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.

3 Responses to “Spring-Summer Rain Outlook Update October 5 2012”

  1. cementafriend Says:

    Good work Ken had 2.6 mm last night (reading 9AM 27th). Total for October now 20.7 mm compared to 120 yr average of 103.4 mm (total month). Other rain was on 1st & 2nd, 12th.(15.1 mm) and a tiny 0.1 on 15th. Fairly,dry in the garden looking forward to more rain.

  2. Ken Stewart Says:

    Thanks, this current upper level system arrived right on cue with beautiful rain this morning. However I got the previous one a bit wrong – it was about a week earlier than I predicted. WordPress is playing havoc with formatting so the forecasting table is very difficult to read. I’ll try to fix it with an update in the next few days but I’m going to be pretty busy with family matters.
    Ken

  3. cementafriend Says:

    Thanks Ken, You probably realised from the date of the comment that I typed 27th when it should have been 28th

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