Spring-Summer Rain Outlook Update October 5 2012

This page will be regularly updated, as soon as I have enough RAINFALL and MINIMUM TEMPERATURE data.

This series of posts is a continuing public testing and refining of my hunch that surges in minimum anomalies indicate later upper level disturbances.   Since September last year my success rate is more than 80%.

Progress:

On September 20 I tipped for September 28 +/- 3 days, “Possibly an upper level system- Possible storms” and indicated this could link to an enhancement of upper level activity at October 3 +/- 7 days.  (For those who say, big deal, that’s only a week ahead (!), this prediction was updated from 5 September ( “September 18 +/- 7 days”, and “October 6 +/- 7 days” ) and even earlier, on 1 August I tipped “late September to mid-October”.)

Correct again.  Storms brought rain on 25 and 26 September, and a large front and upper system moved through on the weekend of 29 – 30 September and 1-2 October, bringing light rain to the whole region.  Coastal showers continue, heavier in the north (around Innisfail).

This is how we went: I remind readers again of my area of interest- subtropical Queensland.

Notice the pre-Wet build up of showers and storms in the north.

Here’s a graph of 3 day average rain anomalies:

Outlook:

SOI 30 day mean (to 4 October) is + 2.17.

Weekly NINO 3.4 Index (to 30 September) was + 0.36 and falling.

The Indian Ocean Dipole is currently +0.52 and falling.

We are looking at a weakening El Nino, with a positive IOD, so conditions will be generally dry in spring before returning to normal summer conditions.   Rain events will become more significant as the year progresses.  Alternatively, we could be in for an early and heavier Wet, and a return to La Nina next year- I will discuss this possibility in a future post.  I’m not so sure about January now: earlier I thought it would be hot and dry but I will have to wait until further into the season.  Normal or above wet season rains are likely in early February.

For Central and Southern Queensland, indications for the next 5 months (with updates in BOLD) are:

Commencement period	Description	Likely result
October 3 +/- 7 days 18 +/- 3 days? 28 – 30 +/- 3 days	Upper system likely to start Possible disturbance“ “	Possible storm activity
November 7 +/- 3 days 13 +/- 10 days Possibly 26?	Possible disturbance Enhanced weather activity to begin in this period	Possible storms.  This may last   to early December.
December 4 +/- 4 days 20 +/- 8 days (13-28 December) 26 +/- 2 days	Possible upper systemIndications of a stronger system Possible extra influence	Possible storms Probable heavier storms or   rain starting in this period, possibly lasting past Xmas.
January possible 13 +/- 3 days? 22 +/- 2 days? Late January- February (in the region 28 January-onwards) 30 +/- 7 days	Probable upper system   enhancing wet season begins in this period	Possible early storms?   Widespread rain, amount unknown (no-brainer- this is the wet season)
February 6 +/- 4 days 13 +/- 3 days 18 +/- 3 days 26 +/- 4 days	Probable upper systems enhancing wet season in this period	Widespread rain, amount unknown (no-brainer- this is the wet season)   with several enhancements
March 6 onwards	Possible upper system

I will monitor conditions and refine my predictions as the season develops.

30 day mean Minimum percentage anomaly for the 10 Subtropical Queensland sites I monitor (as at 3 October) was -0.102.

As I will be moving house in the next couple of weeks I may not be able to post or reply to comments for a while.  Remember- next enhancement around 15 – 21 October.

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