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Old March 19th 10, 06:29 PM posted to uk.sci.weather
Graham P Davis Graham P Davis is offline
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Default Some contradictions in long term Met Office forecast

On 19/03/10 18:06, Nick wrote:
On Mar 19, 5:58 pm, "Norman" wrote:
Nick wrote:
On Mar 19, 12:58 pm, "Norman" wrote:
Nick wrote:
To quote:


"The first half of April is likely to remain unsettled, with
temperatures near normal and precipitation likely to be around average
for most areas."


The first statement in that line suggests bad weather, though the
second and third suggest average conditions. Unless April habitually
produces bad weather (and generally, it produces good weather as often
as it does bad) that would suggest a contradiction.


Nick


I don't see the contradiction, Nick. Unsettled with near average temperature
and rainfall is a very common British Isles situation. It's probably quite a
good description of a typical British summer.


--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.


To me I've always taken "unsettled" to mean significantly above-
average rainfall, and significantly below-average pressure, i.e. a
series of deep lows with very active fronts and virtually no dry days,
such as last November.


Nick


This thread emphasises just how difficult it is to communicate weather forecast
information. The default in this country is "unsettled" weather i.e. typically
the weather is very variable over relatively short periods of time. Days with
rain alternated with dry days. This "typical" weather produces moderate
temperatures and moderate amounts of rain. A spell of "settled" weather will,
almost by definition, result in below average rainfall. "Unsettled" weather
might produce above average rainfall but not necessarily so. A spell with a
series of deep lows with very active fronts and virtually no dry days would
probably be best described as "stormy" or "wet".

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.


I've always made something of a, possibly incorrect, distinction in my
mind between "changeable" and "unsettled". The former always seems
relatively benign - the sort of dry/wet mix you describe - while
"unsettled" always seems synonymous to "stormy", "wet" etc - I've
always taken it to mean something *worse* than the average conditions.
So November 2009 was "unsettled" while late October 2008 was merely
"changeable", for instance. Not sure where I've picked that up but
it's possibly through use in the past.

Nick


Looks like the Met Office have got the right idea to avoid the "barbecue
summer" problem. Express the forecast in terms that mean different
things to different people. After the event, you can then explain what
you meant and that the forecast was perfect.

--
Graham P Davis, Bracknell, Berks., UK. E-mail: newsman not newsboy
"I wear the cheese. It does not wear me."