NW Europe - synoptic chart
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School Weather News 1999
From: "Malcolm Walker"
Subject: MetLinkInternational
Day 2 Date: Tue, 26 Jan 1999 21:33:11 -0000
Dear MetLinkInternational friends
Well ..... pride of place must go today to northern Scandinavia,
where temperatures made deep freezes unnecessary! I have sent a
separate e-mail with an attached image showing
today's temperatures and sea- level
pressures across Europe. The temperature gradient across northern
Europe today was remarkable, with the air comparatively mild
(temperatures several degrees above freezing) in southern Sweden and
southern Norway.
The weather in the British Isles has continued to be unsettled, with
'troughs' (as they are called on weather charts) crossing the
country. These bring bursts of heavy rain. Here in Reading, we had
bursts this morning, about 8.30 am, another about 4 pm and the 'best'
of all about 5.30 pm, when hail (from cumulonimbus clouds) fell for
two or three minutes, causing the road outside my apartment to be
white over for a few minutes. With air temperatures of 6 or 7 deg C,
the hailstones soon melted. If you have received the large image I
sent this evening, you will see that gales are marked over the sea
south of Ireland and over the English Channel. The weather report
from Pennar, west Wales, was interesting for the high wind speed (62
km/h = 34 knots = Force 8). That speed is, in fact, broadly
consistent with the reports from the buoys on the seas near Ireland
and western parts of England and Wales for a short period this
afternoon.
Pennar:- you appear to have chosen a very interesting moment to
make your observation. Is there anything more you would like to tell
us about the weather at the time of your observation?
Everyone:- I gave you, in a contact message, the Web address for the
ocean buoys around the British Isles. It's interesting to look at
these from time to time. The wind is typically much stronger over the
sea than over the land. How much stronger is a question you may like
to investigate.
Once again, Tarragona and Malta appear to have had pleasant weather,
but a cold front appears to have moved across Spain today.
Did this give any rain at Bilbao? Did it reach Tarragona about
1800 GMT?
If you look at the DTOT Meteosat Image 26 Jan
1999 (which is also available from the Nottingham University Web
site given on the list of Web addresses I sent you a few days ago),
you will see two interesting features:
1... The Intertropical Convergence Zone is conspicuously absent over
a large part of the Atlantic Ocean west of Africa. The continuous
feature shown in text books does not always occur. Let's keep our
eyes on the ITCZ over the next few days to see what happens to
it.
2... There's a swirl of cloud in mid-Atlantic west of the Canary
Islands and a belt of cloud stretching southwestwards from the Canary
Islands to about 8 deg N 40 deg W. This does not look at all
consistent with the idea of a subtropical anticyclone west of the
Canary Islands and north-east trade winds on its southern flank.
Would anyone like to comment on this tropical Atlantic weather
situation?
Now to Zambia and Zimbabwe ..... In an arc from Madagascar to about
10 deg S 25 deg E and then southwestwards to the Atlantic, you appear
from the satellite images to have numerous clusters of cumulonimbus
clouds -- tropical convection typical of this time of year. It's very
impressive, but what is also impressive is the sharp cut-off on the
southern side of the cumulonimbus activity, suggesting the presence
of some kind of front. And then, near 30 deg S 20 deg E, there's
another area of clouds which are clearly cumulonimbus clouds from the
characteristic white patches shown on satellite images.
The map of sea-level pressure I obtained from the South African
Weather Bureau's Web site, shows areas of low pressure between
Madagascar and the coast of Africa and an area of low pressure over
southwest Africa. These appear to be consistent with the rain clouds
over southern Africa. There is still an area of high pressure a
little to the north and northwest of Tristan da Cunha, but it has
declined a little to about 1021 mb.
What weather will tomorrow bring?
More of the same in southern Africa and the South Atlantic? I
wonder!
The forecast chart from the British Meteorological Office indicates
more rain from warm, occluded and cold fronts crossing the British
Isles. Oh dear! Most people would like a spell of dry weather in
Britain -- but not so long ago they were asking for rain, to help
refill the aquifers after the dry weather we have had in recent
years!
The forecast chart suggests that Spain and Malta will soon have
weather less settled than in recent days, and very cold weather seems
likely to continue in Finland and Sweden. The weather may remain
comparatively mild in southern Norway.
That's all for today.
Best regards Malcolm