Well, there you go.The possible warmth has continued for 5 runs, I can
now be 75-80% certain of this:

By 18th April at T240, the effects of the first warm plume of the year
will be being felt in Southern England. Temperatures on the 17th and
18th of April will peak above 18C and may well be higher. Winds around
this time will be from a Southerly quadrant and the air will have had
its source in North Africa. This air could well be unstable enough to
bring the possibility of heavy, perhaps thundery showers. If the
showers stay away, Southern England, at least, will have some
pleasant, warm conditions for April.

It can never be a higher confidence forecast than 75-80%, as my
success from the past is about 78%. It's not a certain forecast, as
certainty doesn't come in to forecasting. See how it goes.

Paul

On Apr 7, 12:08 pm, Dawlish wrote:
On Apr 7, 11:46 am, "Dave R." wrote: "Dawlish" wrote in message

...
Not fine warm and settled Dave, just warmer. It certainly looks
unsettled during the early part of next week, with high pressure -
fine and settled - only after T300. Anything there is, of course,
unlikely.

Neither is that forecast of warmer than average conditions a forecast;
just yet.

Paul

I hate this country.

Dave R.

I have to disagree there! It's one of the most interesting in the
world for weather watching; maybe THE most interesting. Just imagine
being in Bahrain! Mind you, if you hate this country, there are a
whole load of others that you could hate living in! *))

Wrong.

This country IS "the most interesting in the world for weather
watching"

Consider this spell which is (apparently) governed by an High in the
Arctic. So rather than talk about Polar Lows this group should have
been considering Polar Highs. Not that I know what a polar low is.

Or supposed to be.

On Apr 7, 4:01 pm, Dawlish wrote:
On Apr 7, 1:58 pm, "Norman" normanthis...@thisbitweather-



consultancy.com wrote:
Dave R. wrote:

Another run with hints of a warming, but a subtly different set-up and
the outside chance of a plume heading our way.

http://www.wetterzentrale.de/pics/Rtavn1802.png

Still not enough confidence for any kind of forecast at T240. This
mildness has come in under my radar. Some warmth would be very
welcome, though.

Paul

Wow that looks fantastic I hadn't seen that one at the wetterzentrale
site and only have to wait until the 12th! fingers crossed and thks
Dave R.

The 06Z GFS ensemble mean show 850 mb temps rising only to around
average in the south of the British Isles, implying daytime max temps
probably around 10-12c. The 850mb ensemble for London can be found at

http://85.214.49.20/wz/pics/MT8_London_ens.png

The 06z GFS operational run is on the warm side of the ensemble mean.

Norman
--
Norman Lynagh
Chalfont St Giles, Buckinghamshire
85m a.s.l.
(remove "thisbit" twice to e-mail)- Hide quoted text -

- Show quoted text -

Hi Norman,

At 10 days it could be on the backside, underside, or the inside out
of the ensemble mean for all it means in terms of forecasting! (insert
smiley!) Spaghetti is impossible to untangle at that distance.
Patterns becoming established in a significant number of sucessive
operational runs makes for a better forecasting tool, in my
experience. No patterns: no forecast, but if a pattern stays for over
a day on the gfs at T240+, you've got over a 75% of giving a
reasonable forecast of the outcome conditions at 10 days distant. I
don't see anyone using the position relative to the ensemble mean to
get that kind of accuracy at 10 days, though I do find people still
telling me it's the thing I should do!

The ensembles provide a good tool to 7 days, but why use ensembles to
give you a forecasting tool when each ensemble has so little chance of
being correct at 10 days? Accuracy falls away like rotten skin off a
chicken at 7days. The operational run is the one that the computer
has selected as the most likely to achieve outcome and even that is
often hopelessly wrong at 10 days and each single operational run has
a very low probability of achieving outcome. It is only when you
compare successive runs and see the same pattern emerging, from
different data inputs for over a day, that anything at that distance
cane be relied upon. Even then, I've found it very hard to maintain
80% accuracy with forecasting using this method. Forecasting at 10
days, with any kind of decent accuracy is just about impossible for
any organisation, including the Met Office - who effectively don't.
All they do is give a 6-15 day idea and they produce no accuracy
statistics at 10 days.

You do realise that the short range models are only accurate once the
meteorologist has rectified all the mistakes in the various models?
Asking for better fromlong range models is stupid.

Anyway this is my stab at it:
Apr 20 / 10:25 * 04:25 10:25 16:25 22:25 4
Apr 12 / 18:32 06:32 12:32 18:32 00:32 6
Apr 6 / 03:55 ** 03:55 09:55 15:55 21:55 3
Mar 29 / 21:47 ** 03:47 09:47 15:47 21:47 3
Mar 21 / 18:40 ** 06:40 12: 40 18: 40 00: 40 6
Mar 14 / 10:46 * 04: 46 10: 46 16: 46 22:25 4
Mar 7 / 17:14 05:14 11:14 17:14 23:14 5
Feb 29 / 02:18 02:18 08:18 14:18 20:18 2
Feb 21 / 03:31 ** 03: 31 09: 31 15: 31 21: 31 3

Which are dates and times of lunar phases. And their similarities are
pointed out with asterisks. The columns following them are the same
times shifted by 6 hours. They are there to help me draw the
similarities.

So:
The 20th is similar to the phase some 5 weeks earlier: 14th March.
Which is referenced at:
http://groups.google.com/group/uk.sc...a32f2e99df224#

And says:

There was a preponderance NW-ly and cyclonic weather types during
March, and a notable Arctic outbreak coincided with the Easter
weekend.

The main anomaly centres were -15 mbar over the Baltic and +5mbar just
north of the Azores, resulting in a northwesterly anomalous flow over
the British Isles; the northerly component to the flow over the UK was
the highest in March since 1970. Mean monthly sea-level pressure
ranged from 6mbar below normal at Scilly and Valentia to 13mbar below
in Shetland.

The month started as it meant to go on, with a vigorous northwesterly
airflow covering the UK.
A strong ridge of high pressure crossed the country overnight 4th/5th,
followed by a very disturbed westerly type which lasted until the
13th.
The first four days were bright, blustery days with scattered showers
of sleet, snow and hail although heavier snow fell in the Central Belt
on the 3rd with 15cm at Wishaw.
The 5th began fine a frosty with a minimum of -8.1°C at Loch
Glascarnoch (Sutherland) and it stayed fine all day in southern
districts, but it became very wet in the north and west, with 50mm of
rain at Kinlochewe (Wester Ross).

Very unsettled weather continued until the 13th with periods of heavy
rain, especially over the western highlands, the Lake District and the
Welsh hills; Tyndrum (Perthshire) collected 211mm between the 5th and
13th. It was very windy at times, particularly on the 10th when a
depression deepened to 949 mbar as it tracked across southern Ireland,
and there was a good deal of coastal flooding in Cornwall and Devon.
Strongest gusts included 75kn at Alderney (Channel Is) and 70kn at
Mumbles (near Swansea).

It was temporarily very mild in the south on the 11th with a high of
15.3°C at Southampton.

14th to the 21st:

A depression developed in the southwest approaches on the 14th, thence
travelling slowly across southern England on the 15th and 16th; the
temperature climbed to 15.4°C at Gravesend (Kent) on the 15th before
the rain set in, then most central and southern parts of England and
Wales had 18 hours of continuous rain amounting to 25-45mm, and to
60mm at Raunds (Northants).
At several places this was the heaviest March fall in a single day on
record.

In the wake of the depression a northerly flow became established but
a temporary rise in pressure meant that the period 17th-19th was cold
and quite sunny with night frosts, while snow and hail showers were
confined to eastern counties.
Ronaldsway (Isle of Man) measured 11.1h of bright sunshine on the
17th, while Tulloch Bridge (Lochaber) fell to -7.0°C early on the
19th.

A deepening depression tracked from Iceland past Shetland to Denmark
during the 20th bringing some rain, strong winds, and temporary rise
in temperature (up to 15.0°C at Leuchars), but in the rear of the
depression northerly winds returned with renewed vigour.

The Easter holiday (21st-24th) was one of the coldest on record with
sharp night frosts and widespread snow and hail showers, although
amounts of snow were mostly slight.
It was windy on the 21st and 22nd with a gust of 70kn at Langdon Bay
(Kent) on the latter date, but winds subsequently subsided.
On the 24th the temperature remained below zero all day at a few sites
in the highlands, notably at Braemar (Aberdeenshire) where the maximum
that day was -0.9°C.
And early on the 26th, the mercury sank to -11.4°C at Braemar and to
-11.1°C at Altnaharra (Sutherland).
Milder but changeable and rather windy weather returned for the last
few days of the month, and all areas had outbreaks of rain.

The 30th was rather warm with long sunny spells but also isolated
thunderstorms, and Howden (East Yorkshire) reported a high of 15.1°C.
Mean maximum temperatures were 0.0-1.0degC below the 1971-2000 normal
in most regions, but mean minima were within 0.5 degC of the normal.
In northern Scotland, though, both values were 1.0-1.5degC below.
The month's absolute maximum of 15.4°C was lower than February's; the
last time this happened was in 1998.

It was a rather wet month generally, and rainfall percentages
approached 200 locally in western Scotland, southeast England and East
Anglia where locally it was the wettest March since 1947.
Small sunshine excesses, relative to the long-term average were
observed in most parts of the country except for southeast England.

http://www.climate-uk.com/monthly/0803.htm

You do realise that the short range models are only accurate once the
meteorologist has rectified all the mistakes in the various models?
Asking for better fromlong range models is stupid.

Anyway this is my stab at it:
Apr 20 / 10:25 ** * * * 04:25 * 10:25 * 16:25 * 22:25 * 4
Apr 12 / 18:32 * * * * *06:32 * 12:32 * 18:32 * 00:32 * 6
Apr 6 / 03:55 * ** * * *03:55 * 09:55 * 15:55 * 21:55 * 3
Mar 29 / 21:47 *** * * *03:47 * 09:47 * 15:47 * 21:47 * 3
Mar 21 / 18:40 *** * * *06:40 * 12: 40 *18: 40 *00: 40 *6
Mar 14 / 10:46 ** * * * 04: 46 *10: 46 *16: 46 *22:25 * 4
Mar 7 / 17:14 * * * * * 05:14 * 11:14 * 17:14 * 23:14 * 5
Feb 29 / 02:18 * * * * *02:18 * 08:18 * 14:18 * 20:18 * 2
Feb 21 / 03:31 *** * * *03: 31 *09: 31 *15: 31 *21: 31 *3

Which are dates and times of lunar phases. And their similarities are
pointed out with asterisks. The columns following them are the same
times shifted by 6 hours. They *are there to help me draw the
similarities.

So:
The 20th is similar to the phase some 5 weeks earlier: 14th March.
Which is referenced at:http://groups.google.com/group/uk.sc...m/thread/5eea3...


So you are trying to say that last month's weather was down, at least
in part, to atmospheric responses to the changing phases of the moon?

Paul

On Apr 8, 5:29 pm, Dawlish wrote:

So you are trying to say that last month's weather was down, at least
in part, to atmospheric responses to the changing phases of the moon?

No, of course not.

If you learn to read you will readily see that is not so. Have whoever
reads to you go over it again, slowly.

same old sw zephyr
banned from net weather, banned from TWO

now here to trash USW no doubt

zonal to the edge of reality
blah blah blah

No forecast at T240 on GFS, its too hard to forecast

No doubt some unrealstic stats about your forecasts soon?

blah blah

kill file


Dawlish wrote:
Well, there you go.The possible warmth has continued for 5 runs, I can
now be 75-80% certain of this:

By 18th April at T240, the effects of the first warm plume of the year
will be being felt in Southern England. Temperatures on the 17th and
18th of April will peak above 18C and may well be higher. Winds around
this time will be from a Southerly quadrant and the air will have had
its source in North Africa. This air could well be unstable enough to
bring the possibility of heavy, perhaps thundery showers. If the
showers stay away, Southern England, at least, will have some
pleasant, warm conditions for April.

It can never be a higher confidence forecast than 75-80%, as my
success from the past is about 78%. It's not a certain forecast, as
certainty doesn't come in to forecasting. See how it goes.

Paul

On 8 Apr, 17:29, Dawlish wrote:

So you are trying to say that last month's weather was down, at least
in part, to atmospheric responses to the changing phases of the moon?

Paul

For heaven's sake Paul - don't criticise him or ask for more on the
method. It'll only end in pram-based toy-expulsion and swearing. You
have been warned !!

Richard

On Apr 8, 1:14*pm, Dawlish wrote:
Well, there you go.The possible warmth has continued for 5 runs, I can
now be 75-80% certain of this:

By 18th April at T240, the effects of the first warm plume of the year
will be being felt in Southern England. Temperatures on the 17th and
18th of April will peak above 18C and may well be higher. Winds around
this time will be from a Southerly quadrant and the air will have had
its source in North Africa. This air could well be unstable enough to
bring the possibility of heavy, perhaps thundery showers. If the
showers stay away, Southern England, at least, will have some
pleasant, warm conditions for April.

It can never be a higher confidence forecast than 75-80%, as my
success from the past is about 78%. It's not a certain forecast, as
certainty doesn't come in to forecasting. See how it goes.

Paul

The gfs develops the North African plume further this morning, with
some pretty scorching spring weather over Spain (El Horno could be
fired up early!) on the 18th but this run terminates the Northerly
extent of its influence in the Gironde and leaves us in cool North-
Westerlies. That could change over the next couple of days, but if
this forecast joins the 20-25% of complete and utter faliiures - oh
well! So be it! It happens. It's still a lot of fun trying. My
forecast of a Northerly plunge and a cold Easter in 2007 wasn't the
best *)) , but there have been 42 successes over the last couple of
years! Plumes seem to be very hard to correctly forecast at 10 days.
They require such specific synoptics to reach the UK. The gfs is still
wrestling with the position of that Atlantic Low sitting off Iberia on
the 00z.

http://www.wetterzentrale.de/pics/Rtavn2282.png

This run puts it further South than it was when I made the forecast
yesterday. For the plume to reach the UK, it needs to be several
hundred miles further North. It'll be interesting watching it.


Paul

On Apr 9, 9:31*am, Dawlish wrote:
On Apr 8, 1:14*pm, Dawlish wrote:





Well, there you go.The possible warmth has continued for 5 runs, I can
now be 75-80% certain of this:

By 18th April at T240, the effects of the first warm plume of the year
will be being felt in Southern England. Temperatures on the 17th and
18th of April will peak above 18C and may well be higher. Winds around
this time will be from a Southerly quadrant and the air will have had
its source in North Africa. This air could well be unstable enough to
bring the possibility of heavy, perhaps thundery showers. If the
showers stay away, Southern England, at least, will have some
pleasant, warm conditions for April.

It can never be a higher confidence forecast than 75-80%, as my
success from the past is about 78%. It's not a certain forecast, as
certainty doesn't come in to forecasting. See how it goes.

Paul

The gfs develops the North African plume further this morning, with
some pretty scorching spring weather over Spain (El Horno could be
fired up early!) on the 18th but this run terminates the Northerly
extent of its influence in the Gironde and leaves us in cool North-
Westerlies. That could change over the next couple of days, but if
this forecast joins the 20-25% of complete and utter faliiures - oh
well! So be it! It happens. It's still a lot of fun trying. My
forecast of a Northerly plunge and a cold Easter in 2007 wasn't the
best *)) , but there have been 42 successes over the last couple of
years! Plumes seem to be very hard to correctly forecast at 10 days.
They require such specific synoptics to reach the UK. The gfs is still
wrestling with the position of that Atlantic Low sitting off Iberia on
the 00z.

http://www.wetterzentrale.de/pics/Rtavn2282.png

This run puts it further South than it was when I made the forecast
yesterday. For the plume to reach the UK, it needs to be several
hundred miles further North. It'll be interesting watching it.

Paul- Hide quoted text -

- Show quoted text -

Further out, another thing I'm watching is a possible cooler plunge,
with High pressure to our west and low pressure to the East, which
would lead to .......you guessed it! Another bout of cool, showery
Northerlies to end April. Just what we need to cheer us up in mid-
spring! If the plume doesn't get to us, April may is likely to end up
with a colder CET than average.

Presently: CET: (Apr 1- 8): 7.4°C (-0.1 degC)
(C/O climate-uk.com Thanks Philip)

Paul

On Apr 9, 9:40*am, Dawlish wrote:
On Apr 9, 9:31*am, Dawlish wrote:





On Apr 8, 1:14*pm, Dawlish wrote:

Well, there you go.The possible warmth has continued for 5 runs, I can
now be 75-80% certain of this:

By 18th April at T240, the effects of the first warm plume of the year
will be being felt in Southern England. Temperatures on the 17th and
18th of April will peak above 18C and may well be higher. Winds around
this time will be from a Southerly quadrant and the air will have had
its source in North Africa. This air could well be unstable enough to
bring the possibility of heavy, perhaps thundery showers. If the
showers stay away, Southern England, at least, will have some
pleasant, warm conditions for April.

It can never be a higher confidence forecast than 75-80%, as my
success from the past is about 78%. It's not a certain forecast, as
certainty doesn't come in to forecasting. See how it goes.

Paul

The gfs develops the North African plume further this morning, with
some pretty scorching spring weather over Spain (El Horno could be
fired up early!) on the 18th but this run terminates the Northerly
extent of its influence in the Gironde and leaves us in cool North-
Westerlies. That could change over the next couple of days, but if
this forecast joins the 20-25% of complete and utter faliiures - oh
well! So be it! It happens. It's still a lot of fun trying. My
forecast of a Northerly plunge and a cold Easter in 2007 wasn't the
best *)) , but there have been 42 successes over the last couple of
years! Plumes seem to be very hard to correctly forecast at 10 days.
They require such specific synoptics to reach the UK. The gfs is still
wrestling with the position of that Atlantic Low sitting off Iberia on
the 00z.

http://www.wetterzentrale.de/pics/Rtavn2282.png

This run puts it further South than it was when I made the forecast
yesterday. For the plume to reach the UK, it needs to be several
hundred miles further North. It'll be interesting watching it.

Paul- Hide quoted text -

- Show quoted text -

Further out, another thing I'm watching is a possible cooler plunge,
with High pressure to our west and low pressure to the East, which
would lead to .......you guessed it! Another bout of cool, showery
Northerlies to end April. Just what we need to cheer us up in mid-
spring! If the plume doesn't get to us, April may is likely to end up
with a colder CET than average.

Presently: * CET: (Apr 1- 8): 7.4°C (-0.1 degC)
(C/O climate-uk.com Thanks Philip)

Paul- Hide quoted text -

- Show quoted text -

Seems reasonable. I've gone for a cooler than average April to follow
the "technically" correct wet,windy and cool March although in many
ways it wasn't that far from average. Theres little zonal movement
currently and unfortunately we are not yet able to tap into the very
warm air that keeps drifting into S Europe. This will be more likely
in May.