TM2

TM2
Bay of Plenty II

Thursday, 17 March 2011

Result (I think...)

I have over the past few weeks been tirelessly trying to improve the weather up here, and the MetOffice seem to agree that we deserve better. To their credit they have responded magnificently and we now have a new model for Ullapool (although new weather is what I was really after).

So here is the good news from my new best friend, Sarah Spedding at the MetOffice in Exeter (who, despite her cheery note, must be heartily sick of me by now. Bless you Sarah...)

The joy of Strathkanaird in the sunshine (but note the rainbow)

Good morning Adrian,

I do hope the weather is coming up to expectation this morning?

The changes my scientific colleagues intend to make to the model have yet to be applied but the first part should become operational today. However, to be effective some site information needs to be adjusted which will be via a subsequent change in the next couple of weeks.  This might not resolve everything especially in the context of air flow because it is a product of how the model resolves the difficult terrain on a 4km grid in the Ullapool vicinity.

In terms of the changing forecast you highlighted, this is unfortunately unavoidable at present.  Both the days were showery and we suspect all weather types occurred at some point.  We cannot predict the formation, growth, movement and decay of individual showers with any accuracy beyond a few hours ahead.  What we can do is produce reasonable forecasts of the areas in which the showers will occur and the likely intensity and distribution.  But just as in reality on a showery day, some locations can miss the showers, so there will be points in the model that are between showers, particularly where showers are slow moving and well scattered.  This explains the difference noted because in one run the showers happen to miss Ullapool and in the next the shower distribution is slightly different and Ullapool gets showers!  It is possible to resolve this simply by blending together model runs, thereby smoothing out run to run "noise" and giving more consistency between web forecast updates; we are pursuing this for a late summer release. We are also as you know, moving in the direction of probabilities, for example "sunny intervals with a 30% chance of showers".

Whatever approach we take, there will always be instances where new information makes the forecast change and occasions where straighforwardly we get it wrong. As previously advised it is always our recommendation to read the regional text forecast alongside the location-specific forecast because, whilst the forecasters cannot give local detail, (the model does that), they can bring out in the text forecast far more of the uncertainty and indicate possible alternative outcomes.

Finally, thank you for our exchange of emails.  I do hope I have been able to reassure you that we do listen and take feedback seriously and I hope you agree we are moving in the right direction to make the forecasts more helpful to you and other Ullapool residents. 

Kind Regards
Sarah Spedding   Customer Feedback Co-ordinator
Met Office   FitzRoy Road   Exeter   EX1 3PB   United Kingdom
Tel: +44 (0)0870 900 0100   Fax: +44 (0)1392 885681 
E-mail: enquiries@metoffice.gov.uk   http://www.metoffice.gov.uk

No comments:

Post a Comment