I bet this will confound some opinions on anticyclonic weather, with a band
of rain moving in from the west on Friday across Ireland and then into
other northern areas on Saturday. Six hour rainfall figures of up to 5mm
seem to be forecast

http://www.wetterzentrale.de/pics/Rtavn364.html

It seems to be associated with a short wave upper vortex moving through the
high.

http://www.wetterzentrale.de/pics/Rtavn361.html

The MO FAX charts have this marked as a cold front.

http://www.wetterzentrale.de/pics/brack0a.html

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 12/02/2004 13:22:57 UTC
Temperature +8C

"Mike Tullett" wrote in message
...
I bet this will confound some opinions on anticyclonic weather, with a
band
of rain moving in from the west on Friday across Ireland and then into
other northern areas on Saturday. Six hour rainfall figures of up to 5mm
seem to be forecast

http://www.wetterzentrale.de/pics/Rtavn364.html

It seems to be associated with a short wave upper vortex moving through
the
high.

http://www.wetterzentrale.de/pics/Rtavn361.html

The MO FAX charts have this marked as a cold front.

http://www.wetterzentrale.de/pics/brack0a.html

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 12/02/2004
13:22:57 UTC
Temperature +8C


Not come across this before.....what causes it, interested in exactly what a
short wave upper vortex is..

JP

"J.Poyner" wrote in message


Not come across this before.....what causes it, interested in exactly what a
short wave upper vortex is..

In fact go the whole hog and fit the present accepted understanding in
with the fact that the weather setled down all at once world wide.

DDT?


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

On Thu, 12 Feb 2004 23:45:43 -0000, J.Poyner wrote in

snip
Not come across this before.....what causes it, interested in exactly what a
short wave upper vortex is..

The flow in the middle to upper troposhere usually takes on a wave pattern,
seen best by the colours on say the 500 mb chart. This is the latest from
the GFS analysis.

http://www.wetterzentrale.de/pics/Rtavn001.html

You can think of the upper winds blowing along constant colour - just as at
the surface they blow along isobars, and the sinusoidal pattern is clear to
see. But, note the very small area of yellow moving into NW Scotland.
That is the feature I was referring to. It is up at about 16,000 to 17,000
feet and is moving into the deep high. That pool of cold air will cause
some mid level instability and cause cloud precipitation to be produced at
quite high levels. A band of rain crossed here during the night, as that
feature made its presence felt high up.

It looks as if it is going to be a persistent feature (posing problems for
the forecasters) and is still around in two days time. Here is the same
chart for Sunday and the yellow area - the upper low - is still clear to
see.

http://www.wetterzentrale.de/pics/Rtavn481.html

I'd refer you also to Martin Rowley's good explanation in MID



That is in the thread "Low in the High" started by Phil Layton.

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 13/02/2004 09:43:14 UTC

"Mike Tullett" wrote in message
...
On Thu, 12 Feb 2004 23:45:43 -0000, J.Poyner wrote in

snip
Not come across this before.....what causes it, interested in exactly
what a
short wave upper vortex is..

The flow in the middle to upper troposhere usually takes on a wave
pattern,
seen best by the colours on say the 500 mb chart. This is the latest from
the GFS analysis.

http://www.wetterzentrale.de/pics/Rtavn001.html

You can think of the upper winds blowing along constant colour - just as
at
the surface they blow along isobars, and the sinusoidal pattern is clear
to
see. But, note the very small area of yellow moving into NW Scotland.
That is the feature I was referring to. It is up at about 16,000 to
17,000
feet and is moving into the deep high. That pool of cold air will cause
some mid level instability and cause cloud precipitation to be produced at
quite high levels. A band of rain crossed here during the night, as that
feature made its presence felt high up.

It looks as if it is going to be a persistent feature (posing problems for
the forecasters) and is still around in two days time. Here is the same
chart for Sunday and the yellow area - the upper low - is still clear to
see.

http://www.wetterzentrale.de/pics/Rtavn481.html

I'd refer you also to Martin Rowley's good explanation in MID



That is in the thread "Low in the High" started by Phil Layton.

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 13/02/2004
09:43:14 UTC

Thanks......most helpful.

JP