nw australia Severe Tropical Cyclone Victoria

[Somerset Squall]

Tropical Cyclone Victoria has formed in the eastern South Indian Ocean, near Cocos Island. Victoria has sustained winds of 40kts and is characterised by a tight LLC with intense convection covering it. As Victoria is small, shear is very low and waters warm, the cyclone could rapidly strengthen over the next 36hrs before shear rises on the southerly track. Troughing to the west and ridging to the east will guide Victoria south and not towards the NW Australian coast.

[Coast]

IDW27600

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION

Issued by PERTH TROPICAL CYCLONE WARNING CENTRE

at: 0706 UTC 09/04/2013

Name: Tropical Cyclone Victoria

Identifier: 17U

Data At: 0600 UTC

Latitude: 12.3S

Longitude: 102.7E

Location Accuracy: within 20 nm [35 km]

Movement Towards: south southeast [160 deg]

Speed of Movement: 9 knots [16 km/h]

Maximum 10-Minute Wind: 40 knots [75 km/h]

Maximum 3-Second Wind Gust: 55 knots [100 km/h]

Central Pressure: 996 hPa

Radius of 34-knot winds NE quadrant: 90 nm [165 km]

Radius of 34-knot winds SE quadrant: 90 nm [165 km]

Radius of 34-knot winds SW quadrant: 90 nm [165 km]

Radius of 34-knot winds NW quadrant: 90 nm [165 km]

Radius of 48-knot winds NE quadrant:

Radius of 48-knot winds SE quadrant:

Radius of 48-knot winds SW quadrant:

Radius of 48-knot winds NW quadrant:

Radius of 64-knot winds:

Radius of Maximum Winds: 20 nm [35 km]

Dvorak Intensity Code: T3.0/3.0/D2.0/24HRS

Pressure of outermost isobar: 1006 hPa

Radius of outermost closed isobar: 120 nm [220 km]

Storm Depth: Deep

FORECAST DATA

Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure

[uTC] : degrees : nm [km]: knots[km/h]: hPa

+12: 09/1800: 13.9S 103.4E: 045 [080]: 050 [095]: 990

+24: 10/0600: 15.3S 104.1E: 070 [130]: 060 [110]: 983

+36: 10/1800: 16.5S 104.7E: 090 [165]: 055 [100]: 986

+48: 11/0600: 18.2S 105.3E: 110 [200]: 045 [085]: 992

+60: 11/1800: 20.0S 105.8E: 130 [235]: 030 [055]: 1002

+72: 12/0600: 22.7S 106.3E: 145 [270]: 030 [055]: 1002

REMARKS:

Tropical Cyclone Victoria has developed over open waters, well away from Cocos

and Christmas Islands.

Microwave imagery overnight showed a small and tight circulation with deep

convection wrapping around the low level circulation centre [LLCC]. The vortex

was tilted due to northeast wind shear. During Tuesday the system has steadily

intensified. A curved band wrap of 0.6 to 0.7 on visible imagery yielded DTs of

3.0 between 0300 and 0600 UTC. Given the initial Dvorak T1.0 classification was

made at 0600UTC 8 April, the FT constraint [24hrs after initial T1.0, storm's

T-No must be <= T2.5] is being broken. Given the small size of the system and

potential for rapid development, this seems appropriate. FT/CI set to 3.0.

Tropical Cyclone Victoria was located using microwave and visible satellite

imagery, in particular the TRMM 0221 UTC image.

CIMSS shear at 0600UTC showed between 10 and 20 knots of northeast wind shear.

SSTs and Ocean Heat Potential are conducive for development and there is good

poleward outflow due to an approaching upper level trough. Conditions should

remain favourable for the next 24 hours or so.

The system is forecast to reach category 2 intensity overnight. Late Wednesday

and particularly Thursday, northwest wind shear is forecast to increase and with

lower SSTs the system should weaken.

General south to southeast motion is expected under the influence of an upper

level ridge to the east and an approaching upper level trough.

The system is not expected to impact Cocos or Christmas Island or the Western

Australian mainland. Moderate to heavy rainfall and squally conditions are

possible over Christmas Island until Thursday due to the outermost rain bands.

http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDW27600.txt

Tropical Storm TWENTYTWO: Probability of Cat 1 or above winds to 96 hours lead

[Somerset Squall]

Victoria has developed a central dense overcast feature and sustained winds have increased to 50kts this evening. Further quick strengthening is possible over the next 24hrs, as outflow is impressive, particularly in a poleward direction, and for now, waters are warm.

[Somerset Squall]

Victoria has continued to strengthen quickly overnight, and has been upgraded to a severe tropical cyclone by BOM, with sustained winds now at 65kts. An eye feature is emerging embedded in the central dense overcast (CDO) this morning, with strong banding flanking the southern side of the CDO. Victoria still has about another 18 hours to strengthen before it runs into higher shear to the south.

[Coast]

A MASSIVE Category three cyclone is intensifying in the Indian Ocean, off Western Australia's North-West coast.

Tropical Cyclone Victoria, a large system which is about 400km south-west of Christmas Island, is moving south and gathering strength. Category two overnight, the system strengthened to a Category Three earlier today. A Hurricane Force wind warning has been issued for shipping in the area affected by the cyclone.

At 3pm yesterday the cyclone was about 385km west-southwest of Christmas Island, moving south at 16km/h. The system has affected Christmas Island weather, but lies is well to the south-west of the island. "Tropical Cyclone Victoria lies well to the south-southwest of the island and is forecast to continue moving in a south-southeasterly direction,'' the Bureau of Meteorology said.

"Squally conditions may be experienced (on the island) until Thursday under the influence of the system.'' The cyclone could affect Perth's weather by the weekend, with showers forecast for Saturday, as the mass of unstable tropical air continues its path southwards. The cyclone has a central pressure of 988 hPa, but remains hundreds of kilometres from the WA coast and appears unlikely to make landfall. Seas are being affected within 90 nautical miles of the centre.

The forecast is for maximum winds to 120km/h near the centre increasing to 130km/h today. Winds above 48 knots within 30 nautical miles of the centre bring very rough to high seas and moderate to heavy swell.

http://www.perthnow.com.au/news/western-australia/category-two-cyclone-victoria-brewing-out-to-sea/story-fnhocxo3-1226617148523

[Coast]

Tropical Storm VICTORIA: Probability of Cat 1 or above winds to 72 hours lead

[Somerset Squall]

Victoria has strengthened further, and sustained winds are now at 75kts. Victoria was displaying a pinhole eye earlier which has since become cloud obscured. Victoria is likely near peak intensity.

[Somerset Squall]

Intensity is now up to 80kts according to JTWC, time is running out for Victoria's intensification however. The CDO is already shrinking but remains very intense.

[Somerset Squall]

Strong northwesterly shear has affected Victoria overnight. The eye has gone, and the convection is mostly over the southeast quadrant of the storm, displaced by the shear. Intensity has fallen to 60kts. On the generally southward track, sea temps decline, and with the continued shear, Victoria should progressively weaken.

[Somerset Squall]

There is nothing left of Victoria now. The cyclone was destroyed this morning by high wind shear and cold water as Victoria raced south out of the tropics.