical wind shear on the eastern half of the circulation.  The combination of shear and cooler SSTs should steadily weaken the hurricane on Sunday.  However, it has a well organized circulation and it will spin down relatively slowly.  The rate of weakening will increase once it moves over SSTs that are cooler than 26°C.  Blanca could still have hurricane force winds when it nears the southern tip of Baja California.

A mid-level ridge over Texas and northern Mexico and a trough over the southwestern U.S. are combining to steer Blanca toward the north-northwest.  That track should continue as long as the vertical structure of the hurricane remains intact.  As Blanca weakens over cooler water, the vertical integrity of the circulation will not be as strong.  Some storms that move just west of Baja California, as Blanca is forecast to do, have the upper portion of their circulation decouple from the lower level circulation.  In those cases the middle and upper level portions of the circulation continue to move northward across Baja California and into the southwestern U.S., while the low level circulation stalls and spins down west of Baja California.  On its anticipated track Blanca could bring some strong winds to portions of southern Baja California, but the greater risks are high waves and locally heavy rainfall that could produce flooding.