On Sep 21, 6:59*pm, "Will Hand" wrote:
"Dawlish" wrote in message

...

I don't see a wet September. I have 75% confidence that high pressure
will be dominating our weather towards the end of the month.

**at T240, on Wednesday 29th September, most of the UK will be under
anticyclonic conditions, leading to quiet, dry and settled weather for
most**

A nice end to September. Dry days, some frost at night further north
and not a great deal of rain for most between now and then. No storms,
the jet to our NW, subsiding air over the UK and little evidence of
the influence of these extra-tropical depressions. The exception may
well be the far NW. That's my take on the weather at 10 days!

Are you still sure about this Paul? I'm still going for a warm and wet
Autumn BTW.
You made this prediction at the worst possible time, before extratropical
transistion of Igor where models were indicating all sorts of subtle
dynamical possibilities despite the agreement you happened to find around
this time from succesive runs. Ex Igor warm air advection west of Greenland
will undoubtedly throw up an anticyclone downstream near UK, but as always
with these systems there is a high probability of them injecting energy into
the jet which will make the high topple and/or receed east. the latter now
looks like taking place. An interesting development is that ex Igor rotates
west of Greenland and injects cold air south towards Newfoundland by
strengthening northerly flow this also accentuating the jet. I would not be
at all surprised to see a stormy end to September (at least up north).

Will
--

I'm right 80% of the time Will, over 90 different forecasts at all
times of the year. That means I will be wrong once in 5 times. I
wouldn't be surprised to see a wet end to September in the far NW
either. 2 days ago, that's what I suggested may well happen. I don't
see this as the worst possible time to forecast; that implies that
other times are easier. 5 years of doing this have shown me there are
no "easy" times and the difficult times are when we see no agreement
and no consistency. An 80% success rate shows me the system works.

Judge the forecast at outcome and not 2 days in, is what I would
always say. As it stands now, I'm less confident than I was 2 days ago
and if this forecast is one of the 20% that end up as incorrect and it
ends up a wet end to Autumn - oh well! Let's wait another 8 days
though.

To link any changes directly to a particular extra-tropical storm,
however, I feel is wrong, as evidenced by no forecastability from the
past and several tropical storms already this autumn, most of which
have appeared to have very little attributable effect and at least one
of which you said would influence our weather, but didn't seemingly
inject any energy into the jet and we ended up with quiet and settled
conditions instead.