Judah Cohen: “bar for seasonal forecasting is set pretty low”

Posted: September 16, 2012 by tallbloke in atmosphere, Forecasting, general circulation, weather

Here’s an entertaining piece from Roger Harrabin of the BBC sci/environment team:
Met Office model ‘better at predicting extreme winters’

UK weather forecasters can predict cold winter weather a season ahead with more confidence, according to analysis of a new computer model.

Writing in Environmental Research Letters, scientists say the model is better at simulating phenomena known as sudden stratospheric warmings (SSWs).

These happen when the usual westerly winds at 10-50km altitude break down, causing cold weather on the surface.

Developers at the Met Office say it is an incremental advance for forecasts.

Seasonal forecasting is still in its relative infancy, but the report’s authors from the Met Office say that improving their ability to represent SSWs [Sudden Stratospheric Warmings] is a help.

The high-top model was devised in time for the winter of 2010-2011.

Using its data, the Met Office forecast in autumn 2010 that there was a 40% chance of a cold start to the winter, with a 30% chance of a mild start, and a 30% chance of an average start.

However, Judah Cohen, of the US-based Atmospheric and Environmental Research (AER) said:

“The Met Office have shown great creativity in exploring gaps in our knowledge and deficiencies in the models. But frankly, the bar for seasonal forecasting is set pretty low so any advance is very welcome.”

So low in fact, that the MET Office has declined to give seasonal forecasts for winter over the last couple of years, after the spanking they got from the media about the failed ‘mild winter’ forecast in 2009.

Perhaps part of the issue is that they don’t include the QBO in models of the atmosphere, as Dr Tim Ball recently pointed out.

Read the whole story at the BBC website.

  1. Gray says:

    Using its data, the Met Office forecast in autumn 2010 that there was a 40% chance of a cold start to the winter, with a 30% chance of a mild start, and a 30% chance of an average start.

    That’s called hedging your bets… 🙂

  2. Caz says:

    Well they will never be wrong by predicting it could be cold, mild or average. Money well spent. Sadly I don’t think they were joking and made that forecast in all seriousness.

  3. Phillip Bratby says:

    “Seasonal forecasting is still in its relative infancy”. They will never admit that Piers Corbyn has been doing it successfully for years.

  4. Stephen Richards says:

    These are the models that the prat betts believes are perfect. The UK MO are pierlessly stupid. I have said it many times, shut them down and pay the money saved to the poor of the UK to heat and feed themselves in winter. These people are despicable. All this crap while their citizens die from cold.

  5. Sleepalot says:

    And those categories (cold, average, mild) overlapped so much that one particular temperature fell into all three!

  6. RKS says:

    The Met office margins of error are enormously wide.

    Over at Bishop Hill on the unthreaded section Richard Betts posted the following when challenged on the flatlining over the past 15 years.

    Note he did not deny the flatlining but still tried to imply this was still “just about” within the model predictions.

    “RKS: no, the last 15 years cannot be ignored. To date, this flatlining is still (just about) within the range of natural variability simulated by the models, so on the face of it, it doesn’t disprove the models. However, it is part of our research programme to understand the reasons for this – is it just internal variability, or negative external forcing (sun, aerosols, etc) – or indeed is it the case that the positive forcing has been overestimated? There are genuine scientific questions here, which should not be dismissed.

    Aug 21, 2012 at 12:27 PM | Richard Betts”

    And they say the science is ‘settled’!