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#1422742 - 04/05/2017 08:38 TC Donna
petethemoskeet Offline
Weatherzone Addict

Registered: 13/08/2003
Posts: 1256
Loc: toowoomba

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#1422743 - 04/05/2017 08:58 Re: TC Donna [Re: petethemoskeet]
glendale Offline
Cloud Gazer

Registered: 19/02/2011
Posts: 20
Loc: Glendale, north of Rockhampton
Just saw it on the Sat viewer on the BOM site..... looks quite large - very large system.

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#1422758 - 04/05/2017 13:55 Re: TC Donna [Re: petethemoskeet]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4360
Loc: Brisbane
Might push some big seas on to the QLD coast in a few days time.
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This post and any other post by Locke is NOT an official forecast & should not be used as such. It's just my opinion & may or may not be backed by sound meteorological data. For official information, refer to Australian Bureau of Meteorology products.

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#1422939 - 08/05/2017 14:28 TC Donna (threatening New Caledonia)
Ken Kato Offline
Weatherzone Addict

Registered: 05/03/2012
Posts: 4680
The Fiji Met Service has upgraded Donna's intensity further to a Cat 5 (at time of writing this).

I believe it may be the strongest TC on record for May in the southern hemisphere since the satellite era began.

Donna's centre is currently on track to brush New Caledonia before continuing SSE and eventually towards the North Island of NZ as it transitions into an extratropical system.

Below is the latest track spread from some of the models and a Himawari-8 shot taken at midday today:





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#1422940 - 08/05/2017 14:30 Re: TC Donna [Re: petethemoskeet]
Ken Kato Offline
Weatherzone Addict

Registered: 05/03/2012
Posts: 4680
Donna is now a Cat 5 at time of writing.

I've just created a new thread for Donna in the World Section of the forums if anyone's interested:
http://forum.weatherzone.com.au/ubbthrea...led#Post1422939

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#1422959 - 08/05/2017 18:11 Re: TC Donna (threatening New Caledonia) [Re: Ken Kato]
JimmyGray Offline
Weatherzone Addict

Registered: 29/08/2008
Posts: 1579
Loc: Palmerston NT
That's staggering ... nice work Ken

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#1422967 - 08/05/2017 20:48 Re: TC Donna (threatening New Caledonia) [Re: Ken Kato]
Red Watch Offline
Weather Freak

Registered: 14/03/2010
Posts: 352
Loc: Cranbrook, Townsville
The central pressure of the system is estimated at 916 hPa. Winds close to the center are estimated at 215 KM/HR , gusting to 300 KM/HR.


Edited by Red Watch (08/05/2017 20:48)

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#1422971 - 08/05/2017 22:00 Re: TC Donna (threatening New Caledonia) [Re: Ken Kato]
Popeye Offline
Meteorological Motor Mouth

Registered: 30/12/2006
Posts: 7775
Loc: Cable Beach - Broome WA
They seem pretty quick to call CAT 5 these days. Whilst it looked pretty good for an hour I still think CAT 5 was a bit premature with Donna. Good solid CAT 4 but has anywhere got evidence to prove otherwise.
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#1422973 - 08/05/2017 22:05 Re: TC Donna (threatening New Caledonia) [Re: Ken Kato]
Popeye Offline
Meteorological Motor Mouth

Registered: 30/12/2006
Posts: 7775
Loc: Cable Beach - Broome WA
I guess when you see a CAT 5 its pure beautiful structure gives it away immediately. Donna just didnt quite seem to get there. Nasty one though. Lets hope it winds down quick enough before hitting populated areas especially Noumea. That would be ugly if it maintained severe intensity through there.
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#1422975 - 08/05/2017 22:22 Re: TC Donna (threatening New Caledonia) [Re: Ken Kato]
Ken Kato Offline
Weatherzone Addict

Registered: 05/03/2012
Posts: 4680
There's a lot more that goes into analysing TC intensity over oceans than simply having a glance at it on a satellite photo. Things like the Dvorak technique, satellite intensity estimates, any available buoy data, etc all figure into the mix.

While many Cat 5 TC's "look" Cat 5 on visible satellite images, appearances can sometimes be deceiving and not all have a clear eye.

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#1422976 - 08/05/2017 22:58 Re: TC Donna (threatening New Caledonia) [Re: Ken Kato]
Popeye Offline
Meteorological Motor Mouth

Registered: 30/12/2006
Posts: 7775
Loc: Cable Beach - Broome WA
Yeah Agree. Dvorak maxed out at 6.3T 935.6hpa 122.2knt. Does that scrape into CAT 5 status with those figures?
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#1422977 - 08/05/2017 23:00 Re: TC Donna (threatening New Caledonia) [Re: Ken Kato]
Popeye Offline
Meteorological Motor Mouth

Registered: 30/12/2006
Posts: 7775
Loc: Cable Beach - Broome WA
JTWC

REMARKS:
080900Z POSITION NEAR 17.8S 165.3E.
TROPICAL CYCLONE (TC) 18P (DONNA), LOCATED APPROXIMATELY 183 NM WEST
OF PORT VILA, VANUATU, HAS TRACKED SOUTH-SOUTHEASTWARD AT 07 KNOTS
OVER THE PAST SIX HOURS. AFTER A PERIOD OF RAPID INTENSIFICATION, TC
18P APPEARS TO BE WEAKENING SLIGHTLY WITH THE EYE BECOMING CLOUD-
FILLED AND CORE CONVECTION INCREASINGLY ASYMMETRIC. A 080446Z SSMIS
91 GHZ IMAGE INDICATES EROSION OF EYEWALL CONVECTION OVER THE WEST
QUADRANT WITH THE BULK OF DEEP CONVECTION NOW OVER THE SOUTHERN SEMI-
CIRCLE. TC 18P PEAKED EARLIER NEAR 120 KNOTS BUT IS NOW ASSESSED AT
115 KNOTS BASED ON THE LOWER END OF DVORAK ESTIMATES RANGING FROM
115 TO 127 KNOTS (T6.0 TO 6.5), CONSISTENT WITH THE CONVECTIVE
STRUCTURE. TC 18P IS FORECAST TO TRACK SOUTH-SOUTHEASTWARD THROUGH
THE FORECAST PERIOD ALONG THE WESTERN PERIPHERY OF A NORTH-SOUTH
ORIENTED SUBTROPICAL RIDGE. DYNAMIC GUIDANCE REMAINS IN GOOD
AGREEMENT LENDING HIGH CONFIDENCE TO THE FORECAST TRACK. TC DONNA IS
EXPECTED TO WEAKEN GRADUALLY AS IT TRACKS EAST OF NEW CALEDONIA DUE
TO COOLER SST AND LAND INTERACTION. AFTER TAU 24, THE SYSTEM WILL
BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT INTERACTS WITH A MAJOR
SHORTWAVE TROUGH AND BAROCLINIC ZONE. RAPID WEAKENING IS EXPECTED
AFTER TAU 36 DUE TO STRONG VERTICAL WIND SHEAR AND COLD SST. TC 18P
SHOULD COMPLETE ETT BY TAU 60. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
080600Z IS 27 FEET. NEXT WARNINGS AT 081500Z, 082100Z, 090300Z AND
090900Z.//
NNNN
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#1422979 - 08/05/2017 23:15 Re: TC Donna (threatening New Caledonia) [Re: Popeye]
Ken Kato Offline
Weatherzone Addict

Registered: 05/03/2012
Posts: 4680
Originally Posted By: Popeye
Yeah Agree. Dvorak maxed out at 6.3T 935.6hpa 122.2knt. Does that scrape into CAT 5 status with those figures?

I'm assuming you're referring to the automated Dvorak figures? They, and other automated sources are but one factor taken into consideration when estimating TC intensity which also includes manual Dvorak analysis leading to the final T and CI numbers.

This was one of the automated Dvorak analyses:



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