"Isobel" never existed, says BoM

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Chacor
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#21 Postby Chacor » Tue Jan 02, 2007 5:11 am

IDW27300
TROPICAL CYCLONE TECHNICAL SUMMARY: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0845 UTC 02/01/2007
Tropical Cyclone: Isobel
Data At: 0600 UTC
Latitude: 15.0S
Longitude: 119.3E
Location Accuracy: within 50 nm (95 km)
Movement Towards: south (180 deg)
Speed of Movement: 12 knots (22 km/h)
Maximum 10-Minute Wind: 35 knots (65 km/h)
Maximum 3-Second Wind Gust: 50 knots (95 km/h)
Central Pressure: 988 hPa
Radius of 34-knot winds NE quadrant: 50 nm (95 km)
Radius of 34-knot winds SE quadrant: 50 nm (95 km)
Radius of 34-knot winds SW quadrant: 50 nm (95 km)
Radius of 34-knot winds NW quadrant: 50 nm (95 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: 40 nm (75 km)
Dvorak Intensity Code: T2.5/2.5/D1.0/12HRS
Pressure of outermost isobar: 1004 hPa
Radius of outermost closed isobar: 180 nm (335 km)
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
(UTC) : degrees : nm (km): knots(km/h): hPa
+12: 02/1800: 17.4S 119.5E: 080 (150): 045 (085): 982
+24: 03/0600: 20.7S 120.6E: 100 (185): 045 (085): 982
+36: 03/1800: 26.1S 123.1E: 130 (240): 030 (055): 990
+48: 04/0600: 31.7S 124.5E: 140 (260): 030 (055): 992
REMARKS:
The system is entering a more favourable shear environment and shows some promise of developing into a tropical cyclone overnight. Although Dvorak analysis suggests the system is still below tropical cyclone intenisty its expected rapid movement toward the coast combined with impending nightfall has led to a decision to name the system at this stage.

There is still evidence of multiple LLCCs within a broader gyre. Interaction with a developing mid level trough to the south is expected, with the intense mid latitude trough dominating the interaction.
Notes:
This product is issued every six hours; the Cyclone Advices (Watches and Warnings) are
usually issued more frequently and contain more useful information for coastal communities.

Time Conversion from UTC to local:
WST add 8 hrs (Add another hour for daylight saving)
CST add 9 hrs 30 min
EST add 10 hrs (Add another hour for daylight saving)
==
The next bulletin for this system will be issued by: 02/1300 UTC by Perth TCWC.
[or]
There will be no further bulletins for this system unless it re-intensifies.
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#22 Postby HURAKAN » Tue Jan 02, 2007 6:41 am

HIGH SEAS WEATHER WARNING FOR METAREA 10 ISSUED BY THE
AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING
CENTRE PERTH AT 0657UTC 2 JANUARY 2007

STORM WARNING FOR THE WESTERN AREA

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 Isobel was located within 50 nautical miles of
latitude fifteen decimal zero south [15.0S]
longitude one hundred and nineteen decimal three east [119.3E]
Recent movement : south at 12 knots
Maximum winds : 35 knots
Central pressure: 988 hPa.


AREA AFFECTED
Within 60 nautical miles of the centre extending to within 120 nautical miles in
eastern quadrants by 1800 UTC 2 January.


FORECAST
Clockwise winds 30/45 knots, with rough to very rough seas and moderate swell.
Winds within 45 nautical miles of the centre increasing to 45/50 knots for a
period after 0000 UTC 03 January 2007, with very rough seas and moderate swell.
The cyclone is expected to make landfall during Wednesday and winds will rapidly
ease over marine areas.

At 1800UTC 02 January: Within 80 nautical miles of 17.4 south 119.5 east
Central pressure 982 hPa.
Winds to 45 knots near centre.
At 0600UTC 03 January: Within 100 nautical miles of 20.7 south 120.6 east
Central pressure 982 hPa.
Winds to 45 knots near centre [over land].


Next warning issued by 1300 UTC 02 January 2007.


WEATHER PERTH
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#23 Postby HURAKAN » Tue Jan 02, 2007 8:30 am

HIGH SEAS WEATHER WARNING FOR METAREA 10 ISSUED BY THE
AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING
CENTRE PERTH AT 1253UTC 2 JANUARY 2007

STORM WARNING FOR THE WESTERN AREA

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 1200 UTC Tropical Cyclone Isobel was located within 40 nautical miles of
latitude sixteen decimal four south [16.4S]
longitude one hundred and eighteen decimal six east [118.6E]
Recent movement : south southwest at 14 knots
Maximum winds : 45 knots
Central pressure: 982 hPa.

AREA AFFECTED
Within 90 nautical miles of the centre extending to within 120 nautical miles in
eastern quadrants.

FORECAST
Clockwise winds 30/45 knots, with rough to very rough seas and moderate swell.
Winds within 45 nautical miles of the centre increasing to 45/55 knots for a
period after 0000 UTC 03 January 2007, with very rough seas and moderate swell.

At 0000 UTC 03 January: Within 60 nautical miles of 19.2 south 119.0 east
Central pressure 970 hPa.
Winds to 55 knots near centre.
At 1200 UTC 03 January: Within 90 nautical miles of 22.5 south 120.7 east
Central pressure 988 hPa.
Winds to 35 knots near centre.


Next warning issued by 1900 UTC 02 January 2007.


WEATHER PERTH
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#24 Postby CrazyC83 » Thu Jan 04, 2007 12:41 pm

It must be easy to confuse "Isobel" with "Isabel"...
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#25 Postby AussieMark » Thu Jan 04, 2007 5:40 pm

this cyclone will deliver much needed rains to the southern states where its desperately needed.

They are saying its interaction with a cold front is a once in a decade event

here are the rainfall anomalities for 2006

1 Month
Image

3 Month
Image

6 Month
Image

9 Month
Image

12 Month
Image
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#26 Postby Chacor » Sat Mar 03, 2007 10:49 pm

The Bureau of Meteorology has de-classified Isobel.

http://www.bom.gov.au/announcements/med ... 0201.shtml

The season so far
There have been no tropical cyclones in the northwest region so far. Around New Years Day a tropical low developed south of Indonesia. On 2 January the low was named as Tropical Cyclone Isobel, however after the event Isobel was reanalysed as not reaching tropical cyclone intensity. During mid-January a monsoon low caused heavy rain over the Kimberley and then through central Australia. Otherwise conditions have been drier than normal, particularly through the Pilbara.
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#27 Postby HURAKAN » Sat Mar 03, 2007 11:14 pm

So the next storm in the Perth responsibility area will be called Isobel?
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#28 Postby Chacor » Sat Mar 03, 2007 11:20 pm

HURAKAN wrote:So the next storm in the Perth responsibility area will be called Isobel?


I would think they would still use "Jacob".
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#29 Postby AussieMark » Sat Mar 03, 2007 11:20 pm

I knew this. on the aussie weather board I use someone got a email from BOM in that Isobel was not totally cyclonic or soemthing.

SO knew it was only a matter of time before BOM wrote it on the website
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#30 Postby HURAKAN » Sat Mar 03, 2007 11:59 pm

Chacor wrote:The season so far
There have been no tropical cyclones in the northwest region so far.


Chacor wrote:
HURAKAN wrote:So the next storm in the Perth responsibility area will be called Isobel?


I would think they would still use "Jacob".


If the sentence in bold is true, then the next storm has to be named "Isobel" because if not then a name has to be omitted.
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Coredesat

#31 Postby Coredesat » Sun Mar 04, 2007 12:53 am

I fired off an e-mail, let's see what they say.
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#32 Postby P.K. » Sun Mar 04, 2007 10:43 am

Indeed Mark but I don't remember anyone actually posting on there that it had been downgraded. To be honest it would seem odd if they used Isobel again this season.
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Coredesat

#33 Postby Coredesat » Sun Mar 04, 2007 5:13 pm

Reply:

The BOM wrote:We agree with you and so the next cyclone named by Perth TCWC will be
called Jacob.

Regards
Andrew Burton
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Coredesat

#34 Postby Coredesat » Sun Mar 04, 2007 5:18 pm

My e-mail:

Coredesat wrote:I have a question about cyclone naming in the TCWC Perth area of
responsibility. I know that Cyclone Isobel formed earlier in the season.
However, I just read the page that says that Isobel was downgraded to a
tropical low in post-analysis. In this case, would the next cyclone to
form in this basin be named Isobel or Jacob (the next name on the list),
since Isobel technically never occurred? I've talked to a few people
about this and they keep suggesting Isobel, but having two storms
operationally named Isobel would seem to make little sense.


The reply:
The BOM wrote:We agree with you and so the next cyclone named by Perth TCWC will be
called Jacob.

Regards
Andrew Burton
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#35 Postby HURAKAN » Tue Mar 06, 2007 8:51 am

Is this the first time a cyclone named is downgraded and thus jumping a name before the following name is used?

Atlantic situations:
The name Mike was used for a cyclone that was not considered a tropical storm after the fact late in the season, and was not included in the official tropical cyclone database. [1] Mike and Kendra (1966) are the only two known named cyclones to be removed from the hurricane database, after the fact, in the Atlantic Basin due to their lack of tropical storm status.

In 1966 went from A-L, but in post-analysis it was shortened to A-J, L. In 1950 Mike was the last storm, so removing it didn't cause any jumping.
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#36 Postby Chacor » Tue Mar 06, 2007 9:14 am

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