Long range weather forecast for the Western Isles – 18th November

Welcome to our long range forecast for the Western Isles. This is our twice weekly update covering up to two ahead. We look at trends and patterns. Usually posted on a Thursday and Sunday.

Please note there is not a lot of accuracy for this kind of time frame. Anything beyond 4/5 days out becomes really difficult and subject to change so we will be looking at trends. Mainly take with a large vat of salt. We will be using the main two computer models for this. The ECMWF ( European Centre for medium range weather forecasts) which is based in Reading and the GFS (Global forecasting system) which is the American based global model.

This comes from the GFS 06z run and ECMWF 00Z run. I will refer to EC to save on typing.

EC – Monday 22nd November to Saturday 27th November

So the EC is suggesting that for Monday high pressure will dominate across most of the UK but rain and showers will feed across the Western isles along with brisk winds. Feeling chilly in the wind chill. Tuesday high pressure sits close to Ireland and we see rain and showers moving across the Western Isles heavy at times along with brisk winds. Into Wednesday and low pressure scoots across the far North across Orkney and shetland as it does winds will increase across the Western Isles a band of heavy rain will sweep across the islands. Behind it, rain sleet and snow showers will move across the islands. For the Thursday yet more rain and snow showers feeding across the islands. The next band of rain moves across the islands as another area of low pressure moves across the North. Into the Friday and a broad area of low pressure spirals down from the North feeding yet more rain sleet and snow showers across the islands. Saturday someone leaves the freezer door open and another blast of cold air feeds down from the North with further rain, sleet and snow showers and brisk winds.

GFS  – Monday 22nd November to Wednesday 1st December

So the GFS has high pressure dominating across the UK with a fine and dry day across the Western isles with sunshine and cloud along with brisk winds. Tuesday a band of rain moves down from the North after a dry icy start. This will bring rain across the Western Isles. Followed by some wintry showers later in the day. For Wednesday high pressure sits to the West feeding sleet and snow showers down from the North. Moving on to Thursday a deep area of low pressure forms to our North West of the UK and will bring heavy rain across the Western isles with strong winds. Friday will see further wintry showers and brisk winds but improving later with sunshine and cloud. On Saturday two areas of low pressure move across UK after a dry and chilly start sleet and snow showers will move across the Western isles possibly merging into some longer spells of snow later. For the final four days of the time period additional low pressure systems move across the UK feeding further spells of and wintry conditions across the islands.

Thanks for reading any feedback is welcome. Our featured photo is Eriskay by Julie Donaldson

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