Cyclone Rosie (2008)

Tropical Cyclone Rosie

Category 2 cyclone (Australian scale)
Tropical Cyclone (SSHS)
Tropical Cyclone Rosie
Formed	April 20, 2008 (2008-04-20)
Dissipated	April 25, 2008 (2008-04-26)
Highest winds	10-minute sustained: 95 km/h (60 mph) 1-minute sustained: 95 km/h (60 mph) Gusts: 130 km/h (80 mph)
Lowest pressure	988 mbar (hPa; 29.18 inHg)
Fatalities	0
Damage	Minimal
Areas affected	Christmas Island
Part of the 2007-08 Australian region cyclone season

Tropical Cyclone Rosie (BOM Designation:22U, JTWC Designation:28S) was the first tropical cyclone to ever be monitored by the Tropical Cyclone Warning Center in Jakarta, Indonesia. Rosie was also the ninth cyclone to be monitored by the Bureau of Meteorology during the 2007-08 Australian region cyclone season.

On April 20, TCWC Jakarta started to issue warnings on a tropical depression located about 1000 kilometres to the west of Jakarta. Over the next couple of days the depression slowly intensified whilst moving towards the southeast. On April 22, as the depression moved to the south of 10S the depression was upgraded and named as Rosie by TCWC Perth. The cyclone quickly intensified in to a category two cyclone on the Australian Tropical Cyclone Intensity Scale as it passed to the south of Christmas Island. Rosie was downgraded to a tropical low on April 23, and with TCWC Perth issuing the last advisory on April 25.

Meteorological history

Storm path

On April 20 2008, the Tropical Cyclone Warning Center in Jakarta, Indonesia, started to issue warnings on a tropical depression that was located about 500 nautical miles (1000 kilometres) to the west of Jakarta.^[1] Later that day, as the depression was moving towards the southeast the Joint Typhoon Warning Center assessed the depressions chances of forming in to a significant tropical cyclone within 24 hours as poor.^[2] Later that evening the JTWC reassessed the depressions chances of forming in to a significant tropical cyclone within 24 hours as fair.^[3] This was because of a slowly consolidating Low Level Circulation Center and a good outflow from the depression.^[3] Early the next day, as the depression moved closer to the southern edge of TCWC Jakarta's area of responsibility the Joint Typhoon Warning Center issued a Tropical Cyclone Formation Alert on the depression as they upgraded the depressions chances of forming in to a significant tropical cyclone within 24 hours to good.^[4]

Later on April 21, the JTWC upgraded the depression to a tropical cyclone and designated it as Tropical Cyclone 27S.^[5] Early the next day, the depression moved south of 10S into TCWC Perth's area of responsibility. As TCWC Perth, issued their first advisory on the tropical depression they upgraded the depression to a tropical cyclone and assigned the name Rosie to the cyclone.^[6] This came as the depression was located approximately 50 nm (100 km) to the west of Christmas Island.^[7] Later that day, Rosie intensified and reached its peak wind speeds of 50 kts (60 mph 95 km/h) which made Rosie a category two cyclone.^[8] The JTWC also reported at this time, that Rosie had reached peak wind speeds of 45 knots (50 mph, 80 km/h), though this was later revised to 50 kts (60 mph 95 km/h) in their best track which made Rosie a tropical storm on the Saffir Simpson Hurricane Scale.^[9][10]

Later that day, TCWC Perth reported that Cyclone Rosie had weakened in to a category one cyclone, with winds of 40 knots (45 mph, 70 km/h). Rosie then weakened further, becoming a tropical low during the afternoon of April 23.^[11] The Joint Typhoon Warning Center then downgraded Rosie to an a tropical depression and released their final advisory early the next morning.^[12] TCWC Perth carried on issuing high seas weather warnings on "Tropical Low ex Rosie" until the next morning when they released their final warning.^[13]

During their post storm reanalysis, TCWC Perth noted that whilst Rosie, had been named by TCWC Perth early on April 22, when the depression moved in to their Area of responsibility. However Rosie actually had reached tropical cyclone intensity on April 21 whilst it was within TCWC Jakarta’s Area of responsibility.^[14]

Preparations and impact

The Australian Bureau of Meteorology reported late on April 20 that a tropical cyclone watch had been issued for Christmas Island. This watch was issued when the tropical depression was located about 515 nautical miles (950 km) to the northwest of Christmas Island. The next day, as the depression moved closer to Christmas Island, a blue tropical cyclone alert was issued by the Christmas Island Emergency Management Committee. Later that day when the depression was named Rosie the blue alert was upgraded to a yellow tropical cyclone alert. At this time large waves coming from Rosie were already starting to affect the island's port area. However, this yellow alert was cancelled later that day as Rosie had weakened and had also moved to the south of Christmas Island.^[14]

The main impact caused by Rosie was at the port area of Christmas Island. This came as the depression was upgraded to a cyclone and named Rosie. The Harbour master reported that waves of 5-7 metres, (16-23 Feet) had damaged some of the facilities on the shore and had torn a long-line mooring from its anchor.^[14][15]

Records and naming

Rosie was the first ever tropical depression to be monitored by TCWC Jakarta.^[14] In their post season analysis, TCWC Perth determined that Rosie should have been the first tropical depression to receive a name by TCWC Jakarta.^[14] Rosie was also the last tropical depression to be named by any of the three tropical cyclone warning centres run by the Australian Bureau of Meteorology, before they merged the three lists into one at the beginning of the 2008-09 tropical cyclone year.^[16][17]

The name Rosie has been used twice worldwide. Once during the 1970–71 Southern Hemisphere tropical cyclone season by the Bureau of Meteorology and once by the Joint Typhoon Warning Center during the 1997 Pacific typhoon season. After this season, the name Rosie was one of the names removed by the Bureau of Meteorology when they merged their three lists into one.^[17]

See also

• 2007–08 Australian region cyclone season
• 2007–08 South-West Indian Ocean cyclone season
• Timeline of the 2007–08 Australian region cyclone season

References

1. ^ "BMG Extreme Weather Warning 20-04-08 03z". Indonesian Meteorological and Geophysical Agency. http://www.webcitation.org/5XDMkjtn1. Retrieved 2008-11-19. 
2. ^ "Significant Tropical Weather Advisory for the Indian Ocean 20-04-08 18z". Joint Typhoon Warning Center. ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2008042018-ABIO.PGTW. Retrieved 2008-11-19. 
3. ^ ^{a b} "Significant Tropical Weather Advisory for the Indian Ocean 20-04-08 21z". Joint Typhoon Warning Center. ftp://ftp.met.fsu.edu/pub/weather/tropical/GuamStuff/2008042021-ABIO.PGTW. Retrieved 2008-11-19. 
4. ^ "Tropical Cyclone Formation Alert 21-04-08 05z". Joint Typhoon Warning Center. http://www.webcitation.org/5XEuQOAvu. Retrieved 2008-11-19. 
5. ^ "JTWC Advisory 21-04-08 21z". Joint Typhoon Warning Center. http://www.webcitation.org/5XFw2cgLC. Retrieved 2008-11-19. 
6. ^ "TCWC Perth Technical Bulletin 22-04-08 00z". Bureau of Meteorology. http://www.webcitation.org/5cShh81UK. Retrieved 2008-11-19. 
7. ^ "Gary Padgett’s Monthly Global Tropical Cyclone Summary April 2008". Typhoon 2000. http://www.maybagyo.com/garyp_mgtcs/apr08sum.txt. Retrieved 2008-11-19. 
8. ^ "TCWC Perth Technical Bulletin 22-04-08 06z". Bureau of Meteorology. http://www.webcitation.org/5cSiTHLrz. Retrieved 2008-11-19. 
9. ^ "JTWC Advisory 22-04-08 09z". Joint Typhoon Warning Center. http://www.webcitation.org/5XHAeeL9p. Retrieved 2008-11-19. 
10. ^ "JTWC Best Track:Rosie". Joint Typhoon Warning Center. http://199.9.2.143/tcdat/tc08/SHEM/28S.ROSIE/trackfile.txt. Retrieved 2008-11-19. 
11. ^ "High Seas Weather Warning - Gale Force Wind Warning for the Western Area 23-04-08 12z". Bureau of Meteorology. ftp://ftp.met.fsu.edu/pub/weather/tropical/Australia/2008042312.WTAUT. Retrieved 2008-11-19. 
12. ^ "JTWC Advisory 24-04-08 09z". Joint Typhoon Warning Center. http://www.webcitation.org/5XKImYppw. Retrieved 2008-11-19. 
13. ^ "High Seas Weather Warning Cancellation 25-04-08 00z". Bureau of Meteorology. ftp://ftp.met.fsu.edu/pub/weather/tropical/Australia/2008042500.WTAUT. Retrieved 2008-11-19. 
14. ^ ^{a b c d e} Joe Courtney (2008-08-28). "Tropical Cyclone Rosie Report" (PDF). Bureau of Meteorology. http://www.bom.gov.au/weather/wa/cyclone/about/Rosie_report.pdf. Retrieved 2008-11-19. 
15. ^ "Significant Weather Summary- April 2008" (PDF). Bureau of Meteorology. http://www.bom.gov.au/inside/services_policy/public/sigwxsum/pdf/sigw0408.pdf. Retrieved 2008-11-19. 
16. ^ "Tropical Cyclone Season Summary Western Australian Region 2007–2008". Bureau of Meteorology. http://www.bom.gov.au/weather/wa/cyclone/about/seasonsummary200708.pdf. Retrieved 2008-11-19. 
17. ^ ^{a b} "Tropical Cyclone Names". Bureau of Meteorology. http://www.webcitation.org/5cScseJui. Retrieved 2008-11-19. 

External links

• Joint Typhoon Warning Center (JTWC).
• Australian Bureau of Meteorology.
• Tropical Cyclone Warning Center Jakarta.

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Tropical cyclones of the 2007–08 Australian region cyclone season
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