Hurricane Emilia (1994)

Hurricane Emilia (1994)
Category 5 major hurricane (SSHWS/NWS)

Hurricane Emilia near peak intensity on July 19
Formed July 16, 1994
Dissipated July 25, 1994
Highest winds 1-minute sustained: 160 mph (260 km/h)
Lowest pressure 926 mbar (hPa); 27.34 inHg
Fatalities None
Damage None
Areas affected Hawaii
Part of the 1994 Pacific hurricane season

Hurricane Emilia was, at the time, the strongest tropical cyclone on record in the central Pacific Ocean, and the first of such to be classified as a Category 5 hurricane – the highest rating on the Saffir–Simpson hurricane wind scale. However, hurricanes Gilma later that year and Ioke in 2006 later reached lower barometric pressures in the Central Pacific. The fifth named storm and the first of three Category 5 hurricanes of the 1994 hurricane season, Emilia developed from an area of low pressure southeast of Hawaii on July 16. Tracking westward, the initial tropical depression intensified into a tropical storm several hours after tropical cyclogenesis. Subsequently, Emilia entered Central Pacific Ocean and moved into the area of responsibility of the Central Pacific Hurricane Center (CPHC).

After reaching hurricane intensity the following day, the tropical cyclone began to rapidly intensify, and late on July 17, Emilia reached its record peak intensity with maximum sustained winds of 160 mph (260 km/h) and a minimum barometric pressure of 926 mbar (hPa; 27.34 inHg), rating it as a Category 5 hurricane. After slight oscillations in strength, and upper-level trough forced the intense hurricane northwest on July 21, and Emilia began to weaken thereafter. The tropical cyclone encountered an area of vertical wind shear and cool sea surface temperatures, which further weakened the system. The following day, Emilia made its closest approach to the Big Island of Hawaii, but subsequently weakened to below hurricane intensity. This weakening trend continued, and the tropical cyclone fully dissipated on July 25. Though the hurricane per se did not make landfall, Emilia brought strong surf to the islands of Hawaii and caused gusty winds, which resulted in some property damage. Precipitation was also reported, but remained under moderate levels.

Meteorological history

Map plotting the track and intensity of the storm according to the Saffir–Simpson hurricane wind scale

On June 29, a weak tropical wave exited the west African coast and traversed the Atlantic with no signs of organization or convective activity. Moving within the Intertropical Convergence Zone, the tropical disturbance remained inactive until July 14, when it developed into an area of low pressure roughly 2,110 mi (3,400 km) east-southeast of the Hawaiian Islands. A low-level circulation was present, and a tropical depression is believed to have formed on July 17 due to increasing organization. Later, satellite imagery suggested that the system had intensified to Tropical Storm Emilia with 40 mph (65 km/h) sustained winds.[1][2] Emilia steadily strengthened to a minimal hurricane, moving west-northwest.[2] It crossed 140°W and entered the Central Pacific Hurricane Center's (CPHC) area of responsibility, which noted that Emilia was "well developed."[3] Emilia attained winds of 100 mph (160 km/h), which marked the beginning of a rapid intensification period.[2][3] Maximum sustained winds increased from 115 mph (185 km/h) on July 17 to 160 mph (260 km/h) late on July 19, which was a period of 42 hours.[3] At the time, an Air Force reconnaissance aircraft measured a minimum central pressure of 926 mbar (27.34 inHg) and maximum winds of 160 mph (260 km/h), hinting that the storm has reached peak intensity.[4][nb 1]

Oblique view from orbit

On July 20, Emilia briefly weakened to a Category 4 hurricane, but it re-intensified to Category 5 status 12 hours later during the day.[3] Subsequently, Emilia began to weaken for the final time. An upper-level trough in the westerlies caused the cyclone to turn northwest on July 21.[3][4] Emilia moved over progressively cooler waters, and vertical wind shear from the westerlies negatively impacted the hurricane.[3] The central pressure steadily rose to 965 mbar (28.50 inHg), and Emilia diminished to a marginal Category 3 hurricane.[3] On July 22, Emilia continued to weaken, and it passed within 170 mi (270 km) of the Big Island.[4] It was the closest approach to the islands.[4] Later, the peak winds dropped to 75 mph (120 km/h).[3] Emilia gradually turned west-northwest, and the circulation moved with the trade winds.[4] Emilia weakened to a tropical depression on July 24,[3] and a remnant swirl of stratocumulus clouds was noted.[4] The system dissipated on the same day.[3][5]

Preparations

Initially, forecasts significantly underestimated the intensification of Emilia,[1] which was one of three tropical cyclones to attain Category 5 status in the central Pacific during the season.[3] On July 16, a 72-hour forecast misjudged the strengthening of Emilia by 41 m/s (92 mph).[1] Later, winds at 72 hours were 31 m/s (69 mph) too high when the cyclone began to weaken.[1] Tropical cyclone forecast models consistently predicted Emilia to remain south of the Hawaiian Islands because of the upper troughs' climatologically weak nature during the summer.[6] This led to high confidence in the forecasts,[7] resulting in a lack of watches or warnings.[3] Nonetheless, a high surf advisory was issued for the south and east coasts of all islands.[8]

Impact and records

Emilia passing to the south of Hawaii on July 22

Despite the storm's offshore anture, wells of 6–10 feet (2–3.3 m) were reported near the Puna and Ka‘ū coasts.[9] Waikiki Beach in Honolulu reported a 5 ft high (1.5 m) surf. Surf was lower along the Kona and Kohala coasts.[3][10] Winds were gusty, causing a few trees to be blown over and branches to be broken. Some minor roof damage was caused by the winds.[3] International observatories and the Keck Telescope on the top of Mauna Kea were forced to close their domes due to the high winds.[11] Rainfall ranged from light to moderate. The storm passed near two National Oceanic and Atmospheric Administration (NOAA) weather buoys during its passage through the state. All in all, Hurricane Emilia had mostly minor effects in the Hawaiian Islands.[3]

Emilia is one of the most intense tropical cyclones on record in the Eastern Pacific, with a lowest pressure of 926 mbar (hPa; 27.34 inHg). In the CPHC warning zone, only Gilma and Ioke of 2006 attained deeper pressures.[2] Emilia was also a Category 5 hurricane for 18 hours, the most ever at the time in the Central Pacific. That record was broken later in the season by Hurricane John.[12]

The storm was the subject of a disagreement between the Central Pacific Hurricane Center and the National Hurricane Center. Specifically, they debated Emilia's peak strength in relation to the Saffir-Simpson hurricane scale (SSHWS). The CPHC reported that Emilia's maximum winds peaked at 140 knots (260 km/h), making it a Category 5 hurricane.[3] However, the NHC considered Emilia to be a high-end Category 4 with maximum winds of 135 knots (250 km/h), in both its "best track"[13] and its preliminary report.[14] During 2008, the NHC upgraded its "best track" to make Emilia a Category 5, although there continues to be a discrepancy in Emilia's duration at Category 5 intensity.[2][3]

See also

Wikimedia Commons has media related to Hurricane Emilia (1994).

Notes

  1. ↑ The Central Pacific Hurricane Center (CPHC) lists Emilia as a Category 5 cyclone, but the National Hurricane Center (NHC) classified Emilia as a strong Category 4 hurricane with 155 mph (250 km/h) sustained winds. However, in 2008, the NHC upgraded the storm into a Category 5 hurricane for 6 hours.[2]

References

  1. ↑ 1.0 1.1 1.2 1.3 Mayfield, Max and Pasch, Richard J. (1996). "Eastern North Pacific Hurricane Season of 1994" (PDF). NOAA. Retrieved 2008-02-20.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 National Hurricane Center; Hurricane Research Division; Central Pacific Hurricane Center (July 7, 2014). "The Northeast and North Central Pacific hurricane database 1949–2013". United States National Oceanic and Atmospheric Administration's National Weather Service. Retrieved July 10, 2014. A guide on how to read the database is available here.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 Central Pacific Hurricane Center (1994). "The 1994 Central Pacific Tropical Cyclone Season". NOAA. Retrieved 2008-02-20.
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Lawrence, Miles (1994). "Hurricane Emilia July 16–25, 1994". NOAA. Retrieved 2008-02-22.
  5. ↑ Blake, Eric S; Gibney, Ethan J; Brown, Daniel P; Mainelli, Michelle; Franklin, James L; Kimberlain, Todd B; Hammer, Gregory R (2009). Tropical Cyclones of the Eastern North Pacific Basin, 1949-2006 (PDF). United States National Oceanic and Atmospheric Administration. Archived from the original on July 28, 2013. Retrieved June 14, 2013.
  6. ↑ "Hurricane Emilia Discussion Number 11". Central Pacific Hurricane Center. Retrieved 2008-02-23.
  7. ↑ "Hurricane Emilia Discussion Number 13". Central Pacific Hurricane Center. Retrieved 2008-02-23.
  8. ↑ Larry W. Tarleton (1994-07-21). "Hurricane may pass Hawaii". Associated Press. Retrieved 2013-07-09.
  9. ↑ Lawrence, Miles (1994). "Hurricane Emilia Preliminary Report (Page 2)". NOAA. Retrieved 2008-02-23.
  10. ↑ Larry W. Tarleton (1994-07-22). "Hurricane Emilia Skirts Hawaiian Islands". Associated Press. Retrieved 2013-07-09.
  11. ↑ Malcolm W. Browne (1994-07-23). "Fiery comet concludes spectacular displays". New York Times. Retrieved 2013-07-09.
  12. ↑ "8. What hurricanes have been at Category Five status the longest?". Central Pacific Hurricane Center. Retrieved 2008-02-23.
  13. ↑ "EMILIA Tracking information". Unisys. Archived from the original on 2007-08-06. Retrieved 2008-11-01.
  14. ↑ Lawrence, Miles (1994). "Hurricane Emilia Preliminary Report (Page 3)". NOAA. Retrieved 2008-02-23.