Cyclone Cilla

{{storm path|Cilla 2003 track.png}}

On January 25, 2003, a low-pressure area formed within a monsoon trough about {{convert|300|mi|km|abbr=on|round=5}} northwest of Fiji and moved to the east-southeast.{{cite report|url=http://www.bom.gov.au/jshess/docs/2005/courtney.pdf|title=The South Pacific and Southeast Indian Ocean tropical cyclone season 2003–2003|last=Courtney, Joseph B|date=2005|publisher=Australian Bureau of Meteorology|pages=11–12|access-date=January 2, 2010}} That morning, the Joint Typhoon Warning Center (JTWC) began to issue warnings on the system, designating it as 12P. Shortly thereafter, Cilla turned southeast hours later in the general direction of Tonga{{cite web|url={{IBTRACS url|id=2003025S16173}}|title=2003 Tropical Cyclone Cilla (2003025S16173)|publisher=International Best Track Archive for Climate Stewardship|accessdate=February 28, 2023}} Early on January 26, RSMC Nadi designated the low as Tropical Depression 07F, after attaining 10-minute sustained winds of 35 mph (55 km/h).{{cite report|url=ftp://ftp.met.fsu.edu/pub/weather/tropical/Fiji/2003/Jan/2003012603.WTPS12 |title=Tropical Disturbance Advisory Number B1 |date=January 26, 2003 |publisher=Fiji Meteorological Service |access-date=January 2, 2010 }}{{dead link|date=May 2017 |bot=InternetArchiveBot |fix-attempted=yes }} At the time, the slow moving system had a poorly defined center of circulation that was hard to identify via radar and satellite imagery. In addition, most of the deep thunderstorm activity was displaced to the north and southeast of the center. Later that morning, the JTWC reported winds of {{convert|35|mph|km/h|round=5|abbr=on}}; however, the depression did not become any better organized throughout the day.{{cite report|url=ftp://ftp.met.fsu.edu/pub/weather/tropical/Fiji/2003/Jan/2003012612.WTPS12 |title=Tropical Disturbance Advisory B3 |date=January 26, 2003 |publisher=Fiji Meteorological Service |access-date=January 2, 2010 }}{{dead link|date=May 2017 |bot=InternetArchiveBot |fix-attempted=yes }}{{cite report|url=ftp://ftp.met.fsu.edu/pub/weather/tropical/Fiji/2003/Jan/2003012618.WTPS12 |title=Tropical Disturbance Advisory B4 |date=January 26, 2003 |publisher=Fiji Meteorological Service |access-date=January 2, 2010 }}{{dead link|date=May 2017 |bot=InternetArchiveBot |fix-attempted=yes }} Early the next day, RSMC Nadi upgraded the tropical depression to a Category 1 tropical cyclone on the Australian intensity scale and named it Cilla.{{cite report|url=ftp://ftp.met.fsu.edu/pub/weather/tropical/Fiji/2003/Jan/2003012700.WTPS02 |title=Gale Warning 029 |date=January 27, 2003 |publisher=Fiji Meteorological Service |access-date=January 2, 2010 }}{{dead link|date=May 2017 |bot=InternetArchiveBot |fix-attempted=yes }} By 0600 UTC January 27, the JTWC reported that Cilla had attained 1-minute sustained winds of {{convert|40|mph|km/h|abbr=on|round=5}}, which according to JTWC data, was its peak intensity. Subsequently, Cilla turned east-southeast.

Throughout the day, wind shear conditions lessened further; however, shower activity separated from the center, prompting the JTWC to issue its last warning on Tropical Cyclone Cilla later that day. At 2100 UTC January 27, RMSC Nadi remarked that the cyclone had become better organized. Upon attaining peak intensity, the storm passed fairly closed to Tonga. At 0600 UTC January 28, Cilla reached its peak intensity, with 10–minute sustained winds of {{convert|45|mph|km/h|round=5|abbr=on}} per RMSC Nadi. At this time, the tropical cyclone was located about {{convert|400|mi|km|abbr=on|round=5}} south-southeast of Pago Pago. Rapidly moving, Cilla showed baroclinic characteristics, hinting that the system was a hybrid low, sustaining characteristics of both tropical and nontropical cyclones.{{cite report|title=January 2003|url=http://www.australiansevereweather.com/cyclones/2003/summ0301.htm|work=Monthly Global Tropical Cyclone Summary|publisher=Australian Severe Weather|access-date=December 7, 2012|author=Padgett, Gary}} According to RMSC Nadi, Cilla weakened slightly as the storm lost organization due to increased wind shear.

On January 29, thunderstorm activity once again increased in converge around the center, though at first, the convection was sheared at times. On 0000 UTC, Dvorak satellite intensity estimates yielded a 3.0, suggesting a tropical cyclone with 10–minute winds of {{convert|45|mph|km/h|round=5|abbr=on}}, Cilla's secondary peak intensity. Satellite images indicated a banding pattern associated with the cyclone. The JTWC briefly watched this system for regeneration, noting it had a "fair" chance. However, continued wind shear began to weaken Cilla, and by 1200 UTC on January 29, Cilla was reduced to a tropical depression just before the system turned south-southeast. With the center exposed from the deep convection, Tropical Depression Cilla transitioned into an extratropical cyclone at 1100 UTC the next day, on January 30. The extratropical cyclone completely dissipated two days later.

As a tropical depression, Cilla passed over Vanua Levu. Even though the region had been severely affected by Cyclone Ami two weeks earlier, flood waters that resulted from rains associated with the cyclone quickly receded due to the storm's rapid motion.{{cite news|title=Cyclone Cilla moving towards Tonga's Ha'apai islands|url=http://www.rnzi.com/pages/news.php?id=289&op=read|access-date=December 7, 2012|date=January 27, 2003|agency=Radio New Zealand International}}

When Cilla first posed a threat to Tonga, the Fiji Meteorological Service (FMS) issued a tropical cyclone alert for the entire island chain. Damage in Tonga was mostly limited to vegetation and coconut and banana trees;{{cite news|title=Two cyclones continue to batter South Pacific|url=http://www.highbeam.com/doc/1P1-71337530.html|archive-url=https://archive.today/20130125042722/http://www.highbeam.com/doc/1P1-71337530.html|url-status=dead|archive-date=January 25, 2013|access-date=December 7, 2012|date=January 28, 2003|agency=Associated Press|location=Suva, Fiji}} (Subscription required) damage to infrastructure was minor.{{cite news|title=Only minor damage in initial reports as cyclone hits Tonga.|url=http://www.accessmylibrary.com/coms2/summary_0286-22386440_ITM|access-date=December 7, 2012|date=January 28, 2003|author=Asia Africa Intelligence Wire|agency=BBC Monitoring}} Peak winds of {{convert|32|mph|km/h|abbr=on}} and peak gusts of {{convert|67|mph|km/h|abbr=on}} were recorded in Ha'apai.{{cite report|title=Tropical Cyclone Seasonal Summary 2002-2003 season |publisher=Fiji Meteorological Service |url=http://www.met.gov.fj/documents/TC_Seasonal_Summary_02-031190690457.pdf |access-date=October 13, 2012 |author=RSMC Nadi — Tropical Cyclone Centre |archive-url=https://web.archive.org/web/20081001150746/http://www.met.gov.fj/documents/TC_Seasonal_Summary_02-031190690457.pdf |archive-date=October 1, 2008 |date=August 29, 2007 |url-status=dead }} Power was lost on Lifuka for about three hours during the night of January 27. Communications services were also affected but restored on January 28.

Cilla also affected the American Samoa, providing moderate rainfall over the area, peaking at {{convert|2.21|in|mm|abbr=on}} in Asasfou.{{Tropical Cyclone Point Maxima}} The name Cilla was retired by the World Meteorological Organization after the season, and was replaced by Cody.{{RA V Tropical cyclone operational plan}}

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• Cyclone Cliff
• Cyclone Tam (2006)
• Cyclone Ami

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Category:2002–03 South Pacific cyclone season

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Cilla