Welcome to the 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 – Thursday 21st October – Tuesday 26th October
The EC is suggesting for Thursday that the area of low pressure that has been dominating our weather at the start of the week clears away and high pressure builds in slowly from the West for us in the Western Isles we will see rain and showers squally showers heavy at times. Onto the Friday a ridge of high pressure builds in. The rain and showers ease down for us in the Western isles with plenty of cloud before showers increase later in the day. Into the Saturday and and the ridge of high pressure clears away but a band of rain moves in off the Atlantic. For us in the Western Isles this would bring us some heavy and persistent rain and blustery winds once this clears we will see rain and showers. For the Sunday and brisk airflow across the UK with rain and showers pushing across the Western Isles which will be heavy at times. Then the Monday and Tuesday low pressure systems skirt to the North West with spells of rain heavy and blustery winds across the Western Isles.
GFS – Thursday 21st October to Saturday 30th October
The GFS is suggesting for the Thursday that low pressure moves away and high pressure builds across the UK rain and showers clearing the Western Isles and becoming drier and brighter later. Onto the Friday and high pressure dominates across the UK with sunshine and cloud across the Western isles with some light rain at times. For the Saturday high pressure moves Eastward and a shallow area of low pressure moves in from the West introducing spells of rain after a dry and sunny day start to the day across the Western Isles. The rain will be mostly light. Into Sunday and low pressure slowly moves across the UK with early rain for the Western Isles and plenty of sunshine once the rain clears away. On Monday and a slack airflow across the UK with sunshine and some rain for us in the Western Isles. Into the Tuesday and a deeper area of low pressure moves across the North of Scotland bringing heavy rain and stronger winds across the Western Isles. The final four days of the time period we will see a mixture of sunshine and showers across the Western Isles heavy at times as area of low pressure skirt past the UK to the North.
Thanks for reading any feedback is welcome.