Category Archives: Eastern and Central Pacific

TCs between Mexico and Hawaii

Tropical Storm Norbert Intensifying

Tropical Storm Norbert is becoming more organized as it moves in the general direction of Baja California.  At 8:00 a.m. EDT the center of Norbert was located at latitude 19.7°N and longitude 108.3°W which put it about 245 miles south-southeast of the southern tip of Baja California.  Norbert was moving toward the west-northwest at 8 m.p.h.  The maximum sustained wind speed was 60 m.p.h. and the minimum surface pressure was 999 mb.  The Tropical Storm Watch for the portion of the coast from La Paz to Sante Fe, Mexico has been upgraded to a Tropical Storm Warning.  A Tropical Storm Watch has been issued for the portion of the coast from Sante Fe northward to Cabo San Lazaro.

Norbert is over warm Sea Surface Temperatures (SSTs) and the upper level wind shear appears to be decreasing.  Some satellite imagery is indicating that an eye could be forming in the mid-levels of the circulation.  Further intensification is likely and a period of more rapid intensification is possible.  Norbert could become a hurricane before it reaches cooler SSTs west of Baja California.

 

Tropical Storm Norbert Forms

A center of circulation developed within a trough of low pressure southwest of Manzanillo, Mexico and the National Hurricane Center classified it as Tropical Storm Norbert.  At 5:00 p.m. EDT the center of Tropical Storm Norbert was located at latitude 18.5°N and longitude 106.5°W which put it about 150 miles west-southwest of Manzanillo and about 375 miles south of the southern tip of Baja California.  Norbert was moving toward the north at 9 m.p.h.  The maximum sustained wind speed was 40 m.p.h. and the minimum surface pressure was 1004 mb.  The government of Mexico has issued a Tropical Storm Watch for Baja California Sur from La Paz, around the southern tip of Baja California to Santa Fe.

Although there is some northeasterly shear over Norbert, the tropical storm is expected to intensify and at least one numerical model is predicting that it will become a hurricane.  Since Norbert is still in the organization stage, the track forecast has a higher than normal degree of uncertainty.  Many models are predicting that Norbert will move toward Baja California, but turn west-northwest before the storm reaches the coast.  The government of Mexico issued a Tropical Storm Watch for a portion in the coast in case Norbert moves closer to the coast than is currently expected.

 

Category 5 Hurricane Marie

Hurricane Marie continued to intensify rapidly as it moved westward away from Mexico.  It now has maximum sustained winds to 160 m.p.h. which makes it a Category 5 hurricane on the Saffir-Simpson Scale.  Marie is the first hurricane to reach Category 5 intensity over the Eastern North Pacific since Hurricane Celia in 2010.  Marie is a large hurricane and it is approximately half the size of Hurricane Sandy, but Marie is a symmetrical storm.  Hurricane force winds extend out 35-60 miles in all quadrants of Marie.  Marie is in a favorable environment with warm Sea Surface Temperatures and little vertical wind shear.  It could strengthen a little more or it may have attained its peak intensity.  Some satellite imagery suggests that a second eyewall may be forming and an eyewall replacement cycle would initially produce weakening followed possibly by fluctuations in intensity.

The Hurricane Intensity Index (HII) for Marie is 35.0.  The Hurricane Size Index (HSI) is 21.5.  The Hurricane Wind Intensity Size Index (HWISI) is 56.5.

Karina, Lowell and Marie

The atmosphere over the tropical Eastern North Pacific Ocean remains active with two hurricanes and a tropical storm.  Karina re-intensified into a hurricane about 1400 miles east of Hawaii.  It is moving slowly to the northeast as it is drawn into the large circulation around tropical storm Lowell.  Although the atmospheric conditions are allowing it to maintain hurricane force winds at the moment, it will encounter less favorable conditions as it moves farther north.

Tropical Storm Lowell is slowly spinning down about 1000 miles west of Baja California.  Lowell is moving slowly northwestward over cooler Sea Surface Temperatures (SSTs).  The SSTs are cool enough that Lowell is only generating lower clouds and it has not produced any deep thunderstorms in recent hours.  Lowell could be reclassified as a non-tropical low later today or tomorrow.  Lowell has a large circulation and it will take it a few days to spin down completely.

Hurricane Marie is intensifying rapidly about 330 miles south-southwest of Manzanillo, Mexico.  It currently has a maximum sustained wind speed of 85 m.p.h. and it could become a major hurricane during the next day or two.  Marie has a large well organized circulation and upper level divergence is well established over it.  It is expected to move northwestward parallel to the west coast of Mexico.  Marie is the 13th named tropical cyclone and 8th hurricane of the Eastern North Pacific 2014 season.

Tropical Storms Karina and Lowell and the Fujiwhara Effect

I am sometimes asked what happens when two tropical cyclones get close to each other.  The answer depends on the relative size and intensity of the two systems and how close they come to each other.  The Fujiwhara Effect is the name given to the tracks taken by the two vorticies.  If the two tropical cyclones are of nearly equal size and intensity, then they tend to move cyclonically around a center of rotation that is roughly half way between them.  If one cyclone is much bigger and stronger, then the center of rotation is shifted toward the bigger and stronger cyclone.

Tropical Storm Lowell has a large circulation and a maximum sustained wind speed of around 50 m.p.h.  Tropical Storm Karina is located about 700 miles to the west-southwest of Lowell.  Karina has a much smaller circulation and it also has a maximum sustained wind speed of 50 m.p.h.  Some of the models are forecasting that the two tropical storms will rotate around a point closer to Lowell than to Karina (i.e. the Fujiwara Effect).  This would result in Lowell moving general west-northwest and pass to the north of Karina.  The larger circulation of Lowell could also pull Karina back toward the east-northeast as Karina passes south of Lowell.  It is also possible that the circulation of Lowell could be so big that it captures Karina and Karina eventually gets absorbed by Lowell.

 

Julio becomes a hurricane again

An eye developed in Julio and it has been upgraded to hurricane status.  Even though Julio is located 600 miles north of Hawaii, it is over Sea Surface Temperatures (SSTs) that are warm enough to support a hurricane.  The upper level winds around Julio are light enough to allow for Julio to maintain a warm core.  Eventually, wind shear should increase and cooler SSTs will likely weaken Julio back to a tropical storm.

A new tropical depression has formed west of Mexico.  Tropical Depression Eleven-E (TD11E) is about 385 miles west-southwest of Manzanillo, Mexico and about 400 miles south of the southern tip of Baja, California.  it is moving toward the west-northwest at 16 m.p.h.  It is expected to intensify and if it becomes a tropical storm its name will be Karina.  Some numerical models are showing that it could eventually move in the general direction of Hawaii.