Hurricane Hernan (2002)

Infobox Hurricane
Name=Hurricane Hernan
Type=hurricane
Year=2002
Basin=EPac
Image location=Hurricane hernan 2002.jpeg


Formed=August 30, 2002
Dissipated=September 6, 2002
1-min winds=145
Pressure=921
Da

Inflated=
Fatalities=None
Areas=Pacific coast of Mexico, Socorro Island, California
Hurricane season=2002 Pacific hurricane season

Hurricane Hernan was the second of three Category 5 hurricanes during the 2002 Pacific hurricane season. The twelfth tropical cyclone, tenth named storm and sixth hurricane of the season, Hernan originated from a tropical wave that formed in the Atlantic Ocean and crossed to the Pacific Ocean. The wave spawned a low pressure system which organized into a tropical depression on August 30, a tropical storm on August 31 and a hurricane later that day. Hernan rapidly intensified and reached peak intensity as a Category 5 storm on the Saffir-Simpson Hurricane Scale. Proceeding northwest, it maintained this strength for eight hours, but on September 2 it entered cooler waters and began to weaken. By September 6 it had degenerated into a remnant area of low pressure.

Hernan was the second most intense hurricane of the season, and it maintained Category 5 status for the second-longest time of the season, behind Hurricane Kenna.cite web| author=NHC Hurricane Research Division|title=Atlantic hurricane best track|publisher=National Oceanic and Atmospheric Administration|year=2007|accessdate=2008-01-31|url=http://www.aoml.noaa.gov/hrd/hurdat/easyhurdat_5106.html] Although Hernan remained far from land, swells of nowrap|15 to 20 feet nowrap|(4 to 6 meters) caused minor beach erosion along the coast of Mexico. In addition, an associated remnant plume of moisture generated light shower activity in southern California as it tracked just offshore.cite web|author=|title=Showers along the Southwest coast|year=2002|publisher="Syracuse Post-Standard"|accessdate=2008-02-20|url=http://thehurricanearchive.com/Viewer.aspx?
]

Meteorological history

On August 16, a tropical wave left the coast of Africa. It traveled westward across the Atlantic Ocean, crossing over Central America and emerging in the eastern Pacific, where it merged with a pre–existing intertropical convergence zone disturbance. The system gradually developed moderate convection, and on August 30 it had developed sufficient convection to be designated Tropical Depression 10–E.Cite web|author=Miles B. Lawrence|title=Hurricane Hernan Tropical Cyclone Report|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/2002hernan.shtml] The depression produced persistent strong thunderstorms, primarily in two areas of deep convection located to the northeast and west of the center of circulation. Although the center was elongated, wind shear over the system remained light and outflow was good, which led forecasters to predict modest intensification.cite web|author=Franklin|title=Tropical Depression 10-E Discussion Number 2|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.002.html] On the afternoon of August 30, banding features became evident, and the depression was upgraded to Tropical Storm Hernan with sustained winds of 45 mph (72 km/h).Cite web|author=Franklin|title=Tropical Storm Hernan Public Advisory Number 3|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.003.html] Further organization occurred, and the center of circulation became encircled by convective thunderstorms.Cite web|author=Beven|title=Tropical Storm Hernan Public Advisory Number 4|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.004.html] On August 31, the storm was upgraded to Hurricane Hernan as it moved northwestward about 400 miles (634 km) southwest of Acapulco.Cite web|author=Lawrence|title=Hurricane Hernan Public Advisory Number 5|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.005.html]

Light wind shear and favorable ocean temperatures led to steady intensification of the storm, and satellite images indicated that an eye had developed late on August 31.cite web|author=Avila|title=Hurricane Hernan Public Advisory Number 6|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.006.html] Minimum pressure lowered to nowrap|987 mb (hPa), and the maximum winds increased to 100 mph,cite web|author=Avila|title=Hurricane Hernan Public Advisory Number 6|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.006.html] Category 2 on the Saffir-Simpson Hurricane Scale. The storm quickly reached Category 3, a major hurricane, and soon after, Category 4. As it did so, its eye became ragged,Cite web|author=Jarvinen/Knabb|title=Hurricane Hernan Public Advisory Number 8|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.008.html] while its lateral movement to the northwest rose to 17 mph around the southern periphery of a strong deep–layer ridge over the United States.Cite web|author=Jarvinen/Knabb|title=Hurricane Hernan Public Advisory Number 8|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.008.html] By September 1, the hurricane reached its peak intensity of 165 mph (270 km/h) and a minimum pressure of 921 mb (hPa). It had reached Category 5, the second of three such powerful storms that would do so during the season.

By September 2, the storm's convective thunderstorms warmed slightly, indicating weakening to just below Category 5. An eyewall replacement cycle took place, and two eye structures formedCite web|author=Jarvinen/Molleda|title=Hurricane Hernan Public Advisory Number 12|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.012.html] as gradual weakening continued. By September 2, the storm was downgraded to Category 3 just before it turned slightly to the west.Cite web|author=Stewart|title=Hurricane Hernan Public Advisory Number 14|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.014.html] The storm underwent another eyewall replacement cycle as winds decreased further.Cite web|author=Stewart|title=Hurricane Hernan Public Advisory Number 15|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.015.html] As the storm entered cooler waters, winds decreased to 100 mph (160 km/h), below major hurricane intensity. Soon Hernan was downgraded to Category 1, and the eye became cloud-filled.Cite web|author=Avila|title=Hurricane Hernan Public Advisory Number 19|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.019.html] On September 5, Hernan was downgraded to a tropical storm as winds rapidly weakened to 45 mph (72 km/h) despite developing a new band of convection.cite web|author=Stewart/Rhome|title=Tropicla Storm Hernan Public Advisory Number 25|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.025.html] That same day, the storm was downgraded to a tropical depression as it began to lose tropical characteristics. Strong wind shear developed, further dissipating the depression.Cite web|author=Stewart/Rhome|title=Tropical Depression Hernan Public Advisory Number 29|year=2002|publisher=National Hurricane Center|accessdate=2008-02-18|url=http://www.nhc.noaa.gov/archive/2002/dis/ep102002.discus.029.html] On September 6, the system degenerated into a remnant low-pressure system which spawned a remnant plume of moisture that meandred off the coast of California, producing light showers.

Impact, records and naming

Hurricane Hernan remained far from shore and caused little damage to land. It brought light wind to Socorro Island off the coast of Mexico. Rough surf caused minor impacts; in the open waters near the center of Hernan, waves generated by the storm were unofficially reported to exceed 70 feet (21 meters). However, official buoys reported swells of 57 feet (17 meters).Cite web|author=Nathan Todd Cool|title=70 waves generated by Hernan|year=|publisher=|accessdate=2008-02-18|url=http://wavecast.com/guide/questions.shtml] Along the coast of Mexico, waves reached nowrap|15 to 20 feet (4 to 6 meters), causing minor beach erosion.cite web|author=National Climatic Data Center|title=Event Report for Hurricane Hernan|year=2002|publisher=|accessdate=2008-02-20|url=http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~ShowEvent~450914] A portion of Hernan's remnant moisture off the southern California coast produced light rainfall and slippery roads.cite web|author=|title=Showers along the Southwest coast|year=2002|publisher="Syracuse Post-Standard"|accessdate=2008-02-20|url=http://thehurricanearchive.com/Viewer.aspx?
] Hernan had no known effects on shipping.

Hernan and Hurricane Elida tied for second place behind Hurricane Kenna in the list of most intense storms of the 2002 Pacific hurricane season. Hernan's time as a Category 5 hurricane, 12 hours, was second to Kenna's.cite web| author=NHC Hurricane Research Division|title=Atlantic hurricane best track|publisher=National Oceanic and Atmospheric Administration|year=2007|accessdate=2008-01-31|url=http://www.aoml.noaa.gov/hrd/hurdat/easyhurdat_5106.html] When Hernan grew from tropical storm to Category 5, it intensified at a rate of nowrap|1.73 mbar (hPa) per hour, just under the threshold for "rapid intensification". However, for a 12–hour period from August 31 to September 1, it deepened at nowrap|2.58 mbar (hPa) per hour, within the range of "explosive deepening" due to favorable conditions including light wind shear and warm water.cite web|author=Gary Padgett|title=August Tropical Cyclone Summary|year=|publisher=|accessdate=2008-02-20|url=http://www.weathermatrix.net/archive/tropical/summaries-2002/0012.html] Hernan was one of three Category 5 hurricanes in the 2002 Pacific hurricane season.cite web| author=NHC Hurricane Research Division|title=Atlantic hurricane best track|publisher=National Oceanic and Atmospheric Administration|year=2007|accessdate=2008-01-31|url=http://www.aoml.noaa.gov/hrd/hurdat/easyhurdat_5106.html] Because Hernan caused no severe effects, the name "Hernan" was not retired and was used again in the 2008 Pacific hurricane season.cite web|title=Worldwide Tropical Cyclone Names|year=2007|publisher=National Hurricane Center|accessdate=2008-02-19|url=http://www.nhc.noaa.gov/aboutnames.shtml]

See also

* Other tropical cyclones named Hernan
* List of Category 5 Pacific hurricanes

References

External links

* [http://www.nhc.noaa.gov/2002hernan.shtml Tropical Cyclone Report]
* [http://www.weather.unisys.com/hurricane/e_pacific/2002/HERNAN/track.gifPath]