Hurricane Guillermo (1997)

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Hurricane Guillermo
Guillermo at peak intensity on August 4
Meteorological history
FormedJuly 30, 1997
ExtratropicalAugust 15, 1997
DissipatedAugust 24, 1997
Category 5 major hurricane
1-minute sustained (SSHWS/NWS)
Highest winds160 mph (260 km/h)
Lowest pressure919 mbar (hPa); 27.14 inHg
Overall effects
Fatalities3
DamageNone
Areas affectedMexico, Hawaii, California
IBTrACSEdit this at Wikidata
Part of the 1997 Pacific hurricane season

Hurricane Guillermo was the ninth-most intense

Category 5 hurricane. The storm began to weaken during the afternoon of August 5 and was downgraded to a tropical storm on August 8. Once entering the Central Pacific Hurricane Center's area of responsibility, Guillermo briefly weakened to a tropical depression before re-attaining tropical storm status. On August 15, the storm reached an unusually high latitude of 41.8°N before transitioning into an extratropical cyclone
. The remnants persisted for more than a week as they tracked towards the northeast and later south and east before being absorbed by a larger extratropical system off the coast of California on August 24.

Throughout Guillermo's lengthy track, the storm never threatened any major landmass, resulting in little impact on land. However, because of its extreme intensity, it produced large swells across the Pacific Ocean, affecting areas from Hawaii to coastal Mexico. Along the American Pacific coast, three people drowned amid high waves, two in Baja California and one in California. At its peak, Guillermo was the second strongest known Pacific hurricane on record; however, it has since been surpassed by seven other storms, including Linda later that year. The effects of Guillermo were not deemed severe enough to justify retirement of its name.

Meteorological history

Map plotting the storm's track and intensity, according to the Saffir–Simpson scale
Map key
Saffir–Simpson scale
  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown
Storm type
triangle Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression

Hurricane Guillermo began its extensive track as a

named storm of the 1997 season.[1]

By the afternoon of August 1, a strong

Saffir–Simpson Hurricane Scale. Throughout the next day, the system gradually developed an eye within the central dense overcast, leading to further strengthening.[1] Operationally, Guillermo was thought to have briefly leveled out in intensity on August 2;[2] however, in post-storm analysis, the NHC discovered that a steady period of rapid intensification took place.[1] Unlike most hurricanes in the eastern Pacific, Guillermo was investigated by hurricane hunters reconnaissance aircraft during its rapid intensification stage. The aircraft released several dropsondes into the storm to gather meteorological data.[3] This mission marked the first time the hurricane hunters recorded high-resolution wind data from flight level to within several meters of the ocean surface inside the eyewall of a major hurricane.[4]

Hurricane Guillermo undergoing rapid intensification on August 4

inHg). A brief period of weakening took place later that day before further strengthening ensued.[1] Late on August 4, Guillermo intensified into a Category 5 hurricane, attaining peak winds of 160 mph (260 km/h).[1] Operational analysis of satellite information indicated a minimum pressure of 921 hPa (27.20 inHg);[2] however, post-storm studies stated that the pressure was more likely around 919 hPa (27.14 inHg).[1]

At its peak, cloud temperatures within the eyewall were estimated to be as low as −79 °C (−110 °F). Using the Dvorak technique, a method used to estimate the intensity of tropical cyclones, a value of 7.6 was obtained. This indicated that maximum winds at the surface could have been as high as 181 mph (291 km/h); however, this was not used as the reported intensity as six- to twelve-hour averages indicated sustained winds around 160 mph (260 km/h).[6] After maintaining this intensity for roughly 18 hours, the system began to weaken as it moved into a less favorable environment with moderate wind shear.[1][3] Cloud temperatures within the eyewall also began to increase, indicating that the hurricane was losing intensity.[1]

Radar image of Hurricane Guillermo on August 3

Steady weakening took place over the following several days, and the storm dropped below major hurricane status on August 6. By August 8, Guillermo moved over colder waters and was downgraded to a tropical storm as sustained winds dropped below 75 mph (121 km/h). Around this time, the storm started to move along the western edge of the ridge that previously steered it towards the west-northwest, causing Guillermo to turn northwest. On August 9, the storm crossed longitude 140°W, denoting a shift in warning responsibility from the NHC to the Central Pacific Hurricane Center (CPHC).[1] Not long after crossing into the CPHC's area of responsibility, the storm further weakened to a tropical depression as it moved over 24 °C (75 °F) waters.[7]

Although most tropical cyclones generally weaken as they increase in

Hawaiian islands.[7] Later that day, Guillermo transitioned into an extratropical cyclone at an unusually high latitude of 41.8°N,[1] roughly 850 mi (1,370 km) south-southeast of Unalaska, Alaska.[8] Over the following days, the remnants of the hurricane turned northeastward towards the Pacific coast of North America. On August 19, the system moved within 575 mi (925 km) of Vancouver Island, British Columbia, before Guillermo tracked southward. Over the following few days, the system slowed significantly and turned towards the east.[1] By August 20, moisture from the remnants of Tropical Storm Ignacio were entrained into the eastern portion of Guillermo's circulation.[9] On August 24, Guillermo's remnant low was finally absorbed by a larger extratropical system, while situated roughly 345 mi (555 km) off of the northern California coastline.[1]

Impact and records

Most intense Pacific hurricanes[8]
Rank Hurricane Season Pressure
hPa inHg
1 Patricia 2015 872 25.75
2 Linda 1997 902 26.64
3 Rick 2009 906 26.76
4 Kenna 2002 913 26.96
5 Ava 1973 915 27.02
Ioke 2006
7 Marie 2014 918 27.11
Odile
9 Guillermo 1997 919 27.14
10 Gilma 1994 920 27.17
Listing is only for tropical cyclones in the Pacific Ocean
north of the equator and east of the
International Dateline

Along the Pacific coast of Mexico, 12-foot (3.7 m) surf produced by Hurricane Guillermo affected numerous beaches. From Cabo San Lucas to San José del Cabo, the storm sent waves from the Gulf of California over the grounds of beachside resorts. Tourists were driven off some of Cabo's most popular beaches by the rough ocean conditions which flooded homes situated along the coast. Two sightseers were killed after being swept out to sea.[10]

Due to accurate forecasts, emergency officials across California were able to close off swimming zones and warn the public about dangerous

Corona Del Mar, while an 18-year-old was pulled ashore and sent to the hospital with neck injuries. In Newport Beach, lifeguards made nearly 300 rescues on August 5 and 6 alone.[15]

In addition to coastal impacts, the system brought a surge of warm, moist air into Southern California, bringing temperatures in some areas as high as 110 °F (43 °C).[16] Between August 15 and 17, large waves generated while Guillermo was at peak intensity came ashore in Hawaii. The swells caused no damage and reached heights of 10 feet (3.0 m) in eastern-facing shores of the state.[7]

At the time, Hurricane Guillermo's central pressure of 919 mbar (27.14 inHg) established it as the second-most intense Pacific hurricane on record, behind

Patricia all achieved lower minimum pressures, leaving Guillermo in ninth place. Guillermo persisted for 16.5 days from its classification as a tropical depression to its transition into an extratropical storm, making it the sixth longest-lasting storm in the basin.[8]

See also

References

  1. ^ a b c d e f g h i j k l Mayfield, Britt M (October 2, 1997). Preliminary Report: Hurricane Guillermo (PDF) (Report). United States National Hurricane Center. Retrieved January 31, 2023.
  2. ^ a b National Hurricane Center (1997). "Operational Track for Hurricane Guillermo". Unisys Weather. Archived from the original on October 2, 2012. Retrieved July 6, 2010.
  3. ^
    doi:10.1175/2008MWR2487.1
    .
  4. S2CID 119404326
    .
  5. ^ Matthew Sitkowski; Klaus Dolling; Gary Barnes (2005). "The Rapid Intensification of Hurricane Guillermo (1997) As Viewed With GPS Dropwindsondes" (PDF). Department of Meteorology, University of Hawaii. American Meteorological Society. Retrieved July 6, 2010.
  6. ^ Regional And Mesoscale Meteorology Team (August 7, 1997). "Daily Satellite Discussion: Thursday August 7, 1997". National Oceanic and Atmospheric Administration.
  7. ^ a b c Hablutzel, Benjamin C; Rosendal, Hans E; Weyman, James C; Hoag, Jonathan D (1997). Hurricane Guillermo Preliminary Report (PDF) (Report). United States Central Pacific Hurricane Center. Retrieved July 6, 2010.
  8. ^ a b c National Hurricane Center; Hurricane Research Division; Central Pacific Hurricane Center (April 4, 2023). "The Northeast and North Central Pacific hurricane database 1949–2022". United States National Oceanic and Atmospheric Administration's National Weather Service. A guide on how to read the database is available here. Public Domain This article incorporates text from this source, which is in the public domain.
  9. ^ Edward N. Rappaport (August 27, 1997). "Tropical Storm Ignacio Preliminary Report". National Hurricane Center. Retrieved July 26, 2010.
  10. ^ Cabo Bob (2007). "Hurricanes in Cabo San Lucas". Unknown. Archived from the original on February 6, 2012. Retrieved March 6, 2007.
  11. ^ Scott Hadly (August 10, 1997). "Area Surfers Catch Wave of Forecast Data". Los Angeles Times. Retrieved July 8, 2010.
  12. ^ a b "California Event Report: High Surf". National Climatic Data Center. 1997. Archived from the original on July 6, 2010. Retrieved March 6, 2007.
  13. ^ Steve Carney (August 8, 1997). "Board Meeting; Competition Draws 500 Surfers, Big Crowds and Storm-Stoked Waves". Los Angeles Times. p. 3. Retrieved July 8, 2010.
  14. ^ Jim Benning (August 30, 2005). "A swell season takes shape". Los Angeles Times. Retrieved July 8, 2010.
  15. ^ a b "California Event Report: Rip Currents". National Climatic Data Center. 1997. Archived from the original on September 6, 2009. Retrieved March 6, 2007.
  16. ^ Ed Jahn (August 6, 1997). "As summer turns up heat, SDG&E says 'cool it' Temperatures might retreat by weekend". The San Diego Union – Tribune. p. A.1. Retrieved July 8, 2010.[permanent dead link]

External links

Wikimedia Commons has media related to Hurricane Guillermo (1997).

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