Will Hand wrote:
On 10 Feb 2017 19:03:11 GMT
"Norman Lynagh" wrote:
There's a yellow snow warning in force for here from 1800 this evening till
1000 on Saturday. The current automated forecast for Tideswell gives the
following:
Fri 10th
--------
1800: Cloudy. Probability of precipitation 10%
1900: Cloudy. PoP 10%
2000: Cloudy. PoP 10%
2100: Partly cloudy. PoP 5%
2200: Slight snow. PoP 50%
2300: Cloudy. PoP 10%
Sat 11th
--------
0000: Cloudy. PoP 10%
0100: Cloudy. PoP 10%
0200: Slight snow. PoP 50%
0300: Slight snow. PoP 60%
0400: Slight snow. PoP 70%
0500: Heavy snow. PoP 90%
0600: Heavy snow. PoP 80%
0700: Slight snow. PoP 60%
0800: Slight snow. PoP 60%
0900: Slight snow. PoP 60%
1000: Slight snow. PoP 60%
That takes us to the end of the period of validity of the yellow warning.
Yet, after that the Tideswell forecast has slight snow continuing till 1300
then it predicts heavy snow from 1400 on Saturday right through to 1500 on
Sunday, with no current warning in force for this.
So, we have a warning for a 16-hour period during which not much snow is
forecast to fall then a forecast of 24 hours of heavy snow for which no
warning has been issued. It doesn't hang together very well :-(
Produced by two different methods. I suspect the human Chief Forecaster is not
aware of the automated forecast. I agree it's an utter shambles and a
disgrace.
Will
This then raises the question: If the Chief Forecaster does not slavishly
follow the machine output then why is the machine output considered to be
satisfactory end-user material? That brings me back to the opinion that I have
aired on here recently i.e. that numerical model output is a tool to be used by
experienced forecasters to assist them in their decision-making. It is not
reliable enough to be issued as an end-user product. It is not fit for that
purpose. The sort of conflicts that I have highlighted above lay the Met Office
wide open to possible legal action from someone who suffers a loss resulting
from relying on a product which tells a different story from the 'party line'
story. Getting the forecast wrong is one thing but having 2 conflicting
forecasts valid concurrently is quite another.
--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org
@TideswellWeathr