Summer Rain Outlook Update November 27 2012

Progress so far:

I remind readers again of my area of interest- subtropical Queensland.

Here’s a summary of my predictions since 1 August, illustrating changes and refinements to my methods as I attempted to be more precise.

On 1 August I predicted enhanced activity for early to mid November and early to mid December.

On 5 September I refined this to November 15 +/- 10 days, December 5 +/- 7 days, and December 16 +/- 7 days.

On 20 September I changed this to November 13 +/- 10 days, November 26(?), and December 4 +/- 4 days, December 20 +/- 8 days, and December 26 +/- 2 days.

On October 5 I included November 7 +/- 3 days.

On 6 November I added November 20 +/- 3 days, and December 9 +/- 3 days.

On 12 November, I predicted enhanced activity with surges around 18, 22, and 25 November, and on 14 November updated this to include “I expect a vigorous disturbance bringing heavy rain in early December (5th +/- 5 days), and another vigorous disturbance with heavy rain around December 20 +/- 5 days and probably extending past Christmas. I expect more rain around the New Year.”

Violent storms passed through south east Queensland on 17-18 November.  There were scattered storms on 22 November (though no rain fell in the rain gauges I monitor) and on the night of 24-25 November a large storm brewed up in south west Queensland around Augathella and moved rapidly north east, reaching the coast at the Whitsundays next morning.  The graph shows this as a small blip, as only 16mm was recorded at only one of my sites (Clermont Aero).  I’m not sure whether to attribute this to the predicted surges for 22 or 25 November- the next couple of days will tell if we get a disturbance from the system bringing rain to Victoria at the moment, but that is more likely to be the 1 December disturbance.

This map is for one day- 25 November:

Outlook for the rest of the year:

There will be further activity in early December (possibly a small event around 1st, with a larger system with widespread rain around 5th +/- 5 days, and 9th  +/- 5 days, most likely 5 to 9 December), and a major disturbance mid to late December with surges around 18-22 and 26, plus possibly 30 (and probably 2-4 January), all +/- 5 days.  I expect this to bring heavy rain, especially in the week leading up to Christmas.  This may include the appearance of the monsoon in north Queensland.  If so the monsoon could return around 30 January and possibly 8 March.

It will be difficult to match individual events with predictions (as they are so close as to overlap, and sometimes enhancements bring cloud but little rain), but I can say early to mid December, and mid to late December will see several rain events.

I should mention that rainfall is measured at 9.00 a.m. on the day after it falls.

Outlook for 2013:

January:  3, 14, 18, 25, and the big one 30-31.

February:  7, 14, 20, and maybe 26th.  (Rain will continue through the first three weeks of February, but with peaks near these days.)

March:  2, 7-8, maybe 13, maybe 17, 20, 31st .

April:  7, 13-14, 19.

All of the above +/- 5 days.

I will concentrate on the accuracy of my algorithm (for want of a better word) for the rest of this year before I improve on forecasts for next year.

SOI 30 day mean (to 25 November) is + 3.51 (neutral).

Weekly NINO 3.4 Index (to 18 November) was + 0.39 (neutral).

The Indian Ocean Dipole is currently +0.44 (neutral).

30 day mean Minimum percentage anomaly for the 10 subtropical Queensland sites I monitor (as at 27 November) was -0.005.  It has been negative for all but 30 days of this year so far.  With 34 days to go for 2012, the 365 day running mean is -0.29 and has been negative since 10 August 2011 so there is no doubt that this has been the coolest year of the last 10.

4 Responses to “Summer Rain Outlook Update November 27 2012”

  1. Nicole Kanofski Photography Says:

    hi Ken, great work!, interesting to see that all the SOI/ NINO/ and IOD are all neutral!

  2. cementafriend Says:

    Good going Ken, 7.6mm in the gauge this morning at 8.30AM (Friday 7th). You are more reliable than BOM who has been hyping up high temperatures then falling short as shown by Warwick Hughes

  3. Ken Stewart Says:

    I think you’re probably having coastal showers but I’ll check in a couple of days to see if it shows up with any significance. The change that went through was huge but largely dry. A few more days to the 9th (+5??). There’s a system coming through from the west in a couple of days time so we’ll see. I should stick to the timing and forget about intensity hey.

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