Topic: Tropical Cyclone Kirrily : NT / Timor Sea 26 - 28 April 2009

[Colin Maitland]

This low has been sitting around the region of PNG and NT  for some time and has now formed into a tropical low. It has been rated a very high chance to form into a cyclone as of today.

BOM warning for Tropical low:

Coastal Waters Wind Warning
For offshore waters from Cape Don to Cape Wessel
Issued at 5:25 am CST on Monday 27 April 2009

Synoptic situation
At 3:30 am CST a Tropical Low was located within 50 nautical miles of 7.1 S 134.6 E about 390 nautical miles northeast of Darwin with central pressure 1002 hectopascals moving north northwest at 4 knots.

Centre forecast to be within 110 nautical miles of 5.5 S 132.0 E about 420 nautical miles north of Darwin at 3:30 am CST Tuesday.

Strong Wind Warning
Offshore waters from Cape Don to Cape Wessel....
Easterly winds 20/30 knots developing over offshore waters early on Monday. Scattered squalls to 45 knots. Seas rising to 3 metres on a 2 metre easterly swell.

[Colin Maitland]

The tropical low postioned in the Arafura Sea, North of Darwin, has developed into a Cat.1 cyclone named Kirrily.

Bom stats:

SITUATION
At 0600 UTC Tropical Cyclone Kirrily was centred within 30 nautical miles of
 latitude six decimal five south [6.5S]
 longitude one hundred and thirty four decimal one east [134.1E]
Recent movement : northwest at 4 knots
Maximum winds   : 35 knots
Central pressure: 998 hPa

AREA AFFECTED
Within 60 nautical miles of the centre.

Technical details from BOM regarding Kirrily:

The consensus of MWP models indicates west northwest
movement over the next 2 days, with steering dominated by a strengthening
mid-level ridge to the south. The environment remains favourable with good upper
divergence, weak vertical wind shear and deep moisture near the system. A
standard development rate is forecast as the TC moves away from the Aru
Archipelago, possibly reaching T4.0 within 24 hours. In the longer term,
intensification may be hindered by dry air to the west and increasing vertical
wind shear as the system moves north of the upper ridge axis
 

[Peter J]

I have been tracking this storm too, and have noticed it is not the usual shaped cyclone, but it is only a small storm - similar size to Tracey (Dec 1974).

Worth keeping an eye on it, especially as it does have some favourability to intensify to Cat 2 status within the next 24 hrs. Also, it won't affect the mainland area, but may have significant impact on Papua New Guinnea shortly.

Big Pete

[Jimmy Deguara]

Pete,

Not that I am an expert in tropical cyclones but it does seem this tropical cyclone has developed further north than is normal most likely because the ITCZ (Intertropical Convergence Zone) is retreating northwards. I personally don't recall a tropical cyclone in this region this late in the season and also one that affects New Guinea.

Regards,

Jimmy Deguara

[Michael Bath]

It's certainly uncommon in this region - this is the only similar event I've found so far:

http://australiasevereweather.com/tropical_cyclones/1972_1973/bom/tropical_cyclone_197215.htm

[Jimmy Deguara]

Michael,

Wow! Nice comparison in terms of both time frame and location.

Regards,

Jimmy Deguara

[Colin Maitland]

TC Kirrily was short lived, it is now ex TC but could regenerate according to BOM.

Update regarding the situation from BOM

SITUATION
At 0600 UTC Ex-Tropical Cyclone Kirrily was centred within 30 nautical miles of
 latitude five decimal eight south [5.8S]
 longitude one hundred and thirty three decimal one east [133.1E]
Recent movement : northwest at 4 knots
Maximum winds   : 30 knots
Central pressure: 1002 hPa
Ex-TC Kirrily may redevelop into a tropical cyclone in the next 12 to 18 hours.

[Peter J]

If it does redevelop, it will still be a midget TC, I was surprised it reached Cat 1 with it being so small, but not as intense as normal Cat1 storms can be. But I like to be proven wrong. And yes, Mike and Jim both highlighted, this storm is unusual for this area - especially if it has been near 37 years since the last one.

Big Pete

[Richary]

Well they stuffed that one up, as the first TC Low forecast I looked at had it developing to a possible Cat 4 before hitting Indonesia near Ambon. Fizzled out obviously.

Never posted anything as it was moving well away from Australia and seemed to be a bit of a hit and miss.

[Colin Maitland]

I am in the process of compiling a list of cyclones in that region NT/ Arafura Sea, and is it is quite common to have cyclones this late in the season through that area in April/May. Due to technical problems, I will post the list shortly.  I am at 1992 at this stage with cyclone Neville 7-13 April. You will able to check all the cyclones with the programme that Michael has produced on this forum.

If any one has made a list already that would be great, but I will keep working on it .

Cheers
Col

[Colin Maitland]

Most of the cyclones are mid April were TC Kirrily formed on the 27th of April, from a low that developed in the area days earlier

This is a short list of some of the Cyclones that have formed in April in the Arafura Sea/NT region. They do not include those in the Indian Ocean of WA or the Coral Sea N QLD although the first 2 cyclones highlighted have formed in the Coral Sea, but were used to show that it is not uncommon for these later seasoned cyclones to form well into May.
 
  You can cross reference the cyclones with the archived data that can be found in this forum, under Tropical cyclones.   (http://www.australiasevereweather.com/cyclones/index.html).

Another useful tool is that of the tracking map that Michael Bath has designed/ produced, (if that is the right term), it has proven absolutely brilliant in cyclone research.

The cross reference number and the end of each line is the corresponding cyclone number on the tracking page.

[Michael Bath]

Thanks for looking those up Col. There is a list of all TCs which will help with your research and also has links to each TC map:

http://australiasevereweather.com/cyclones/summary_bom.htm

and the JTWC database list:

http://australiasevereweather.com/cyclones/summary_jtwc.htm

regards, Michael

[Peter J]

Officially, "Kirrily" was the last TC of the Australian cyclone season 08/09.
Now to look forward to winter dry in the north and winter cold down south.

Big Pete