South Pacific and Coral Sea TC Season - 2009/10

[jrj]

http://tropicalcyclones.blogspot.com/

[Nev]

TC Tomas (NW of Samoa) officially became a TC when RSMC Nadi named it at 3pm today NZDT (despite some web-sites, such as NASA's, jumping-the-gun and erroneously naming it earlier today)...

From RSMC Nadi Tropical Cyclone Centre Advisories...

Code: Select all

TROPICAL DISTURBANCE ADVISORY NUMBER A6 ISSUED FROM RSMC NADI
Mar 12/0202 UTC 2010 UTC.

TROPICAL CYCLONE TOMAS 995 HPA WAS LOCATED NEAR 10.6S 176.3W AT
120000 UTC.  POSITION POOR BASED ON HR GMS/GOES EIR/VIS IMAGERY WITH
ANIMATION. DEPRESSION MOVING WEST AT ABOUT 6 KNOTS.  MAXIMUM
10-MINUTE AVERAGE WINDS NEAR THE CENTRE ESTIMATED AT ABOUT 35 KNOTS. 

ORGANISATION HAS IMPROVED PAST 12 HRS. THE SYSTEM LIES OVER A WEAKLY
SHEARED AND DIFFLUENT ENVIROMENT. SST 30C. SYSTEM STEERED
WEST-SOUTHWEST BY NORTHEAST DEEP LAYER MEAN FLOW. DVORAK ANALYSIS
BASED ON 0.6 WRAP ON LOG10 SPIRAL YIELDING DT=3.0. MET AND PT AGREE,
THUS T3.0/3.0/D1.0/24HRS. GLOBAL MODELS AGREE ON SOUTHWEST TRACK AND
INTENSIFICATION.

-------------------

TROPICAL DISTURBANCE ADVISORY NUMBER B01 ISSUED FROM RSMC NADI
Mar 11/2112 UTC 2010 UTC.

TROPICAL DEPRESSION 13F CENTRE [998 HPA] WAS LOCATED NEAR 14.7S
166.0E AT 111800 UTC.  POSITION POOR BASED ON HR GMS EIR  IMAGERY AND
PERIPHERAL SURFACE REPORTS.   CYCLONE MOVING SLOW.  MAXIMUM 10-MINUTE
AVERAGE WINDS NEAR THE CENTRE ESTIMATED AT ABOUT 30 KNOTS.  

ORGANISATION HAS IMPROVED OVER THE LAST 24 HOURS. THE SYSTEM LIES IN
A MODERATELY SHEARED ENVIRONMENT. 
SST AROUND 30C. DVORAK ANALYSIS BASED ON 0.35 WRAP ON LOG10 SPIRAL
YIELDING DT=2, MET AND PT AGREE, THUS T2.0/2.0/D0.5/24HOURS. EC
GLOBAL MODEL EXPECTED THE SYSTEM TO MOVE WEST-NORTHWEST AND
INTENSIFY.

[bjb]

Nev

Yes, some other web sites may have jumped the gun but Fiji Met appear to be behind everyone else, again.
Meteo.nc had already come out with the name Tomas a good six hours before it become public on the Fiji web site. JTWC had also put it up as TC19P long before Fiji got their act together.

The same with the TC above Vanuatu (& I believe it is a TC even though Fiji haven't named it, yet!).
JTWC (TC20P)and the Vanuatu Meteo have been calling it a Cyclone in all but name for 12 hours.
Even radio NZ International was giving warnings to the Pacific this morning on both storms.
But Fiji seems to be too busy watching their own patch in the Pacific, rather than being a regional center.
They are a regional center, WMO considers them as such, so they need to do their job.

Cargo, passenger and cruise ships in the Pacific depend on accurate met information.
At present there are three cruise ships in Vanuatu waters and one in Solomon waters.
All these ships need a reliable Met service that accurately advises people what is happening.

If Fiji Met want to do the job of Pacific Cyclone center they need to do it right.
Peoples lives in the Islands depend on it.

Barry

[Michael]

The western one is Ului its on the fiji synoptic with tomas.

[Nev]

TC Ului was named by Nadi last night...

[Manukau heads obs]

GFS now is alignment with ECMWF for this to head towards queensland....I hope they are getting prepared!

[bjb]

TC Ului does look like it is heading all the way to QLD.
BOM already have an ocean warning on their web site.

Cyclone Justine did a similar Coral Sea wander in 1997.
Almost lasted a month, from early March till the 29th.
Justine hit Cairns around 22nd March as a Cat. 2-3.
Did a lot of damage to the marina area.
I was in PNG at the time and we had a lot of Gubu's coming through.
(They are the Northerly storms that come in the wet season).

Ului may be 200km north of us but we are still getting a lot of rain.
We had over 100mm yesterday, and it looks like we will get similar today (heavy showers here at present).
Not a lot of wind here in Vila, but Luganville, Santo got gusts to 56kph and a constant 33kph.

Barry

[Philip Duncan]

Thanks for the updates Barry - really good to get them.

Totally agree re: Fiji warnings. The South Pacific is such a messy zone for tropical storm monitoring. I think Australia would be best equipped to manage the entire area from Aussie out to at least Fiji...possibly even as far east as Tahiti. I guess it comes down to funding and the best interests of that country.

Phil.

[Nev]

HI Barry,

Re your earlier criticism of Fiji Met, yes I agree they may been a little tardy in the past, most notably seriously underestimating TC Mick's time of landfall on mainland Fiji by several hours, despite what was fairly obvious on sat-pics.

However, re these current 2 TC's, I believe Fiji Met made the right call as to when to name them as TC's. I have no idea why JTWC decided to call them TC's when they did, as even their own wind-speed estimates wouldn't have equated to Cat 1 TC's on the BoM Scale (which Fiji uses), let alone the American Saffir-Simpson Scale, which has a much higher wind-speed threshold for Cat 1 hurricanes.

A Cat 1 TC on the BoM Scale is primarily based on peak gusts of 90 to 125 km/h (48.6 kts to 67.5kts), whereas the Americans base their Cat 1 TC's (or hurricanes) on 1-min avg max sustained winds of 64 to 82kts. It's also worth noting that most other countries (including those in the Sth Pac) base max avg sustained winds on 10-min averages, so when JTWC report mean winds of 35 kts, that would generally equate to less than 31 kts for 10-min mean winds.

JTWC have also been known to report wind-speeds based on model estimates, rather than the traditional Dvorak system of measuring speeds. Unlike Fiji Met, I can't find any ref to Dvorak T-Numbers in JTWC's reports, although NOAA do have a newer method using AMSU (Advanced Microwave Sounding Unit).

I've also looked at Vanuatu Met's TC Warnings for Ului and, prior to Nadi naming it, they all refer to it as being a 'tropical low'. Vanuatu Met's track-maps on Friday also weren't expecting it to become a TC until later that night, with maps earlier in the day even suggesting Saturday evening. Below is Vanuatu Met's TC Warning issued about an hour or two before Nadi named Ului...

Tropical Cyclone Warning Number 6 for Sanma and Torba.

Tropical Cyclone Warning Number 6 issued by the Vanuatu Meteorological
Service, Port Vila at 11:07pm VUT Friday 12 March 2010 for Sanma and Torba.

At 11:00pm local time today, The Tropical Low was located at 14.7 degrees South
164.8 degrees East; positioned at square letter E, number 4 (E, 4) on the
Vanuatu Tropical Cyclone Map. This is about 200 KM west of Santo
and 250 KM southwest of Torres. The Tropical Low has moved in a west southwest
direction at 15 KM/HR (8 knots) in the past 3 hours.

The central pressure of the system is estimated at 997 hPa. Winds close to
the centre are estimated at 55 KM/HR (30 knots). The Tropical Low is forecast
to be at 14.2 degrees South 163.4 degrees East within the next 06 to 12 hours.
Damaging gale force winds of 70KM/HR to 80 KM/HR (38-43 knots) are expected to
affect Sanma and Torba later tonight or early tomorrow.

Forecast Positions
Date and Time Position Intensity
+06 hours (5am, 13 Mar) 14.4S, 164.1E 40 KTS (75 KM/HR)
+12 hours (11am, 13 Mar) 14.2S, 163.4E 40 KTS (75 KM/HR)
+18 hours (5pm, 13 Mar) 13.9S, 162.7E 40 KTS (75 KM/HR)
+24 hours (11pm, 13 Mar) 13.8S, 162.0E 40 KTS (75 KM/HR)
+36 hours (11am, 14 Mar) 13.5S, 160.5E 50 KTS (95 KM/HR)
+48 hours (11pm, 14 Mar) 13.5S, 159.2E 50 KTS (95 KM/HR)

Even the Australian BoM referred to it as a tropical low earlier that afternoon...

IDQ10810
Australian Government Bureau of Meteorology
Brisbane

Tropical Cyclone 3-day outlook for The Coral Sea
Issued at 2:30pm EST on Friday the 12th of March 2010 and valid until end of
Monday

Existing cyclones:

Nil.

Potential Cyclones:

A developing tropical low is located near Vanuatu and is expected to intensify
further and become a tropical cyclone within 12 to 24 hours. This system is
expected to move slowly westward during the weekend.

Likelihood of a new tropical cyclone in the Eastern Region on:
Saturday: Low
Sunday: Moderate
Monday: Moderate

And Australia's Weatherzone were also so confident it wouldn't be named until it entered Australia's area of responsibility, they included the name 'TC Paul' in their future synoptic charts (since amended).

I think it's also worth noting that Fiji Met had been issuing statements about the possible development of these TC's long before any mention from JTWC or any other agency.

[bjb]

Nev

Appreciate the comments.
It is always a bit hard when a TD is close to forming and there are differing views on the trigger to a Cyclone.
In the Pacific weather stations are often far apart, with limited access to radar.
I believe that Vanuatu Met service did a very good job on the warnings on this, as detailed above.
It was a high risk in the northern islands and they treated it as such.

I agree that Fiji Met were late with the warnings in TC Mick. But they should not have been.
When it was still a depression above Vanuatu it had all the signs of forming over the weekend.
In fact on the Friday afternoon and Sat morning I had an email exchange with a friend here in Vanuatu.
Sure we are both amateurs, but in our view it was going to form as a Cyclone on Sunday and it did.
JTWC also listed it as a Cyclone on their web site early Sunday, but Fiji not till much later.
But the general public and in particular the Fiji public did not have a good warning.
A cruise ship in Fiji ended up grounded (photos in the Australian papers as well).
Luckily all the passengers and crew got off safely, but a timely warning could have prevented this.

Well Cyclone Ului is really going to be interesting over the next few days.
Already the predictions are it will be Cat. 5 by Monday.
That will be the first South Pacific Cat. 5 since Zoe in the 2002-2003 season.
Just lucky it is in the mid Coral Sea, away from any major islands.
Then it is expected to skirt the QLD coast, and ECMWF is suggesting a NZ approach.

Barry

[Vertigo]

the two cyclones look beautiful on sat loops!

[Andrew Massie]

the two cyclones look beautiful on sat loops!

Link? Please?!!

[Manukau heads obs]

uh, check out the latest ECMWF forecast....a long way off...but check out next monday....
http://www.ecmwf.int/products/forecasts ... 2010031312!!/

[Nev]

the two cyclones look beautiful on sat loops!

Link? Please?!!

Try this one.

[Andrew Massie]

Link? Please?!!

Try this one.

BRILLIANT! Thanks, Nev! It is beautiful, and quite scary when you scroll down to NZ!

[Nev]

TC Ului is now at Cat 5 and is expected to reach Cat 6 tomorrow - YES, CAT 6???

With gusts to 350km/h tomorrow, this is the first Cat 5 (let alone Cat 6) in the South Pacific since Severe TC Percy in Feb of 2005. She's also turning and looks to be heading our way...

TROPICAL DISTURBANCE ADVISORY NUMBER B10 ISSUED FROM RSMC NADI
Mar 14/0252 UTC 2010 UTC.

SEVERE TROPICAL CYCLONE ULUI CENTRE 930 HPA CATEGORY 5 WAS LOCATED
NEAR 12.7S 161.7E AT 140000 UTC. POSITION GOOD BASED ON HR GMS
VIS/EIR IMAGERY WITH ANIMATION. CYCLONE MOVING WEST NORTHWEST AT
ABOUT 7 KNOTS. MAXIMUM 10-MINUTE AVERAGE WINDS NEAR THE CENTRE
ESTIMATED AT ABOUT 115 KNOTS INCREASING TO 125 KNOTS IN THE NEXT 18
TO 24 HOURS. EXPECT WINDS OVER 63 KNOTS WITHIN 40 NAUTICAL MILES OF
THE CENTRE. EXPECT WINDS OVER 47 KNOTS WITHIN 60 NAUTICAL MILES OF
THE CENTRE. EXPECT WINDS OVER 33 KNOTS WITHIN 120 NAUTICAL MILES OF
THE CENTRE IN THE EASTERN SEMI-CIRCLE AND 150 NAUTICAL MILES OF
CENTRE ELSEWHERE.

THE SYSTEM HAS RAPIDLY INTENSIFIED IN THE LAST 18 HOURS. SYSTEM LIES
IN A LIGHTLY SHEARED ENVIRONMENT. UPPER OUTFLOW GOOD IN ALL SECTORS.
SST AROUND 30C. THE CYCLONE CONTINUES TO BE STEERED IN A
WEST-NORTHWEST DIRECTION BY AN EAST TO SOUTHEAST DEEP LAYER MEAN
FLOW. DVORAK ANALYSIS, OW EYE SURROUNDED BY CMG GIVES 6.5 WITH AN 0.5
EYE ADJUSTMENT, THUS DT OF 7.5. MET IS UNREPRESENTATIVE DUE TO THE
RAPID INTENSIFICATION. FT BASED ON DT, BUT CONSTRAINTS ONLY ALLOW FT
TO REACH 6.5 THUS T6.5/6.5/D2.0/24HRS. GLOBAL MODELS AGREE ON A
WESTERLY.

[David]

Wow, this sure is a beast! Thanks for the updates, Nev

[Manukau heads obs]

what a monster!

[Willoughby]

Interesting times!!

So with TC Tomas, the JTWC expect gusts to 135 knots as it ravages over Vanua Levu, early Tuesday morning NZT. NZ Air force and Navy would be on standby I would hope unless both nations play politics.

[Manukau heads obs]

a water vapour link
http://www.goes.noaa.gov/sohemi/sohemil ... wvgms.html

[NZstorm]

that water vapour link is excellent Brian.

GFS has Tomas centre passing east of Vanua Levu tomorrow afternoon. Not sure how well the gfs handles a tropical cyclone.

[Philip Duncan]

Anyone know when a storm as big as Ului came in to our neck of the woods? Seems incredibly intense.

Also, I thought Hamish was a cat 5 storm last year? Or am does my brain have rain fade?!

[Nev]

...Also, I thought Hamish was a cat 5 storm last year? Or am does my brain have rain fade?!

Yes, Cat 5 Hamish pretty much stayed just off the N Qld coast, i.e. well within Australia's area responsibility. So perhaps I should have said in the 'South Pacific Region', although technically both Hamish and now Ului were/are in the Coral Sea.

[Vertigo]

im seeing analyses done on TC Ului showing a central pressure peak of 870mb, following a previous analysis of 890mb.. that is exceptionally strong if correct.

and wow.. the ECMWF model looks tantalyzingly promising.. heres hoping civil defense is watching this one closely!

[Philip Duncan]

Hey Vertigo - you're the second person to say that tonight - where are you getting that info from? (re air pressure).

That would be a record breaker if correct.