Earth Snapshot RSS Feed Twitter
 
 
 
 

Posts tagged American Samoa

Tropical Cyclone Garry (10P) North of American Samoa

14.3S 170.7W

January 22nd, 2013 Category: Tropical Storms

Tropical Cyclone Garry (10P) – January 21st, 2013

Enhanced image

Track of Tropical Cyclone Garry (10P) - January 21st, 2013 © Univ. of Wisconsin

Track of TC 10P

Tropical Cyclone Garry (10P), located approximately 140 nm north of Pago Pago, American Samoa, has tracked east-southeastward at 07 knots over the past six hours. Maximum significant wave height is 16 feet.

Animated infrared satellite imagery continues to indicate slow consolidation with deep convective banding confined to the eastern semi-circle. An SSMIS 37ghz image depicts curved convective banding wrapping into the LLCC. There is fair confidence in the initial position, which is positioned on the western edge of the deep convection.

The initial intensity is assessed at 40 knots based on an average of Dvorak estimates ranging from 35 to 45 knots. Surface observations at Pago Pago remain light at 10 to 15 knots. Upper-level analysis indicates a generally favorable environment with weak northwesterly vertical wind shear and fair poleward outflow.

TC 10P is forecast to track east-southeastward under the steering influence of the low- to mid- level near-equatorial ridge through TAU 72 but should turn southeastward in the extended TAUs as the subtropical ridge builds east of the system. With the exception of NOGAPS, model guidance is in good agreement. There is high confidence in the JTWC forecast track, which is positioned faster and equatorward of the multi-model consensus. TC 10P is forecast to intensify to a peak intensity of 75 knots by TAU 72.

Severe Tropical Cyclone Evan (04P) Hits Samoa

22.5S 154.6W

December 17th, 2012 Category: Tropical Cyclones

Tropical Cyclone Evan (TC 04P) – December 17th, 2012

Enhanced image

Track of Tropical Cyclone Evan (TC 04P) - December 17th, 2012 © Univ. of Wisconsin

Track of TC 04P

Severe Tropical Cyclone Evan (RSMC Nadi designation: 04F, JTWC designation: 04P) is considered to be the worst tropical cyclone to hit the island nation of Samoa since Severe Tropical Cyclone Val.

The first cyclone of the 2012–13 South Pacific cyclone season, Evan developed from a tropical disturbance on December 9 north-northeast of Fiji. The storm moved east and impacted Samoa and American Samoa; Evan also hit the French islands of Wallis and Futuna and is currently active.

On December 9, the Fiji Meteorological Service’s Regional Specialized Meteorological Centre in Nadi (RSMC Nadi) started to monitor a weak tropical depression, that had developed within the South Pacific Convergence Zone (SPCZ), about 700 km (430 mi) to the northeast of Suva. Over the next two days, the depression gradually developed further in an area of low vertical windshear and favourable sea surface temperatures of about 28 – 30 °C (82 – 86 °F), as it was steered eastwards by an upper level ridge of high pressure.

At 1800 UTC on December 11, the United States Joint Typhoon Warning Center (JTWC) started to issue advisories on the system and designated it as Tropical Cyclone 04P, after 1-minute sustained winds had become equivalent to a tropical storm while the system’s low level circulation centre was rapidly consolidating. RSMC Nadi then reported early the next day that the system had become a category one tropical cyclone on the Australian tropical cyclone intensity scale and named it Evan, while located about 410 km (250 mi) to the west of Pago Pago on the American Samoan island of Tutuila.

Throughout December 12, Evan continued to be steered eastwards towards the Samoan islands by the upper level ridge, as it quickly intensified further with RSMC Nadi reporting at 1200 UTC that the system had become a category two tropical cyclone. At 1800 UTC the JTWC reported that the system had become equivalent to a category one hurricane on the Saffir-Simpson hurricane scale (SSHS) with 1-minute sustained windspeeds of 120 km/h (75 mph), while it was located about 40 km (25 mi) to the southeast of Apia, Western Samoa.

Over the next 12 hours the system developed a 17 km (11 mi) cloud filled eye on visible imagery, while the systems forward motion started to slow down as it entered a weak steering environment with the upper level ridge of high pressure to the north of the system weakened and a subtropical ridge of high pressure developed to the south of the system.

At 0600 UTC RSMC Nadi reported that Evan had become a category 3 severe tropical cyclone, as it passed over the island of Upolu. During that day the system continued to intensify as started to recurve towards the west, before at 1800 UTC the JTWC reported that Evan had reached its initial peak intensity of 185 km/h (115 mph), which made it equivalent to a category 3 hurricane on the SSHS. On December 16, Evan completed a cyclonic loop, and by December 17, the system strengthened into a Category 4–equivalent cyclone on the SSHS.

Tropical Cyclone Nisha (10P) Expected to Intensify

January 29th, 2010 Category: Tropical Storms

Tropical Cyclone Nisha (10P) - January 27th, 2010

Tropical Cyclone Nisha (10P) - January 27th, 2010

Enhanced image

Enhanced image

Track of TC 10P - January 28th, 2010 © Univ. of Wisconsin

Track of TC 10P

Tropical Cyclone Nisha (10P), located approximately 450 nautical miles southeast of Pago Pago, American Samoa, has tracked eastsoutheastward at 16 knots over the past six hours. The maximum significant wave height is 13 feet.

Animated infrared imagery and a TRMM microwave image show an increase in low level organization within the past 12 hours as well as deep, convective banding wrapping into the low level circulation center (LLCC) from the east.

Upper level analysis shows the system is located just poleward of the near-equatorial ridge axis, causing moderate vertical wind shear, and that a mid-latitude trough to the southeast is currently supporting good poleward outflow.

The near-equatorial ridge is currently steering TC 10P and will continue to do so through TAU 96 when Nisha will track more south-southeastward due to a passing mid-latitude trough and subsequent reorientation of the ridge.

Additionally, Nisha will remain over warm waters (greater than 28 degrees celsius) and in favorable conditions for gradual intensification during the remainder of the forecast period. Numerical model guidance is in relatively good agreement with an east-southeastward track with the exception of the GFDN model which takes the system northward due to a forecast of weaker intensities.

About Us

Earth Observation

Organisations

Archive

July 2019
M T W T F S S
« Mar    
1234567
891011121314
15161718192021
22232425262728
293031  

Categories


Bulletin Board


Featured Posts

Information

28


Take Action

Widgets