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strengthening or weakening (positive if better than chance). Central pressure bias - mean bias in the forecast central pressure See below for a diagrammatic explanation of track error statistics.  Sign conventions DPE values are always positive ATE values are positive if the forecast position lies ahead

to air frost. However, those places into which cold air can drain are particularly prone to frost. Examples include the deep valley of the River Dee around Braemar which lies well within the Grampian Mountains. The graphs show the average frequency of air and ground frost at Braemar and Edinburgh

Résumé exécutif Ce rapport présente les risques climatiques principaux à considérer pour toute planification de développement résilient au climat pour la région du Sahel. Les risques clé liés au climat dans le Sahel ont été identifiés en considérant les prévisions du changement climatique et les

, with the wettest area being to the northwest of Fort William (over 4000 mm per year). Over the lower lying islands the average is less than about 1600 mm whilst near the Moray Firth, to the lee of the mountains, it is only about 700 mm. These values can be compared with annual totals around 500 mm in the driest

significant disruption, with Manchester Airport closed on 5th and the A66 between Cumbria and County Durham closed across the Pennines. Other airports were also affected including Bristol, Leeds and Liverpool. Many motorists had difficult journeys with higher routes in the Pennines affected by lying snow

at the station, days with snow lying and the total depth of undrifted snow at the station, normally at about 09 GMT. Observers also sent, where possible, notes on snow cover in the surrounding hills or mountains at various heights (at intervals of about 150 metres) even if snow cover did not extend

are shown as white curves, with red shading representing their probable range, such that the observations are expected to lie within the shading 90% of the time. The most recent forecast (thick blue curve with thin blue curves showing range) starts from November 2012. All data are rolling annual mean

night is expected tonight with temperatures dipping as low as -16°C where we have lying snow in Scotland and northern England. Temperatures will also be well below freezing across much of the UK so there is a continued risk of ice overnight and through Friday morning’s rush hour. “Milder air

Station Based Monthly Planning Averages for LERWICK (Lat=60.14N Long=1.18W) 1-in-10 year values - based on station data between 1961 and 2020 Month Daily rainfall total (mm) Days with rainfall >5mm Days with air frost Days with snow lying at 0900 UTC January 206.1 18 15 12 February 170.7 14 16 12

is linked closely with temperature, with falls rarely occurring if the temperature is higher than 4 °C. The numbers of days with snow falling and snow lying increase with latitude and altitude, so values reflect topography. Snow is comparatively rare near sea level in Wales, but much more frequent over