Tropical Cyclone Alenga

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Re: Northern Wet Season 2011/12

Postby Fu Manchu » Sat Dec 03, 2011 4:41 pm

IDW10800
Australian Government Bureau of Meteorology
Western Australia

Tropical Cyclone three-day outlook for the Western Region
Issued at 2:00pm WST on Saturday the 3rd of December 2011
Valid until midnight WST Tuesday


Existing Cyclones in the Western region:
Nil.

Potential Cyclones:
A weak low has developed near 08S 097E. The low is expected to drift south of
10S into the Western Region during Sunday. It should then move westwards, and is
expected to pass west of 090E during Monday. The low may develop into a cyclone
during Monday or Tuesday, but is likely to remain below cyclone strength until
it moves west of 090E.

Likelihood of this system being a tropical cyclone in the Western Region:
Sunday :Low
Monday :Moderate
Tuesday :Low [out of the area]

There are no other lows expected in the Western Region over the next three days.


NOTES: Development Potential is an estimate of the chance of each system being a
tropical cyclone in the Region for each day.
Very Low: less than 5% Low: 5% - 20%,
Moderate: 20% - 50% High: Over 50%

The Western Region refers to the Indian Ocean between Longitudes 90-125E and
south of 10S.
Further information on Tropical Cyclones is available at:
www.bom.gov.au/cyclone/

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Re: Northern Wet Season 2011/12

Postby Fu Manchu » Sat Dec 03, 2011 4:45 pm

2. South Indian Ocean area (135e west to coast of Africa):
a. Tropical cyclone summary: none.
B. Tropical disturbance summary:
(1) the area of convection previously located near 6.7s 95.8e,
is now located near 8.3s 96.0e, approximately 655 nm west-southwest
of jakarta, Indonesia. Animated infrared satellite imagery and a
022016z AMSU microwave image indicate persistent convection and
improved low level banding wrapping into a weak low level
circulation center off the coast of Sumatra. A 021642z scatterometry
pass shows 20-25 knot winds at the center. Upper level analysis
reveals that the disturbance is located within a region of moderate
vertical wind shear. However, as the system slowly tracks southward
toward the ridge axis, vws should subside and may allow a window for
further development. Maximum sustained surface winds are estimated
at 20 to 25 knots. Minimum sea level pressure is estimated to be
near 1006 mb. The potential for the development of a significant
tropical cyclone within the next 24 hours remains medium.

http://www.wunderground.com/tropical/ABIO10.RAW.html

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Northern Wet Season 2011/12

Postby Fu Manchu » Sun Dec 04, 2011 2:35 pm

Alex from WZ suggesting we take a look at EC and GFS runs for tropical low later in the week.

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Re: Northern Wet Season 2011/12

Postby Pete » Sun Dec 04, 2011 3:21 pm

Australian Government Bureau of Meteorology
Western Australia

Tropical Cyclone three-day outlook for the Western Region
Issued at 2:00pm WST on Sunday the 4th of December 2011
Valid until midnight WST Wednesday


Existing Cyclones in the Western region:
Nil.

Potential Cyclones:
At midday WST a low was located near 11.4S 91.3E. The low is moving towards the
southwest and is likely to cross 90E late Sunday or early Monday. The low may
develop into a cyclone during Monday or Tuesday west of 90E. The system may
re-enter the Western region during Wednesday.

Likelihood of this system being a tropical cyclone in the Western Region:
Monday :Low [out of area]
Tuesday :Low [out of area]
Wednesday :Moderate

There are no other significant lows in the region and none are expected to
develop over the next three days.


NOTES: Development Potential is an estimate of the chance of each system being a
tropical cyclone in the Region for each day.
Very Low: less than 5% Low: 5% - 20%,
Moderate: 20% - 50% High: Over 50%

The Western Region refers to the Indian Ocean between Longitudes 90-125E and
south of 10S.
Further information on Tropical Cyclones is available at:
www.bom.gov.au/cyclone/

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Re: Northern Wet Season 2011/12

Postby Pete » Sun Dec 04, 2011 3:23 pm

Fu Manchu wrote:Alex from WZ suggesting we take a look at EC and GFS runs for tropical low later in the week.


Yeah Wednesday's low might do something, but I reckon the ridge will destroy it. The only other possible system is a low developing off the Kimberly coast next Tuesday. But again, its running against strong SE'ly shear at this stage.

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Northern Wet Season 2011/12

Postby Fu Manchu » Sun Dec 04, 2011 7:36 pm

BoM wrote:The MJO strengthens in the Indian Ocean

During the past week, the Madden-Julian Oscillation (MJO) has gained strength over the Indian Ocean as it progresses eastwards towards Australia. The majority of climate models surveyed by the Bureau of Meteorology suggest that this MJO event will move into Australian longitudes during the first two weeks of December.

An active MJO event in the Australian region during December brings an increased probability of tropical cyclone formation, and development of the monsoon trough over northern waters. Rainfall across northern Australia is expected to be above average during this period.

It is likely that this MJO event will spawn the first tropical cyclone for the Australian cyclone season, and the Bureau of Meteorology will be monitoring the situation very closely.

See the Bureau's MJO Monitoring for more information, including rainfall maps.

Next update expected by 6 December 2011 | Product Code IDCKGEWOOO

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Re: Northern Wet Season 2011/12

Postby @weather_wa » Tue Dec 06, 2011 5:02 am

5.2 Quake hits off WA coast

A small earthquake has hit off the north-west coast of Western Australia.

The US Geological Survey recorded the 5.2-magnitude tremor at 1:40am local time this morning, 522 kilometres west of Port Hedland.

There are no reports of damage.

A similar size quake measuring 5.0 struck Western Australia's Goldfields town of Kalgoorlie-Boulder on April 20 last year leaving one woman trapped under rubble

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Re: Northern Wet Season 2011/12

Postby Pete » Tue Dec 06, 2011 8:24 am

Tropical Cyclone three-day outlook for the Western Region
Issued at 2:18pm WST on Monday the 5th of December 2011
Valid until midnight WST Thursday


Existing Cyclones in the Western region:
Nil.

Potential Cyclones:
At midday WST Monday, a tropical low was located near 12.2S 87.9E. The low is
expected to develop into a tropical cyclone to the west of 90E during Monday.
The system is expected to remain west of 90E on Tuesday but is likely to move
into the Western region as a cyclone during Wednesday.

Likelihood of this system being a tropical cyclone in the Western Region:
Tuesday :Low [out of area]
Wednesday :High
Thursday :High

There are no other significant lows in the region and none are expected to
develop over the next three days.


NOTES: Development Potential is an estimate of the chance of each system being a
tropical cyclone in the Region for each day.
Very Low: less than 5% Low: 5% - 20%,
Moderate: 20% - 50% High: Over 50%

The Western Region refers to the Indian Ocean between Longitudes 90-125E and
south of 10S.
Further information on Tropical Cyclones is available at:
http://www.bom.gov.au/cyclone/

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Northern Wet Season 2011/12

Postby Fu Manchu » Tue Dec 06, 2011 9:14 am

The system out to the west is still looking good to be the seasons first.

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Re: Northern Wet Season 2011/12

Postby Pete » Tue Dec 06, 2011 6:13 pm

And a cyclone was born...
Tropical Cyclone three-day outlook for the Western Region
Issued at 2:00pm WST on Tuesday the 6th of December 2011
Valid until midnight WST Friday


Existing Cyclones in the Western region:
Nil.

Potential Cyclones:
At 8am WST Tuesday, Tropical Cyclone Alenga was located near 12.8S 86.9E, moving
southwest at 9 kilometers per hour. The cyclone is likely to move towards the
southeast and enter the Western region on Wednesday before weakening during
Thursday or Friday.


Likelihood of this system being a tropical cyclone in the Western Region:
Wednesday :High
Thursday :High
Friday :Low

There are no other significant lows in the region and none are expected to
develop over the next three days.


NOTES: Development Potential is an estimate of the chance of each system being a
tropical cyclone in the Region for each day.
Very Low: less than 5% Low: 5% - 20%,
Moderate: 20% - 50% High: Over 50%

The Western Region refers to the Indian Ocean between Longitudes 90-125E and
south of 10S.
Further information on Tropical Cyclones is available at:
www.bom.gov.au/cyclone/

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Re: Northern Wet Season 2011/12

Postby @weather_wa » Wed Dec 07, 2011 10:05 am

First tropical cyclone of the season forms:

The first tropical cyclone of the season is edging across the Indian Ocean, towards Australian waters and may impact northwestern parts of WA later this weekend.

Tropical Cyclone Alenga is currently located 990km's west of the Cocos Islands and has max wind gusts of 100km/h. The cyclone is expected to track southeast into Australian waters during the next 24-48 hours, strengthening slightly as it moves.

This first cyclone is forming in a phase of enhanced monsoonal activity, known as the Madden-Julian Oscillation (MJO). The MJO is an eastward moving pulse of cloud and rainfall near the equator, which recurs every 30 to 60 days. This weather pattern brings an increase in monsoonal activity and also creates higher potential for cyclone development.

While cyclone tracks and forecast intensity can vary widely beyond three to four days, Alenga is expected to weaken below cyclone intensity by the time it approaches WA. However, the remants of the cyclone could still bring heavier rainfall totals to parts of the Pilbara and Gascoyne later this weekend.

- Weatherzone

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Tropical Cyclone Alenga

Postby Pete » Wed Dec 07, 2011 3:58 pm

Track map.
Image

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Re: Tropical Cyclone Alenga

Postby Pete » Wed Dec 07, 2011 3:59 pm

IDW23100
40:3:2:24:14S090E999:11:00
PAN PAN

HIGH SEAS WEATHER WARNING FOR METAREA 10 ISSUED BY THE
AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE PERTH
AT 0711UTC 7 DECEMBER 2011

HURRICANE FORCE WIND WARNING

Please be aware, wind gusts can be a further 40 percent stronger than the
averages given here, and maximum waves may be up to twice the height.

SITUATION
At 0600 UTC Tropical Cyclone Alenga was centred within 20 nautical miles of
latitude fourteen decimal three south (14.3S)
longitude eighty nine decimal nine east (89.9E)
Recent movement : east southeast at 7 knots
Maximum winds : 55 knots
Central pressure: 986 hPa

AREA AFFECTED
Within 90 nautical miles of the centre.

FORECAST
Maximum winds to 55 knots near the centre increasing to 65 knots by 0000 UTC 08
December.

Winds above 64 knots within 20 nautical miles of centre with very high seas
from 0000 UTC 08 December.

Winds above 48 knots within 40 nautical miles of centre with high seas and
moderate swell.

Winds above 34 knots within 90 nautical miles of centre with very rough seas
and moderate swell.

Forecast positions
At 1800 UTC 07 December: Within 50 nautical miles of 14.9 south 91.6 east
Central pressure 983 hPa.
Winds to 60 knots near centre.
At 0600 UTC 08 December: Within 80 nautical miles of 16.0 south 94.1 east
Central pressure 981 hPa.
Winds to 65 knots near centre.

REMARKS
All ships in the area please send weather reports every three hours.
Regular weather observing ships use normal channels.
Other ships please use either email to tcwcwa@bom.gov.au or fax to +61892632261
or satellite using SAC1241 through Land Earth Station Burum 312 [or 212 as
appropriate] via Perth.

Next warning will be issued by 1300 UTC 07 December 2011.

WEATHER PERTH

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Re: Tropical Cyclone Alenga

Postby Pete » Wed Dec 07, 2011 4:01 pm


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Re: Tropical Cyclone Alenga

Postby @weather_wa » Wed Dec 07, 2011 5:18 pm

First tropical cyclone of the season forms:

The first tropical cyclone of the season is edging across the Indian Ocean, towards Australian waters and may impact northwestern parts of WA later this weekend.

Tropical Cyclone Alenga is currently located 990km's west of the Cocos Islands and has max wind gusts of 100km/h. The cyclone is expected to track southeast into Australian waters during the next 24-48 hours, strengthening slightly as it moves.

This first cyclone is forming in a phase of enhanced monsoonal activity, known as the Madden-Julian Oscillation (MJO). The MJO is an eastward moving pulse of cloud and rainfall near the equator, which recurs every 30 to 60 days. This weather pattern brings an increase in monsoonal activity and also creates higher potential for cyclone development.

While cyclone tracks and forecast intensity can vary widely beyond three to four days, Alenga is expected to weaken below cyclone intensity by the time it approaches WA. However, the remants of the cyclone could still bring heavier rainfall totals to parts of the Pilbara and Gascoyne later this weekend.

- Weatherzone

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Re: Tropical Cyclone Alenga

Postby Pete » Thu Dec 08, 2011 12:11 pm

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0149 UTC 08/12/2011
Name: Severe Tropical Cyclone Alenga
Identifier: 01U
Data At: 0000 UTC
Latitude: 16.2S
Longitude: 94.9E
Location Accuracy: within 20 nm [35 km]
Movement Towards: east southeast [115 deg]
Speed of Movement: 19 knots [34 km/h]
Maximum 10-Minute Wind: 70 knots [130 km/h]
Maximum 3-Second Wind Gust: 100 knots [185 km/h]
Central Pressure: 976 hPa
Radius of 34-knot winds NE quadrant: 80 nm [150 km]
Radius of 34-knot winds SE quadrant: 80 nm [150 km]
Radius of 34-knot winds SW quadrant: 80 nm [150 km]
Radius of 34-knot winds NW quadrant: 80 nm [150 km]
Radius of 48-knot winds NE quadrant: 40 nm [75 km]
Radius of 48-knot winds SE quadrant: 40 nm [75 km]
Radius of 48-knot winds SW quadrant: 40 nm [75 km]
Radius of 48-knot winds NW quadrant: 40 nm [75 km]
Radius of 64-knot winds: 25 nm [45 km]
Radius of Maximum Winds: 20 nm [35 km]
Dvorak Intensity Code: T4.5/4.5/D1.5/24HRS STT:D1.0/12HRS
Pressure of outermost isobar: 1004 hPa
Radius of outermost closed isobar: 300 nm [555 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 08/1200: 17.8S 97.7E: 045 [085]: 065 [120]: 979
+24: 09/0000: 19.3S 99.9E: 065 [120]: 055 [100]: 983
+36: 09/1200: 20.2S 101.5E: 095 [180]: 045 [085]: 989
+48: 10/0000: 21.0S 102.3E: 130 [240]: 040 [075]: 991
+60: 10/1200: 21.6S 102.6E: 175 [325]: 030 [055]: 997
+72: 11/0000: 22.2S 102.6E: 225 [415]: 025 [045]: 1000
REMARKS:
Tropical Cyclone Alenga was located by microwave and infra-red satellite imagery
over the past 6 hours. DT has averaged 5.0 over the last 3 images based on an
EIR pattern. MET is consistently 4.0 [based on D trend] and PAT 4.5. FT and CI
set to 4.5. This is generally consistent with ADT though ADT has an increasing
trend towards 5.0 in recent images. No AMSU/SATCON available since 14Z. No
recent ascat pass.Vmax is set at 70 knots 10-min.

Recent microwave imagery shows development of the system around a reasonably
well defined eye.

The system has been in a low shear environment and CIMSS shear at 00 UTC was
about 8 knots from the westnorthwest. Shear is forecast to increase in the next
24 to 48 hours as an upper low and trough approach from the west.

NWP guidance is quite consistent with general southeast motion likely over the
next 48 hours due to the upper trough. In the longer term the weakening system
may be steered towards the west southwest by a developing ridge well to the
south. Gales may persist to the south of the system in the tight easterly
pressure gradient.

Alenga is now near its maximum forecast intensity and should begin to weaken
beyond the next 12 hours as the system moves southeast into a high shear
environment with cooler SST's. The mid-level trough has also brought dry air in
close proximity which may also weaken the system if it is entrained into the
core.


Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 08/0700 UTC by Perth TCWC.

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Re: Tropical Cyclone Alenga

Postby Pete » Thu Dec 08, 2011 12:12 pm

Image

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Re: Tropical Cyclone Alenga

Postby brayden » Thu Dec 08, 2011 12:35 pm

Wonder if Carnarvon will get the left overs and hopefully not flood again. They do need some precip. but not lots
Image

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