MetLink Report 1 Feb 1999
(Day 6)
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School Weather News 1999
Weather analysis - 1 Feb 1999
In the United Kingdom, we have high pressure (1044 mb over southern
England) and this is a very good time to check your barometers.
Please note that anticyclones do not necessarily bring sunny weather.
Over most parts of the British Isles today, the skies have been
overcast. Winds have been very light in most parts of the UK.
There are now winds from the north-west over northern Scandinavia and
an occluded front has moved across northern parts of Norway, Sweden
and Finland. A warm front has moved across southern parts of Norway
and Sweden. The temperature was +5 deg C in northern Finland at 1200
GMT today. What a change from last week!
As you will see from a separate e-mail, Malta has had interesting
weather this weekend. There have been westerly winds over Spain and
thick cloud over the Costa del Sol!! There are many, many
cumulonimbus clusters over southern Africa -- and that coastal strip
of Namibia is clear of cloud again. The ITCZ is well-marked again
today over the ocean. The subtropical anticyclone over the South
Atlantic has drifted back towards
Tristan da Cunha but is
not very intense (only about 1020 mb). There is also a small area of
low pressure not far to the west of Tristan and the
Meteosat Image shows a lot of cloud in
the vicinity of Tristan da Cunha and Gough Island.
MetLinkInternational Week 2: Monday 1 Feb 1999
From:
education@royal-met-soc.org.uk
Subject: MetLinkInternational Week 2: Monday 1 Feb 1999
Date: Mon, 1 Feb 1999 22:36:02 -0000
Dear MetLink friends
I had planned to call this message 'MetLinkInternational Day 6'.
However, so many of you entered observations in the data base for
Saturday and Sunday that I thought I should be specific over which
day I meant. It was great to see so much activity over the
weekend.
Who has pride of place today? Well ..... in my mind, two of you share
the honour.
In Malta, there was some extraordinary weather yesterday. Large
hailstones fell and the weather was unusually cold, as it was again
today. And the weather wasn't very warm at
Tarragona, either. Over
the whole of the western Mediterranean, the winds have been from the
east or north-east today -- and that's a cold direction, as you will
see if you look at today's temperatures over southern and central
Europe (only 2 deg C at Marseilles at 1200 GMT today and 5 deg C at
Rome). Malta has remained
close to a squally 'trough' which extends westwards from the
depression over the Ionian Sea (1009 mb) which I have mentioned
before. The centre of that depression lies just to the west of Greece
now and the weather has been rather wet in parts of Greece today and
snowy in Bulgaria.
The other place with remarkable weather has been Sweden, as Christer
reported from Varnamo. He
told us about the dramatic rise in temperature and the problems
caused by wet, heavy snow. He also mentioned severe fog, which
resulted from the warm, moist air of the fronts which crossed
Scandinavia yesterday being cooled as it passed over very cold
ground. It was advection fog, a type of fog which may form at any
time of day or night and persist for many hours. In contrast,
radiation fog forms in the evening and at night when the sky is clear
and the wind speed is 1 or 2 m/s. The clear sky allows radiation to
escape from the earth's surface and the air in contact with the
ground to cool to its dew-point temperature. This type of fog usually
dissipates during the morning, when sunlight heats the ground under
the fog and thereby raises the temperature above the air's dew-point
temperature. Yes .... sunlight does get through the fog. It's not all
reflected off the top of the fog. If there is daylight, some sunlight
is reaching the ground.
Over northern Scandinavia today, a battle is going on, between very
cold air over north-west Russia and much milder air to the west. At
1200 GMT today, the temperature was -28 deg C near Murmansk and -18
deg C in northern Finland, but +5 deg C in central Sweden and +4 deg
C near Stockholm. Will the cold air win and turn the cars back into
kangaroos? From the forecast chart it is
not easy to decide. Let's watch this situation with interest.
For those in parts of the world where people have grown tired of rain
recently, such as the British Isles,
Tristan da Cunha has not
been a place to visit these past few days. There has been a lot of
rain there, brought by a small but active area of low pressure.
Again, this a weather battle area just now, with high pressure (1018
mb) not far to the east of Tristan da Cunha and a deep depression
(970 mb) about 2,000 km to the south-west. Will the high pressure
win, or will the unsettled weather continue to give Tristan da Cunha
rain?
Over southern Africa, the satellite
image shows large patches of upper cloud (cirrus-type cloud made
of ice crystals), recognisable by its diffuse nature, as distinct
from the sharply-defined edges of lower cloud. There would appear to
many cumulonimbus (thundery) clouds.
Zambia, Zimbabwe and Madagascar: was there a lot of upper cloud
today?
The Intertropical Convergence Zone is still quite well defined, but
notice that it is not joined up to the convective clouds over
southern Africa. This is not consistent with the European text-book
concept of the ITCZ at this time of year.
Finally, we turn to the part of the MetLink world with the highest
barometric pressure, the British Isles. At 1200 GMT today, the
pressure was 1043 mb over south-west England, near Plymouth. As one
would expect near the centre of an anticyclone, winds have been very
light. There hasn't been much sun over England and a large part of
Wales, though. I was in Cardiff until 1000 GMT. Then, I drove to
Pinewood School, near
Swindon. I was there from 1130 until 1430 and then I drove to
Reading. All this time, the cloud condition was the same: 8/8 of a
low, grey, featureless stratus cloud. At
Pennar and
Larne, though, the sun
shone, and Gillespie's reported a pleasant day, too. The forecast for
tomorrow is for high pressure to persist over southern parts of the
British Isles, with the centre of the High drifting south-westwards
and a cold front moving southwards across Scotland and Northern
Ireland.
That's all for today.
Best regards Malcolm
This week's weather - some thoughts
From: "Dr. Steve Dorling" <S.Dorling@uea.ac.uk>
Subject: This week's weather - some thoughts
Date: Mon, 1 Feb 1999 10:06:42 +0000
Dear MetLink participants,
Greetings from Norwich, England. Malcolm asked me to send some
thoughts on current weather conditions, in his absence this
morning.
It isn't just school work which benefits from exchanging weather
information and hearing about extreme weather. I was talking to my
meteorology undergraduate students last week on the subject of air
masses and the extreme conditions in Finland were a perfect focus for
the debate. At the other extreme, I take my 2 young children (age 1
and 3) to their nursery on my bike in the morning and hence the
weather is very relevant to us! Of course when the wind is from the
north, they notice! However, my daughter has also begun to talk about
which direction the smoke is blowing in from some local chimneys. She
now 'predicts' how cold it is outside by observing the plume from
indoors and chooses her coat accordingly! I keep telling her there is
no money to be made in meteorology but it seems to have captured her
interest, just like the rest of us! She is now colouring in a
'Weather Tree' where each leaf represents the weather conditions each
day on our bicycle journey. At the end of the year we can see 'at a
glance' how variable the weather is at any particular time. Suffice
to say that her yellow crayon (representing sun) hasn't had a lot of
use yet!
One web site which I tend to visit quite often is
http://www-imk.physik.uni-karlsruhe.de/~gmueller/pics/ukmpanel1.gif
There is a graphic on this page which shows the forecast (from the UK
Met Office Weather Forecast model) for a couple of days ahead for
Europe and the North Atlantic. It shows that the High Pressure System
which the whole of the UK is presently experiencing is set to remain
dominant over the next two days, although its centre will slip a
little further south allowing the pressure gradient to intensify
somewhat over northern Britain. Cloud conditions in these winter
Highs really are variable. Sometimes old fronts get incorporated into
the circulation of anticyclones and we get extended periods of
'gloom' sometimes with light drizzle (as this morning in
Norwich).
Well, winter is getting on and Southern Britain is yet to see a
significant dose of snow. A very localised inch fell shortly before
Christmas in the Norwich area (hardly worth mentioning in the context
of typical falls in Finland I'm sure) but I wonder if we will escape
major disruption this year ? Of course it doesn't take much snow in
England to cause havoc - we are not equipped for it!
Finally, browsing the excellent MetLink web site maintained by John
Harris, I was most impressed by the 'Students Guide to Meteorology
& Climate' developed by the Kings School, Worcester. Take a look
at this very valuable resource if you have a chance ...
http://www.ksw.org.uk/atmosphere/pages/index.html
Best wishes
Steve Dorling
Dr. Steve Dorling, School of Environmental Sciences, University of
East Anglia, Norwich, NR4-7TJ, UK Tel: +44 1603 592533, Fax: +44 1603
507719
e-mail: s.dorling@uea.ac.uk,
http://www.uea.ac.uk/~e870/dorling.html
UEA Weather Station:
http://www.uea.ac.uk/~e870/weather/weather_welcome.shtml
DTOT Meteosat Image 1 Feb 1999
N Atlantic synoptic chart 1 Feb 1999
S Atlantic synoptic chart 1 Feb 1999
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