Thursday, 27 December 2012

The Weather

The weather in 2012 has been quite notable, and people will remember it as wet and miserable, forgetting the warm Spring and the remarkable fact that in the south east, six months were wetter than normal while six months were drier than the official long term average (Jan; Feb; March; May; Aug; Sept).

Even though the UK has fairly uniform weather the whole year through, it remains the perennial talking point. Panic sets in when it is too cold, too hot or too wet, but UK extremes are nothing like as bad as elsewhere in the World. Each year people express surprise at heavy rain, hot sun or deep snow as though it was something new. The main reason that it is so significant is that it is unpredictable. Some countries can guarantee heat in summer, cold in winter; and when seasons begin and end; whereas in the UK it is much more 'random'. Old adages like 'three fine days and a thunderstorm' highlight the unstable nature of our weather. It is still not possible to be confident of weather in a week's time let alone a month. Each year, unwise pundits predict, apparently confidently that it will be a hot 'barbecue' summer or a 'cold' winter. At present the Winter 2012/13 is supposed to be the coldest winter in a 100 years. So far it has turned out to be close to average. 2012 will stand as a monument to these wild predictions, once drought was predicted and hosepipe bans were officially declared, the heavens opened and floods were the chief concern.

I thought I would share my favourite weather sites on this page. I am lucky to be able to chose which days to go for long walks and the weather plays the biggest role in the choice. The selection also takes account of the season and the direction of the sun to provide best opportunity for seeing wildlife and photographs. For distant views I like to chose a day with a dry, cool wind from the north while for butterflies little wind and warm sunshine.

Current Conditions

rainfall radar

Before setting out I look for problems on the roads and the current weather situation with regards rain and cloud. For rain, the best site is Will it Rain Today The site shows rainfall radar images of the last few hours with the ability to zoom in and track individual rain clouds.

visible cloud radar

For cloud cover the best site is the Met. Office with its Infra-red and Visible radar images. Low thin cloud does not show up on Infra-red so it is important to see the visible radar image too.

current observations

Another site that concentrates on current observations from mainly public weather stations is the XC Weather web site. It displays wind, temperature, weather, pressure and cloud conditions on the maps. It also gives animations for the last 24 hour's readings. The site is aimed at people involved in outdoor activities.

Europe satellite

For a broader picture of the whole of Europe Sat24 give recent satellite images. The Met Office also provide one for Europe

current observations

There is a detailed cloud radar for Reading showing cloud height and depth which can sometimes be helpful.

Tomorrow's Weather

Met office forecast

I like to be prepared for a walk the day before and make the final decision in the morning to allow an early start. The best site for looking at predictions for the following day is the Met. Office forecast. The BBC get their data from the Met. Office and used to present the data in a clearer way, but now I prefer the more up-to-date detail of the Met. Office site. Another useful web site is Norweigan it gives a good graphical prediction.

Met office pressure forecast

If I feel like making my own predictions as a 'weatherman' I need to know the pressure patterns, these are missing from the rather poor BBC web site so I often look at the old-fashioned Met. Office surface pressure charts. I have a barometer and it remains a very useful tool, I have a rule of thumb that pressure below 30 inches means it is likely to rain; and if above unlikely. [30 inches of mercury is 1016millibars or 762mms mercury if you insist]. To go even more professional you can view a range of European observation maps on the WXMaps site.

The Week Ahead

ECMWF forecast

Beyond a day or two the current forecast models can not be entirely trusted, however they do give advance notice of likely clear days in the week ahead. Avoid 'The Weather Outlook' site, I have found it poorly presented and inaccurate. The official medium range forecast provided by the European Centre for Medium-Range Weather Forecasts ECMWF is best. It give pressure and rainfall predictions for up to ten days ahead.

Storm Caribbean

During the summer and autumn a major influence on the weather are remnants of Tropical storms and Hurricanes. These originate in the Equatorial region of West Africa cross the Atlantic to batter the Caribbean and then travel north and then east to hit northern Europe. These storms have the power to knock 'stable' weather systems out of the way. There are two sites I look at to see what is brewing. Storm Caribbean has an excellent range of maps from various sources, click on the map on the top page to gain access to them.

MIMIC

There is a useful animation of the North Atlantic from MIMIC-TPW often indicating weather on its way from the Atlantic. A similar one showing water vapour is on the NOAA site. Our weather is usually driven by the Jet Stream that powers the depressions as they track east over the North Atlantic. Deviations from the normal flow have a marked effect on our weather, an old fashioned Java animation is available to view here.

Trends and Historical Data

Environment Agency rainfall

It's interesting to put the current weather into context. My main source of data on rainfall is the Environment Agency's weekly and monthly reports. These include rainfall, aquifer, reservoir and river statistics with comparison to long term data. For individual reservoir levels the ones in Kent/Sussex are important as they seem to suffer most from drought stress and give an immediate idea of how wet/dry it has been. Thames Water do one too.

Thatcham weekly rainfall

On a local area basis I pay tribute to the many people who keep personal weather monitoring stations going. Many feed their readings into sites like Weather Underground. The site gives sunrise and sunset times which helps when planning a long winter walk. A local one for me with lots of interesting charts and historical extremes is at Thatcham.

Extreme Weather

Weather Underground severe

There are sites that come into play when we are subject to extreme conditions. For flooding there is of course the Environment Agency. For thunderstorm tracking there are sites such as one on the Isle of Wight. Weather Underground have one for Europe severe weather of alerts for all weather types. For more of a global climate trends I like the maps of snow cover on the Climate4u site comparing this with the previous year.

Weather France

When we get very hot weather it usually comes as a 'bubble' of hot air from the south. Looking at neighbouring countries' weather sites can help to see what is going on. Meteo France and La Chaine Meteo have useful maps.


I hope you find some of these sites of interest, if you come across other useful UK weather web sites please let me know.

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