On Course For The Quiestest South Pacific Tropical Cyclone Season On Record

[Somerset Squall]

With only two tropical cyclones having formed or crossed into the basin so far, the 2011-12 season could end up being the quiestest on record for the South Pacific. The record quietest is 3, set back only a short while ago in the 2008-09/2003-04 season. La Nina is partially to blame for the lack of activity, but obviously this record breaking lack of activity was unexpected. Forecasts called for 5-8 TC's to form or cross into the basin, which 2011-12 has fallen spectacularly short so far. So 2011-12 needs two more TC's to stop itself from tieing with 2008-09/2003-04 for the quiestest season on record, which I don't see happening. Looks likely this is one for the history books.

Just what has gone wrong? Any thoughts?

http://en.wikipedia...._Depression_14F

May not be significant but I find it rather interesting this comes off the back of the 2010 West and East Pacific seasons, both of which were the quietest on record for both basins.

Edited March 27, 2012 by Somerset Squall

[Konstantinos]

So, do we need 2 tropical Cyclones until May 31? What is your opinion Somerset Squall? How many chances do we have?

[Somerset Squall]

The season ends April 30th. It now looks like there are two invests forming, things look to be hotting up for a possible tropical cyclone forming out there. So 2011-12 may be saved from being the quietest on record yet. Yes, we need two to save it from being joint quietest on record and one to save it from being the quietest on record.

[4wd]

It's funny the Horizon programme yesterday evening asserted Hurricanes (and Tropical storms) were growing stronger and more frequent as a result of higher sea temperatures.

Not playing the game the last couple of years at all.

[Konstantinos]

The season ends April 30th.

Wait. Isn't the duration of one season 6 months? When does season begin and end in North and South hemisphere? Please if I am not right, correct me:

1) North Hemisphere: Begin: June. End: November.

2) South Hemisphere: Begin: December. End: May.

Or it depends on which ocean we are talking about?

[Somerset Squall]

The South Pacific season starts on November 1st and lasts until April 30th. The same goes for the Australian cyclone season. In the southwest Indian Ocean, it starts on November 15th and lasts until April 30th, except for Mauritius and the Seychelles, where it ends May 15th. So yes, it does depend on the basin.

Though these are the season boundries, storms can still form on the off season. The 2011-12 cyclone year is between 1st July 2011 and 30th June 2012, meaning any cyclones that form in this period count towards the 2011-12 total, not just the cyclones that form "in season".

[Konstantinos]

The South Pacific season starts on November 1st and lasts until April 30th. The same goes for the Australian cyclone season. In the southwest Indian Ocean, it starts on November 15th and lasts until April 30th, except for Mauritius and the Seychelles, where it ends May 15th. So yes, it does depend on the basin.

Though these are the season boundries, storms can still form on the off season. The 2011-12 cyclone year is between 1st July 2011 and 30th June 2012, meaning any cyclones that form in this period count towards the 2011-12 total, not just the cyclones that form "in season".

Thank you very much. And what about north Atlantic? northeast Pacific? northwest Pacific? north Indian? Thanks again.

Edited March 30, 2012 by Konstantinos

[Somerset Squall]

Atlantic runs from June 1st to November 30th. Northeast Pacific runs from May 15th to November 30th. The Northwest Pacific and North Indian Ocean basins have no official defined season as storms can form all year round, but storms are most common between May and November in the NW Pacific and between April and November for the north Indian Ocean, with peaks in May and November. Hope this helps.

[Somerset Squall]

The two invests in the South Pacific look like they are dissipating. Time is running out.

[Konstantinos]

The two invests in the South Pacific look like they are dissipating. Time is running out.

So, what are we waiting for?

Edited April 1, 2012 by Konstantinos

[Somerset Squall]

The formation of TC Daphne has prevented this South Pacific season from being the quietest on record. It currently ties the 2008-09 and 2003-04 season for this title.

[J07]

What went wrong? A few thoughts:

1) Notably unsettled summer over New Zealand. Highs have been too far south. Typical NZ summer has migratory anticyclones, with intervening troughs. When a replacement high builds, it often gives a surge of easterlies into the tropics and this helps with initial development of a disturbance. This has rarely happened this year.

2) In conjunction with (1) there has been a lot of subtropical depressions this year. i.e. a mixture of frontal lows forming close to 30S, also some hybrid subtropical cyclones. All this hinders the development in the tropics. This was partly helped by highs being a long way south. There was lots of blocking to the southeast of NZ this summer.

3) MJO active phases in these longitudes have resulted in reasonably tropical cyclogenesis, but I think we also ended up with very ugly, messy monsoonal flooding rains. There were plenty of lows forming on the MT (extending over the Solomons, Vanuatu and notably Fiji) that in India would be called monsoon depressions. They were never really looking like becoming TCs.

4) Jasmine was a very strange TC. Named by Brisbane, long lived in Nadi's area, long lived in Wellington's area, then returns to Nadi's area and comes very close to re-entering Wellington's area as a TC. This sort of oddness typifies the season I think!

On the whole, a quiet season for TCs, but an extremely expensive one for Fiji which has had two long periods of serious flooding rains.